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Diffstat (limited to 'kernel/sched/fair.c')
| -rw-r--r-- | kernel/sched/fair.c | 12205 |
1 files changed, 12205 insertions, 0 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c new file mode 100644 index 000000000000..29d80146eb8a --- /dev/null +++ b/kernel/sched/fair.c @@ -0,0 +1,12205 @@ +/* + * Completely Fair Scheduling (CFS) Class (SCHED_NORMAL/SCHED_BATCH) + * + * Copyright (C) 2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> + * + * Interactivity improvements by Mike Galbraith + * (C) 2007 Mike Galbraith <efault@gmx.de> + * + * Various enhancements by Dmitry Adamushko. + * (C) 2007 Dmitry Adamushko <dmitry.adamushko@gmail.com> + * + * Group scheduling enhancements by Srivatsa Vaddagiri + * Copyright IBM Corporation, 2007 + * Author: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> + * + * Scaled math optimizations by Thomas Gleixner + * Copyright (C) 2007, Thomas Gleixner <tglx@linutronix.de> + * + * Adaptive scheduling granularity, math enhancements by Peter Zijlstra + * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra + */ + +#include <linux/latencytop.h> +#include <linux/sched.h> +#include <linux/cpumask.h> +#include <linux/cpuidle.h> +#include <linux/slab.h> +#include <linux/profile.h> +#include <linux/interrupt.h> +#include <linux/mempolicy.h> +#include <linux/migrate.h> +#include <linux/task_work.h> +#include <linux/module.h> + +#include "sched.h" +#include <trace/events/sched.h> +#include "tune.h" +#include "walt.h" + +/* + * Targeted preemption latency for CPU-bound tasks: + * (default: 6ms * (1 + ilog(ncpus)), units: nanoseconds) + * + * NOTE: this latency value is not the same as the concept of + * 'timeslice length' - timeslices in CFS are of variable length + * and have no persistent notion like in traditional, time-slice + * based scheduling concepts. + * + * (to see the precise effective timeslice length of your workload, + * run vmstat and monitor the context-switches (cs) field) + */ +unsigned int sysctl_sched_latency = 6000000ULL; +unsigned int normalized_sysctl_sched_latency = 6000000ULL; + +unsigned int sysctl_sched_sync_hint_enable = 1; +unsigned int sysctl_sched_cstate_aware = 1; + +/* + * The initial- and re-scaling of tunables is configurable + * (default SCHED_TUNABLESCALING_LOG = *(1+ilog(ncpus)) + * + * Options are: + * SCHED_TUNABLESCALING_NONE - unscaled, always *1 + * SCHED_TUNABLESCALING_LOG - scaled logarithmical, *1+ilog(ncpus) + * SCHED_TUNABLESCALING_LINEAR - scaled linear, *ncpus + */ +enum sched_tunable_scaling sysctl_sched_tunable_scaling + = SCHED_TUNABLESCALING_LOG; + +/* + * Minimal preemption granularity for CPU-bound tasks: + * (default: 0.75 msec * (1 + ilog(ncpus)), units: nanoseconds) + */ +unsigned int sysctl_sched_min_granularity = 750000ULL; +unsigned int normalized_sysctl_sched_min_granularity = 750000ULL; + +/* + * is kept at sysctl_sched_latency / sysctl_sched_min_granularity + */ +static unsigned int sched_nr_latency = 8; + +/* + * After fork, child runs first. If set to 0 (default) then + * parent will (try to) run first. + */ +unsigned int sysctl_sched_child_runs_first __read_mostly; + +/* + * SCHED_OTHER wake-up granularity. + * (default: 1 msec * (1 + ilog(ncpus)), units: nanoseconds) + * + * This option delays the preemption effects of decoupled workloads + * and reduces their over-scheduling. Synchronous workloads will still + * have immediate wakeup/sleep latencies. + */ +unsigned int sysctl_sched_wakeup_granularity = 1000000UL; +unsigned int normalized_sysctl_sched_wakeup_granularity = 1000000UL; + +const_debug unsigned int sysctl_sched_migration_cost = 500000UL; + +/* + * The exponential sliding window over which load is averaged for shares + * distribution. + * (default: 10msec) + */ +unsigned int __read_mostly sysctl_sched_shares_window = 10000000UL; + +#ifdef CONFIG_CFS_BANDWIDTH +/* + * Amount of runtime to allocate from global (tg) to local (per-cfs_rq) pool + * each time a cfs_rq requests quota. + * + * Note: in the case that the slice exceeds the runtime remaining (either due + * to consumption or the quota being specified to be smaller than the slice) + * we will always only issue the remaining available time. + * + * default: 5 msec, units: microseconds + */ +unsigned int sysctl_sched_cfs_bandwidth_slice = 5000UL; +#endif + +/* + * The margin used when comparing utilization with CPU capacity: + * util * margin < capacity * 1024 + */ +unsigned int capacity_margin = 1280; /* ~20% */ + +static inline void update_load_add(struct load_weight *lw, unsigned long inc) +{ + lw->weight += inc; + lw->inv_weight = 0; +} + +static inline void update_load_sub(struct load_weight *lw, unsigned long dec) +{ + lw->weight -= dec; + lw->inv_weight = 0; +} + +static inline void update_load_set(struct load_weight *lw, unsigned long w) +{ + lw->weight = w; + lw->inv_weight = 0; +} + +/* + * Increase the granularity value when there are more CPUs, + * because with more CPUs the 'effective latency' as visible + * to users decreases. But the relationship is not linear, + * so pick a second-best guess by going with the log2 of the + * number of CPUs. + * + * This idea comes from the SD scheduler of Con Kolivas: + */ +static unsigned int get_update_sysctl_factor(void) +{ + unsigned int cpus = min_t(unsigned int, num_online_cpus(), 8); + unsigned int factor; + + switch (sysctl_sched_tunable_scaling) { + case SCHED_TUNABLESCALING_NONE: + factor = 1; + break; + case SCHED_TUNABLESCALING_LINEAR: + factor = cpus; + break; + case SCHED_TUNABLESCALING_LOG: + default: + factor = 1 + ilog2(cpus); + break; + } + + return factor; +} + +static void update_sysctl(void) +{ + unsigned int factor = get_update_sysctl_factor(); + +#define SET_SYSCTL(name) \ + (sysctl_##name = (factor) * normalized_sysctl_##name) + SET_SYSCTL(sched_min_granularity); + SET_SYSCTL(sched_latency); + SET_SYSCTL(sched_wakeup_granularity); +#undef SET_SYSCTL +} + +void sched_init_granularity(void) +{ + update_sysctl(); +} + +#define WMULT_CONST (~0U) +#define WMULT_SHIFT 32 + +static void __update_inv_weight(struct load_weight *lw) +{ + unsigned long w; + + if (likely(lw->inv_weight)) + return; + + w = scale_load_down(lw->weight); + + if (BITS_PER_LONG > 32 && unlikely(w >= WMULT_CONST)) + lw->inv_weight = 1; + else if (unlikely(!w)) + lw->inv_weight = WMULT_CONST; + else + lw->inv_weight = WMULT_CONST / w; +} + +/* + * delta_exec * weight / lw.weight + * OR + * (delta_exec * (weight * lw->inv_weight)) >> WMULT_SHIFT + * + * Either weight := NICE_0_LOAD and lw \e prio_to_wmult[], in which case + * we're guaranteed shift stays positive because inv_weight is guaranteed to + * fit 32 bits, and NICE_0_LOAD gives another 10 bits; therefore shift >= 22. + * + * Or, weight =< lw.weight (because lw.weight is the runqueue weight), thus + * weight/lw.weight <= 1, and therefore our shift will also be positive. + */ +static u64 __calc_delta(u64 delta_exec, unsigned long weight, struct load_weight *lw) +{ + u64 fact = scale_load_down(weight); + int shift = WMULT_SHIFT; + + __update_inv_weight(lw); + + if (unlikely(fact >> 32)) { + while (fact >> 32) { + fact >>= 1; + shift--; + } + } + + /* hint to use a 32x32->64 mul */ + fact = (u64)(u32)fact * lw->inv_weight; + + while (fact >> 32) { + fact >>= 1; + shift--; + } + + return mul_u64_u32_shr(delta_exec, fact, shift); +} + +#ifdef CONFIG_SMP +static int active_load_balance_cpu_stop(void *data); +#endif + +const struct sched_class fair_sched_class; + +/************************************************************** + * CFS operations on generic schedulable entities: + */ + +#ifdef CONFIG_FAIR_GROUP_SCHED + +/* cpu runqueue to which this cfs_rq is attached */ +static inline struct rq *rq_of(struct cfs_rq *cfs_rq) +{ + return cfs_rq->rq; +} + +/* An entity is a task if it doesn't "own" a runqueue */ +#define entity_is_task(se) (!se->my_q) + +static inline struct task_struct *task_of(struct sched_entity *se) +{ +#ifdef CONFIG_SCHED_DEBUG + WARN_ON_ONCE(!entity_is_task(se)); +#endif + return container_of(se, struct task_struct, se); +} + +/* Walk up scheduling entities hierarchy */ +#define for_each_sched_entity(se) \ + for (; se; se = se->parent) + +static inline struct cfs_rq *task_cfs_rq(struct task_struct *p) +{ + return p->se.cfs_rq; +} + +/* runqueue on which this entity is (to be) queued */ +static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se) +{ + return se->cfs_rq; +} + +/* runqueue "owned" by this group */ +static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp) +{ + return grp->my_q; +} + +static inline void list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq) +{ + if (!cfs_rq->on_list) { + struct rq *rq = rq_of(cfs_rq); + int cpu = cpu_of(rq); + /* + * Ensure we either appear before our parent (if already + * enqueued) or force our parent to appear after us when it is + * enqueued. The fact that we always enqueue bottom-up + * reduces this to two cases and a special case for the root + * cfs_rq. Furthermore, it also means that we will always reset + * tmp_alone_branch either when the branch is connected + * to a tree or when we reach the beg of the tree + */ + if (cfs_rq->tg->parent && + cfs_rq->tg->parent->cfs_rq[cpu]->on_list) { + /* + * If parent is already on the list, we add the child + * just before. Thanks to circular linked property of + * the list, this means to put the child at the tail + * of the list that starts by parent. + */ + list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list, + &(cfs_rq->tg->parent->cfs_rq[cpu]->leaf_cfs_rq_list)); + /* + * The branch is now connected to its tree so we can + * reset tmp_alone_branch to the beginning of the + * list. + */ + rq->tmp_alone_branch = &rq->leaf_cfs_rq_list; + } else if (!cfs_rq->tg->parent) { + /* + * cfs rq without parent should be put + * at the tail of the list. + */ + list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list, + &rq->leaf_cfs_rq_list); + /* + * We have reach the beg of a tree so we can reset + * tmp_alone_branch to the beginning of the list. + */ + rq->tmp_alone_branch = &rq->leaf_cfs_rq_list; + } else { + /* + * The parent has not already been added so we want to + * make sure that it will be put after us. + * tmp_alone_branch points to the beg of the branch + * where we will add parent. + */ + list_add_rcu(&cfs_rq->leaf_cfs_rq_list, + rq->tmp_alone_branch); + /* + * update tmp_alone_branch to points to the new beg + * of the branch + */ + rq->tmp_alone_branch = &cfs_rq->leaf_cfs_rq_list; + } + + cfs_rq->on_list = 1; + } +} + +static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq) +{ + if (cfs_rq->on_list) { + list_del_rcu(&cfs_rq->leaf_cfs_rq_list); + cfs_rq->on_list = 0; + } +} + +/* Iterate thr' all leaf cfs_rq's on a runqueue */ +#define for_each_leaf_cfs_rq(rq, cfs_rq) \ + list_for_each_entry_rcu(cfs_rq, &rq->leaf_cfs_rq_list, leaf_cfs_rq_list) + +/* Do the two (enqueued) entities belong to the same group ? */ +static inline struct cfs_rq * +is_same_group(struct sched_entity *se, struct sched_entity *pse) +{ + if (se->cfs_rq == pse->cfs_rq) + return se->cfs_rq; + + return NULL; +} + +static inline struct sched_entity *parent_entity(struct sched_entity *se) +{ + return se->parent; +} + +static void +find_matching_se(struct sched_entity **se, struct sched_entity **pse) +{ + int se_depth, pse_depth; + + /* + * preemption test can be made between sibling entities who are in the + * same cfs_rq i.e who have a common parent. Walk up the hierarchy of + * both tasks until we find their ancestors who are siblings of common + * parent. + */ + + /* First walk up until both entities are at same depth */ + se_depth = (*se)->depth; + pse_depth = (*pse)->depth; + + while (se_depth > pse_depth) { + se_depth--; + *se = parent_entity(*se); + } + + while (pse_depth > se_depth) { + pse_depth--; + *pse = parent_entity(*pse); + } + + while (!is_same_group(*se, *pse)) { + *se = parent_entity(*se); + *pse = parent_entity(*pse); + } +} + +#else /* !CONFIG_FAIR_GROUP_SCHED */ + +static inline struct task_struct *task_of(struct sched_entity *se) +{ + return container_of(se, struct task_struct, se); +} + +static inline struct rq *rq_of(struct cfs_rq *cfs_rq) +{ + return container_of(cfs_rq, struct rq, cfs); +} + +#define entity_is_task(se) 1 + +#define for_each_sched_entity(se) \ + for (; se; se = NULL) + +static inline struct cfs_rq *task_cfs_rq(struct task_struct *p) +{ + return &task_rq(p)->cfs; +} + +static inline struct cfs_rq *cfs_rq_of(struct sched_entity *se) +{ + struct task_struct *p = task_of(se); + struct rq *rq = task_rq(p); + + return &rq->cfs; +} + +/* runqueue "owned" by this group */ +static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp) +{ + return NULL; +} + +static inline void list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq) +{ +} + +static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq) +{ +} + +#define for_each_leaf_cfs_rq(rq, cfs_rq) \ + for (cfs_rq = &rq->cfs; cfs_rq; cfs_rq = NULL) + +static inline struct sched_entity *parent_entity(struct sched_entity *se) +{ + return NULL; +} + +static inline void +find_matching_se(struct sched_entity **se, struct sched_entity **pse) +{ +} + +#endif /* CONFIG_FAIR_GROUP_SCHED */ + +static __always_inline +void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec); + +/************************************************************** + * Scheduling class tree data structure manipulation methods: + */ + +static inline u64 max_vruntime(u64 max_vruntime, u64 vruntime) +{ + s64 delta = (s64)(vruntime - max_vruntime); + if (delta > 0) + max_vruntime = vruntime; + + return max_vruntime; +} + +static inline u64 min_vruntime(u64 min_vruntime, u64 vruntime) +{ + s64 delta = (s64)(vruntime - min_vruntime); + if (delta < 0) + min_vruntime = vruntime; + + return min_vruntime; +} + +static inline int entity_before(struct sched_entity *a, + struct sched_entity *b) +{ + return (s64)(a->vruntime - b->vruntime) < 0; +} + +static void update_min_vruntime(struct cfs_rq *cfs_rq) +{ + u64 vruntime = cfs_rq->min_vruntime; + + if (cfs_rq->curr) + vruntime = cfs_rq->curr->vruntime; + + if (cfs_rq->rb_leftmost) { + struct sched_entity *se = rb_entry(cfs_rq->rb_leftmost, + struct sched_entity, + run_node); + + if (!cfs_rq->curr) + vruntime = se->vruntime; + else + vruntime = min_vruntime(vruntime, se->vruntime); + } + + /* ensure we never gain time by being placed backwards. */ + cfs_rq->min_vruntime = max_vruntime(cfs_rq->min_vruntime, vruntime); +#ifndef CONFIG_64BIT + smp_wmb(); + cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime; +#endif +} + +/* + * Enqueue an entity into the rb-tree: + */ +static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + struct rb_node **link = &cfs_rq->tasks_timeline.rb_node; + struct rb_node *parent = NULL; + struct sched_entity *entry; + int leftmost = 1; + + /* + * Find the right place in the rbtree: + */ + while (*link) { + parent = *link; + entry = rb_entry(parent, struct sched_entity, run_node); + /* + * We dont care about collisions. Nodes with + * the same key stay together. + */ + if (entity_before(se, entry)) { + link = &parent->rb_left; + } else { + link = &parent->rb_right; + leftmost = 0; + } + } + + /* + * Maintain a cache of leftmost tree entries (it is frequently + * used): + */ + if (leftmost) + cfs_rq->rb_leftmost = &se->run_node; + + rb_link_node(&se->run_node, parent, link); + rb_insert_color(&se->run_node, &cfs_rq->tasks_timeline); +} + +static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + if (cfs_rq->rb_leftmost == &se->run_node) { + struct rb_node *next_node; + + next_node = rb_next(&se->run_node); + cfs_rq->rb_leftmost = next_node; + } + + rb_erase(&se->run_node, &cfs_rq->tasks_timeline); +} + +struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq) +{ + struct rb_node *left = cfs_rq->rb_leftmost; + + if (!left) + return NULL; + + return rb_entry(left, struct sched_entity, run_node); +} + +static struct sched_entity *__pick_next_entity(struct sched_entity *se) +{ + struct rb_node *next = rb_next(&se->run_node); + + if (!next) + return NULL; + + return rb_entry(next, struct sched_entity, run_node); +} + +#ifdef CONFIG_SCHED_DEBUG +struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq) +{ + struct rb_node *last = rb_last(&cfs_rq->tasks_timeline); + + if (!last) + return NULL; + + return rb_entry(last, struct sched_entity, run_node); +} + +/************************************************************** + * Scheduling class statistics methods: + */ + +int sched_proc_update_handler(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, + loff_t *ppos) +{ + int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); + unsigned int factor = get_update_sysctl_factor(); + + if (ret || !write) + return ret; + + sched_nr_latency = DIV_ROUND_UP(sysctl_sched_latency, + sysctl_sched_min_granularity); + +#define WRT_SYSCTL(name) \ + (normalized_sysctl_##name = sysctl_##name / (factor)) + WRT_SYSCTL(sched_min_granularity); + WRT_SYSCTL(sched_latency); + WRT_SYSCTL(sched_wakeup_granularity); +#undef WRT_SYSCTL + + return 0; +} +#endif + +/* + * delta /= w + */ +static inline u64 calc_delta_fair(u64 delta, struct sched_entity *se) +{ + if (unlikely(se->load.weight != NICE_0_LOAD)) + delta = __calc_delta(delta, NICE_0_LOAD, &se->load); + + return delta; +} + +/* + * The idea is to set a period in which each task runs once. + * + * When there are too many tasks (sched_nr_latency) we have to stretch + * this period because otherwise the slices get too small. + * + * p = (nr <= nl) ? l : l*nr/nl + */ +static u64 __sched_period(unsigned long nr_running) +{ + if (unlikely(nr_running > sched_nr_latency)) + return nr_running * sysctl_sched_min_granularity; + else + return sysctl_sched_latency; +} + +/* + * We calculate the wall-time slice from the period by taking a part + * proportional to the weight. + * + * s = p*P[w/rw] + */ +static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + u64 slice = __sched_period(cfs_rq->nr_running + !se->on_rq); + + for_each_sched_entity(se) { + struct load_weight *load; + struct load_weight lw; + + cfs_rq = cfs_rq_of(se); + load = &cfs_rq->load; + + if (unlikely(!se->on_rq)) { + lw = cfs_rq->load; + + update_load_add(&lw, se->load.weight); + load = &lw; + } + slice = __calc_delta(slice, se->load.weight, load); + } + return slice; +} + +/* + * We calculate the vruntime slice of a to-be-inserted task. + * + * vs = s/w + */ +static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + return calc_delta_fair(sched_slice(cfs_rq, se), se); +} + +#ifdef CONFIG_SMP +static int select_idle_sibling(struct task_struct *p, int prev_cpu, int cpu); +static unsigned long task_h_load(struct task_struct *p); + +/* + * We choose a half-life close to 1 scheduling period. + * Note: The tables runnable_avg_yN_inv and runnable_avg_yN_sum are + * dependent on this value. + */ +#define LOAD_AVG_PERIOD 32 +#define LOAD_AVG_MAX 47742 /* maximum possible load avg */ +#define LOAD_AVG_MAX_N 345 /* number of full periods to produce LOAD_AVG_MAX */ + +/* Give new sched_entity start runnable values to heavy its load in infant time */ +void init_entity_runnable_average(struct sched_entity *se) +{ + struct sched_avg *sa = &se->avg; + + sa->last_update_time = 0; + /* + * sched_avg's period_contrib should be strictly less then 1024, so + * we give it 1023 to make sure it is almost a period (1024us), and + * will definitely be update (after enqueue). + */ + sa->period_contrib = 1023; + /* + * Tasks are intialized with full load to be seen as heavy tasks until + * they get a chance to stabilize to their real load level. + * Group entities are intialized with zero load to reflect the fact that + * nothing has been attached to the task group yet. + */ + if (entity_is_task(se)) + sa->load_avg = scale_load_down(se->load.weight); + sa->load_sum = sa->load_avg * LOAD_AVG_MAX; + /* + * In previous Android versions, we used to have: + * sa->util_avg = scale_load_down(SCHED_LOAD_SCALE); + * sa->util_sum = sa->util_avg * LOAD_AVG_MAX; + * However, that functionality has been moved to enqueue. + * It is unclear if we should restore this in enqueue. + */ + /* + * At this point, util_avg won't be used in select_task_rq_fair anyway + */ + sa->util_avg = 0; + sa->util_sum = 0; + /* when this task enqueue'ed, it will contribute to its cfs_rq's load_avg */ +} + +static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq); +static int update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq, bool update_freq); +static void attach_entity_cfs_rq(struct sched_entity *se); +static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se); + +/* + * With new tasks being created, their initial util_avgs are extrapolated + * based on the cfs_rq's current util_avg: + * + * util_avg = cfs_rq->util_avg / (cfs_rq->load_avg + 1) * se.load.weight + * + * However, in many cases, the above util_avg does not give a desired + * value. Moreover, the sum of the util_avgs may be divergent, such + * as when the series is a harmonic series. + * + * To solve this problem, we also cap the util_avg of successive tasks to + * only 1/2 of the left utilization budget: + * + * util_avg_cap = (1024 - cfs_rq->avg.util_avg) / 2^n + * + * where n denotes the nth task. + * + * For example, a simplest series from the beginning would be like: + * + * task util_avg: 512, 256, 128, 64, 32, 16, 8, ... + * cfs_rq util_avg: 512, 768, 896, 960, 992, 1008, 1016, ... + * + * Finally, that extrapolated util_avg is clamped to the cap (util_avg_cap) + * if util_avg > util_avg_cap. + */ +void post_init_entity_util_avg(struct sched_entity *se) +{ + struct cfs_rq *cfs_rq = cfs_rq_of(se); + struct sched_avg *sa = &se->avg; + long cap = (long)(SCHED_CAPACITY_SCALE - cfs_rq->avg.util_avg) / 2; + + if (cap > 0) { + if (cfs_rq->avg.util_avg != 0) { + sa->util_avg = cfs_rq->avg.util_avg * se->load.weight; + sa->util_avg /= (cfs_rq->avg.load_avg + 1); + + if (sa->util_avg > cap) + sa->util_avg = cap; + } else { + sa->util_avg = cap; + } + /* + * If we wish to restore tuning via setting initial util, + * this is where we should do it. + */ + sa->util_sum = sa->util_avg * LOAD_AVG_MAX; + } + + if (entity_is_task(se)) { + struct task_struct *p = task_of(se); + if (p->sched_class != &fair_sched_class) { + /* + * For !fair tasks do: + * + update_cfs_rq_load_avg(now, cfs_rq, false); + attach_entity_load_avg(cfs_rq, se); + switched_from_fair(rq, p); + * + * such that the next switched_to_fair() has the + * expected state. + */ + se->avg.last_update_time = cfs_rq_clock_task(cfs_rq); + return; + } + } + + attach_entity_cfs_rq(se); +} + +#else /* !CONFIG_SMP */ +void init_entity_runnable_average(struct sched_entity *se) +{ +} +void post_init_entity_util_avg(struct sched_entity *se) +{ +} +static void update_tg_load_avg(struct cfs_rq *cfs_rq, int force) +{ +} +#endif /* CONFIG_SMP */ + +/* + * Update the current task's runtime statistics. + */ +static void update_curr(struct cfs_rq *cfs_rq) +{ + struct sched_entity *curr = cfs_rq->curr; + u64 now = rq_clock_task(rq_of(cfs_rq)); + u64 delta_exec; + + if (unlikely(!curr)) + return; + + delta_exec = now - curr->exec_start; + if (unlikely((s64)delta_exec <= 0)) + return; + + curr->exec_start = now; + + schedstat_set(curr->statistics.exec_max, + max(delta_exec, curr->statistics.exec_max)); + + curr->sum_exec_runtime += delta_exec; + schedstat_add(cfs_rq, exec_clock, delta_exec); + + curr->vruntime += calc_delta_fair(delta_exec, curr); + update_min_vruntime(cfs_rq); + + if (entity_is_task(curr)) { + struct task_struct *curtask = task_of(curr); + + trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime); + cpuacct_charge(curtask, delta_exec); + account_group_exec_runtime(curtask, delta_exec); + } + + account_cfs_rq_runtime(cfs_rq, delta_exec); +} + +static void update_curr_fair(struct rq *rq) +{ + update_curr(cfs_rq_of(&rq->curr->se)); +} + +#ifdef CONFIG_SCHEDSTATS +static inline void +update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + u64 wait_start = rq_clock(rq_of(cfs_rq)); + + if (entity_is_task(se) && task_on_rq_migrating(task_of(se)) && + likely(wait_start > se->statistics.wait_start)) + wait_start -= se->statistics.wait_start; + + se->statistics.wait_start = wait_start; +} + +static void +update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + struct task_struct *p; + u64 delta = rq_clock(rq_of(cfs_rq)) - se->statistics.wait_start; + + if (entity_is_task(se)) { + p = task_of(se); + if (task_on_rq_migrating(p)) { + /* + * Preserve migrating task's wait time so wait_start + * time stamp can be adjusted to accumulate wait time + * prior to migration. + */ + se->statistics.wait_start = delta; + return; + } + trace_sched_stat_wait(p, delta); + } + + se->statistics.wait_max = max(se->statistics.wait_max, delta); + se->statistics.wait_count++; + se->statistics.wait_sum += delta; + se->statistics.wait_start = 0; +} +#else +static inline void +update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ +} + +static inline void +update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ +} +#endif + +/* + * Task is being enqueued - update stats: + */ +static void update_stats_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + /* + * Are we enqueueing a waiting task? (for current tasks + * a dequeue/enqueue event is a NOP) + */ + if (se != cfs_rq->curr) + update_stats_wait_start(cfs_rq, se); +} + +static inline void +update_stats_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + /* + * Mark the end of the wait period if dequeueing a + * waiting task: + */ + if (se != cfs_rq->curr) + update_stats_wait_end(cfs_rq, se); +} + +/* + * We are picking a new current task - update its stats: + */ +static inline void +update_stats_curr_start(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + /* + * We are starting a new run period: + */ + se->exec_start = rq_clock_task(rq_of(cfs_rq)); +} + +/************************************************** + * Scheduling class queueing methods: + */ + +#ifdef CONFIG_NUMA_BALANCING +/* + * Approximate time to scan a full NUMA task in ms. The task scan period is + * calculated based on the tasks virtual memory size and + * numa_balancing_scan_size. + */ +unsigned int sysctl_numa_balancing_scan_period_min = 1000; +unsigned int sysctl_numa_balancing_scan_period_max = 60000; + +/* Portion of address space to scan in MB */ +unsigned int sysctl_numa_balancing_scan_size = 256; + +/* Scan @scan_size MB every @scan_period after an initial @scan_delay in ms */ +unsigned int sysctl_numa_balancing_scan_delay = 1000; + +static unsigned int task_nr_scan_windows(struct task_struct *p) +{ + unsigned long rss = 0; + unsigned long nr_scan_pages; + + /* + * Calculations based on RSS as non-present and empty pages are skipped + * by the PTE scanner and NUMA hinting faults should be trapped based + * on resident pages + */ + nr_scan_pages = sysctl_numa_balancing_scan_size << (20 - PAGE_SHIFT); + rss = get_mm_rss(p->mm); + if (!rss) + rss = nr_scan_pages; + + rss = round_up(rss, nr_scan_pages); + return rss / nr_scan_pages; +} + +/* For sanitys sake, never scan more PTEs than MAX_SCAN_WINDOW MB/sec. */ +#define MAX_SCAN_WINDOW 2560 + +static unsigned int task_scan_min(struct task_struct *p) +{ + unsigned int scan_size = READ_ONCE(sysctl_numa_balancing_scan_size); + unsigned int scan, floor; + unsigned int windows = 1; + + if (scan_size < MAX_SCAN_WINDOW) + windows = MAX_SCAN_WINDOW / scan_size; + floor = 1000 / windows; + + scan = sysctl_numa_balancing_scan_period_min / task_nr_scan_windows(p); + return max_t(unsigned int, floor, scan); +} + +static unsigned int task_scan_max(struct task_struct *p) +{ + unsigned int smin = task_scan_min(p); + unsigned int smax; + + /* Watch for min being lower than max due to floor calculations */ + smax = sysctl_numa_balancing_scan_period_max / task_nr_scan_windows(p); + return max(smin, smax); +} + +static void account_numa_enqueue(struct rq *rq, struct task_struct *p) +{ + rq->nr_numa_running += (p->numa_preferred_nid != -1); + rq->nr_preferred_running += (p->numa_preferred_nid == task_node(p)); +} + +static void account_numa_dequeue(struct rq *rq, struct task_struct *p) +{ + rq->nr_numa_running -= (p->numa_preferred_nid != -1); + rq->nr_preferred_running -= (p->numa_preferred_nid == task_node(p)); +} + +struct numa_group { + atomic_t refcount; + + spinlock_t lock; /* nr_tasks, tasks */ + int nr_tasks; + pid_t gid; + + struct rcu_head rcu; + nodemask_t active_nodes; + unsigned long total_faults; + /* + * Faults_cpu is used to decide whether memory should move + * towards the CPU. As a consequence, these stats are weighted + * more by CPU use than by memory faults. + */ + unsigned long *faults_cpu; + unsigned long faults[0]; +}; + +/* Shared or private faults. */ +#define NR_NUMA_HINT_FAULT_TYPES 2 + +/* Memory and CPU locality */ +#define NR_NUMA_HINT_FAULT_STATS (NR_NUMA_HINT_FAULT_TYPES * 2) + +/* Averaged statistics, and temporary buffers. */ +#define NR_NUMA_HINT_FAULT_BUCKETS (NR_NUMA_HINT_FAULT_STATS * 2) + +pid_t task_numa_group_id(struct task_struct *p) +{ + return p->numa_group ? p->numa_group->gid : 0; +} + +/* + * The averaged statistics, shared & private, memory & cpu, + * occupy the first half of the array. The second half of the + * array is for current counters, which are averaged into the + * first set by task_numa_placement. + */ +static inline int task_faults_idx(enum numa_faults_stats s, int nid, int priv) +{ + return NR_NUMA_HINT_FAULT_TYPES * (s * nr_node_ids + nid) + priv; +} + +static inline unsigned long task_faults(struct task_struct *p, int nid) +{ + if (!p->numa_faults) + return 0; + + return p->numa_faults[task_faults_idx(NUMA_MEM, nid, 0)] + + p->numa_faults[task_faults_idx(NUMA_MEM, nid, 1)]; +} + +static inline unsigned long group_faults(struct task_struct *p, int nid) +{ + if (!p->numa_group) + return 0; + + return p->numa_group->faults[task_faults_idx(NUMA_MEM, nid, 0)] + + p->numa_group->faults[task_faults_idx(NUMA_MEM, nid, 1)]; +} + +static inline unsigned long group_faults_cpu(struct numa_group *group, int nid) +{ + return group->faults_cpu[task_faults_idx(NUMA_MEM, nid, 0)] + + group->faults_cpu[task_faults_idx(NUMA_MEM, nid, 1)]; +} + +/* Handle placement on systems where not all nodes are directly connected. */ +static unsigned long score_nearby_nodes(struct task_struct *p, int nid, + int maxdist, bool task) +{ + unsigned long score = 0; + int node; + + /* + * All nodes are directly connected, and the same distance + * from each other. No need for fancy placement algorithms. + */ + if (sched_numa_topology_type == NUMA_DIRECT) + return 0; + + /* + * This code is called for each node, introducing N^2 complexity, + * which should be ok given the number of nodes rarely exceeds 8. + */ + for_each_online_node(node) { + unsigned long faults; + int dist = node_distance(nid, node); + + /* + * The furthest away nodes in the system are not interesting + * for placement; nid was already counted. + */ + if (dist == sched_max_numa_distance || node == nid) + continue; + + /* + * On systems with a backplane NUMA topology, compare groups + * of nodes, and move tasks towards the group with the most + * memory accesses. When comparing two nodes at distance + * "hoplimit", only nodes closer by than "hoplimit" are part + * of each group. Skip other nodes. + */ + if (sched_numa_topology_type == NUMA_BACKPLANE && + dist > maxdist) + continue; + + /* Add up the faults from nearby nodes. */ + if (task) + faults = task_faults(p, node); + else + faults = group_faults(p, node); + + /* + * On systems with a glueless mesh NUMA topology, there are + * no fixed "groups of nodes". Instead, nodes that are not + * directly connected bounce traffic through intermediate + * nodes; a numa_group can occupy any set of nodes. + * The further away a node is, the less the faults count. + * This seems to result in good task placement. + */ + if (sched_numa_topology_type == NUMA_GLUELESS_MESH) { + faults *= (sched_max_numa_distance - dist); + faults /= (sched_max_numa_distance - LOCAL_DISTANCE); + } + + score += faults; + } + + return score; +} + +/* + * These return the fraction of accesses done by a particular task, or + * task group, on a particular numa node. The group weight is given a + * larger multiplier, in order to group tasks together that are almost + * evenly spread out between numa nodes. + */ +static inline unsigned long task_weight(struct task_struct *p, int nid, + int dist) +{ + unsigned long faults, total_faults; + + if (!p->numa_faults) + return 0; + + total_faults = p->total_numa_faults; + + if (!total_faults) + return 0; + + faults = task_faults(p, nid); + faults += score_nearby_nodes(p, nid, dist, true); + + return 1000 * faults / total_faults; +} + +static inline unsigned long group_weight(struct task_struct *p, int nid, + int dist) +{ + unsigned long faults, total_faults; + + if (!p->numa_group) + return 0; + + total_faults = p->numa_group->total_faults; + + if (!total_faults) + return 0; + + faults = group_faults(p, nid); + faults += score_nearby_nodes(p, nid, dist, false); + + return 1000 * faults / total_faults; +} + +bool should_numa_migrate_memory(struct task_struct *p, struct page * page, + int src_nid, int dst_cpu) +{ + struct numa_group *ng = p->numa_group; + int dst_nid = cpu_to_node(dst_cpu); + int last_cpupid, this_cpupid; + + this_cpupid = cpu_pid_to_cpupid(dst_cpu, current->pid); + + /* + * Multi-stage node selection is used in conjunction with a periodic + * migration fault to build a temporal task<->page relation. By using + * a two-stage filter we remove short/unlikely relations. + * + * Using P(p) ~ n_p / n_t as per frequentist probability, we can equate + * a task's usage of a particular page (n_p) per total usage of this + * page (n_t) (in a given time-span) to a probability. + * + * Our periodic faults will sample this probability and getting the + * same result twice in a row, given these samples are fully + * independent, is then given by P(n)^2, provided our sample period + * is sufficiently short compared to the usage pattern. + * + * This quadric squishes small probabilities, making it less likely we + * act on an unlikely task<->page relation. + */ + last_cpupid = page_cpupid_xchg_last(page, this_cpupid); + if (!cpupid_pid_unset(last_cpupid) && + cpupid_to_nid(last_cpupid) != dst_nid) + return false; + + /* Always allow migrate on private faults */ + if (cpupid_match_pid(p, last_cpupid)) + return true; + + /* A shared fault, but p->numa_group has not been set up yet. */ + if (!ng) + return true; + + /* + * Do not migrate if the destination is not a node that + * is actively used by this numa group. + */ + if (!node_isset(dst_nid, ng->active_nodes)) + return false; + + /* + * Source is a node that is not actively used by this + * numa group, while the destination is. Migrate. + */ + if (!node_isset(src_nid, ng->active_nodes)) + return true; + + /* + * Both source and destination are nodes in active + * use by this numa group. Maximize memory bandwidth + * by migrating from more heavily used groups, to less + * heavily used ones, spreading the load around. + * Use a 1/4 hysteresis to avoid spurious page movement. + */ + return group_faults(p, dst_nid) < (group_faults(p, src_nid) * 3 / 4); +} + +static unsigned long weighted_cpuload(const int cpu); +static unsigned long source_load(int cpu, int type); +static unsigned long target_load(int cpu, int type); +static unsigned long capacity_of(int cpu); +static long effective_load(struct task_group *tg, int cpu, long wl, long wg); + +/* Cached statistics for all CPUs within a node */ +struct numa_stats { + unsigned long nr_running; + unsigned long load; + + /* Total compute capacity of CPUs on a node */ + unsigned long compute_capacity; + + /* Approximate capacity in terms of runnable tasks on a node */ + unsigned long task_capacity; + int has_free_capacity; +}; + +/* + * XXX borrowed from update_sg_lb_stats + */ +static void update_numa_stats(struct numa_stats *ns, int nid) +{ + int smt, cpu, cpus = 0; + unsigned long capacity; + + memset(ns, 0, sizeof(*ns)); + for_each_cpu(cpu, cpumask_of_node(nid)) { + struct rq *rq = cpu_rq(cpu); + + ns->nr_running += rq->nr_running; + ns->load += weighted_cpuload(cpu); + ns->compute_capacity += capacity_of(cpu); + + cpus++; + } + + /* + * If we raced with hotplug and there are no CPUs left in our mask + * the @ns structure is NULL'ed and task_numa_compare() will + * not find this node attractive. + * + * We'll either bail at !has_free_capacity, or we'll detect a huge + * imbalance and bail there. + */ + if (!cpus) + return; + + /* smt := ceil(cpus / capacity), assumes: 1 < smt_power < 2 */ + smt = DIV_ROUND_UP(SCHED_CAPACITY_SCALE * cpus, ns->compute_capacity); + capacity = cpus / smt; /* cores */ + + ns->task_capacity = min_t(unsigned, capacity, + DIV_ROUND_CLOSEST(ns->compute_capacity, SCHED_CAPACITY_SCALE)); + ns->has_free_capacity = (ns->nr_running < ns->task_capacity); +} + +struct task_numa_env { + struct task_struct *p; + + int src_cpu, src_nid; + int dst_cpu, dst_nid; + + struct numa_stats src_stats, dst_stats; + + int imbalance_pct; + int dist; + + struct task_struct *best_task; + long best_imp; + int best_cpu; +}; + +static void task_numa_assign(struct task_numa_env *env, + struct task_struct *p, long imp) +{ + if (env->best_task) + put_task_struct(env->best_task); + + env->best_task = p; + env->best_imp = imp; + env->best_cpu = env->dst_cpu; +} + +static bool load_too_imbalanced(long src_load, long dst_load, + struct task_numa_env *env) +{ + long imb, old_imb; + long orig_src_load, orig_dst_load; + long src_capacity, dst_capacity; + + /* + * The load is corrected for the CPU capacity available on each node. + * + * src_load dst_load + * ------------ vs --------- + * src_capacity dst_capacity + */ + src_capacity = env->src_stats.compute_capacity; + dst_capacity = env->dst_stats.compute_capacity; + + /* We care about the slope of the imbalance, not the direction. */ + if (dst_load < src_load) + swap(dst_load, src_load); + + /* Is the difference below the threshold? */ + imb = dst_load * src_capacity * 100 - + src_load * dst_capacity * env->imbalance_pct; + if (imb <= 0) + return false; + + /* + * The imbalance is above the allowed threshold. + * Compare it with the old imbalance. + */ + orig_src_load = env->src_stats.load; + orig_dst_load = env->dst_stats.load; + + if (orig_dst_load < orig_src_load) + swap(orig_dst_load, orig_src_load); + + old_imb = orig_dst_load * src_capacity * 100 - + orig_src_load * dst_capacity * env->imbalance_pct; + + /* Would this change make things worse? */ + return (imb > old_imb); +} + +/* + * This checks if the overall compute and NUMA accesses of the system would + * be improved if the source tasks was migrated to the target dst_cpu taking + * into account that it might be best if task running on the dst_cpu should + * be exchanged with the source task + */ +static void task_numa_compare(struct task_numa_env *env, + long taskimp, long groupimp) +{ + struct rq *src_rq = cpu_rq(env->src_cpu); + struct rq *dst_rq = cpu_rq(env->dst_cpu); + struct task_struct *cur; + long src_load, dst_load; + long load; + long imp = env->p->numa_group ? groupimp : taskimp; + long moveimp = imp; + int dist = env->dist; + bool assigned = false; + + rcu_read_lock(); + + raw_spin_lock_irq(&dst_rq->lock); + cur = dst_rq->curr; + /* + * No need to move the exiting task or idle task. + */ + if ((cur->flags & PF_EXITING) || is_idle_task(cur)) + cur = NULL; + else { + /* + * The task_struct must be protected here to protect the + * p->numa_faults access in the task_weight since the + * numa_faults could already be freed in the following path: + * finish_task_switch() + * --> put_task_struct() + * --> __put_task_struct() + * --> task_numa_free() + */ + get_task_struct(cur); + } + + raw_spin_unlock_irq(&dst_rq->lock); + + /* + * Because we have preemption enabled we can get migrated around and + * end try selecting ourselves (current == env->p) as a swap candidate. + */ + if (cur == env->p) + goto unlock; + + /* + * "imp" is the fault differential for the source task between the + * source and destination node. Calculate the total differential for + * the source task and potential destination task. The more negative + * the value is, the more rmeote accesses that would be expected to + * be incurred if the tasks were swapped. + */ + if (cur) { + /* Skip this swap candidate if cannot move to the source cpu */ + if (!cpumask_test_cpu(env->src_cpu, tsk_cpus_allowed(cur))) + goto unlock; + + /* + * If dst and source tasks are in the same NUMA group, or not + * in any group then look only at task weights. + */ + if (cur->numa_group == env->p->numa_group) { + imp = taskimp + task_weight(cur, env->src_nid, dist) - + task_weight(cur, env->dst_nid, dist); + /* + * Add some hysteresis to prevent swapping the + * tasks within a group over tiny differences. + */ + if (cur->numa_group) + imp -= imp/16; + } else { + /* + * Compare the group weights. If a task is all by + * itself (not part of a group), use the task weight + * instead. + */ + if (cur->numa_group) + imp += group_weight(cur, env->src_nid, dist) - + group_weight(cur, env->dst_nid, dist); + else + imp += task_weight(cur, env->src_nid, dist) - + task_weight(cur, env->dst_nid, dist); + } + } + + if (imp <= env->best_imp && moveimp <= env->best_imp) + goto unlock; + + if (!cur) { + /* Is there capacity at our destination? */ + if (env->src_stats.nr_running <= env->src_stats.task_capacity && + !env->dst_stats.has_free_capacity) + goto unlock; + + goto balance; + } + + /* Balance doesn't matter much if we're running a task per cpu */ + if (imp > env->best_imp && src_rq->nr_running == 1 && + dst_rq->nr_running == 1) + goto assign; + + /* + * In the overloaded case, try and keep the load balanced. + */ +balance: + load = task_h_load(env->p); + dst_load = env->dst_stats.load + load; + src_load = env->src_stats.load - load; + + if (moveimp > imp && moveimp > env->best_imp) { + /* + * If the improvement from just moving env->p direction is + * better than swapping tasks around, check if a move is + * possible. Store a slightly smaller score than moveimp, + * so an actually idle CPU will win. + */ + if (!load_too_imbalanced(src_load, dst_load, env)) { + imp = moveimp - 1; + put_task_struct(cur); + cur = NULL; + goto assign; + } + } + + if (imp <= env->best_imp) + goto unlock; + + if (cur) { + load = task_h_load(cur); + dst_load -= load; + src_load += load; + } + + if (load_too_imbalanced(src_load, dst_load, env)) + goto unlock; + + /* + * One idle CPU per node is evaluated for a task numa move. + * Call select_idle_sibling to maybe find a better one. + */ + if (!cur) + env->dst_cpu = select_idle_sibling(env->p, env->src_cpu, + env->dst_cpu); + +assign: + assigned = true; + task_numa_assign(env, cur, imp); +unlock: + rcu_read_unlock(); + /* + * The dst_rq->curr isn't assigned. The protection for task_struct is + * finished. + */ + if (cur && !assigned) + put_task_struct(cur); +} + +static void task_numa_find_cpu(struct task_numa_env *env, + long taskimp, long groupimp) +{ + int cpu; + + for_each_cpu(cpu, cpumask_of_node(env->dst_nid)) { + /* Skip this CPU if the source task cannot migrate */ + if (!cpumask_test_cpu(cpu, tsk_cpus_allowed(env->p))) + continue; + + env->dst_cpu = cpu; + task_numa_compare(env, taskimp, groupimp); + } +} + +/* Only move tasks to a NUMA node less busy than the current node. */ +static bool numa_has_capacity(struct task_numa_env *env) +{ + struct numa_stats *src = &env->src_stats; + struct numa_stats *dst = &env->dst_stats; + + if (src->has_free_capacity && !dst->has_free_capacity) + return false; + + /* + * Only consider a task move if the source has a higher load + * than the destination, corrected for CPU capacity on each node. + * + * src->load dst->load + * --------------------- vs --------------------- + * src->compute_capacity dst->compute_capacity + */ + if (src->load * dst->compute_capacity * env->imbalance_pct > + + dst->load * src->compute_capacity * 100) + return true; + + return false; +} + +static int task_numa_migrate(struct task_struct *p) +{ + struct task_numa_env env = { + .p = p, + + .src_cpu = task_cpu(p), + .src_nid = task_node(p), + + .imbalance_pct = 112, + + .best_task = NULL, + .best_imp = 0, + .best_cpu = -1 + }; + struct sched_domain *sd; + unsigned long taskweight, groupweight; + int nid, ret, dist; + long taskimp, groupimp; + + /* + * Pick the lowest SD_NUMA domain, as that would have the smallest + * imbalance and would be the first to start moving tasks about. + * + * And we want to avoid any moving of tasks about, as that would create + * random movement of tasks -- counter the numa conditions we're trying + * to satisfy here. + */ + rcu_read_lock(); + sd = rcu_dereference(per_cpu(sd_numa, env.src_cpu)); + if (sd) + env.imbalance_pct = 100 + (sd->imbalance_pct - 100) / 2; + rcu_read_unlock(); + + /* + * Cpusets can break the scheduler domain tree into smaller + * balance domains, some of which do not cross NUMA boundaries. + * Tasks that are "trapped" in such domains cannot be migrated + * elsewhere, so there is no point in (re)trying. + */ + if (unlikely(!sd)) { + p->numa_preferred_nid = task_node(p); + return -EINVAL; + } + + env.dst_nid = p->numa_preferred_nid; + dist = env.dist = node_distance(env.src_nid, env.dst_nid); + taskweight = task_weight(p, env.src_nid, dist); + groupweight = group_weight(p, env.src_nid, dist); + update_numa_stats(&env.src_stats, env.src_nid); + taskimp = task_weight(p, env.dst_nid, dist) - taskweight; + groupimp = group_weight(p, env.dst_nid, dist) - groupweight; + update_numa_stats(&env.dst_stats, env.dst_nid); + + /* Try to find a spot on the preferred nid. */ + if (numa_has_capacity(&env)) + task_numa_find_cpu(&env, taskimp, groupimp); + + /* + * Look at other nodes in these cases: + * - there is no space available on the preferred_nid + * - the task is part of a numa_group that is interleaved across + * multiple NUMA nodes; in order to better consolidate the group, + * we need to check other locations. + */ + if (env.best_cpu == -1 || (p->numa_group && + nodes_weight(p->numa_group->active_nodes) > 1)) { + for_each_online_node(nid) { + if (nid == env.src_nid || nid == p->numa_preferred_nid) + continue; + + dist = node_distance(env.src_nid, env.dst_nid); + if (sched_numa_topology_type == NUMA_BACKPLANE && + dist != env.dist) { + taskweight = task_weight(p, env.src_nid, dist); + groupweight = group_weight(p, env.src_nid, dist); + } + + /* Only consider nodes where both task and groups benefit */ + taskimp = task_weight(p, nid, dist) - taskweight; + groupimp = group_weight(p, nid, dist) - groupweight; + if (taskimp < 0 && groupimp < 0) + continue; + + env.dist = dist; + env.dst_nid = nid; + update_numa_stats(&env.dst_stats, env.dst_nid); + if (numa_has_capacity(&env)) + task_numa_find_cpu(&env, taskimp, groupimp); + } + } + + /* + * If the task is part of a workload that spans multiple NUMA nodes, + * and is migrating into one of the workload's active nodes, remember + * this node as the task's preferred numa node, so the workload can + * settle down. + * A task that migrated to a second choice node will be better off + * trying for a better one later. Do not set the preferred node here. + */ + if (p->numa_group) { + if (env.best_cpu == -1) + nid = env.src_nid; + else + nid = env.dst_nid; + + if (node_isset(nid, p->numa_group->active_nodes)) + sched_setnuma(p, env.dst_nid); + } + + /* No better CPU than the current one was found. */ + if (env.best_cpu == -1) + return -EAGAIN; + + /* + * Reset the scan period if the task is being rescheduled on an + * alternative node to recheck if the tasks is now properly placed. + */ + p->numa_scan_period = task_scan_min(p); + + if (env.best_task == NULL) { + ret = migrate_task_to(p, env.best_cpu); + if (ret != 0) + trace_sched_stick_numa(p, env.src_cpu, env.best_cpu); + return ret; + } + + ret = migrate_swap(p, env.best_task); + if (ret != 0) + trace_sched_stick_numa(p, env.src_cpu, task_cpu(env.best_task)); + put_task_struct(env.best_task); + return ret; +} + +/* Attempt to migrate a task to a CPU on the preferred node. */ +static void numa_migrate_preferred(struct task_struct *p) +{ + unsigned long interval = HZ; + + /* This task has no NUMA fault statistics yet */ + if (unlikely(p->numa_preferred_nid == -1 || !p->numa_faults)) + return; + + /* Periodically retry migrating the task to the preferred node */ + interval = min(interval, msecs_to_jiffies(p->numa_scan_period) / 16); + p->numa_migrate_retry = jiffies + interval; + + /* Success if task is already running on preferred CPU */ + if (task_node(p) == p->numa_preferred_nid) + return; + + /* Otherwise, try migrate to a CPU on the preferred node */ + task_numa_migrate(p); +} + +/* + * Find the nodes on which the workload is actively running. We do this by + * tracking the nodes from which NUMA hinting faults are triggered. This can + * be different from the set of nodes where the workload's memory is currently + * located. + * + * The bitmask is used to make smarter decisions on when to do NUMA page + * migrations, To prevent flip-flopping, and excessive page migrations, nodes + * are added when they cause over 6/16 of the maximum number of faults, but + * only removed when they drop below 3/16. + */ +static void update_numa_active_node_mask(struct numa_group *numa_group) +{ + unsigned long faults, max_faults = 0; + int nid; + + for_each_online_node(nid) { + faults = group_faults_cpu(numa_group, nid); + if (faults > max_faults) + max_faults = faults; + } + + for_each_online_node(nid) { + faults = group_faults_cpu(numa_group, nid); + if (!node_isset(nid, numa_group->active_nodes)) { + if (faults > max_faults * 6 / 16) + node_set(nid, numa_group->active_nodes); + } else if (faults < max_faults * 3 / 16) + node_clear(nid, numa_group->active_nodes); + } +} + +/* + * When adapting the scan rate, the period is divided into NUMA_PERIOD_SLOTS + * increments. The more local the fault statistics are, the higher the scan + * period will be for the next scan window. If local/(local+remote) ratio is + * below NUMA_PERIOD_THRESHOLD (where range of ratio is 1..NUMA_PERIOD_SLOTS) + * the scan period will decrease. Aim for 70% local accesses. + */ +#define NUMA_PERIOD_SLOTS 10 +#define NUMA_PERIOD_THRESHOLD 7 + +/* + * Increase the scan period (slow down scanning) if the majority of + * our memory is already on our local node, or if the majority of + * the page accesses are shared with other processes. + * Otherwise, decrease the scan period. + */ +static void update_task_scan_period(struct task_struct *p, + unsigned long shared, unsigned long private) +{ + unsigned int period_slot; + int ratio; + int diff; + + unsigned long remote = p->numa_faults_locality[0]; + unsigned long local = p->numa_faults_locality[1]; + + /* + * If there were no record hinting faults then either the task is + * completely idle or all activity is areas that are not of interest + * to automatic numa balancing. Related to that, if there were failed + * migration then it implies we are migrating too quickly or the local + * node is overloaded. In either case, scan slower + */ + if (local + shared == 0 || p->numa_faults_locality[2]) { + p->numa_scan_period = min(p->numa_scan_period_max, + p->numa_scan_period << 1); + + p->mm->numa_next_scan = jiffies + + msecs_to_jiffies(p->numa_scan_period); + + return; + } + + /* + * Prepare to scale scan period relative to the current period. + * == NUMA_PERIOD_THRESHOLD scan period stays the same + * < NUMA_PERIOD_THRESHOLD scan period decreases (scan faster) + * >= NUMA_PERIOD_THRESHOLD scan period increases (scan slower) + */ + period_slot = DIV_ROUND_UP(p->numa_scan_period, NUMA_PERIOD_SLOTS); + ratio = (local * NUMA_PERIOD_SLOTS) / (local + remote); + if (ratio >= NUMA_PERIOD_THRESHOLD) { + int slot = ratio - NUMA_PERIOD_THRESHOLD; + if (!slot) + slot = 1; + diff = slot * period_slot; + } else { + diff = -(NUMA_PERIOD_THRESHOLD - ratio) * period_slot; + + /* + * Scale scan rate increases based on sharing. There is an + * inverse relationship between the degree of sharing and + * the adjustment made to the scanning period. Broadly + * speaking the intent is that there is little point + * scanning faster if shared accesses dominate as it may + * simply bounce migrations uselessly + */ + ratio = DIV_ROUND_UP(private * NUMA_PERIOD_SLOTS, (private + shared + 1)); + diff = (diff * ratio) / NUMA_PERIOD_SLOTS; + } + + p->numa_scan_period = clamp(p->numa_scan_period + diff, + task_scan_min(p), task_scan_max(p)); + memset(p->numa_faults_locality, 0, sizeof(p->numa_faults_locality)); +} + +/* + * Get the fraction of time the task has been running since the last + * NUMA placement cycle. The scheduler keeps similar statistics, but + * decays those on a 32ms period, which is orders of magnitude off + * from the dozens-of-seconds NUMA balancing period. Use the scheduler + * stats only if the task is so new there are no NUMA statistics yet. + */ +static u64 numa_get_avg_runtime(struct task_struct *p, u64 *period) +{ + u64 runtime, delta, now; + /* Use the start of this time slice to avoid calculations. */ + now = p->se.exec_start; + runtime = p->se.sum_exec_runtime; + + if (p->last_task_numa_placement) { + delta = runtime - p->last_sum_exec_runtime; + *period = now - p->last_task_numa_placement; + + /* Avoid time going backwards, prevent potential divide error: */ + if (unlikely((s64)*period < 0)) + *period = 0; + } else { + delta = p->se.avg.load_sum / p->se.load.weight; + *period = LOAD_AVG_MAX; + } + + p->last_sum_exec_runtime = runtime; + p->last_task_numa_placement = now; + + return delta; +} + +/* + * Determine the preferred nid for a task in a numa_group. This needs to + * be done in a way that produces consistent results with group_weight, + * otherwise workloads might not converge. + */ +static int preferred_group_nid(struct task_struct *p, int nid) +{ + nodemask_t nodes; + int dist; + + /* Direct connections between all NUMA nodes. */ + if (sched_numa_topology_type == NUMA_DIRECT) + return nid; + + /* + * On a system with glueless mesh NUMA topology, group_weight + * scores nodes according to the number of NUMA hinting faults on + * both the node itself, and on nearby nodes. + */ + if (sched_numa_topology_type == NUMA_GLUELESS_MESH) { + unsigned long score, max_score = 0; + int node, max_node = nid; + + dist = sched_max_numa_distance; + + for_each_online_node(node) { + score = group_weight(p, node, dist); + if (score > max_score) { + max_score = score; + max_node = node; + } + } + return max_node; + } + + /* + * Finding the preferred nid in a system with NUMA backplane + * interconnect topology is more involved. The goal is to locate + * tasks from numa_groups near each other in the system, and + * untangle workloads from different sides of the system. This requires + * searching down the hierarchy of node groups, recursively searching + * inside the highest scoring group of nodes. The nodemask tricks + * keep the complexity of the search down. + */ + nodes = node_online_map; + for (dist = sched_max_numa_distance; dist > LOCAL_DISTANCE; dist--) { + unsigned long max_faults = 0; + nodemask_t max_group = NODE_MASK_NONE; + int a, b; + + /* Are there nodes at this distance from each other? */ + if (!find_numa_distance(dist)) + continue; + + for_each_node_mask(a, nodes) { + unsigned long faults = 0; + nodemask_t this_group; + nodes_clear(this_group); + + /* Sum group's NUMA faults; includes a==b case. */ + for_each_node_mask(b, nodes) { + if (node_distance(a, b) < dist) { + faults += group_faults(p, b); + node_set(b, this_group); + node_clear(b, nodes); + } + } + + /* Remember the top group. */ + if (faults > max_faults) { + max_faults = faults; + max_group = this_group; + /* + * subtle: at the smallest distance there is + * just one node left in each "group", the + * winner is the preferred nid. + */ + nid = a; + } + } + /* Next round, evaluate the nodes within max_group. */ + if (!max_faults) + break; + nodes = max_group; + } + return nid; +} + +static void task_numa_placement(struct task_struct *p) +{ + int seq, nid, max_nid = -1, max_group_nid = -1; + unsigned long max_faults = 0, max_group_faults = 0; + unsigned long fault_types[2] = { 0, 0 }; + unsigned long total_faults; + u64 runtime, period; + spinlock_t *group_lock = NULL; + + /* + * The p->mm->numa_scan_seq field gets updated without + * exclusive access. Use READ_ONCE() here to ensure + * that the field is read in a single access: + */ + seq = READ_ONCE(p->mm->numa_scan_seq); + if (p->numa_scan_seq == seq) + return; + p->numa_scan_seq = seq; + p->numa_scan_period_max = task_scan_max(p); + + total_faults = p->numa_faults_locality[0] + + p->numa_faults_locality[1]; + runtime = numa_get_avg_runtime(p, &period); + + /* If the task is part of a group prevent parallel updates to group stats */ + if (p->numa_group) { + group_lock = &p->numa_group->lock; + spin_lock_irq(group_lock); + } + + /* Find the node with the highest number of faults */ + for_each_online_node(nid) { + /* Keep track of the offsets in numa_faults array */ + int mem_idx, membuf_idx, cpu_idx, cpubuf_idx; + unsigned long faults = 0, group_faults = 0; + int priv; + + for (priv = 0; priv < NR_NUMA_HINT_FAULT_TYPES; priv++) { + long diff, f_diff, f_weight; + + mem_idx = task_faults_idx(NUMA_MEM, nid, priv); + membuf_idx = task_faults_idx(NUMA_MEMBUF, nid, priv); + cpu_idx = task_faults_idx(NUMA_CPU, nid, priv); + cpubuf_idx = task_faults_idx(NUMA_CPUBUF, nid, priv); + + /* Decay existing window, copy faults since last scan */ + diff = p->numa_faults[membuf_idx] - p->numa_faults[mem_idx] / 2; + fault_types[priv] += p->numa_faults[membuf_idx]; + p->numa_faults[membuf_idx] = 0; + + /* + * Normalize the faults_from, so all tasks in a group + * count according to CPU use, instead of by the raw + * number of faults. Tasks with little runtime have + * little over-all impact on throughput, and thus their + * faults are less important. + */ + f_weight = div64_u64(runtime << 16, period + 1); + f_weight = (f_weight * p->numa_faults[cpubuf_idx]) / + (total_faults + 1); + f_diff = f_weight - p->numa_faults[cpu_idx] / 2; + p->numa_faults[cpubuf_idx] = 0; + + p->numa_faults[mem_idx] += diff; + p->numa_faults[cpu_idx] += f_diff; + faults += p->numa_faults[mem_idx]; + p->total_numa_faults += diff; + if (p->numa_group) { + /* + * safe because we can only change our own group + * + * mem_idx represents the offset for a given + * nid and priv in a specific region because it + * is at the beginning of the numa_faults array. + */ + p->numa_group->faults[mem_idx] += diff; + p->numa_group->faults_cpu[mem_idx] += f_diff; + p->numa_group->total_faults += diff; + group_faults += p->numa_group->faults[mem_idx]; + } + } + + if (faults > max_faults) { + max_faults = faults; + max_nid = nid; + } + + if (group_faults > max_group_faults) { + max_group_faults = group_faults; + max_group_nid = nid; + } + } + + update_task_scan_period(p, fault_types[0], fault_types[1]); + + if (p->numa_group) { + update_numa_active_node_mask(p->numa_group); + spin_unlock_irq(group_lock); + max_nid = preferred_group_nid(p, max_group_nid); + } + + if (max_faults) { + /* Set the new preferred node */ + if (max_nid != p->numa_preferred_nid) + sched_setnuma(p, max_nid); + + if (task_node(p) != p->numa_preferred_nid) + numa_migrate_preferred(p); + } +} + +static inline int get_numa_group(struct numa_group *grp) +{ + return atomic_inc_not_zero(&grp->refcount); +} + +static inline void put_numa_group(struct numa_group *grp) +{ + if (atomic_dec_and_test(&grp->refcount)) + kfree_rcu(grp, rcu); +} + +static void task_numa_group(struct task_struct *p, int cpupid, int flags, + int *priv) +{ + struct numa_group *grp, *my_grp; + struct task_struct *tsk; + bool join = false; + int cpu = cpupid_to_cpu(cpupid); + int i; + + if (unlikely(!p->numa_group)) { + unsigned int size = sizeof(struct numa_group) + + 4*nr_node_ids*sizeof(unsigned long); + + grp = kzalloc(size, GFP_KERNEL | __GFP_NOWARN); + if (!grp) + return; + + atomic_set(&grp->refcount, 1); + spin_lock_init(&grp->lock); + grp->gid = p->pid; + /* Second half of the array tracks nids where faults happen */ + grp->faults_cpu = grp->faults + NR_NUMA_HINT_FAULT_TYPES * + nr_node_ids; + + node_set(task_node(current), grp->active_nodes); + + for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++) + grp->faults[i] = p->numa_faults[i]; + + grp->total_faults = p->total_numa_faults; + + grp->nr_tasks++; + rcu_assign_pointer(p->numa_group, grp); + } + + rcu_read_lock(); + tsk = READ_ONCE(cpu_rq(cpu)->curr); + + if (!cpupid_match_pid(tsk, cpupid)) + goto no_join; + + grp = rcu_dereference(tsk->numa_group); + if (!grp) + goto no_join; + + my_grp = p->numa_group; + if (grp == my_grp) + goto no_join; + + /* + * Only join the other group if its bigger; if we're the bigger group, + * the other task will join us. + */ + if (my_grp->nr_tasks > grp->nr_tasks) + goto no_join; + + /* + * Tie-break on the grp address. + */ + if (my_grp->nr_tasks == grp->nr_tasks && my_grp > grp) + goto no_join; + + /* Always join threads in the same process. */ + if (tsk->mm == current->mm) + join = true; + + /* Simple filter to avoid false positives due to PID collisions */ + if (flags & TNF_SHARED) + join = true; + + /* Update priv based on whether false sharing was detected */ + *priv = !join; + + if (join && !get_numa_group(grp)) + goto no_join; + + rcu_read_unlock(); + + if (!join) + return; + + BUG_ON(irqs_disabled()); + double_lock_irq(&my_grp->lock, &grp->lock); + + for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++) { + my_grp->faults[i] -= p->numa_faults[i]; + grp->faults[i] += p->numa_faults[i]; + } + my_grp->total_faults -= p->total_numa_faults; + grp->total_faults += p->total_numa_faults; + + my_grp->nr_tasks--; + grp->nr_tasks++; + + spin_unlock(&my_grp->lock); + spin_unlock_irq(&grp->lock); + + rcu_assign_pointer(p->numa_group, grp); + + put_numa_group(my_grp); + return; + +no_join: + rcu_read_unlock(); + return; +} + +/* + * Get rid of NUMA staticstics associated with a task (either current or dead). + * If @final is set, the task is dead and has reached refcount zero, so we can + * safely free all relevant data structures. Otherwise, there might be + * concurrent reads from places like load balancing and procfs, and we should + * reset the data back to default state without freeing ->numa_faults. + */ +void task_numa_free(struct task_struct *p, bool final) +{ + struct numa_group *grp = p->numa_group; + unsigned long *numa_faults = p->numa_faults; + unsigned long flags; + int i; + + if (!numa_faults) + return; + + if (grp) { + spin_lock_irqsave(&grp->lock, flags); + for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++) + grp->faults[i] -= p->numa_faults[i]; + grp->total_faults -= p->total_numa_faults; + + grp->nr_tasks--; + spin_unlock_irqrestore(&grp->lock, flags); + RCU_INIT_POINTER(p->numa_group, NULL); + put_numa_group(grp); + } + + if (final) { + p->numa_faults = NULL; + kfree(numa_faults); + } else { + p->total_numa_faults = 0; + for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++) + numa_faults[i] = 0; + } +} + +/* + * Got a PROT_NONE fault for a page on @node. + */ +void task_numa_fault(int last_cpupid, int mem_node, int pages, int flags) +{ + struct task_struct *p = current; + bool migrated = flags & TNF_MIGRATED; + int cpu_node = task_node(current); + int local = !!(flags & TNF_FAULT_LOCAL); + int priv; + + if (!static_branch_likely(&sched_numa_balancing)) + return; + + /* for example, ksmd faulting in a user's mm */ + if (!p->mm) + return; + + /* Allocate buffer to track faults on a per-node basis */ + if (unlikely(!p->numa_faults)) { + int size = sizeof(*p->numa_faults) * + NR_NUMA_HINT_FAULT_BUCKETS * nr_node_ids; + + p->numa_faults = kzalloc(size, GFP_KERNEL|__GFP_NOWARN); + if (!p->numa_faults) + return; + + p->total_numa_faults = 0; + memset(p->numa_faults_locality, 0, sizeof(p->numa_faults_locality)); + } + + /* + * First accesses are treated as private, otherwise consider accesses + * to be private if the accessing pid has not changed + */ + if (unlikely(last_cpupid == (-1 & LAST_CPUPID_MASK))) { + priv = 1; + } else { + priv = cpupid_match_pid(p, last_cpupid); + if (!priv && !(flags & TNF_NO_GROUP)) + task_numa_group(p, last_cpupid, flags, &priv); + } + + /* + * If a workload spans multiple NUMA nodes, a shared fault that + * occurs wholly within the set of nodes that the workload is + * actively using should be counted as local. This allows the + * scan rate to slow down when a workload has settled down. + */ + if (!priv && !local && p->numa_group && + node_isset(cpu_node, p->numa_group->active_nodes) && + node_isset(mem_node, p->numa_group->active_nodes)) + local = 1; + + task_numa_placement(p); + + /* + * Retry task to preferred node migration periodically, in case it + * case it previously failed, or the scheduler moved us. + */ + if (time_after(jiffies, p->numa_migrate_retry)) + numa_migrate_preferred(p); + + if (migrated) + p->numa_pages_migrated += pages; + if (flags & TNF_MIGRATE_FAIL) + p->numa_faults_locality[2] += pages; + + p->numa_faults[task_faults_idx(NUMA_MEMBUF, mem_node, priv)] += pages; + p->numa_faults[task_faults_idx(NUMA_CPUBUF, cpu_node, priv)] += pages; + p->numa_faults_locality[local] += pages; +} + +static void reset_ptenuma_scan(struct task_struct *p) +{ + /* + * We only did a read acquisition of the mmap sem, so + * p->mm->numa_scan_seq is written to without exclusive access + * and the update is not guaranteed to be atomic. That's not + * much of an issue though, since this is just used for + * statistical sampling. Use READ_ONCE/WRITE_ONCE, which are not + * expensive, to avoid any form of compiler optimizations: + */ + WRITE_ONCE(p->mm->numa_scan_seq, READ_ONCE(p->mm->numa_scan_seq) + 1); + p->mm->numa_scan_offset = 0; +} + +/* + * The expensive part of numa migration is done from task_work context. + * Triggered from task_tick_numa(). + */ +void task_numa_work(struct callback_head *work) +{ + unsigned long migrate, next_scan, now = jiffies; + struct task_struct *p = current; + struct mm_struct *mm = p->mm; + struct vm_area_struct *vma; + unsigned long start, end; + unsigned long nr_pte_updates = 0; + long pages, virtpages; + + WARN_ON_ONCE(p != container_of(work, struct task_struct, numa_work)); + + work->next = work; /* protect against double add */ + /* + * Who cares about NUMA placement when they're dying. + * + * NOTE: make sure not to dereference p->mm before this check, + * exit_task_work() happens _after_ exit_mm() so we could be called + * without p->mm even though we still had it when we enqueued this + * work. + */ + if (p->flags & PF_EXITING) + return; + + if (!mm->numa_next_scan) { + mm->numa_next_scan = now + + msecs_to_jiffies(sysctl_numa_balancing_scan_delay); + } + + /* + * Enforce maximal scan/migration frequency.. + */ + migrate = mm->numa_next_scan; + if (time_before(now, migrate)) + return; + + if (p->numa_scan_period == 0) { + p->numa_scan_period_max = task_scan_max(p); + p->numa_scan_period = task_scan_min(p); + } + + next_scan = now + msecs_to_jiffies(p->numa_scan_period); + if (cmpxchg(&mm->numa_next_scan, migrate, next_scan) != migrate) + return; + + /* + * Delay this task enough that another task of this mm will likely win + * the next time around. + */ + p->node_stamp += 2 * TICK_NSEC; + + start = mm->numa_scan_offset; + pages = sysctl_numa_balancing_scan_size; + pages <<= 20 - PAGE_SHIFT; /* MB in pages */ + virtpages = pages * 8; /* Scan up to this much virtual space */ + if (!pages) + return; + + + if (!down_read_trylock(&mm->mmap_sem)) + return; + vma = find_vma(mm, start); + if (!vma) { + reset_ptenuma_scan(p); + start = 0; + vma = mm->mmap; + } + for (; vma; vma = vma->vm_next) { + if (!vma_migratable(vma) || !vma_policy_mof(vma) || + is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_MIXEDMAP)) { + continue; + } + + /* + * Shared library pages mapped by multiple processes are not + * migrated as it is expected they are cache replicated. Avoid + * hinting faults in read-only file-backed mappings or the vdso + * as migrating the pages will be of marginal benefit. + */ + if (!vma->vm_mm || + (vma->vm_file && (vma->vm_flags & (VM_READ|VM_WRITE)) == (VM_READ))) + continue; + + /* + * Skip inaccessible VMAs to avoid any confusion between + * PROT_NONE and NUMA hinting ptes + */ + if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) + continue; + + do { + start = max(start, vma->vm_start); + end = ALIGN(start + (pages << PAGE_SHIFT), HPAGE_SIZE); + end = min(end, vma->vm_end); + nr_pte_updates = change_prot_numa(vma, start, end); + + /* + * Try to scan sysctl_numa_balancing_size worth of + * hpages that have at least one present PTE that + * is not already pte-numa. If the VMA contains + * areas that are unused or already full of prot_numa + * PTEs, scan up to virtpages, to skip through those + * areas faster. + */ + if (nr_pte_updates) + pages -= (end - start) >> PAGE_SHIFT; + virtpages -= (end - start) >> PAGE_SHIFT; + + start = end; + if (pages <= 0 || virtpages <= 0) + goto out; + + cond_resched(); + } while (end != vma->vm_end); + } + +out: + /* + * It is possible to reach the end of the VMA list but the last few + * VMAs are not guaranteed to the vma_migratable. If they are not, we + * would find the !migratable VMA on the next scan but not reset the + * scanner to the start so check it now. + */ + if (vma) + mm->numa_scan_offset = start; + else + reset_ptenuma_scan(p); + up_read(&mm->mmap_sem); +} + +/* + * Drive the periodic memory faults.. + */ +void task_tick_numa(struct rq *rq, struct task_struct *curr) +{ + struct callback_head *work = &curr->numa_work; + u64 period, now; + + /* + * We don't care about NUMA placement if we don't have memory. + */ + if ((curr->flags & (PF_EXITING | PF_KTHREAD)) || work->next != work) + return; + + /* + * Using runtime rather than walltime has the dual advantage that + * we (mostly) drive the selection from busy threads and that the + * task needs to have done some actual work before we bother with + * NUMA placement. + */ + now = curr->se.sum_exec_runtime; + period = (u64)curr->numa_scan_period * NSEC_PER_MSEC; + + if (now > curr->node_stamp + period) { + if (!curr->node_stamp) + curr->numa_scan_period = task_scan_min(curr); + curr->node_stamp += period; + + if (!time_before(jiffies, curr->mm->numa_next_scan)) { + init_task_work(work, task_numa_work); /* TODO: move this into sched_fork() */ + task_work_add(curr, work, true); + } + } +} +#else +static void task_tick_numa(struct rq *rq, struct task_struct *curr) +{ +} + +static inline void account_numa_enqueue(struct rq *rq, struct task_struct *p) +{ +} + +static inline void account_numa_dequeue(struct rq *rq, struct task_struct *p) +{ +} +#endif /* CONFIG_NUMA_BALANCING */ + +static void +account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + update_load_add(&cfs_rq->load, se->load.weight); + if (!parent_entity(se)) + update_load_add(&rq_of(cfs_rq)->load, se->load.weight); +#ifdef CONFIG_SMP + if (entity_is_task(se)) { + struct rq *rq = rq_of(cfs_rq); + + account_numa_enqueue(rq, task_of(se)); + list_add(&se->group_node, &rq->cfs_tasks); + } +#endif + cfs_rq->nr_running++; +} + +static void +account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + update_load_sub(&cfs_rq->load, se->load.weight); + if (!parent_entity(se)) + update_load_sub(&rq_of(cfs_rq)->load, se->load.weight); + if (entity_is_task(se)) { + account_numa_dequeue(rq_of(cfs_rq), task_of(se)); + list_del_init(&se->group_node); + } + cfs_rq->nr_running--; +} + +#ifdef CONFIG_FAIR_GROUP_SCHED +# ifdef CONFIG_SMP +static long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg) +{ + long tg_weight, load, shares; + + /* + * This really should be: cfs_rq->avg.load_avg, but instead we use + * cfs_rq->load.weight, which is its upper bound. This helps ramp up + * the shares for small weight interactive tasks. + */ + load = scale_load_down(cfs_rq->load.weight); + + tg_weight = atomic_long_read(&tg->load_avg); + + /* Ensure tg_weight >= load */ + tg_weight -= cfs_rq->tg_load_avg_contrib; + tg_weight += load; + + shares = (tg->shares * load); + if (tg_weight) + shares /= tg_weight; + + if (shares < MIN_SHARES) + shares = MIN_SHARES; + if (shares > tg->shares) + shares = tg->shares; + + return shares; +} +# else /* CONFIG_SMP */ +static inline long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg) +{ + return tg->shares; +} +# endif /* CONFIG_SMP */ + +static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, + unsigned long weight) +{ + if (se->on_rq) { + /* commit outstanding execution time */ + if (cfs_rq->curr == se) + update_curr(cfs_rq); + account_entity_dequeue(cfs_rq, se); + } + + update_load_set(&se->load, weight); + + if (se->on_rq) + account_entity_enqueue(cfs_rq, se); +} + +static inline int throttled_hierarchy(struct cfs_rq *cfs_rq); + +static void update_cfs_shares(struct sched_entity *se) +{ + struct cfs_rq *cfs_rq = group_cfs_rq(se); + struct task_group *tg; + long shares; + + if (!cfs_rq) + return; + + if (throttled_hierarchy(cfs_rq)) + return; + + tg = cfs_rq->tg; + +#ifndef CONFIG_SMP + if (likely(se->load.weight == tg->shares)) + return; +#endif + shares = calc_cfs_shares(cfs_rq, tg); + + reweight_entity(cfs_rq_of(se), se, shares); +} + +#else /* CONFIG_FAIR_GROUP_SCHED */ +static inline void update_cfs_shares(struct sched_entity *se) +{ +} +#endif /* CONFIG_FAIR_GROUP_SCHED */ + +#ifdef CONFIG_SMP +u32 sched_get_wake_up_idle(struct task_struct *p) +{ + u32 enabled = p->flags & PF_WAKE_UP_IDLE; + + return !!enabled; +} +EXPORT_SYMBOL(sched_get_wake_up_idle); + +int sched_set_wake_up_idle(struct task_struct *p, int wake_up_idle) +{ + int enable = !!wake_up_idle; + + if (enable) + p->flags |= PF_WAKE_UP_IDLE; + else + p->flags &= ~PF_WAKE_UP_IDLE; + + return 0; +} +EXPORT_SYMBOL(sched_set_wake_up_idle); + +static const u32 runnable_avg_yN_inv[] = { + 0xffffffff, 0xfa83b2da, 0xf5257d14, 0xefe4b99a, 0xeac0c6e6, 0xe5b906e6, + 0xe0ccdeeb, 0xdbfbb796, 0xd744fcc9, 0xd2a81d91, 0xce248c14, 0xc9b9bd85, + 0xc5672a10, 0xc12c4cc9, 0xbd08a39e, 0xb8fbaf46, 0xb504f333, 0xb123f581, + 0xad583ee9, 0xa9a15ab4, 0xa5fed6a9, 0xa2704302, 0x9ef5325f, 0x9b8d39b9, + 0x9837f050, 0x94f4efa8, 0x91c3d373, 0x8ea4398a, 0x8b95c1e3, 0x88980e80, + 0x85aac367, 0x82cd8698, +}; + +/* + * Precomputed \Sum y^k { 1<=k<=n }. These are floor(true_value) to prevent + * over-estimates when re-combining. + */ +static const u32 runnable_avg_yN_sum[] = { + 0, 1002, 1982, 2941, 3880, 4798, 5697, 6576, 7437, 8279, 9103, + 9909,10698,11470,12226,12966,13690,14398,15091,15769,16433,17082, + 17718,18340,18949,19545,20128,20698,21256,21802,22336,22859,23371, +}; + +/* + * Approximate: + * val * y^n, where y^32 ~= 0.5 (~1 scheduling period) + */ +static __always_inline u64 decay_load(u64 val, u64 n) +{ + unsigned int local_n; + + if (!n) + return val; + else if (unlikely(n > LOAD_AVG_PERIOD * 63)) + return 0; + + /* after bounds checking we can collapse to 32-bit */ + local_n = n; + + /* + * As y^PERIOD = 1/2, we can combine + * y^n = 1/2^(n/PERIOD) * y^(n%PERIOD) + * With a look-up table which covers y^n (n<PERIOD) + * + * To achieve constant time decay_load. + */ + if (unlikely(local_n >= LOAD_AVG_PERIOD)) { + val >>= local_n / LOAD_AVG_PERIOD; + local_n %= LOAD_AVG_PERIOD; + } + + val = mul_u64_u32_shr(val, runnable_avg_yN_inv[local_n], 32); + return val; +} + +/* + * For updates fully spanning n periods, the contribution to runnable + * average will be: \Sum 1024*y^n + * + * We can compute this reasonably efficiently by combining: + * y^PERIOD = 1/2 with precomputed \Sum 1024*y^n {for n <PERIOD} + */ +static u32 __compute_runnable_contrib(u64 n) +{ + u32 contrib = 0; + + if (likely(n <= LOAD_AVG_PERIOD)) + return runnable_avg_yN_sum[n]; + else if (unlikely(n >= LOAD_AVG_MAX_N)) + return LOAD_AVG_MAX; + + /* Compute \Sum k^n combining precomputed values for k^i, \Sum k^j */ + do { + contrib /= 2; /* y^LOAD_AVG_PERIOD = 1/2 */ + contrib += runnable_avg_yN_sum[LOAD_AVG_PERIOD]; + + n -= LOAD_AVG_PERIOD; + } while (n > LOAD_AVG_PERIOD); + + contrib = decay_load(contrib, n); + return contrib + runnable_avg_yN_sum[n]; +} + +#ifdef CONFIG_SCHED_HMP + +/* CPU selection flag */ +#define SBC_FLAG_PREV_CPU 0x1 +#define SBC_FLAG_BEST_CAP_CPU 0x2 +#define SBC_FLAG_CPU_COST 0x4 +#define SBC_FLAG_MIN_COST 0x8 +#define SBC_FLAG_IDLE_LEAST_LOADED 0x10 +#define SBC_FLAG_IDLE_CSTATE 0x20 +#define SBC_FLAG_COST_CSTATE_TIE_BREAKER 0x40 +#define SBC_FLAG_COST_CSTATE_PREV_CPU_TIE_BREAKER 0x80 +#define SBC_FLAG_CSTATE_LOAD 0x100 +#define SBC_FLAG_BEST_SIBLING 0x200 +#define SBC_FLAG_WAKER_CPU 0x400 +#define SBC_FLAG_PACK_TASK 0x800 + +/* Cluster selection flag */ +#define SBC_FLAG_COLOC_CLUSTER 0x10000 +#define SBC_FLAG_WAKER_CLUSTER 0x20000 +#define SBC_FLAG_BACKUP_CLUSTER 0x40000 +#define SBC_FLAG_BOOST_CLUSTER 0x80000 + +struct cpu_select_env { + struct task_struct *p; + struct related_thread_group *rtg; + u8 reason; + u8 need_idle:1; + u8 need_waker_cluster:1; + u8 sync:1; + enum sched_boost_policy boost_policy; + u8 pack_task:1; + int prev_cpu; + DECLARE_BITMAP(candidate_list, NR_CPUS); + DECLARE_BITMAP(backup_list, NR_CPUS); + u64 task_load; + u64 cpu_load; + u32 sbc_best_flag; + u32 sbc_best_cluster_flag; + struct cpumask search_cpus; +}; + +struct cluster_cpu_stats { + int best_idle_cpu, least_loaded_cpu; + int best_capacity_cpu, best_cpu, best_sibling_cpu; + int min_cost, best_sibling_cpu_cost; + int best_cpu_wakeup_latency; + u64 min_load, best_load, best_sibling_cpu_load; + s64 highest_spare_capacity; +}; + +/* + * Should task be woken to any available idle cpu? + * + * Waking tasks to idle cpu has mixed implications on both performance and + * power. In many cases, scheduler can't estimate correctly impact of using idle + * cpus on either performance or power. PF_WAKE_UP_IDLE allows external kernel + * module to pass a strong hint to scheduler that the task in question should be + * woken to idle cpu, generally to improve performance. + */ +static inline int wake_to_idle(struct task_struct *p) +{ + return (current->flags & PF_WAKE_UP_IDLE) || + (p->flags & PF_WAKE_UP_IDLE); +} + +static int spill_threshold_crossed(struct cpu_select_env *env, struct rq *rq) +{ + u64 total_load; + + total_load = env->task_load + env->cpu_load; + + if (total_load > sched_spill_load || + (rq->nr_running + 1) > sysctl_sched_spill_nr_run) + return 1; + + return 0; +} + +static int skip_cpu(int cpu, struct cpu_select_env *env) +{ + int tcpu = task_cpu(env->p); + int skip = 0; + + if (!env->reason) + return 0; + + if (is_reserved(cpu)) + return 1; + + switch (env->reason) { + case UP_MIGRATION: + skip = !idle_cpu(cpu); + break; + case IRQLOAD_MIGRATION: + /* Purposely fall through */ + default: + skip = (cpu == tcpu); + break; + } + + return skip; +} + +static inline int +acceptable_capacity(struct sched_cluster *cluster, struct cpu_select_env *env) +{ + int tcpu; + + if (!env->reason) + return 1; + + tcpu = task_cpu(env->p); + switch (env->reason) { + case UP_MIGRATION: + return cluster->capacity > cpu_capacity(tcpu); + + case DOWN_MIGRATION: + return cluster->capacity < cpu_capacity(tcpu); + + default: + break; + } + + return 1; +} + +static int +skip_cluster(struct sched_cluster *cluster, struct cpu_select_env *env) +{ + if (!test_bit(cluster->id, env->candidate_list)) + return 1; + + if (!acceptable_capacity(cluster, env)) { + __clear_bit(cluster->id, env->candidate_list); + return 1; + } + + return 0; +} + +static struct sched_cluster * +select_least_power_cluster(struct cpu_select_env *env) +{ + struct sched_cluster *cluster; + + if (env->rtg) { + int cpu = cluster_first_cpu(env->rtg->preferred_cluster); + + env->task_load = scale_load_to_cpu(task_load(env->p), cpu); + + if (task_load_will_fit(env->p, env->task_load, + cpu, env->boost_policy)) { + env->sbc_best_cluster_flag |= SBC_FLAG_COLOC_CLUSTER; + + if (env->boost_policy == SCHED_BOOST_NONE) + return env->rtg->preferred_cluster; + + for_each_sched_cluster(cluster) { + if (cluster != env->rtg->preferred_cluster) { + __set_bit(cluster->id, + env->backup_list); + __clear_bit(cluster->id, + env->candidate_list); + } + } + + return env->rtg->preferred_cluster; + } + + /* + * Since the task load does not fit on the preferred + * cluster anymore, pretend that the task does not + * have any preferred cluster. This allows the waking + * task to get the appropriate CPU it needs as per the + * non co-location placement policy without having to + * wait until the preferred cluster is updated. + */ + env->rtg = NULL; + } + + for_each_sched_cluster(cluster) { + if (!skip_cluster(cluster, env)) { + int cpu = cluster_first_cpu(cluster); + + env->task_load = scale_load_to_cpu(task_load(env->p), + cpu); + if (task_load_will_fit(env->p, env->task_load, cpu, + env->boost_policy)) + return cluster; + + __set_bit(cluster->id, env->backup_list); + __clear_bit(cluster->id, env->candidate_list); + } + } + + return NULL; +} + +static struct sched_cluster * +next_candidate(const unsigned long *list, int start, int end) +{ + int cluster_id; + + cluster_id = find_next_bit(list, end, start - 1 + 1); + if (cluster_id >= end) + return NULL; + + return sched_cluster[cluster_id]; +} + +static void +update_spare_capacity(struct cluster_cpu_stats *stats, + struct cpu_select_env *env, int cpu, int capacity, + u64 cpu_load) +{ + s64 spare_capacity = sched_ravg_window - cpu_load; + + if (spare_capacity > 0 && + (spare_capacity > stats->highest_spare_capacity || + (spare_capacity == stats->highest_spare_capacity && + ((!env->need_waker_cluster && + capacity > cpu_capacity(stats->best_capacity_cpu)) || + (env->need_waker_cluster && + cpu_rq(cpu)->nr_running < + cpu_rq(stats->best_capacity_cpu)->nr_running))))) { + /* + * If sync waker is the only runnable of CPU, cr_avg of the + * CPU is 0 so we have high chance to place the wakee on the + * waker's CPU which likely causes preemtion of the waker. + * This can lead migration of preempted waker. Place the + * wakee on the real idle CPU when it's possible by checking + * nr_running to avoid such preemption. + */ + stats->highest_spare_capacity = spare_capacity; + stats->best_capacity_cpu = cpu; + } +} + +static inline void find_backup_cluster( +struct cpu_select_env *env, struct cluster_cpu_stats *stats) +{ + struct sched_cluster *next = NULL; + int i; + struct cpumask search_cpus; + + extern int num_clusters; + + while (!bitmap_empty(env->backup_list, num_clusters)) { + next = next_candidate(env->backup_list, 0, num_clusters); + __clear_bit(next->id, env->backup_list); + + cpumask_and(&search_cpus, &env->search_cpus, &next->cpus); + for_each_cpu(i, &search_cpus) { + trace_sched_cpu_load_wakeup(cpu_rq(i), idle_cpu(i), + sched_irqload(i), power_cost(i, task_load(env->p) + + cpu_cravg_sync(i, env->sync)), 0); + + update_spare_capacity(stats, env, i, next->capacity, + cpu_load_sync(i, env->sync)); + } + env->sbc_best_cluster_flag = SBC_FLAG_BACKUP_CLUSTER; + } +} + +struct sched_cluster * +next_best_cluster(struct sched_cluster *cluster, struct cpu_select_env *env, + struct cluster_cpu_stats *stats) +{ + struct sched_cluster *next = NULL; + + extern int num_clusters; + + __clear_bit(cluster->id, env->candidate_list); + + if (env->rtg && preferred_cluster(cluster, env->p)) + return NULL; + + do { + if (bitmap_empty(env->candidate_list, num_clusters)) + return NULL; + + next = next_candidate(env->candidate_list, 0, num_clusters); + if (next) { + if (next->min_power_cost > stats->min_cost) { + clear_bit(next->id, env->candidate_list); + next = NULL; + continue; + } + + if (skip_cluster(next, env)) + next = NULL; + } + } while (!next); + + env->task_load = scale_load_to_cpu(task_load(env->p), + cluster_first_cpu(next)); + return next; +} + +#ifdef CONFIG_SCHED_HMP_CSTATE_AWARE +static void __update_cluster_stats(int cpu, struct cluster_cpu_stats *stats, + struct cpu_select_env *env, int cpu_cost) +{ + int wakeup_latency; + int prev_cpu = env->prev_cpu; + + wakeup_latency = cpu_rq(cpu)->wakeup_latency; + + if (env->need_idle) { + stats->min_cost = cpu_cost; + if (idle_cpu(cpu)) { + if (wakeup_latency < stats->best_cpu_wakeup_latency || + (wakeup_latency == stats->best_cpu_wakeup_latency && + cpu == prev_cpu)) { + stats->best_idle_cpu = cpu; + stats->best_cpu_wakeup_latency = wakeup_latency; + } + } else { + if (env->cpu_load < stats->min_load || + (env->cpu_load == stats->min_load && + cpu == prev_cpu)) { + stats->least_loaded_cpu = cpu; + stats->min_load = env->cpu_load; + } + } + + return; + } + + if (cpu_cost < stats->min_cost) { + stats->min_cost = cpu_cost; + stats->best_cpu_wakeup_latency = wakeup_latency; + stats->best_load = env->cpu_load; + stats->best_cpu = cpu; + env->sbc_best_flag = SBC_FLAG_CPU_COST; + return; + } + + /* CPU cost is the same. Start breaking the tie by C-state */ + + if (wakeup_latency > stats->best_cpu_wakeup_latency) + return; + + if (wakeup_latency < stats->best_cpu_wakeup_latency) { + stats->best_cpu_wakeup_latency = wakeup_latency; + stats->best_load = env->cpu_load; + stats->best_cpu = cpu; + env->sbc_best_flag = SBC_FLAG_COST_CSTATE_TIE_BREAKER; + return; + } + + /* C-state is the same. Use prev CPU to break the tie */ + if (cpu == prev_cpu) { + stats->best_cpu = cpu; + env->sbc_best_flag = SBC_FLAG_COST_CSTATE_PREV_CPU_TIE_BREAKER; + return; + } + + if (stats->best_cpu != prev_cpu && + ((wakeup_latency == 0 && env->cpu_load < stats->best_load) || + (wakeup_latency > 0 && env->cpu_load > stats->best_load))) { + stats->best_load = env->cpu_load; + stats->best_cpu = cpu; + env->sbc_best_flag = SBC_FLAG_CSTATE_LOAD; + } +} +#else /* CONFIG_SCHED_HMP_CSTATE_AWARE */ +static void __update_cluster_stats(int cpu, struct cluster_cpu_stats *stats, + struct cpu_select_env *env, int cpu_cost) +{ + int prev_cpu = env->prev_cpu; + + if (cpu != prev_cpu && cpus_share_cache(prev_cpu, cpu)) { + if (stats->best_sibling_cpu_cost > cpu_cost || + (stats->best_sibling_cpu_cost == cpu_cost && + stats->best_sibling_cpu_load > env->cpu_load)) { + stats->best_sibling_cpu_cost = cpu_cost; + stats->best_sibling_cpu_load = env->cpu_load; + stats->best_sibling_cpu = cpu; + } + } + + if ((cpu_cost < stats->min_cost) || + ((stats->best_cpu != prev_cpu && + stats->min_load > env->cpu_load) || cpu == prev_cpu)) { + if (env->need_idle) { + if (idle_cpu(cpu)) { + stats->min_cost = cpu_cost; + stats->best_idle_cpu = cpu; + } + } else { + stats->min_cost = cpu_cost; + stats->min_load = env->cpu_load; + stats->best_cpu = cpu; + env->sbc_best_flag = SBC_FLAG_MIN_COST; + } + } +} +#endif /* CONFIG_SCHED_HMP_CSTATE_AWARE */ + +static void update_cluster_stats(int cpu, struct cluster_cpu_stats *stats, + struct cpu_select_env *env) +{ + int cpu_cost; + + /* + * We try to find the least loaded *busy* CPU irrespective + * of the power cost. + */ + if (env->pack_task) + cpu_cost = cpu_min_power_cost(cpu); + + else + cpu_cost = power_cost(cpu, task_load(env->p) + + cpu_cravg_sync(cpu, env->sync)); + + if (cpu_cost <= stats->min_cost) + __update_cluster_stats(cpu, stats, env, cpu_cost); +} + +static void find_best_cpu_in_cluster(struct sched_cluster *c, + struct cpu_select_env *env, struct cluster_cpu_stats *stats) +{ + int i; + struct cpumask search_cpus; + + cpumask_and(&search_cpus, &env->search_cpus, &c->cpus); + + env->need_idle = wake_to_idle(env->p) || c->wake_up_idle; + + for_each_cpu(i, &search_cpus) { + env->cpu_load = cpu_load_sync(i, env->sync); + + trace_sched_cpu_load_wakeup(cpu_rq(i), idle_cpu(i), + sched_irqload(i), + power_cost(i, task_load(env->p) + + cpu_cravg_sync(i, env->sync)), 0); + + if (skip_cpu(i, env)) + continue; + + update_spare_capacity(stats, env, i, c->capacity, + env->cpu_load); + + /* + * need_idle takes precedence over sched boost but when both + * are set, idlest CPU with in all the clusters is selected + * when boost_policy = BOOST_ON_ALL whereas idlest CPU in the + * big cluster is selected within boost_policy = BOOST_ON_BIG. + */ + if ((!env->need_idle && + env->boost_policy != SCHED_BOOST_NONE) || + env->need_waker_cluster || + sched_cpu_high_irqload(i) || + spill_threshold_crossed(env, cpu_rq(i))) + continue; + + update_cluster_stats(i, stats, env); + } +} + +static inline void init_cluster_cpu_stats(struct cluster_cpu_stats *stats) +{ + stats->best_cpu = stats->best_idle_cpu = -1; + stats->best_capacity_cpu = stats->best_sibling_cpu = -1; + stats->min_cost = stats->best_sibling_cpu_cost = INT_MAX; + stats->min_load = stats->best_sibling_cpu_load = ULLONG_MAX; + stats->highest_spare_capacity = 0; + stats->least_loaded_cpu = -1; + stats->best_cpu_wakeup_latency = INT_MAX; + /* No need to initialize stats->best_load */ +} + +static inline bool env_has_special_flags(struct cpu_select_env *env) +{ + if (env->need_idle || env->boost_policy != SCHED_BOOST_NONE || + env->reason) + return true; + + return false; +} + +static inline bool +bias_to_prev_cpu(struct cpu_select_env *env, struct cluster_cpu_stats *stats) +{ + int prev_cpu; + struct task_struct *task = env->p; + struct sched_cluster *cluster; + + if (!task->ravg.mark_start || !sched_short_sleep_task_threshold) + return false; + + prev_cpu = env->prev_cpu; + if (!cpumask_test_cpu(prev_cpu, &env->search_cpus)) + return false; + + if (task->ravg.mark_start - task->last_cpu_selected_ts >= + sched_long_cpu_selection_threshold) + return false; + + /* + * This function should be used by task wake up path only as it's + * assuming p->last_switch_out_ts as last sleep time. + * p->last_switch_out_ts can denote last preemption time as well as + * last sleep time. + */ + if (task->ravg.mark_start - task->last_switch_out_ts >= + sched_short_sleep_task_threshold) + return false; + + env->task_load = scale_load_to_cpu(task_load(task), prev_cpu); + cluster = cpu_rq(prev_cpu)->cluster; + + if (!task_load_will_fit(task, env->task_load, prev_cpu, + sched_boost_policy())) { + + __set_bit(cluster->id, env->backup_list); + __clear_bit(cluster->id, env->candidate_list); + return false; + } + + env->cpu_load = cpu_load_sync(prev_cpu, env->sync); + if (sched_cpu_high_irqload(prev_cpu) || + spill_threshold_crossed(env, cpu_rq(prev_cpu))) { + update_spare_capacity(stats, env, prev_cpu, + cluster->capacity, env->cpu_load); + cpumask_clear_cpu(prev_cpu, &env->search_cpus); + return false; + } + + return true; +} + +static inline bool +wake_to_waker_cluster(struct cpu_select_env *env) +{ + return env->sync && + task_load(current) > sched_big_waker_task_load && + task_load(env->p) < sched_small_wakee_task_load; +} + +static inline bool +bias_to_waker_cpu(struct cpu_select_env *env, int cpu) +{ + return sysctl_sched_prefer_sync_wakee_to_waker && + cpu_rq(cpu)->nr_running == 1 && + cpumask_test_cpu(cpu, &env->search_cpus); +} + +static inline int +cluster_allowed(struct cpu_select_env *env, struct sched_cluster *cluster) +{ + return cpumask_intersects(&env->search_cpus, &cluster->cpus); +} + +/* return cheapest cpu that can fit this task */ +static int select_best_cpu(struct task_struct *p, int target, int reason, + int sync) +{ + struct sched_cluster *cluster, *pref_cluster = NULL; + struct cluster_cpu_stats stats; + struct related_thread_group *grp; + unsigned int sbc_flag = 0; + int cpu = raw_smp_processor_id(); + bool special; + + struct cpu_select_env env = { + .p = p, + .reason = reason, + .need_idle = wake_to_idle(p), + .need_waker_cluster = 0, + .sync = sync, + .prev_cpu = target, + .rtg = NULL, + .sbc_best_flag = 0, + .sbc_best_cluster_flag = 0, + .pack_task = false, + }; + + env.boost_policy = task_sched_boost(p) ? + sched_boost_policy() : SCHED_BOOST_NONE; + + bitmap_copy(env.candidate_list, all_cluster_ids, NR_CPUS); + bitmap_zero(env.backup_list, NR_CPUS); + + cpumask_and(&env.search_cpus, tsk_cpus_allowed(p), cpu_active_mask); + cpumask_andnot(&env.search_cpus, &env.search_cpus, cpu_isolated_mask); + + init_cluster_cpu_stats(&stats); + special = env_has_special_flags(&env); + + rcu_read_lock(); + + grp = task_related_thread_group(p); + + if (grp && grp->preferred_cluster) { + pref_cluster = grp->preferred_cluster; + if (!cluster_allowed(&env, pref_cluster)) + clear_bit(pref_cluster->id, env.candidate_list); + else + env.rtg = grp; + } else if (!special) { + cluster = cpu_rq(cpu)->cluster; + if (wake_to_waker_cluster(&env)) { + if (bias_to_waker_cpu(&env, cpu)) { + target = cpu; + sbc_flag = SBC_FLAG_WAKER_CLUSTER | + SBC_FLAG_WAKER_CPU; + goto out; + } else if (cluster_allowed(&env, cluster)) { + env.need_waker_cluster = 1; + bitmap_zero(env.candidate_list, NR_CPUS); + __set_bit(cluster->id, env.candidate_list); + env.sbc_best_cluster_flag = + SBC_FLAG_WAKER_CLUSTER; + } + } else if (bias_to_prev_cpu(&env, &stats)) { + sbc_flag = SBC_FLAG_PREV_CPU; + goto out; + } + } + + if (!special && is_short_burst_task(p)) { + env.pack_task = true; + sbc_flag = SBC_FLAG_PACK_TASK; + } +retry: + cluster = select_least_power_cluster(&env); + + if (!cluster) + goto out; + + /* + * 'cluster' now points to the minimum power cluster which can satisfy + * task's perf goals. Walk down the cluster list starting with that + * cluster. For non-small tasks, skip clusters that don't have + * mostly_idle/idle cpus + */ + + do { + find_best_cpu_in_cluster(cluster, &env, &stats); + + } while ((cluster = next_best_cluster(cluster, &env, &stats))); + + if (env.need_idle) { + if (stats.best_idle_cpu >= 0) { + target = stats.best_idle_cpu; + sbc_flag |= SBC_FLAG_IDLE_CSTATE; + } else if (stats.least_loaded_cpu >= 0) { + target = stats.least_loaded_cpu; + sbc_flag |= SBC_FLAG_IDLE_LEAST_LOADED; + } + } else if (stats.best_cpu >= 0) { + if (stats.best_sibling_cpu >= 0 && + stats.best_cpu != task_cpu(p) && + stats.min_cost == stats.best_sibling_cpu_cost) { + stats.best_cpu = stats.best_sibling_cpu; + sbc_flag |= SBC_FLAG_BEST_SIBLING; + } + sbc_flag |= env.sbc_best_flag; + target = stats.best_cpu; + } else { + if (env.rtg && env.boost_policy == SCHED_BOOST_NONE) { + env.rtg = NULL; + goto retry; + } + + /* + * With boost_policy == SCHED_BOOST_ON_BIG, we reach here with + * backup_list = little cluster, candidate_list = none and + * stats->best_capacity_cpu points the best spare capacity + * CPU among the CPUs in the big cluster. + */ + if (env.boost_policy == SCHED_BOOST_ON_BIG && + stats.best_capacity_cpu >= 0) + sbc_flag |= SBC_FLAG_BOOST_CLUSTER; + else + find_backup_cluster(&env, &stats); + + if (stats.best_capacity_cpu >= 0) { + target = stats.best_capacity_cpu; + sbc_flag |= SBC_FLAG_BEST_CAP_CPU; + } + } + p->last_cpu_selected_ts = sched_ktime_clock(); +out: + sbc_flag |= env.sbc_best_cluster_flag; + rcu_read_unlock(); + trace_sched_task_load(p, sched_boost_policy() && task_sched_boost(p), + env.reason, env.sync, env.need_idle, sbc_flag, target); + return target; +} + +#ifdef CONFIG_CFS_BANDWIDTH + +static inline struct task_group *next_task_group(struct task_group *tg) +{ + tg = list_entry_rcu(tg->list.next, typeof(struct task_group), list); + + return (&tg->list == &task_groups) ? NULL : tg; +} + +/* Iterate over all cfs_rq in a cpu */ +#define for_each_cfs_rq(cfs_rq, tg, cpu) \ + for (tg = container_of(&task_groups, struct task_group, list); \ + ((tg = next_task_group(tg)) && (cfs_rq = tg->cfs_rq[cpu]));) + +void reset_cfs_rq_hmp_stats(int cpu, int reset_cra) +{ + struct task_group *tg; + struct cfs_rq *cfs_rq; + + rcu_read_lock(); + + for_each_cfs_rq(cfs_rq, tg, cpu) + reset_hmp_stats(&cfs_rq->hmp_stats, reset_cra); + + rcu_read_unlock(); +} + +static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq); + +static void inc_cfs_rq_hmp_stats(struct cfs_rq *cfs_rq, + struct task_struct *p, int change_cra); +static void dec_cfs_rq_hmp_stats(struct cfs_rq *cfs_rq, + struct task_struct *p, int change_cra); + +/* Add task's contribution to a cpu' HMP statistics */ +void _inc_hmp_sched_stats_fair(struct rq *rq, + struct task_struct *p, int change_cra) +{ + struct cfs_rq *cfs_rq; + struct sched_entity *se = &p->se; + + /* + * Although below check is not strictly required (as + * inc/dec_nr_big_task and inc/dec_cumulative_runnable_avg called + * from inc_cfs_rq_hmp_stats() have similar checks), we gain a bit on + * efficiency by short-circuiting for_each_sched_entity() loop when + * sched_disable_window_stats + */ + if (sched_disable_window_stats) + return; + + for_each_sched_entity(se) { + cfs_rq = cfs_rq_of(se); + inc_cfs_rq_hmp_stats(cfs_rq, p, change_cra); + if (cfs_rq_throttled(cfs_rq)) + break; + } + + /* Update rq->hmp_stats only if we didn't find any throttled cfs_rq */ + if (!se) + inc_rq_hmp_stats(rq, p, change_cra); +} + +/* Remove task's contribution from a cpu' HMP statistics */ +static void +_dec_hmp_sched_stats_fair(struct rq *rq, struct task_struct *p, int change_cra) +{ + struct cfs_rq *cfs_rq; + struct sched_entity *se = &p->se; + + /* See comment on efficiency in _inc_hmp_sched_stats_fair */ + if (sched_disable_window_stats) + return; + + for_each_sched_entity(se) { + cfs_rq = cfs_rq_of(se); + dec_cfs_rq_hmp_stats(cfs_rq, p, change_cra); + if (cfs_rq_throttled(cfs_rq)) + break; + } + + /* Update rq->hmp_stats only if we didn't find any throttled cfs_rq */ + if (!se) + dec_rq_hmp_stats(rq, p, change_cra); +} + +static void inc_hmp_sched_stats_fair(struct rq *rq, struct task_struct *p) +{ + _inc_hmp_sched_stats_fair(rq, p, 1); +} + +static void dec_hmp_sched_stats_fair(struct rq *rq, struct task_struct *p) +{ + _dec_hmp_sched_stats_fair(rq, p, 1); +} + +static void fixup_hmp_sched_stats_fair(struct rq *rq, struct task_struct *p, + u32 new_task_load, u32 new_pred_demand) +{ + struct cfs_rq *cfs_rq; + struct sched_entity *se = &p->se; + s64 task_load_delta = (s64)new_task_load - task_load(p); + s64 pred_demand_delta = PRED_DEMAND_DELTA; + + for_each_sched_entity(se) { + cfs_rq = cfs_rq_of(se); + + fixup_cumulative_runnable_avg(&cfs_rq->hmp_stats, p, + task_load_delta, + pred_demand_delta); + fixup_nr_big_tasks(&cfs_rq->hmp_stats, p, task_load_delta); + if (cfs_rq_throttled(cfs_rq)) + break; + } + + /* Fix up rq->hmp_stats only if we didn't find any throttled cfs_rq */ + if (!se) { + fixup_cumulative_runnable_avg(&rq->hmp_stats, p, + task_load_delta, + pred_demand_delta); + fixup_nr_big_tasks(&rq->hmp_stats, p, task_load_delta); + } +} + +static int task_will_be_throttled(struct task_struct *p); + +#else /* CONFIG_CFS_BANDWIDTH */ + +inline void reset_cfs_rq_hmp_stats(int cpu, int reset_cra) { } + +static void +inc_hmp_sched_stats_fair(struct rq *rq, struct task_struct *p) +{ + inc_nr_big_task(&rq->hmp_stats, p); + inc_cumulative_runnable_avg(&rq->hmp_stats, p); +} + +static void +dec_hmp_sched_stats_fair(struct rq *rq, struct task_struct *p) +{ + dec_nr_big_task(&rq->hmp_stats, p); + dec_cumulative_runnable_avg(&rq->hmp_stats, p); +} +static void +fixup_hmp_sched_stats_fair(struct rq *rq, struct task_struct *p, + u32 new_task_load, u32 new_pred_demand) +{ + s64 task_load_delta = (s64)new_task_load - task_load(p); + s64 pred_demand_delta = PRED_DEMAND_DELTA; + + fixup_cumulative_runnable_avg(&rq->hmp_stats, p, task_load_delta, + pred_demand_delta); + fixup_nr_big_tasks(&rq->hmp_stats, p, task_load_delta); +} + +static inline int task_will_be_throttled(struct task_struct *p) +{ + return 0; +} + +void _inc_hmp_sched_stats_fair(struct rq *rq, + struct task_struct *p, int change_cra) +{ + inc_nr_big_task(&rq->hmp_stats, p); +} + +#endif /* CONFIG_CFS_BANDWIDTH */ + +/* + * Reset balance_interval at all sched_domain levels of given cpu, so that it + * honors kick. + */ +static inline void reset_balance_interval(int cpu) +{ + struct sched_domain *sd; + + if (cpu >= nr_cpu_ids) + return; + + rcu_read_lock(); + for_each_domain(cpu, sd) + sd->balance_interval = 0; + rcu_read_unlock(); +} + +/* + * Check if a task is on the "wrong" cpu (i.e its current cpu is not the ideal + * cpu as per its demand or priority) + * + * Returns reason why task needs to be migrated + */ +static inline int migration_needed(struct task_struct *p, int cpu) +{ + int nice; + struct related_thread_group *grp; + + if (p->state != TASK_RUNNING || p->nr_cpus_allowed == 1) + return 0; + + /* No need to migrate task that is about to be throttled */ + if (task_will_be_throttled(p)) + return 0; + + if (sched_boost_policy() == SCHED_BOOST_ON_BIG && + cpu_capacity(cpu) != max_capacity && task_sched_boost(p)) + return UP_MIGRATION; + + if (sched_cpu_high_irqload(cpu)) + return IRQLOAD_MIGRATION; + + nice = task_nice(p); + rcu_read_lock(); + grp = task_related_thread_group(p); + /* + * Don't assume higher capacity means higher power. If the task + * is running on the power efficient CPU, avoid migrating it + * to a lower capacity cluster. + */ + if (!grp && (nice > SCHED_UPMIGRATE_MIN_NICE || + upmigrate_discouraged(p)) && + cpu_capacity(cpu) > min_capacity && + cpu_max_power_cost(cpu) == max_power_cost) { + rcu_read_unlock(); + return DOWN_MIGRATION; + } + + if (!task_will_fit(p, cpu)) { + rcu_read_unlock(); + return UP_MIGRATION; + } + rcu_read_unlock(); + + return 0; +} + +static inline int +kick_active_balance(struct rq *rq, struct task_struct *p, int new_cpu) +{ + unsigned long flags; + int rc = 0; + + /* Invoke active balance to force migrate currently running task */ + raw_spin_lock_irqsave(&rq->lock, flags); + if (!rq->active_balance) { + rq->active_balance = 1; + rq->push_cpu = new_cpu; + get_task_struct(p); + rq->push_task = p; + rc = 1; + } + raw_spin_unlock_irqrestore(&rq->lock, flags); + + return rc; +} + +static DEFINE_RAW_SPINLOCK(migration_lock); + +static bool do_migration(int reason, int new_cpu, int cpu) +{ + if ((reason == UP_MIGRATION || reason == DOWN_MIGRATION) + && same_cluster(new_cpu, cpu)) + return false; + + /* Inter cluster high irqload migrations are OK */ + return new_cpu != cpu; +} + +/* + * Check if currently running task should be migrated to a better cpu. + * + * Todo: Effect this via changes to nohz_balancer_kick() and load balance? + */ +void check_for_migration(struct rq *rq, struct task_struct *p) +{ + int cpu = cpu_of(rq), new_cpu; + int active_balance = 0, reason; + + reason = migration_needed(p, cpu); + if (!reason) + return; + + raw_spin_lock(&migration_lock); + new_cpu = select_best_cpu(p, cpu, reason, 0); + + if (do_migration(reason, new_cpu, cpu)) { + active_balance = kick_active_balance(rq, p, new_cpu); + if (active_balance) + mark_reserved(new_cpu); + } + + raw_spin_unlock(&migration_lock); + + if (active_balance) + stop_one_cpu_nowait(cpu, active_load_balance_cpu_stop, rq, + &rq->active_balance_work); +} + +#ifdef CONFIG_CFS_BANDWIDTH + +static void init_cfs_rq_hmp_stats(struct cfs_rq *cfs_rq) +{ + cfs_rq->hmp_stats.nr_big_tasks = 0; + cfs_rq->hmp_stats.cumulative_runnable_avg = 0; + cfs_rq->hmp_stats.pred_demands_sum = 0; +} + +static void inc_cfs_rq_hmp_stats(struct cfs_rq *cfs_rq, + struct task_struct *p, int change_cra) +{ + inc_nr_big_task(&cfs_rq->hmp_stats, p); + if (change_cra) + inc_cumulative_runnable_avg(&cfs_rq->hmp_stats, p); +} + +static void dec_cfs_rq_hmp_stats(struct cfs_rq *cfs_rq, + struct task_struct *p, int change_cra) +{ + dec_nr_big_task(&cfs_rq->hmp_stats, p); + if (change_cra) + dec_cumulative_runnable_avg(&cfs_rq->hmp_stats, p); +} + +static void inc_throttled_cfs_rq_hmp_stats(struct hmp_sched_stats *stats, + struct cfs_rq *cfs_rq) +{ + stats->nr_big_tasks += cfs_rq->hmp_stats.nr_big_tasks; + stats->cumulative_runnable_avg += + cfs_rq->hmp_stats.cumulative_runnable_avg; + stats->pred_demands_sum += cfs_rq->hmp_stats.pred_demands_sum; +} + +static void dec_throttled_cfs_rq_hmp_stats(struct hmp_sched_stats *stats, + struct cfs_rq *cfs_rq) +{ + stats->nr_big_tasks -= cfs_rq->hmp_stats.nr_big_tasks; + stats->cumulative_runnable_avg -= + cfs_rq->hmp_stats.cumulative_runnable_avg; + stats->pred_demands_sum -= cfs_rq->hmp_stats.pred_demands_sum; + + BUG_ON(stats->nr_big_tasks < 0 || + (s64)stats->cumulative_runnable_avg < 0); + BUG_ON((s64)stats->pred_demands_sum < 0); +} + +#else /* CONFIG_CFS_BANDWIDTH */ + +static inline void inc_cfs_rq_hmp_stats(struct cfs_rq *cfs_rq, + struct task_struct *p, int change_cra) { } + +static inline void dec_cfs_rq_hmp_stats(struct cfs_rq *cfs_rq, + struct task_struct *p, int change_cra) { } + +#endif /* CONFIG_CFS_BANDWIDTH */ + +#else /* CONFIG_SCHED_HMP */ + +static inline void init_cfs_rq_hmp_stats(struct cfs_rq *cfs_rq) { } + +static inline void inc_cfs_rq_hmp_stats(struct cfs_rq *cfs_rq, + struct task_struct *p, int change_cra) { } + +static inline void dec_cfs_rq_hmp_stats(struct cfs_rq *cfs_rq, + struct task_struct *p, int change_cra) { } + +#define dec_throttled_cfs_rq_hmp_stats(...) +#define inc_throttled_cfs_rq_hmp_stats(...) + +#endif /* CONFIG_SCHED_HMP */ + +#if (SCHED_LOAD_SHIFT - SCHED_LOAD_RESOLUTION) != 10 || SCHED_CAPACITY_SHIFT != 10 +#error "load tracking assumes 2^10 as unit" +#endif + +#define cap_scale(v, s) ((v)*(s) >> SCHED_CAPACITY_SHIFT) + +/* + * We can represent the historical contribution to runnable average as the + * coefficients of a geometric series. To do this we sub-divide our runnable + * history into segments of approximately 1ms (1024us); label the segment that + * occurred N-ms ago p_N, with p_0 corresponding to the current period, e.g. + * + * [<- 1024us ->|<- 1024us ->|<- 1024us ->| ... + * p0 p1 p2 + * (now) (~1ms ago) (~2ms ago) + * + * Let u_i denote the fraction of p_i that the entity was runnable. + * + * We then designate the fractions u_i as our co-efficients, yielding the + * following representation of historical load: + * u_0 + u_1*y + u_2*y^2 + u_3*y^3 + ... + * + * We choose y based on the with of a reasonably scheduling period, fixing: + * y^32 = 0.5 + * + * This means that the contribution to load ~32ms ago (u_32) will be weighted + * approximately half as much as the contribution to load within the last ms + * (u_0). + * + * When a period "rolls over" and we have new u_0`, multiplying the previous + * sum again by y is sufficient to update: + * load_avg = u_0` + y*(u_0 + u_1*y + u_2*y^2 + ... ) + * = u_0 + u_1*y + u_2*y^2 + ... [re-labeling u_i --> u_{i+1}] + */ +static __always_inline int +__update_load_avg(u64 now, int cpu, struct sched_avg *sa, + unsigned long weight, int running, struct cfs_rq *cfs_rq) +{ + u64 delta, scaled_delta, periods; + u32 contrib; + unsigned int delta_w, scaled_delta_w, decayed = 0; + unsigned long scale_freq, scale_cpu; + + delta = now - sa->last_update_time; + /* + * This should only happen when time goes backwards, which it + * unfortunately does during sched clock init when we swap over to TSC. + */ + if ((s64)delta < 0) { + sa->last_update_time = now; + return 0; + } + + /* + * Use 1024ns as the unit of measurement since it's a reasonable + * approximation of 1us and fast to compute. + */ + delta >>= 10; + if (!delta) + return 0; + sa->last_update_time = now; + + scale_freq = arch_scale_freq_capacity(NULL, cpu); + scale_cpu = arch_scale_cpu_capacity(NULL, cpu); + trace_sched_contrib_scale_f(cpu, scale_freq, scale_cpu); + + /* delta_w is the amount already accumulated against our next period */ + delta_w = sa->period_contrib; + if (delta + delta_w >= 1024) { + decayed = 1; + + /* how much left for next period will start over, we don't know yet */ + sa->period_contrib = 0; + + /* + * Now that we know we're crossing a period boundary, figure + * out how much from delta we need to complete the current + * period and accrue it. + */ + delta_w = 1024 - delta_w; + scaled_delta_w = cap_scale(delta_w, scale_freq); + if (weight) { + sa->load_sum += weight * scaled_delta_w; + if (cfs_rq) { + cfs_rq->runnable_load_sum += + weight * scaled_delta_w; + } + } + if (running) + sa->util_sum += scaled_delta_w * scale_cpu; + + delta -= delta_w; + + /* Figure out how many additional periods this update spans */ + periods = delta / 1024; + delta %= 1024; + + sa->load_sum = decay_load(sa->load_sum, periods + 1); + if (cfs_rq) { + cfs_rq->runnable_load_sum = + decay_load(cfs_rq->runnable_load_sum, periods + 1); + } + sa->util_sum = decay_load((u64)(sa->util_sum), periods + 1); + + /* Efficiently calculate \sum (1..n_period) 1024*y^i */ + contrib = __compute_runnable_contrib(periods); + contrib = cap_scale(contrib, scale_freq); + if (weight) { + sa->load_sum += weight * contrib; + if (cfs_rq) + cfs_rq->runnable_load_sum += weight * contrib; + } + if (running) + sa->util_sum += contrib * scale_cpu; + } + + /* Remainder of delta accrued against u_0` */ + scaled_delta = cap_scale(delta, scale_freq); + if (weight) { + sa->load_sum += weight * scaled_delta; + if (cfs_rq) + cfs_rq->runnable_load_sum += weight * scaled_delta; + } + + if (running) + sa->util_sum += scaled_delta * scale_cpu; + + sa->period_contrib += delta; + + if (decayed) { + sa->load_avg = div_u64(sa->load_sum, LOAD_AVG_MAX); + if (cfs_rq) { + cfs_rq->runnable_load_avg = + div_u64(cfs_rq->runnable_load_sum, LOAD_AVG_MAX); + } + sa->util_avg = sa->util_sum / LOAD_AVG_MAX; + } + + return decayed; +} + +/* + * Signed add and clamp on underflow. + * + * Explicitly do a load-store to ensure the intermediate value never hits + * memory. This allows lockless observations without ever seeing the negative + * values. + */ +#define add_positive(_ptr, _val) do { \ + typeof(_ptr) ptr = (_ptr); \ + typeof(_val) val = (_val); \ + typeof(*ptr) res, var = READ_ONCE(*ptr); \ + \ + res = var + val; \ + \ + if (val < 0 && res > var) \ + res = 0; \ + \ + WRITE_ONCE(*ptr, res); \ +} while (0) + +#ifdef CONFIG_FAIR_GROUP_SCHED +/** + * update_tg_load_avg - update the tg's load avg + * @cfs_rq: the cfs_rq whose avg changed + * @force: update regardless of how small the difference + * + * This function 'ensures': tg->load_avg := \Sum tg->cfs_rq[]->avg.load. + * However, because tg->load_avg is a global value there are performance + * considerations. + * + * In order to avoid having to look at the other cfs_rq's, we use a + * differential update where we store the last value we propagated. This in + * turn allows skipping updates if the differential is 'small'. + * + * Updating tg's load_avg is necessary before update_cfs_share() (which is + * done) and effective_load() (which is not done because it is too costly). + */ +static inline void update_tg_load_avg(struct cfs_rq *cfs_rq, int force) +{ + long delta = cfs_rq->avg.load_avg - cfs_rq->tg_load_avg_contrib; + + /* + * No need to update load_avg for root_task_group as it is not used. + */ + if (cfs_rq->tg == &root_task_group) + return; + + if (force || abs(delta) > cfs_rq->tg_load_avg_contrib / 64) { + atomic_long_add(delta, &cfs_rq->tg->load_avg); + cfs_rq->tg_load_avg_contrib = cfs_rq->avg.load_avg; + } +} + +/* + * Called within set_task_rq() right before setting a task's cpu. The + * caller only guarantees p->pi_lock is held; no other assumptions, + * including the state of rq->lock, should be made. + */ +void set_task_rq_fair(struct sched_entity *se, + struct cfs_rq *prev, struct cfs_rq *next) +{ + if (!sched_feat(ATTACH_AGE_LOAD)) + return; + + /* + * We are supposed to update the task to "current" time, then its up to + * date and ready to go to new CPU/cfs_rq. But we have difficulty in + * getting what current time is, so simply throw away the out-of-date + * time. This will result in the wakee task is less decayed, but giving + * the wakee more load sounds not bad. + */ + if (se->avg.last_update_time && prev) { + u64 p_last_update_time; + u64 n_last_update_time; + +#ifndef CONFIG_64BIT + u64 p_last_update_time_copy; + u64 n_last_update_time_copy; + + do { + p_last_update_time_copy = prev->load_last_update_time_copy; + n_last_update_time_copy = next->load_last_update_time_copy; + + smp_rmb(); + + p_last_update_time = prev->avg.last_update_time; + n_last_update_time = next->avg.last_update_time; + + } while (p_last_update_time != p_last_update_time_copy || + n_last_update_time != n_last_update_time_copy); +#else + p_last_update_time = prev->avg.last_update_time; + n_last_update_time = next->avg.last_update_time; +#endif + __update_load_avg(p_last_update_time, cpu_of(rq_of(prev)), + &se->avg, 0, 0, NULL); + se->avg.last_update_time = n_last_update_time; + } +} + +/* Take into account change of utilization of a child task group */ +static inline void +update_tg_cfs_util(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + struct cfs_rq *gcfs_rq = group_cfs_rq(se); + long delta = gcfs_rq->avg.util_avg - se->avg.util_avg; + + /* Nothing to update */ + if (!delta) + return; + + /* Set new sched_entity's utilization */ + se->avg.util_avg = gcfs_rq->avg.util_avg; + se->avg.util_sum = se->avg.util_avg * LOAD_AVG_MAX; + + /* Update parent cfs_rq utilization */ + add_positive(&cfs_rq->avg.util_avg, delta); + cfs_rq->avg.util_sum = cfs_rq->avg.util_avg * LOAD_AVG_MAX; +} + +/* Take into account change of load of a child task group */ +static inline void +update_tg_cfs_load(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + struct cfs_rq *gcfs_rq = group_cfs_rq(se); + long delta, load = gcfs_rq->avg.load_avg; + + /* + * If the load of group cfs_rq is null, the load of the + * sched_entity will also be null so we can skip the formula + */ + if (load) { + long tg_load; + + /* Get tg's load and ensure tg_load > 0 */ + tg_load = atomic_long_read(&gcfs_rq->tg->load_avg) + 1; + + /* Ensure tg_load >= load and updated with current load*/ + tg_load -= gcfs_rq->tg_load_avg_contrib; + tg_load += load; + + /* + * We need to compute a correction term in the case that the + * task group is consuming more CPU than a task of equal + * weight. A task with a weight equals to tg->shares will have + * a load less or equal to scale_load_down(tg->shares). + * Similarly, the sched_entities that represent the task group + * at parent level, can't have a load higher than + * scale_load_down(tg->shares). And the Sum of sched_entities' + * load must be <= scale_load_down(tg->shares). + */ + if (tg_load > scale_load_down(gcfs_rq->tg->shares)) { + /* scale gcfs_rq's load into tg's shares*/ + load *= scale_load_down(gcfs_rq->tg->shares); + load /= tg_load; + } + } + + delta = load - se->avg.load_avg; + + /* Nothing to update */ + if (!delta) + return; + + /* Set new sched_entity's load */ + se->avg.load_avg = load; + se->avg.load_sum = se->avg.load_avg * LOAD_AVG_MAX; + + /* Update parent cfs_rq load */ + add_positive(&cfs_rq->avg.load_avg, delta); + cfs_rq->avg.load_sum = cfs_rq->avg.load_avg * LOAD_AVG_MAX; + + /* + * If the sched_entity is already enqueued, we also have to update the + * runnable load avg. + */ + if (se->on_rq) { + /* Update parent cfs_rq runnable_load_avg */ + add_positive(&cfs_rq->runnable_load_avg, delta); + cfs_rq->runnable_load_sum = cfs_rq->runnable_load_avg * LOAD_AVG_MAX; + } +} + +static inline void set_tg_cfs_propagate(struct cfs_rq *cfs_rq) +{ + cfs_rq->propagate_avg = 1; +} + +static inline int test_and_clear_tg_cfs_propagate(struct sched_entity *se) +{ + struct cfs_rq *cfs_rq = group_cfs_rq(se); + + if (!cfs_rq->propagate_avg) + return 0; + + cfs_rq->propagate_avg = 0; + return 1; +} + +/* Update task and its cfs_rq load average */ +static inline int propagate_entity_load_avg(struct sched_entity *se) +{ + struct cfs_rq *cfs_rq; + + if (entity_is_task(se)) + return 0; + + if (!test_and_clear_tg_cfs_propagate(se)) + return 0; + + cfs_rq = cfs_rq_of(se); + + set_tg_cfs_propagate(cfs_rq); + + update_tg_cfs_util(cfs_rq, se); + update_tg_cfs_load(cfs_rq, se); + + return 1; +} + +#else /* CONFIG_FAIR_GROUP_SCHED */ + +static inline void update_tg_load_avg(struct cfs_rq *cfs_rq, int force) {} + +static inline int propagate_entity_load_avg(struct sched_entity *se) +{ + return 0; +} + +static inline void set_tg_cfs_propagate(struct cfs_rq *cfs_rq) {} + +#endif /* CONFIG_FAIR_GROUP_SCHED */ + +static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq) +{ + if (&this_rq()->cfs == cfs_rq) { + /* + * There are a few boundary cases this might miss but it should + * get called often enough that that should (hopefully) not be + * a real problem -- added to that it only calls on the local + * CPU, so if we enqueue remotely we'll miss an update, but + * the next tick/schedule should update. + * + * It will not get called when we go idle, because the idle + * thread is a different class (!fair), nor will the utilization + * number include things like RT tasks. + * + * As is, the util number is not freq-invariant (we'd have to + * implement arch_scale_freq_capacity() for that). + * + * See cpu_util(). + */ + cpufreq_update_util(rq_of(cfs_rq), 0); + } +} + +static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq); + +/* + * Unsigned subtract and clamp on underflow. + * + * Explicitly do a load-store to ensure the intermediate value never hits + * memory. This allows lockless observations without ever seeing the negative + * values. + */ +#define sub_positive(_ptr, _val) do { \ + typeof(_ptr) ptr = (_ptr); \ + typeof(*ptr) val = (_val); \ + typeof(*ptr) res, var = READ_ONCE(*ptr); \ + res = var - val; \ + if (res > var) \ + res = 0; \ + WRITE_ONCE(*ptr, res); \ +} while (0) + +/** + * update_cfs_rq_load_avg - update the cfs_rq's load/util averages + * @now: current time, as per cfs_rq_clock_task() + * @cfs_rq: cfs_rq to update + * @update_freq: should we call cfs_rq_util_change() or will the call do so + * + * The cfs_rq avg is the direct sum of all its entities (blocked and runnable) + * avg. The immediate corollary is that all (fair) tasks must be attached, see + * post_init_entity_util_avg(). + * + * cfs_rq->avg is used for task_h_load() and update_cfs_share() for example. + * + * Returns true if the load decayed or we removed load. + * + * Since both these conditions indicate a changed cfs_rq->avg.load we should + * call update_tg_load_avg() when this function returns true. + */ +static inline int +update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq, bool update_freq) +{ + struct sched_avg *sa = &cfs_rq->avg; + int decayed, removed = 0, removed_util = 0; + + if (atomic_long_read(&cfs_rq->removed_load_avg)) { + s64 r = atomic_long_xchg(&cfs_rq->removed_load_avg, 0); + sub_positive(&sa->load_avg, r); + sub_positive(&sa->load_sum, r * LOAD_AVG_MAX); + removed = 1; + set_tg_cfs_propagate(cfs_rq); + } + + if (atomic_long_read(&cfs_rq->removed_util_avg)) { + long r = atomic_long_xchg(&cfs_rq->removed_util_avg, 0); + sub_positive(&sa->util_avg, r); + sub_positive(&sa->util_sum, r * LOAD_AVG_MAX); + removed_util = 1; + set_tg_cfs_propagate(cfs_rq); + } + + decayed = __update_load_avg(now, cpu_of(rq_of(cfs_rq)), sa, + scale_load_down(cfs_rq->load.weight), cfs_rq->curr != NULL, cfs_rq); + +#ifndef CONFIG_64BIT + smp_wmb(); + cfs_rq->load_last_update_time_copy = sa->last_update_time; +#endif + + /* Trace CPU load, unless cfs_rq belongs to a non-root task_group */ + if (cfs_rq == &rq_of(cfs_rq)->cfs) + trace_sched_load_avg_cpu(cpu_of(rq_of(cfs_rq)), cfs_rq); + + if (update_freq && (decayed || removed_util)) + cfs_rq_util_change(cfs_rq); + + return decayed || removed; +} + +/* + * Optional action to be done while updating the load average + */ +#define UPDATE_TG 0x1 +#define SKIP_AGE_LOAD 0x2 + +/* Update task and its cfs_rq load average */ +static inline void update_load_avg(struct sched_entity *se, int flags) +{ + struct cfs_rq *cfs_rq = cfs_rq_of(se); + u64 now = cfs_rq_clock_task(cfs_rq); + int cpu = cpu_of(rq_of(cfs_rq)); + int decayed; + void *ptr = NULL; + + /* + * Track task load average for carrying it to new CPU after migrated, and + * track group sched_entity load average for task_h_load calc in migration + */ + if (se->avg.last_update_time && !(flags & SKIP_AGE_LOAD)) { + __update_load_avg(now, cpu, &se->avg, + se->on_rq * scale_load_down(se->load.weight), + cfs_rq->curr == se, NULL); + } + + decayed = update_cfs_rq_load_avg(now, cfs_rq, true); + decayed |= propagate_entity_load_avg(se); + + if (decayed && (flags & UPDATE_TG)) + update_tg_load_avg(cfs_rq, 0); + + if (entity_is_task(se)) { +#ifdef CONFIG_SCHED_WALT + ptr = (void *)&(task_of(se)->ravg); +#endif + trace_sched_load_avg_task(task_of(se), &se->avg, ptr); + } +} + +/** + * attach_entity_load_avg - attach this entity to its cfs_rq load avg + * @cfs_rq: cfs_rq to attach to + * @se: sched_entity to attach + * + * Must call update_cfs_rq_load_avg() before this, since we rely on + * cfs_rq->avg.last_update_time being current. + */ +static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + se->avg.last_update_time = cfs_rq->avg.last_update_time; + cfs_rq->avg.load_avg += se->avg.load_avg; + cfs_rq->avg.load_sum += se->avg.load_sum; + cfs_rq->avg.util_avg += se->avg.util_avg; + cfs_rq->avg.util_sum += se->avg.util_sum; + set_tg_cfs_propagate(cfs_rq); + + cfs_rq_util_change(cfs_rq); +} + +/** + * detach_entity_load_avg - detach this entity from its cfs_rq load avg + * @cfs_rq: cfs_rq to detach from + * @se: sched_entity to detach + * + * Must call update_cfs_rq_load_avg() before this, since we rely on + * cfs_rq->avg.last_update_time being current. + */ +static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + + sub_positive(&cfs_rq->avg.load_avg, se->avg.load_avg); + sub_positive(&cfs_rq->avg.load_sum, se->avg.load_sum); + sub_positive(&cfs_rq->avg.util_avg, se->avg.util_avg); + sub_positive(&cfs_rq->avg.util_sum, se->avg.util_sum); + set_tg_cfs_propagate(cfs_rq); + + cfs_rq_util_change(cfs_rq); +} + +/* Add the load generated by se into cfs_rq's load average */ +static inline void +enqueue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + struct sched_avg *sa = &se->avg; + + cfs_rq->runnable_load_avg += sa->load_avg; + cfs_rq->runnable_load_sum += sa->load_sum; + + if (!sa->last_update_time) { + attach_entity_load_avg(cfs_rq, se); + update_tg_load_avg(cfs_rq, 0); + } +} + +/* Remove the runnable load generated by se from cfs_rq's runnable load average */ +static inline void +dequeue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + cfs_rq->runnable_load_avg = + max_t(long, cfs_rq->runnable_load_avg - se->avg.load_avg, 0); + cfs_rq->runnable_load_sum = + max_t(s64, cfs_rq->runnable_load_sum - se->avg.load_sum, 0); +} + +#ifndef CONFIG_64BIT +static inline u64 cfs_rq_last_update_time(struct cfs_rq *cfs_rq) +{ + u64 last_update_time_copy; + u64 last_update_time; + + do { + last_update_time_copy = cfs_rq->load_last_update_time_copy; + smp_rmb(); + last_update_time = cfs_rq->avg.last_update_time; + } while (last_update_time != last_update_time_copy); + + return last_update_time; +} +#else +static inline u64 cfs_rq_last_update_time(struct cfs_rq *cfs_rq) +{ + return cfs_rq->avg.last_update_time; +} +#endif + +/* + * Synchronize entity load avg of dequeued entity without locking + * the previous rq. + */ +void sync_entity_load_avg(struct sched_entity *se) +{ + struct cfs_rq *cfs_rq = cfs_rq_of(se); + u64 last_update_time; + + last_update_time = cfs_rq_last_update_time(cfs_rq); + __update_load_avg(last_update_time, cpu_of(rq_of(cfs_rq)), &se->avg, 0, 0, NULL); +} + +/* + * Task first catches up with cfs_rq, and then subtract + * itself from the cfs_rq (task must be off the queue now). + */ +void remove_entity_load_avg(struct sched_entity *se) +{ + struct cfs_rq *cfs_rq = cfs_rq_of(se); + + /* + * tasks cannot exit without having gone through wake_up_new_task() -> + * post_init_entity_util_avg() which will have added things to the + * cfs_rq, so we can remove unconditionally. + * + * Similarly for groups, they will have passed through + * post_init_entity_util_avg() before unregister_sched_fair_group() + * calls this. + */ + + sync_entity_load_avg(se); + atomic_long_add(se->avg.load_avg, &cfs_rq->removed_load_avg); + atomic_long_add(se->avg.util_avg, &cfs_rq->removed_util_avg); +} + +/* + * Update the rq's load with the elapsed running time before entering + * idle. if the last scheduled task is not a CFS task, idle_enter will + * be the only way to update the runnable statistic. + */ +void idle_enter_fair(struct rq *this_rq) +{ +} + +/* + * Update the rq's load with the elapsed idle time before a task is + * scheduled. if the newly scheduled task is not a CFS task, idle_exit will + * be the only way to update the runnable statistic. + */ +void idle_exit_fair(struct rq *this_rq) +{ +} + +static inline unsigned long cfs_rq_runnable_load_avg(struct cfs_rq *cfs_rq) +{ + return cfs_rq->runnable_load_avg; +} + +static inline unsigned long cfs_rq_load_avg(struct cfs_rq *cfs_rq) +{ + return cfs_rq->avg.load_avg; +} + +static int idle_balance(struct rq *this_rq); + +#else /* CONFIG_SMP */ + +static inline int +update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq, bool update_freq) +{ + return 0; +} + +#define UPDATE_TG 0x0 +#define SKIP_AGE_LOAD 0x0 + +static inline void update_load_avg(struct sched_entity *se, int not_used1){} +static inline void +enqueue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {} +static inline void +dequeue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {} +static inline void remove_entity_load_avg(struct sched_entity *se) {} + +static inline void +attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {} +static inline void +detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {} + +static inline int idle_balance(struct rq *rq) +{ + return 0; +} + +static inline void inc_cfs_rq_hmp_stats(struct cfs_rq *cfs_rq, + struct task_struct *p, int change_cra) { } + +static inline void dec_cfs_rq_hmp_stats(struct cfs_rq *cfs_rq, + struct task_struct *p, int change_cra) { } + +#endif /* CONFIG_SMP */ + +static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ +#ifdef CONFIG_SCHEDSTATS + struct task_struct *tsk = NULL; + + if (entity_is_task(se)) + tsk = task_of(se); + + if (se->statistics.sleep_start) { + u64 delta = rq_clock(rq_of(cfs_rq)) - se->statistics.sleep_start; + + if ((s64)delta < 0) + delta = 0; + + if (unlikely(delta > se->statistics.sleep_max)) + se->statistics.sleep_max = delta; + + se->statistics.sleep_start = 0; + se->statistics.sum_sleep_runtime += delta; + + if (tsk) { + account_scheduler_latency(tsk, delta >> 10, 1); + trace_sched_stat_sleep(tsk, delta); + } + } + if (se->statistics.block_start) { + u64 delta = rq_clock(rq_of(cfs_rq)) - se->statistics.block_start; + + if ((s64)delta < 0) + delta = 0; + + if (unlikely(delta > se->statistics.block_max)) + se->statistics.block_max = delta; + + se->statistics.block_start = 0; + se->statistics.sum_sleep_runtime += delta; + + if (tsk) { + if (tsk->in_iowait) { + se->statistics.iowait_sum += delta; + se->statistics.iowait_count++; + trace_sched_stat_iowait(tsk, delta); + } + + trace_sched_stat_blocked(tsk, delta); + trace_sched_blocked_reason(tsk); + + /* + * Blocking time is in units of nanosecs, so shift by + * 20 to get a milliseconds-range estimation of the + * amount of time that the task spent sleeping: + */ + if (unlikely(prof_on == SLEEP_PROFILING)) { + profile_hits(SLEEP_PROFILING, + (void *)get_wchan(tsk), + delta >> 20); + } + account_scheduler_latency(tsk, delta >> 10, 0); + } + } +#endif +} + +static void check_spread(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ +#ifdef CONFIG_SCHED_DEBUG + s64 d = se->vruntime - cfs_rq->min_vruntime; + + if (d < 0) + d = -d; + + if (d > 3*sysctl_sched_latency) + schedstat_inc(cfs_rq, nr_spread_over); +#endif +} + +static void +place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial) +{ + u64 vruntime = cfs_rq->min_vruntime; + + /* + * The 'current' period is already promised to the current tasks, + * however the extra weight of the new task will slow them down a + * little, place the new task so that it fits in the slot that + * stays open at the end. + */ + if (initial && sched_feat(START_DEBIT)) + vruntime += sched_vslice(cfs_rq, se); + + /* sleeps up to a single latency don't count. */ + if (!initial) { + unsigned long thresh = sysctl_sched_latency; + + /* + * Halve their sleep time's effect, to allow + * for a gentler effect of sleepers: + */ + if (sched_feat(GENTLE_FAIR_SLEEPERS)) + thresh >>= 1; + + vruntime -= thresh; + } + + /* ensure we never gain time by being placed backwards. */ + se->vruntime = max_vruntime(se->vruntime, vruntime); +} + +static void check_enqueue_throttle(struct cfs_rq *cfs_rq); + +static void +enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) +{ + /* + * Update the normalized vruntime before updating min_vruntime + * through calling update_curr(). + */ + if (!(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_WAKING)) + se->vruntime += cfs_rq->min_vruntime; + + /* + * Update run-time statistics of the 'current'. + */ + update_curr(cfs_rq); + update_load_avg(se, UPDATE_TG); + enqueue_entity_load_avg(cfs_rq, se); + update_cfs_shares(se); + account_entity_enqueue(cfs_rq, se); + + if (flags & ENQUEUE_WAKEUP) { + place_entity(cfs_rq, se, 0); + enqueue_sleeper(cfs_rq, se); + } + + update_stats_enqueue(cfs_rq, se); + check_spread(cfs_rq, se); + if (se != cfs_rq->curr) + __enqueue_entity(cfs_rq, se); + se->on_rq = 1; + + if (cfs_rq->nr_running == 1) { + list_add_leaf_cfs_rq(cfs_rq); + check_enqueue_throttle(cfs_rq); + } +} + +static void __clear_buddies_last(struct sched_entity *se) +{ + for_each_sched_entity(se) { + struct cfs_rq *cfs_rq = cfs_rq_of(se); + if (cfs_rq->last != se) + break; + + cfs_rq->last = NULL; + } +} + +static void __clear_buddies_next(struct sched_entity *se) +{ + for_each_sched_entity(se) { + struct cfs_rq *cfs_rq = cfs_rq_of(se); + if (cfs_rq->next != se) + break; + + cfs_rq->next = NULL; + } +} + +static void __clear_buddies_skip(struct sched_entity *se) +{ + for_each_sched_entity(se) { + struct cfs_rq *cfs_rq = cfs_rq_of(se); + if (cfs_rq->skip != se) + break; + + cfs_rq->skip = NULL; + } +} + +static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + if (cfs_rq->last == se) + __clear_buddies_last(se); + + if (cfs_rq->next == se) + __clear_buddies_next(se); + + if (cfs_rq->skip == se) + __clear_buddies_skip(se); +} + +static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq); + +static void +dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) +{ + /* + * Update run-time statistics of the 'current'. + */ + update_curr(cfs_rq); + + /* + * When dequeuing a sched_entity, we must: + * - Update loads to have both entity and cfs_rq synced with now. + * - Substract its load from the cfs_rq->runnable_avg. + * - Substract its previous weight from cfs_rq->load.weight. + * - For group entity, update its weight to reflect the new share + * of its group cfs_rq. + */ + update_load_avg(se, UPDATE_TG); + dequeue_entity_load_avg(cfs_rq, se); + + update_stats_dequeue(cfs_rq, se); + if (flags & DEQUEUE_SLEEP) { +#ifdef CONFIG_SCHEDSTATS + if (entity_is_task(se)) { + struct task_struct *tsk = task_of(se); + + if (tsk->state & TASK_INTERRUPTIBLE) + se->statistics.sleep_start = rq_clock(rq_of(cfs_rq)); + if (tsk->state & TASK_UNINTERRUPTIBLE) + se->statistics.block_start = rq_clock(rq_of(cfs_rq)); + } +#endif + } + + clear_buddies(cfs_rq, se); + + if (se != cfs_rq->curr) + __dequeue_entity(cfs_rq, se); + se->on_rq = 0; + account_entity_dequeue(cfs_rq, se); + + /* + * Normalize the entity after updating the min_vruntime because the + * update can refer to the ->curr item and we need to reflect this + * movement in our normalized position. + */ + if (!(flags & DEQUEUE_SLEEP)) + se->vruntime -= cfs_rq->min_vruntime; + + /* return excess runtime on last dequeue */ + return_cfs_rq_runtime(cfs_rq); + + update_min_vruntime(cfs_rq); + update_cfs_shares(se); +} + +/* + * Preempt the current task with a newly woken task if needed: + */ +static void +check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr) +{ + unsigned long ideal_runtime, delta_exec; + struct sched_entity *se; + s64 delta; + + ideal_runtime = sched_slice(cfs_rq, curr); + delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime; + if (delta_exec > ideal_runtime) { + resched_curr(rq_of(cfs_rq)); + /* + * The current task ran long enough, ensure it doesn't get + * re-elected due to buddy favours. + */ + clear_buddies(cfs_rq, curr); + return; + } + + /* + * Ensure that a task that missed wakeup preemption by a + * narrow margin doesn't have to wait for a full slice. + * This also mitigates buddy induced latencies under load. + */ + if (delta_exec < sysctl_sched_min_granularity) + return; + + se = __pick_first_entity(cfs_rq); + delta = curr->vruntime - se->vruntime; + + if (delta < 0) + return; + + if (delta > ideal_runtime) + resched_curr(rq_of(cfs_rq)); +} + +static void +set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) +{ + /* 'current' is not kept within the tree. */ + if (se->on_rq) { + /* + * Any task has to be enqueued before it get to execute on + * a CPU. So account for the time it spent waiting on the + * runqueue. + */ + update_stats_wait_end(cfs_rq, se); + __dequeue_entity(cfs_rq, se); + update_load_avg(se, UPDATE_TG); + } + + update_stats_curr_start(cfs_rq, se); + cfs_rq->curr = se; +#ifdef CONFIG_SCHEDSTATS + /* + * Track our maximum slice length, if the CPU's load is at + * least twice that of our own weight (i.e. dont track it + * when there are only lesser-weight tasks around): + */ + if (rq_of(cfs_rq)->load.weight >= 2*se->load.weight) { + se->statistics.slice_max = max(se->statistics.slice_max, + se->sum_exec_runtime - se->prev_sum_exec_runtime); + } +#endif + se->prev_sum_exec_runtime = se->sum_exec_runtime; +} + +static int +wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se); + +/* + * Pick the next process, keeping these things in mind, in this order: + * 1) keep things fair between processes/task groups + * 2) pick the "next" process, since someone really wants that to run + * 3) pick the "last" process, for cache locality + * 4) do not run the "skip" process, if something else is available + */ +static struct sched_entity * +pick_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *curr) +{ + struct sched_entity *left = __pick_first_entity(cfs_rq); + struct sched_entity *se; + + /* + * If curr is set we have to see if its left of the leftmost entity + * still in the tree, provided there was anything in the tree at all. + */ + if (!left || (curr && entity_before(curr, left))) + left = curr; + + se = left; /* ideally we run the leftmost entity */ + + /* + * Avoid running the skip buddy, if running something else can + * be done without getting too unfair. + */ + if (cfs_rq->skip == se) { + struct sched_entity *second; + + if (se == curr) { + second = __pick_first_entity(cfs_rq); + } else { + second = __pick_next_entity(se); + if (!second || (curr && entity_before(curr, second))) + second = curr; + } + + if (second && wakeup_preempt_entity(second, left) < 1) + se = second; + } + + /* + * Prefer last buddy, try to return the CPU to a preempted task. + */ + if (cfs_rq->last && wakeup_preempt_entity(cfs_rq->last, left) < 1) + se = cfs_rq->last; + + /* + * Someone really wants this to run. If it's not unfair, run it. + */ + if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, left) < 1) + se = cfs_rq->next; + + clear_buddies(cfs_rq, se); + + return se; +} + +static bool check_cfs_rq_runtime(struct cfs_rq *cfs_rq); + +static void put_prev_entity(struct cfs_rq *cfs_rq, struct sched_entity *prev) +{ + /* + * If still on the runqueue then deactivate_task() + * was not called and update_curr() has to be done: + */ + if (prev->on_rq) + update_curr(cfs_rq); + + /* throttle cfs_rqs exceeding runtime */ + check_cfs_rq_runtime(cfs_rq); + + check_spread(cfs_rq, prev); + if (prev->on_rq) { + update_stats_wait_start(cfs_rq, prev); + /* Put 'current' back into the tree. */ + __enqueue_entity(cfs_rq, prev); + /* in !on_rq case, update occurred at dequeue */ + update_load_avg(prev, 0); + } + cfs_rq->curr = NULL; +} + +static void +entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued) +{ + /* + * Update run-time statistics of the 'current'. + */ + update_curr(cfs_rq); + + /* + * Ensure that runnable average is periodically updated. + */ + update_load_avg(curr, UPDATE_TG); + update_cfs_shares(curr); + +#ifdef CONFIG_SCHED_HRTICK + /* + * queued ticks are scheduled to match the slice, so don't bother + * validating it and just reschedule. + */ + if (queued) { + resched_curr(rq_of(cfs_rq)); + return; + } + /* + * don't let the period tick interfere with the hrtick preemption + */ + if (!sched_feat(DOUBLE_TICK) && + hrtimer_active(&rq_of(cfs_rq)->hrtick_timer)) + return; +#endif + + if (cfs_rq->nr_running > 1) + check_preempt_tick(cfs_rq, curr); +} + + +/************************************************** + * CFS bandwidth control machinery + */ + +#ifdef CONFIG_CFS_BANDWIDTH + +#ifdef HAVE_JUMP_LABEL +static struct static_key __cfs_bandwidth_used; + +static inline bool cfs_bandwidth_used(void) +{ + return static_key_false(&__cfs_bandwidth_used); +} + +void cfs_bandwidth_usage_inc(void) +{ + static_key_slow_inc(&__cfs_bandwidth_used); +} + +void cfs_bandwidth_usage_dec(void) +{ + static_key_slow_dec(&__cfs_bandwidth_used); +} +#else /* HAVE_JUMP_LABEL */ +static bool cfs_bandwidth_used(void) +{ + return true; +} + +void cfs_bandwidth_usage_inc(void) {} +void cfs_bandwidth_usage_dec(void) {} +#endif /* HAVE_JUMP_LABEL */ + +/* + * default period for cfs group bandwidth. + * default: 0.1s, units: nanoseconds + */ +static inline u64 default_cfs_period(void) +{ + return 100000000ULL; +} + +static inline u64 sched_cfs_bandwidth_slice(void) +{ + return (u64)sysctl_sched_cfs_bandwidth_slice * NSEC_PER_USEC; +} + +/* + * Replenish runtime according to assigned quota and update expiration time. + * We use sched_clock_cpu directly instead of rq->clock to avoid adding + * additional synchronization around rq->lock. + * + * requires cfs_b->lock + */ +void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b) +{ + u64 now; + + if (cfs_b->quota == RUNTIME_INF) + return; + + now = sched_clock_cpu(smp_processor_id()); + cfs_b->runtime = cfs_b->quota; + cfs_b->runtime_expires = now + ktime_to_ns(cfs_b->period); +} + +static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg) +{ + return &tg->cfs_bandwidth; +} + +/* rq->task_clock normalized against any time this cfs_rq has spent throttled */ +static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq) +{ + if (unlikely(cfs_rq->throttle_count)) + return cfs_rq->throttled_clock_task; + + return rq_clock_task(rq_of(cfs_rq)) - cfs_rq->throttled_clock_task_time; +} + +/* returns 0 on failure to allocate runtime */ +static int assign_cfs_rq_runtime(struct cfs_rq *cfs_rq) +{ + struct task_group *tg = cfs_rq->tg; + struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(tg); + u64 amount = 0, min_amount, expires; + + /* note: this is a positive sum as runtime_remaining <= 0 */ + min_amount = sched_cfs_bandwidth_slice() - cfs_rq->runtime_remaining; + + raw_spin_lock(&cfs_b->lock); + if (cfs_b->quota == RUNTIME_INF) + amount = min_amount; + else { + start_cfs_bandwidth(cfs_b); + + if (cfs_b->runtime > 0) { + amount = min(cfs_b->runtime, min_amount); + cfs_b->runtime -= amount; + cfs_b->idle = 0; + } + } + expires = cfs_b->runtime_expires; + raw_spin_unlock(&cfs_b->lock); + + cfs_rq->runtime_remaining += amount; + /* + * we may have advanced our local expiration to account for allowed + * spread between our sched_clock and the one on which runtime was + * issued. + */ + if ((s64)(expires - cfs_rq->runtime_expires) > 0) + cfs_rq->runtime_expires = expires; + + return cfs_rq->runtime_remaining > 0; +} + +/* + * Note: This depends on the synchronization provided by sched_clock and the + * fact that rq->clock snapshots this value. + */ +static void expire_cfs_rq_runtime(struct cfs_rq *cfs_rq) +{ + struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); + + /* if the deadline is ahead of our clock, nothing to do */ + if (likely((s64)(rq_clock(rq_of(cfs_rq)) - cfs_rq->runtime_expires) < 0)) + return; + + if (cfs_rq->runtime_remaining < 0) + return; + + /* + * If the local deadline has passed we have to consider the + * possibility that our sched_clock is 'fast' and the global deadline + * has not truly expired. + * + * Fortunately we can check determine whether this the case by checking + * whether the global deadline has advanced. It is valid to compare + * cfs_b->runtime_expires without any locks since we only care about + * exact equality, so a partial write will still work. + */ + + if (cfs_rq->runtime_expires != cfs_b->runtime_expires) { + /* extend local deadline, drift is bounded above by 2 ticks */ + cfs_rq->runtime_expires += TICK_NSEC; + } else { + /* global deadline is ahead, expiration has passed */ + cfs_rq->runtime_remaining = 0; + } +} + +static void __account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec) +{ + /* dock delta_exec before expiring quota (as it could span periods) */ + cfs_rq->runtime_remaining -= delta_exec; + expire_cfs_rq_runtime(cfs_rq); + + if (likely(cfs_rq->runtime_remaining > 0)) + return; + + /* + * if we're unable to extend our runtime we resched so that the active + * hierarchy can be throttled + */ + if (!assign_cfs_rq_runtime(cfs_rq) && likely(cfs_rq->curr)) + resched_curr(rq_of(cfs_rq)); +} + +static __always_inline +void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec) +{ + if (!cfs_bandwidth_used() || !cfs_rq->runtime_enabled) + return; + + __account_cfs_rq_runtime(cfs_rq, delta_exec); +} + +static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq) +{ + return cfs_bandwidth_used() && cfs_rq->throttled; +} + +#ifdef CONFIG_SCHED_HMP +/* + * Check if task is part of a hierarchy where some cfs_rq does not have any + * runtime left. + * + * We can't rely on throttled_hierarchy() to do this test, as + * cfs_rq->throttle_count will not be updated yet when this function is called + * from scheduler_tick() + */ +static int task_will_be_throttled(struct task_struct *p) +{ + struct sched_entity *se = &p->se; + struct cfs_rq *cfs_rq; + + if (!cfs_bandwidth_used()) + return 0; + + for_each_sched_entity(se) { + cfs_rq = cfs_rq_of(se); + if (!cfs_rq->runtime_enabled) + continue; + if (cfs_rq->runtime_remaining <= 0) + return 1; + } + + return 0; +} +#endif + +/* check whether cfs_rq, or any parent, is throttled */ +static inline int throttled_hierarchy(struct cfs_rq *cfs_rq) +{ + return cfs_bandwidth_used() && cfs_rq->throttle_count; +} + +/* + * Ensure that neither of the group entities corresponding to src_cpu or + * dest_cpu are members of a throttled hierarchy when performing group + * load-balance operations. + */ +static inline int throttled_lb_pair(struct task_group *tg, + int src_cpu, int dest_cpu) +{ + struct cfs_rq *src_cfs_rq, *dest_cfs_rq; + + src_cfs_rq = tg->cfs_rq[src_cpu]; + dest_cfs_rq = tg->cfs_rq[dest_cpu]; + + return throttled_hierarchy(src_cfs_rq) || + throttled_hierarchy(dest_cfs_rq); +} + +/* updated child weight may affect parent so we have to do this bottom up */ +static int tg_unthrottle_up(struct task_group *tg, void *data) +{ + struct rq *rq = data; + struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)]; + + cfs_rq->throttle_count--; +#ifdef CONFIG_SMP + if (!cfs_rq->throttle_count) { + /* adjust cfs_rq_clock_task() */ + cfs_rq->throttled_clock_task_time += rq_clock_task(rq) - + cfs_rq->throttled_clock_task; + } +#endif + + return 0; +} + +static int tg_throttle_down(struct task_group *tg, void *data) +{ + struct rq *rq = data; + struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)]; + + /* group is entering throttled state, stop time */ + if (!cfs_rq->throttle_count) + cfs_rq->throttled_clock_task = rq_clock_task(rq); + cfs_rq->throttle_count++; + + return 0; +} + +static void throttle_cfs_rq(struct cfs_rq *cfs_rq) +{ + struct rq *rq = rq_of(cfs_rq); + struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); + struct sched_entity *se; + long task_delta, dequeue = 1; + bool empty; + + se = cfs_rq->tg->se[cpu_of(rq_of(cfs_rq))]; + + /* freeze hierarchy runnable averages while throttled */ + rcu_read_lock(); + walk_tg_tree_from(cfs_rq->tg, tg_throttle_down, tg_nop, (void *)rq); + rcu_read_unlock(); + + task_delta = cfs_rq->h_nr_running; + for_each_sched_entity(se) { + struct cfs_rq *qcfs_rq = cfs_rq_of(se); + /* throttled entity or throttle-on-deactivate */ + if (!se->on_rq) + break; + + if (dequeue) + dequeue_entity(qcfs_rq, se, DEQUEUE_SLEEP); + qcfs_rq->h_nr_running -= task_delta; + dec_throttled_cfs_rq_hmp_stats(&qcfs_rq->hmp_stats, cfs_rq); + + if (qcfs_rq->load.weight) + dequeue = 0; + } + + if (!se) { + sub_nr_running(rq, task_delta); + dec_throttled_cfs_rq_hmp_stats(&rq->hmp_stats, cfs_rq); + } + + cfs_rq->throttled = 1; + cfs_rq->throttled_clock = rq_clock(rq); + raw_spin_lock(&cfs_b->lock); + empty = list_empty(&cfs_b->throttled_cfs_rq); + + /* + * Add to the _head_ of the list, so that an already-started + * distribute_cfs_runtime will not see us. If disribute_cfs_runtime is + * not running add to the tail so that later runqueues don't get starved. + */ + if (cfs_b->distribute_running) + list_add_rcu(&cfs_rq->throttled_list, &cfs_b->throttled_cfs_rq); + else + list_add_tail_rcu(&cfs_rq->throttled_list, &cfs_b->throttled_cfs_rq); + + /* + * If we're the first throttled task, make sure the bandwidth + * timer is running. + */ + if (empty) + start_cfs_bandwidth(cfs_b); + + raw_spin_unlock(&cfs_b->lock); + + /* Log effect on hmp stats after throttling */ + trace_sched_cpu_load_cgroup(rq, idle_cpu(cpu_of(rq)), + sched_irqload(cpu_of(rq)), + power_cost(cpu_of(rq), 0), + cpu_temp(cpu_of(rq))); +} + +void unthrottle_cfs_rq(struct cfs_rq *cfs_rq) +{ + struct rq *rq = rq_of(cfs_rq); + struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); + struct sched_entity *se; + int enqueue = 1; + long task_delta; + struct cfs_rq *tcfs_rq __maybe_unused = cfs_rq; + + se = cfs_rq->tg->se[cpu_of(rq)]; + + cfs_rq->throttled = 0; + + update_rq_clock(rq); + + raw_spin_lock(&cfs_b->lock); + cfs_b->throttled_time += rq_clock(rq) - cfs_rq->throttled_clock; + list_del_rcu(&cfs_rq->throttled_list); + raw_spin_unlock(&cfs_b->lock); + + /* update hierarchical throttle state */ + walk_tg_tree_from(cfs_rq->tg, tg_nop, tg_unthrottle_up, (void *)rq); + + if (!cfs_rq->load.weight) + return; + + task_delta = cfs_rq->h_nr_running; + for_each_sched_entity(se) { + if (se->on_rq) + enqueue = 0; + + cfs_rq = cfs_rq_of(se); + if (enqueue) + enqueue_entity(cfs_rq, se, ENQUEUE_WAKEUP); + cfs_rq->h_nr_running += task_delta; + inc_throttled_cfs_rq_hmp_stats(&cfs_rq->hmp_stats, tcfs_rq); + + if (cfs_rq_throttled(cfs_rq)) + break; + } + + if (!se) { + add_nr_running(rq, task_delta); + inc_throttled_cfs_rq_hmp_stats(&rq->hmp_stats, tcfs_rq); + } + + /* determine whether we need to wake up potentially idle cpu */ + if (rq->curr == rq->idle && rq->cfs.nr_running) + resched_curr(rq); + + /* Log effect on hmp stats after un-throttling */ + trace_sched_cpu_load_cgroup(rq, idle_cpu(cpu_of(rq)), + sched_irqload(cpu_of(rq)), + power_cost(cpu_of(rq), 0), + cpu_temp(cpu_of(rq))); +} + +static u64 distribute_cfs_runtime(struct cfs_bandwidth *cfs_b, + u64 remaining, u64 expires) +{ + struct cfs_rq *cfs_rq; + u64 runtime; + u64 starting_runtime = remaining; + + rcu_read_lock(); + list_for_each_entry_rcu(cfs_rq, &cfs_b->throttled_cfs_rq, + throttled_list) { + struct rq *rq = rq_of(cfs_rq); + + raw_spin_lock(&rq->lock); + if (!cfs_rq_throttled(cfs_rq)) + goto next; + + runtime = -cfs_rq->runtime_remaining + 1; + if (runtime > remaining) + runtime = remaining; + remaining -= runtime; + + cfs_rq->runtime_remaining += runtime; + cfs_rq->runtime_expires = expires; + + /* we check whether we're throttled above */ + if (cfs_rq->runtime_remaining > 0) + unthrottle_cfs_rq(cfs_rq); + +next: + raw_spin_unlock(&rq->lock); + + if (!remaining) + break; + } + rcu_read_unlock(); + + return starting_runtime - remaining; +} + +/* + * Responsible for refilling a task_group's bandwidth and unthrottling its + * cfs_rqs as appropriate. If there has been no activity within the last + * period the timer is deactivated until scheduling resumes; cfs_b->idle is + * used to track this state. + */ +static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun) +{ + u64 runtime, runtime_expires; + int throttled; + + /* no need to continue the timer with no bandwidth constraint */ + if (cfs_b->quota == RUNTIME_INF) + goto out_deactivate; + + throttled = !list_empty(&cfs_b->throttled_cfs_rq); + cfs_b->nr_periods += overrun; + + /* + * idle depends on !throttled (for the case of a large deficit), and if + * we're going inactive then everything else can be deferred + */ + if (cfs_b->idle && !throttled) + goto out_deactivate; + + __refill_cfs_bandwidth_runtime(cfs_b); + + if (!throttled) { + /* mark as potentially idle for the upcoming period */ + cfs_b->idle = 1; + return 0; + } + + /* account preceding periods in which throttling occurred */ + cfs_b->nr_throttled += overrun; + + runtime_expires = cfs_b->runtime_expires; + + /* + * This check is repeated as we are holding onto the new bandwidth while + * we unthrottle. This can potentially race with an unthrottled group + * trying to acquire new bandwidth from the global pool. This can result + * in us over-using our runtime if it is all used during this loop, but + * only by limited amounts in that extreme case. + */ + while (throttled && cfs_b->runtime > 0 && !cfs_b->distribute_running) { + runtime = cfs_b->runtime; + cfs_b->distribute_running = 1; + raw_spin_unlock(&cfs_b->lock); + /* we can't nest cfs_b->lock while distributing bandwidth */ + runtime = distribute_cfs_runtime(cfs_b, runtime, + runtime_expires); + raw_spin_lock(&cfs_b->lock); + + cfs_b->distribute_running = 0; + throttled = !list_empty(&cfs_b->throttled_cfs_rq); + + cfs_b->runtime -= min(runtime, cfs_b->runtime); + } + + /* + * While we are ensured activity in the period following an + * unthrottle, this also covers the case in which the new bandwidth is + * insufficient to cover the existing bandwidth deficit. (Forcing the + * timer to remain active while there are any throttled entities.) + */ + cfs_b->idle = 0; + + return 0; + +out_deactivate: + return 1; +} + +/* a cfs_rq won't donate quota below this amount */ +static const u64 min_cfs_rq_runtime = 1 * NSEC_PER_MSEC; +/* minimum remaining period time to redistribute slack quota */ +static const u64 min_bandwidth_expiration = 2 * NSEC_PER_MSEC; +/* how long we wait to gather additional slack before distributing */ +static const u64 cfs_bandwidth_slack_period = 5 * NSEC_PER_MSEC; + +/* + * Are we near the end of the current quota period? + * + * Requires cfs_b->lock for hrtimer_expires_remaining to be safe against the + * hrtimer base being cleared by hrtimer_start. In the case of + * migrate_hrtimers, base is never cleared, so we are fine. + */ +static int runtime_refresh_within(struct cfs_bandwidth *cfs_b, u64 min_expire) +{ + struct hrtimer *refresh_timer = &cfs_b->period_timer; + u64 remaining; + + /* if the call-back is running a quota refresh is already occurring */ + if (hrtimer_callback_running(refresh_timer)) + return 1; + + /* is a quota refresh about to occur? */ + remaining = ktime_to_ns(hrtimer_expires_remaining(refresh_timer)); + if (remaining < min_expire) + return 1; + + return 0; +} + +static void start_cfs_slack_bandwidth(struct cfs_bandwidth *cfs_b) +{ + u64 min_left = cfs_bandwidth_slack_period + min_bandwidth_expiration; + + /* if there's a quota refresh soon don't bother with slack */ + if (runtime_refresh_within(cfs_b, min_left)) + return; + + hrtimer_start(&cfs_b->slack_timer, + ns_to_ktime(cfs_bandwidth_slack_period), + HRTIMER_MODE_REL); +} + +/* we know any runtime found here is valid as update_curr() precedes return */ +static void __return_cfs_rq_runtime(struct cfs_rq *cfs_rq) +{ + struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg); + s64 slack_runtime = cfs_rq->runtime_remaining - min_cfs_rq_runtime; + + if (slack_runtime <= 0) + return; + + raw_spin_lock(&cfs_b->lock); + if (cfs_b->quota != RUNTIME_INF && + cfs_rq->runtime_expires == cfs_b->runtime_expires) { + cfs_b->runtime += slack_runtime; + + /* we are under rq->lock, defer unthrottling using a timer */ + if (cfs_b->runtime > sched_cfs_bandwidth_slice() && + !list_empty(&cfs_b->throttled_cfs_rq)) + start_cfs_slack_bandwidth(cfs_b); + } + raw_spin_unlock(&cfs_b->lock); + + /* even if it's not valid for return we don't want to try again */ + cfs_rq->runtime_remaining -= slack_runtime; +} + +static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq) +{ + if (!cfs_bandwidth_used()) + return; + + if (!cfs_rq->runtime_enabled || cfs_rq->nr_running) + return; + + __return_cfs_rq_runtime(cfs_rq); +} + +/* + * This is done with a timer (instead of inline with bandwidth return) since + * it's necessary to juggle rq->locks to unthrottle their respective cfs_rqs. + */ +static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b) +{ + u64 runtime = 0, slice = sched_cfs_bandwidth_slice(); + u64 expires; + + /* confirm we're still not at a refresh boundary */ + raw_spin_lock(&cfs_b->lock); + if (cfs_b->distribute_running) { + raw_spin_unlock(&cfs_b->lock); + return; + } + + if (runtime_refresh_within(cfs_b, min_bandwidth_expiration)) { + raw_spin_unlock(&cfs_b->lock); + return; + } + + if (cfs_b->quota != RUNTIME_INF && cfs_b->runtime > slice) + runtime = cfs_b->runtime; + + expires = cfs_b->runtime_expires; + if (runtime) + cfs_b->distribute_running = 1; + + raw_spin_unlock(&cfs_b->lock); + + if (!runtime) + return; + + runtime = distribute_cfs_runtime(cfs_b, runtime, expires); + + raw_spin_lock(&cfs_b->lock); + if (expires == cfs_b->runtime_expires) + cfs_b->runtime -= min(runtime, cfs_b->runtime); + cfs_b->distribute_running = 0; + raw_spin_unlock(&cfs_b->lock); +} + +/* + * When a group wakes up we want to make sure that its quota is not already + * expired/exceeded, otherwise it may be allowed to steal additional ticks of + * runtime as update_curr() throttling can not not trigger until it's on-rq. + */ +static void check_enqueue_throttle(struct cfs_rq *cfs_rq) +{ + if (!cfs_bandwidth_used()) + return; + + /* Synchronize hierarchical throttle counter: */ + if (unlikely(!cfs_rq->throttle_uptodate)) { + struct rq *rq = rq_of(cfs_rq); + struct cfs_rq *pcfs_rq; + struct task_group *tg; + + cfs_rq->throttle_uptodate = 1; + + /* Get closest up-to-date node, because leaves go first: */ + for (tg = cfs_rq->tg->parent; tg; tg = tg->parent) { + pcfs_rq = tg->cfs_rq[cpu_of(rq)]; + if (pcfs_rq->throttle_uptodate) + break; + } + if (tg) { + cfs_rq->throttle_count = pcfs_rq->throttle_count; + cfs_rq->throttled_clock_task = rq_clock_task(rq); + } + } + + /* an active group must be handled by the update_curr()->put() path */ + if (!cfs_rq->runtime_enabled || cfs_rq->curr) + return; + + /* ensure the group is not already throttled */ + if (cfs_rq_throttled(cfs_rq)) + return; + + /* update runtime allocation */ + account_cfs_rq_runtime(cfs_rq, 0); + if (cfs_rq->runtime_remaining <= 0) + throttle_cfs_rq(cfs_rq); +} + +/* conditionally throttle active cfs_rq's from put_prev_entity() */ +static bool check_cfs_rq_runtime(struct cfs_rq *cfs_rq) +{ + if (!cfs_bandwidth_used()) + return false; + + if (likely(!cfs_rq->runtime_enabled || cfs_rq->runtime_remaining > 0)) + return false; + + /* + * it's possible for a throttled entity to be forced into a running + * state (e.g. set_curr_task), in this case we're finished. + */ + if (cfs_rq_throttled(cfs_rq)) + return true; + + throttle_cfs_rq(cfs_rq); + return true; +} + +static enum hrtimer_restart sched_cfs_slack_timer(struct hrtimer *timer) +{ + struct cfs_bandwidth *cfs_b = + container_of(timer, struct cfs_bandwidth, slack_timer); + + do_sched_cfs_slack_timer(cfs_b); + + return HRTIMER_NORESTART; +} + +extern const u64 max_cfs_quota_period; + +static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer) +{ + struct cfs_bandwidth *cfs_b = + container_of(timer, struct cfs_bandwidth, period_timer); + int overrun; + int idle = 0; + int count = 0; + + raw_spin_lock(&cfs_b->lock); + for (;;) { + overrun = hrtimer_forward_now(timer, cfs_b->period); + if (!overrun) + break; + + if (++count > 3) { + u64 new, old = ktime_to_ns(cfs_b->period); + + /* + * Grow period by a factor of 2 to avoid losing precision. + * Precision loss in the quota/period ratio can cause __cfs_schedulable + * to fail. + */ + new = old * 2; + if (new < max_cfs_quota_period) { + cfs_b->period = ns_to_ktime(new); + cfs_b->quota *= 2; + + pr_warn_ratelimited( + "cfs_period_timer[cpu%d]: period too short, scaling up (new cfs_period_us = %lld, cfs_quota_us = %lld)\n", + smp_processor_id(), + div_u64(new, NSEC_PER_USEC), + div_u64(cfs_b->quota, NSEC_PER_USEC)); + } else { + pr_warn_ratelimited( + "cfs_period_timer[cpu%d]: period too short, but cannot scale up without losing precision (cfs_period_us = %lld, cfs_quota_us = %lld)\n", + smp_processor_id(), + div_u64(old, NSEC_PER_USEC), + div_u64(cfs_b->quota, NSEC_PER_USEC)); + } + + /* reset count so we don't come right back in here */ + count = 0; + } + + idle = do_sched_cfs_period_timer(cfs_b, overrun); + } + if (idle) + cfs_b->period_active = 0; + raw_spin_unlock(&cfs_b->lock); + + return idle ? HRTIMER_NORESTART : HRTIMER_RESTART; +} + +void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) +{ + raw_spin_lock_init(&cfs_b->lock); + cfs_b->runtime = 0; + cfs_b->quota = RUNTIME_INF; + cfs_b->period = ns_to_ktime(default_cfs_period()); + + INIT_LIST_HEAD(&cfs_b->throttled_cfs_rq); + hrtimer_init(&cfs_b->period_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED); + cfs_b->period_timer.function = sched_cfs_period_timer; + hrtimer_init(&cfs_b->slack_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + cfs_b->slack_timer.function = sched_cfs_slack_timer; + cfs_b->distribute_running = 0; +} + +static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq) +{ + cfs_rq->runtime_enabled = 0; + INIT_LIST_HEAD(&cfs_rq->throttled_list); + init_cfs_rq_hmp_stats(cfs_rq); +} + +void start_cfs_bandwidth(struct cfs_bandwidth *cfs_b) +{ + lockdep_assert_held(&cfs_b->lock); + + if (!cfs_b->period_active) { + cfs_b->period_active = 1; + hrtimer_forward_now(&cfs_b->period_timer, cfs_b->period); + hrtimer_start_expires(&cfs_b->period_timer, HRTIMER_MODE_ABS_PINNED); + } +} + +static void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) +{ + /* init_cfs_bandwidth() was not called */ + if (!cfs_b->throttled_cfs_rq.next) + return; + + hrtimer_cancel(&cfs_b->period_timer); + hrtimer_cancel(&cfs_b->slack_timer); +} + +static void __maybe_unused update_runtime_enabled(struct rq *rq) +{ + struct cfs_rq *cfs_rq; + + for_each_leaf_cfs_rq(rq, cfs_rq) { + struct cfs_bandwidth *cfs_b = &cfs_rq->tg->cfs_bandwidth; + + raw_spin_lock(&cfs_b->lock); + cfs_rq->runtime_enabled = cfs_b->quota != RUNTIME_INF; + raw_spin_unlock(&cfs_b->lock); + } +} + +static void __maybe_unused unthrottle_offline_cfs_rqs(struct rq *rq) +{ + struct cfs_rq *cfs_rq; + + for_each_leaf_cfs_rq(rq, cfs_rq) { + if (!cfs_rq->runtime_enabled) + continue; + + /* + * clock_task is not advancing so we just need to make sure + * there's some valid quota amount + */ + cfs_rq->runtime_remaining = 1; + /* + * Offline rq is schedulable till cpu is completely disabled + * in take_cpu_down(), so we prevent new cfs throttling here. + */ + cfs_rq->runtime_enabled = 0; + + if (cfs_rq_throttled(cfs_rq)) + unthrottle_cfs_rq(cfs_rq); + } +} + +#else /* CONFIG_CFS_BANDWIDTH */ +static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq) +{ + return rq_clock_task(rq_of(cfs_rq)); +} + +static void account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec) {} +static bool check_cfs_rq_runtime(struct cfs_rq *cfs_rq) { return false; } +static void check_enqueue_throttle(struct cfs_rq *cfs_rq) {} +static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq) {} + +static inline int cfs_rq_throttled(struct cfs_rq *cfs_rq) +{ + return 0; +} + +static inline int throttled_hierarchy(struct cfs_rq *cfs_rq) +{ + return 0; +} + +static inline int throttled_lb_pair(struct task_group *tg, + int src_cpu, int dest_cpu) +{ + return 0; +} + +void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {} + +#ifdef CONFIG_FAIR_GROUP_SCHED +static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq) {} +#endif + +static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg) +{ + return NULL; +} +static inline void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {} +static inline void update_runtime_enabled(struct rq *rq) {} +static inline void unthrottle_offline_cfs_rqs(struct rq *rq) {} + +#endif /* CONFIG_CFS_BANDWIDTH */ + +/************************************************** + * CFS operations on tasks: + */ + +#ifdef CONFIG_SCHED_HRTICK +static void hrtick_start_fair(struct rq *rq, struct task_struct *p) +{ + struct sched_entity *se = &p->se; + struct cfs_rq *cfs_rq = cfs_rq_of(se); + + WARN_ON(task_rq(p) != rq); + + if (rq->cfs.h_nr_running > 1) { + u64 slice = sched_slice(cfs_rq, se); + u64 ran = se->sum_exec_runtime - se->prev_sum_exec_runtime; + s64 delta = slice - ran; + + if (delta < 0) { + if (rq->curr == p) + resched_curr(rq); + return; + } + hrtick_start(rq, delta); + } +} + +/* + * called from enqueue/dequeue and updates the hrtick when the + * current task is from our class. + */ +static void hrtick_update(struct rq *rq) +{ + struct task_struct *curr = rq->curr; + + if (!hrtick_enabled(rq) || curr->sched_class != &fair_sched_class) + return; + + hrtick_start_fair(rq, curr); +} +#else /* !CONFIG_SCHED_HRTICK */ +static inline void +hrtick_start_fair(struct rq *rq, struct task_struct *p) +{ +} + +static inline void hrtick_update(struct rq *rq) +{ +} +#endif + +#ifdef CONFIG_SMP +static bool __cpu_overutilized(int cpu, int delta); +static bool cpu_overutilized(int cpu); +unsigned long boosted_cpu_util(int cpu); +#else +#define boosted_cpu_util(cpu) cpu_util_freq(cpu) +#endif + +/* + * The enqueue_task method is called before nr_running is + * increased. Here we update the fair scheduling stats and + * then put the task into the rbtree: + */ +static void +enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) +{ + struct cfs_rq *cfs_rq; + struct sched_entity *se = &p->se; +#ifdef CONFIG_SMP + int task_new = flags & ENQUEUE_WAKEUP_NEW; +#endif + + /* + * If in_iowait is set, the code below may not trigger any cpufreq + * utilization updates, so do it here explicitly with the IOWAIT flag + * passed. + */ + if (p->in_iowait) + cpufreq_update_this_cpu(rq, SCHED_CPUFREQ_IOWAIT); + + for_each_sched_entity(se) { + if (se->on_rq) + break; + cfs_rq = cfs_rq_of(se); + enqueue_entity(cfs_rq, se, flags); + + /* + * end evaluation on encountering a throttled cfs_rq + * + * note: in the case of encountering a throttled cfs_rq we will + * post the final h_nr_running increment below. + */ + if (cfs_rq_throttled(cfs_rq)) + break; + cfs_rq->h_nr_running++; + inc_cfs_rq_hmp_stats(cfs_rq, p, 1); + + flags = ENQUEUE_WAKEUP; + } + + for_each_sched_entity(se) { + cfs_rq = cfs_rq_of(se); + cfs_rq->h_nr_running++; + inc_cfs_rq_hmp_stats(cfs_rq, p, 1); + + if (cfs_rq_throttled(cfs_rq)) + break; + + update_load_avg(se, UPDATE_TG); + update_cfs_shares(se); + } + + if (!se) { + add_nr_running(rq, 1); + inc_rq_hmp_stats(rq, p, 1); + } + +#ifdef CONFIG_SMP + + /* + * Update SchedTune accounting. + * + * We do it before updating the CPU capacity to ensure the + * boost value of the current task is accounted for in the + * selection of the OPP. + * + * We do it also in the case where we enqueue a throttled task; + * we could argue that a throttled task should not boost a CPU, + * however: + * a) properly implementing CPU boosting considering throttled + * tasks will increase a lot the complexity of the solution + * b) it's not easy to quantify the benefits introduced by + * such a more complex solution. + * Thus, for the time being we go for the simple solution and boost + * also for throttled RQs. + */ + schedtune_enqueue_task(p, cpu_of(rq)); + + if (energy_aware() && !se) { + if (!task_new && !rq->rd->overutilized && + cpu_overutilized(rq->cpu)) { + rq->rd->overutilized = true; + trace_sched_overutilized(true); + } + } + +#endif /* CONFIG_SMP */ + hrtick_update(rq); +} + +static void set_next_buddy(struct sched_entity *se); + +/* + * The dequeue_task method is called before nr_running is + * decreased. We remove the task from the rbtree and + * update the fair scheduling stats: + */ +static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) +{ + struct cfs_rq *cfs_rq; + struct sched_entity *se = &p->se; + int task_sleep = flags & DEQUEUE_SLEEP; + + for_each_sched_entity(se) { + cfs_rq = cfs_rq_of(se); + dequeue_entity(cfs_rq, se, flags); + + /* + * end evaluation on encountering a throttled cfs_rq + * + * note: in the case of encountering a throttled cfs_rq we will + * post the final h_nr_running decrement below. + */ + if (cfs_rq_throttled(cfs_rq)) + break; + cfs_rq->h_nr_running--; + dec_cfs_rq_hmp_stats(cfs_rq, p, 1); + + /* Don't dequeue parent if it has other entities besides us */ + if (cfs_rq->load.weight) { + /* Avoid re-evaluating load for this entity: */ + se = parent_entity(se); + /* + * Bias pick_next to pick a task from this cfs_rq, as + * p is sleeping when it is within its sched_slice. + */ + if (task_sleep && se && !throttled_hierarchy(cfs_rq)) + set_next_buddy(se); + break; + } + flags |= DEQUEUE_SLEEP; + } + + for_each_sched_entity(se) { + cfs_rq = cfs_rq_of(se); + cfs_rq->h_nr_running--; + dec_cfs_rq_hmp_stats(cfs_rq, p, 1); + + if (cfs_rq_throttled(cfs_rq)) + break; + + update_load_avg(se, UPDATE_TG); + update_cfs_shares(se); + } + + if (!se) { + sub_nr_running(rq, 1); + dec_rq_hmp_stats(rq, p, 1); + } + +#ifdef CONFIG_SMP + + /* + * Update SchedTune accounting + * + * We do it before updating the CPU capacity to ensure the + * boost value of the current task is accounted for in the + * selection of the OPP. + */ + schedtune_dequeue_task(p, cpu_of(rq)); + +#endif /* CONFIG_SMP */ + + hrtick_update(rq); +} + +#ifdef CONFIG_SMP + +/* + * per rq 'load' arrray crap; XXX kill this. + */ + +/* + * The exact cpuload at various idx values, calculated at every tick would be + * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load + * + * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called + * on nth tick when cpu may be busy, then we have: + * load = ((2^idx - 1) / 2^idx)^(n-1) * load + * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load + * + * decay_load_missed() below does efficient calculation of + * load = ((2^idx - 1) / 2^idx)^(n-1) * load + * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load + * + * The calculation is approximated on a 128 point scale. + * degrade_zero_ticks is the number of ticks after which load at any + * particular idx is approximated to be zero. + * degrade_factor is a precomputed table, a row for each load idx. + * Each column corresponds to degradation factor for a power of two ticks, + * based on 128 point scale. + * Example: + * row 2, col 3 (=12) says that the degradation at load idx 2 after + * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8). + * + * With this power of 2 load factors, we can degrade the load n times + * by looking at 1 bits in n and doing as many mult/shift instead of + * n mult/shifts needed by the exact degradation. + */ +#define DEGRADE_SHIFT 7 +static const unsigned char + degrade_zero_ticks[CPU_LOAD_IDX_MAX] = {0, 8, 32, 64, 128}; +static const unsigned char + degrade_factor[CPU_LOAD_IDX_MAX][DEGRADE_SHIFT + 1] = { + {0, 0, 0, 0, 0, 0, 0, 0}, + {64, 32, 8, 0, 0, 0, 0, 0}, + {96, 72, 40, 12, 1, 0, 0}, + {112, 98, 75, 43, 15, 1, 0}, + {120, 112, 98, 76, 45, 16, 2} }; + +/* + * Update cpu_load for any missed ticks, due to tickless idle. The backlog + * would be when CPU is idle and so we just decay the old load without + * adding any new load. + */ +static unsigned long +decay_load_missed(unsigned long load, unsigned long missed_updates, int idx) +{ + int j = 0; + + if (!missed_updates) + return load; + + if (missed_updates >= degrade_zero_ticks[idx]) + return 0; + + if (idx == 1) + return load >> missed_updates; + + while (missed_updates) { + if (missed_updates % 2) + load = (load * degrade_factor[idx][j]) >> DEGRADE_SHIFT; + + missed_updates >>= 1; + j++; + } + return load; +} + +/* + * Update rq->cpu_load[] statistics. This function is usually called every + * scheduler tick (TICK_NSEC). With tickless idle this will not be called + * every tick. We fix it up based on jiffies. + */ +static void __update_cpu_load(struct rq *this_rq, unsigned long this_load, + unsigned long pending_updates) +{ + int i, scale; + + this_rq->nr_load_updates++; + + /* Update our load: */ + this_rq->cpu_load[0] = this_load; /* Fasttrack for idx 0 */ + for (i = 1, scale = 2; i < CPU_LOAD_IDX_MAX; i++, scale += scale) { + unsigned long old_load, new_load; + + /* scale is effectively 1 << i now, and >> i divides by scale */ + + old_load = this_rq->cpu_load[i]; + old_load = decay_load_missed(old_load, pending_updates - 1, i); + new_load = this_load; + /* + * Round up the averaging division if load is increasing. This + * prevents us from getting stuck on 9 if the load is 10, for + * example. + */ + if (new_load > old_load) + new_load += scale - 1; + + this_rq->cpu_load[i] = (old_load * (scale - 1) + new_load) >> i; + } + + sched_avg_update(this_rq); +} + +/* Used instead of source_load when we know the type == 0 */ +static unsigned long weighted_cpuload(const int cpu) +{ + return cfs_rq_runnable_load_avg(&cpu_rq(cpu)->cfs); +} + +#ifdef CONFIG_NO_HZ_COMMON +/* + * There is no sane way to deal with nohz on smp when using jiffies because the + * cpu doing the jiffies update might drift wrt the cpu doing the jiffy reading + * causing off-by-one errors in observed deltas; {0,2} instead of {1,1}. + * + * Therefore we cannot use the delta approach from the regular tick since that + * would seriously skew the load calculation. However we'll make do for those + * updates happening while idle (nohz_idle_balance) or coming out of idle + * (tick_nohz_idle_exit). + * + * This means we might still be one tick off for nohz periods. + */ + +/* + * Called from nohz_idle_balance() to update the load ratings before doing the + * idle balance. + */ +static void update_idle_cpu_load(struct rq *this_rq) +{ + unsigned long curr_jiffies = READ_ONCE(jiffies); + unsigned long load = weighted_cpuload(cpu_of(this_rq)); + unsigned long pending_updates; + + /* + * bail if there's load or we're actually up-to-date. + */ + if (load || curr_jiffies == this_rq->last_load_update_tick) + return; + + pending_updates = curr_jiffies - this_rq->last_load_update_tick; + this_rq->last_load_update_tick = curr_jiffies; + + __update_cpu_load(this_rq, load, pending_updates); +} + +/* + * Called from tick_nohz_idle_exit() -- try and fix up the ticks we missed. + */ +void update_cpu_load_nohz(void) +{ + struct rq *this_rq = this_rq(); + unsigned long curr_jiffies = READ_ONCE(jiffies); + unsigned long pending_updates; + + if (curr_jiffies == this_rq->last_load_update_tick) + return; + + raw_spin_lock(&this_rq->lock); + pending_updates = curr_jiffies - this_rq->last_load_update_tick; + if (pending_updates) { + this_rq->last_load_update_tick = curr_jiffies; + /* + * We were idle, this means load 0, the current load might be + * !0 due to remote wakeups and the sort. + */ + __update_cpu_load(this_rq, 0, pending_updates); + } + raw_spin_unlock(&this_rq->lock); +} +#endif /* CONFIG_NO_HZ */ + +/* + * Called from scheduler_tick() + */ +void update_cpu_load_active(struct rq *this_rq) +{ + unsigned long load = weighted_cpuload(cpu_of(this_rq)); + /* + * See the mess around update_idle_cpu_load() / update_cpu_load_nohz(). + */ + this_rq->last_load_update_tick = jiffies; + __update_cpu_load(this_rq, load, 1); +} + +/* + * Return a low guess at the load of a migration-source cpu weighted + * according to the scheduling class and "nice" value. + * + * We want to under-estimate the load of migration sources, to + * balance conservatively. + */ +static unsigned long source_load(int cpu, int type) +{ + struct rq *rq = cpu_rq(cpu); + unsigned long total = weighted_cpuload(cpu); + + if (type == 0 || !sched_feat(LB_BIAS)) + return total; + + return min(rq->cpu_load[type-1], total); +} + +/* + * Return a high guess at the load of a migration-target cpu weighted + * according to the scheduling class and "nice" value. + */ +static unsigned long target_load(int cpu, int type) +{ + struct rq *rq = cpu_rq(cpu); + unsigned long total = weighted_cpuload(cpu); + + if (type == 0 || !sched_feat(LB_BIAS)) + return total; + + return max(rq->cpu_load[type-1], total); +} + + +static unsigned long cpu_avg_load_per_task(int cpu) +{ + struct rq *rq = cpu_rq(cpu); + unsigned long nr_running = READ_ONCE(rq->cfs.h_nr_running); + unsigned long load_avg = weighted_cpuload(cpu); + + if (nr_running) + return load_avg / nr_running; + + return 0; +} + +static void record_wakee(struct task_struct *p) +{ + /* + * Rough decay (wiping) for cost saving, don't worry + * about the boundary, really active task won't care + * about the loss. + */ + if (time_after(jiffies, current->wakee_flip_decay_ts + HZ)) { + current->wakee_flips >>= 1; + current->wakee_flip_decay_ts = jiffies; + } + + if (current->last_wakee != p) { + current->last_wakee = p; + current->wakee_flips++; + } +} + +static void task_waking_fair(struct task_struct *p) +{ + struct sched_entity *se = &p->se; + struct cfs_rq *cfs_rq = cfs_rq_of(se); + u64 min_vruntime; + +#ifndef CONFIG_64BIT + u64 min_vruntime_copy; + + do { + min_vruntime_copy = cfs_rq->min_vruntime_copy; + smp_rmb(); + min_vruntime = cfs_rq->min_vruntime; + } while (min_vruntime != min_vruntime_copy); +#else + min_vruntime = cfs_rq->min_vruntime; +#endif + + se->vruntime -= min_vruntime; + record_wakee(p); +} + +#ifdef CONFIG_FAIR_GROUP_SCHED +/* + * effective_load() calculates the load change as seen from the root_task_group + * + * Adding load to a group doesn't make a group heavier, but can cause movement + * of group shares between cpus. Assuming the shares were perfectly aligned one + * can calculate the shift in shares. + * + * Calculate the effective load difference if @wl is added (subtracted) to @tg + * on this @cpu and results in a total addition (subtraction) of @wg to the + * total group weight. + * + * Given a runqueue weight distribution (rw_i) we can compute a shares + * distribution (s_i) using: + * + * s_i = rw_i / \Sum rw_j (1) + * + * Suppose we have 4 CPUs and our @tg is a direct child of the root group and + * has 7 equal weight tasks, distributed as below (rw_i), with the resulting + * shares distribution (s_i): + * + * rw_i = { 2, 4, 1, 0 } + * s_i = { 2/7, 4/7, 1/7, 0 } + * + * As per wake_affine() we're interested in the load of two CPUs (the CPU the + * task used to run on and the CPU the waker is running on), we need to + * compute the effect of waking a task on either CPU and, in case of a sync + * wakeup, compute the effect of the current task going to sleep. + * + * So for a change of @wl to the local @cpu with an overall group weight change + * of @wl we can compute the new shares distribution (s'_i) using: + * + * s'_i = (rw_i + @wl) / (@wg + \Sum rw_j) (2) + * + * Suppose we're interested in CPUs 0 and 1, and want to compute the load + * differences in waking a task to CPU 0. The additional task changes the + * weight and shares distributions like: + * + * rw'_i = { 3, 4, 1, 0 } + * s'_i = { 3/8, 4/8, 1/8, 0 } + * + * We can then compute the difference in effective weight by using: + * + * dw_i = S * (s'_i - s_i) (3) + * + * Where 'S' is the group weight as seen by its parent. + * + * Therefore the effective change in loads on CPU 0 would be 5/56 (3/8 - 2/7) + * times the weight of the group. The effect on CPU 1 would be -4/56 (4/8 - + * 4/7) times the weight of the group. + */ +static long effective_load(struct task_group *tg, int cpu, long wl, long wg) +{ + struct sched_entity *se = tg->se[cpu]; + + if (!tg->parent) /* the trivial, non-cgroup case */ + return wl; + + for_each_sched_entity(se) { + struct cfs_rq *cfs_rq = se->my_q; + long W, w = cfs_rq_load_avg(cfs_rq); + + tg = cfs_rq->tg; + + /* + * W = @wg + \Sum rw_j + */ + W = wg + atomic_long_read(&tg->load_avg); + + /* Ensure \Sum rw_j >= rw_i */ + W -= cfs_rq->tg_load_avg_contrib; + W += w; + + /* + * w = rw_i + @wl + */ + w += wl; + + /* + * wl = S * s'_i; see (2) + */ + if (W > 0 && w < W) + wl = (w * (long)tg->shares) / W; + else + wl = tg->shares; + + /* + * Per the above, wl is the new se->load.weight value; since + * those are clipped to [MIN_SHARES, ...) do so now. See + * calc_cfs_shares(). + */ + if (wl < MIN_SHARES) + wl = MIN_SHARES; + + /* + * wl = dw_i = S * (s'_i - s_i); see (3) + */ + wl -= se->avg.load_avg; + + /* + * Recursively apply this logic to all parent groups to compute + * the final effective load change on the root group. Since + * only the @tg group gets extra weight, all parent groups can + * only redistribute existing shares. @wl is the shift in shares + * resulting from this level per the above. + */ + wg = 0; + } + + return wl; +} +#else + +static long effective_load(struct task_group *tg, int cpu, long wl, long wg) +{ + return wl; +} + +#endif + +/* + * Returns the current capacity of cpu after applying both + * cpu and freq scaling. + */ +unsigned long capacity_curr_of(int cpu) +{ + return cpu_rq(cpu)->cpu_capacity_orig * + arch_scale_freq_capacity(NULL, cpu) + >> SCHED_CAPACITY_SHIFT; +} + +struct energy_env { + struct sched_group *sg_top; + struct sched_group *sg_cap; + int cap_idx; + int util_delta; + int src_cpu; + int dst_cpu; + int trg_cpu; + int energy; + int payoff; + struct task_struct *task; + struct { + int before; + int after; + int delta; + int diff; + } nrg; + struct { + int before; + int after; + int delta; + } cap; +}; + +static int cpu_util_wake(int cpu, struct task_struct *p); + +/* + * __cpu_norm_util() returns the cpu util relative to a specific capacity, + * i.e. it's busy ratio, in the range [0..SCHED_LOAD_SCALE], which is useful for + * energy calculations. + * + * Since util is a scale-invariant utilization defined as: + * + * util ~ (curr_freq/max_freq)*1024 * capacity_orig/1024 * running_time/time + * + * the normalized util can be found using the specific capacity. + * + * capacity = capacity_orig * curr_freq/max_freq + * + * norm_util = running_time/time ~ util/capacity + */ +static unsigned long __cpu_norm_util(unsigned long util, unsigned long capacity) +{ + if (util >= capacity) + return SCHED_CAPACITY_SCALE; + + return (util << SCHED_CAPACITY_SHIFT)/capacity; +} + +static unsigned long group_max_util(struct energy_env *eenv) +{ + unsigned long max_util = 0; + unsigned long util; + int cpu; + + for_each_cpu(cpu, sched_group_cpus(eenv->sg_cap)) { + util = cpu_util_wake(cpu, eenv->task); + + /* + * If we are looking at the target CPU specified by the eenv, + * then we should add the (estimated) utilization of the task + * assuming we will wake it up on that CPU. + */ + if (unlikely(cpu == eenv->trg_cpu)) + util += eenv->util_delta; + + max_util = max(max_util, util); + } + + return max_util; +} + +/* + * group_norm_util() returns the approximated group util relative to it's + * current capacity (busy ratio), in the range [0..SCHED_LOAD_SCALE], for use + * in energy calculations. + * + * Since task executions may or may not overlap in time in the group the true + * normalized util is between MAX(cpu_norm_util(i)) and SUM(cpu_norm_util(i)) + * when iterating over all CPUs in the group. + * The latter estimate is used as it leads to a more pessimistic energy + * estimate (more busy). + */ +static unsigned +long group_norm_util(struct energy_env *eenv, struct sched_group *sg) +{ + unsigned long capacity = sg->sge->cap_states[eenv->cap_idx].cap; + unsigned long util, util_sum = 0; + int cpu; + + for_each_cpu(cpu, sched_group_cpus(sg)) { + util = cpu_util_wake(cpu, eenv->task); + + /* + * If we are looking at the target CPU specified by the eenv, + * then we should add the (estimated) utilization of the task + * assuming we will wake it up on that CPU. + */ + if (unlikely(cpu == eenv->trg_cpu)) + util += eenv->util_delta; + + util_sum += __cpu_norm_util(util, capacity); + } + + return min_t(unsigned long, util_sum, SCHED_CAPACITY_SCALE); +} + +static int find_new_capacity(struct energy_env *eenv, + const struct sched_group_energy * const sge) +{ + int idx, max_idx = sge->nr_cap_states - 1; + unsigned long util = group_max_util(eenv); + + /* default is max_cap if we don't find a match */ + eenv->cap_idx = max_idx; + + for (idx = 0; idx < sge->nr_cap_states; idx++) { + if (sge->cap_states[idx].cap >= util) { + eenv->cap_idx = idx; + break; + } + } + + return eenv->cap_idx; +} + +static int group_idle_state(struct energy_env *eenv, struct sched_group *sg) +{ + int i, state = INT_MAX; + int src_in_grp, dst_in_grp; + long grp_util = 0; + + /* Find the shallowest idle state in the sched group. */ + for_each_cpu(i, sched_group_cpus(sg)) + state = min(state, idle_get_state_idx(cpu_rq(i))); + + /* Take non-cpuidle idling into account (active idle/arch_cpu_idle()) */ + state++; + + src_in_grp = cpumask_test_cpu(eenv->src_cpu, sched_group_cpus(sg)); + dst_in_grp = cpumask_test_cpu(eenv->dst_cpu, sched_group_cpus(sg)); + if (src_in_grp == dst_in_grp) { + /* both CPUs under consideration are in the same group or not in + * either group, migration should leave idle state the same. + */ + goto end; + } + + /* + * Try to estimate if a deeper idle state is + * achievable when we move the task. + */ + for_each_cpu(i, sched_group_cpus(sg)) { + grp_util += cpu_util_wake(i, eenv->task); + if (unlikely(i == eenv->trg_cpu)) + grp_util += eenv->util_delta; + } + + if (grp_util <= + ((long)sg->sgc->max_capacity * (int)sg->group_weight)) { + /* after moving, this group is at most partly + * occupied, so it should have some idle time. + */ + int max_idle_state_idx = sg->sge->nr_idle_states - 2; + int new_state = grp_util * max_idle_state_idx; + if (grp_util <= 0) + /* group will have no util, use lowest state */ + new_state = max_idle_state_idx + 1; + else { + /* for partially idle, linearly map util to idle + * states, excluding the lowest one. This does not + * correspond to the state we expect to enter in + * reality, but an indication of what might happen. + */ + new_state = min(max_idle_state_idx, (int) + (new_state / sg->sgc->max_capacity)); + new_state = max_idle_state_idx - new_state; + } + state = new_state; + } else { + /* After moving, the group will be fully occupied + * so assume it will not be idle at all. + */ + state = 0; + } +end: + return state; +} + +/* + * sched_group_energy(): Computes the absolute energy consumption of cpus + * belonging to the sched_group including shared resources shared only by + * members of the group. Iterates over all cpus in the hierarchy below the + * sched_group starting from the bottom working it's way up before going to + * the next cpu until all cpus are covered at all levels. The current + * implementation is likely to gather the same util statistics multiple times. + * This can probably be done in a faster but more complex way. + * Note: sched_group_energy() may fail when racing with sched_domain updates. + */ +static int sched_group_energy(struct energy_env *eenv) +{ + struct cpumask visit_cpus; + u64 total_energy = 0; + int cpu_count; + + WARN_ON(!eenv->sg_top->sge); + + cpumask_copy(&visit_cpus, sched_group_cpus(eenv->sg_top)); + /* If a cpu is hotplugged in while we are in this function, + * it does not appear in the existing visit_cpus mask + * which came from the sched_group pointer of the + * sched_domain pointed at by sd_ea for either the prev + * or next cpu and was dereferenced in __energy_diff. + * Since we will dereference sd_scs later as we iterate + * through the CPUs we expect to visit, new CPUs can + * be present which are not in the visit_cpus mask. + * Guard this with cpu_count. + */ + cpu_count = cpumask_weight(&visit_cpus); + + while (!cpumask_empty(&visit_cpus)) { + struct sched_group *sg_shared_cap = NULL; + int cpu = cpumask_first(&visit_cpus); + struct sched_domain *sd; + + /* + * Is the group utilization affected by cpus outside this + * sched_group? + * This sd may have groups with cpus which were not present + * when we took visit_cpus. + */ + sd = rcu_dereference(per_cpu(sd_scs, cpu)); + + if (sd && sd->parent) + sg_shared_cap = sd->parent->groups; + + for_each_domain(cpu, sd) { + struct sched_group *sg = sd->groups; + + /* Has this sched_domain already been visited? */ + if (sd->child && group_first_cpu(sg) != cpu) + break; + + do { + unsigned long group_util; + int sg_busy_energy, sg_idle_energy; + int cap_idx, idle_idx; + + if (sg_shared_cap && sg_shared_cap->group_weight >= sg->group_weight) + eenv->sg_cap = sg_shared_cap; + else + eenv->sg_cap = sg; + + cap_idx = find_new_capacity(eenv, sg->sge); + + if (sg->group_weight == 1) { + /* Remove capacity of src CPU (before task move) */ + if (eenv->trg_cpu == eenv->src_cpu && + cpumask_test_cpu(eenv->src_cpu, sched_group_cpus(sg))) { + eenv->cap.before = sg->sge->cap_states[cap_idx].cap; + eenv->cap.delta -= eenv->cap.before; + } + /* Add capacity of dst CPU (after task move) */ + if (eenv->trg_cpu == eenv->dst_cpu && + cpumask_test_cpu(eenv->dst_cpu, sched_group_cpus(sg))) { + eenv->cap.after = sg->sge->cap_states[cap_idx].cap; + eenv->cap.delta += eenv->cap.after; + } + } + + idle_idx = group_idle_state(eenv, sg); + group_util = group_norm_util(eenv, sg); + + sg_busy_energy = (group_util * sg->sge->cap_states[cap_idx].power); + sg_idle_energy = ((SCHED_LOAD_SCALE-group_util) + * sg->sge->idle_states[idle_idx].power); + + total_energy += sg_busy_energy + sg_idle_energy; + + if (!sd->child) { + /* + * cpu_count here is the number of + * cpus we expect to visit in this + * calculation. If we race against + * hotplug, we can have extra cpus + * added to the groups we are + * iterating which do not appear in + * the visit_cpus mask. In that case + * we are not able to calculate energy + * without restarting so we will bail + * out and use prev_cpu this time. + */ + if (!cpu_count) + return -EINVAL; + cpumask_xor(&visit_cpus, &visit_cpus, sched_group_cpus(sg)); + cpu_count--; + } + + if (cpumask_equal(sched_group_cpus(sg), sched_group_cpus(eenv->sg_top))) + goto next_cpu; + + } while (sg = sg->next, sg != sd->groups); + } + + /* + * If we raced with hotplug and got an sd NULL-pointer; + * returning a wrong energy estimation is better than + * entering an infinite loop. + * Specifically: If a cpu is unplugged after we took + * the visit_cpus mask, it no longer has an sd_scs + * pointer, so when we dereference it, we get NULL. + */ + if (cpumask_test_cpu(cpu, &visit_cpus)) + return -EINVAL; +next_cpu: + cpumask_clear_cpu(cpu, &visit_cpus); + continue; + } + + eenv->energy = total_energy >> SCHED_CAPACITY_SHIFT; + return 0; +} + +static inline bool cpu_in_sg(struct sched_group *sg, int cpu) +{ + return cpu != -1 && cpumask_test_cpu(cpu, sched_group_cpus(sg)); +} + +static inline unsigned long task_util(struct task_struct *p); + +/* + * energy_diff(): Estimate the energy impact of changing the utilization + * distribution. eenv specifies the change: utilisation amount, source, and + * destination cpu. Source or destination cpu may be -1 in which case the + * utilization is removed from or added to the system (e.g. task wake-up). If + * both are specified, the utilization is migrated. + */ +static inline int __energy_diff(struct energy_env *eenv) +{ + struct sched_domain *sd; + struct sched_group *sg; + int sd_cpu = -1, energy_before = 0, energy_after = 0; + int diff, margin; + + struct energy_env eenv_before = { + .util_delta = task_util(eenv->task), + .src_cpu = eenv->src_cpu, + .dst_cpu = eenv->dst_cpu, + .trg_cpu = eenv->src_cpu, + .nrg = { 0, 0, 0, 0}, + .cap = { 0, 0, 0 }, + .task = eenv->task, + }; + + if (eenv->src_cpu == eenv->dst_cpu) + return 0; + + sd_cpu = (eenv->src_cpu != -1) ? eenv->src_cpu : eenv->dst_cpu; + sd = rcu_dereference(per_cpu(sd_ea, sd_cpu)); + + if (!sd) + return 0; /* Error */ + + sg = sd->groups; + + do { + if (cpu_in_sg(sg, eenv->src_cpu) || cpu_in_sg(sg, eenv->dst_cpu)) { + eenv_before.sg_top = eenv->sg_top = sg; + + if (sched_group_energy(&eenv_before)) + return 0; /* Invalid result abort */ + energy_before += eenv_before.energy; + + /* Keep track of SRC cpu (before) capacity */ + eenv->cap.before = eenv_before.cap.before; + eenv->cap.delta = eenv_before.cap.delta; + + if (sched_group_energy(eenv)) + return 0; /* Invalid result abort */ + energy_after += eenv->energy; + } + } while (sg = sg->next, sg != sd->groups); + + eenv->nrg.before = energy_before; + eenv->nrg.after = energy_after; + eenv->nrg.diff = eenv->nrg.after - eenv->nrg.before; + eenv->payoff = 0; +#ifndef CONFIG_SCHED_TUNE + trace_sched_energy_diff(eenv->task, + eenv->src_cpu, eenv->dst_cpu, eenv->util_delta, + eenv->nrg.before, eenv->nrg.after, eenv->nrg.diff, + eenv->cap.before, eenv->cap.after, eenv->cap.delta, + eenv->nrg.delta, eenv->payoff); +#endif + /* + * Dead-zone margin preventing too many migrations. + */ + + margin = eenv->nrg.before >> 6; /* ~1.56% */ + + diff = eenv->nrg.after - eenv->nrg.before; + + eenv->nrg.diff = (abs(diff) < margin) ? 0 : eenv->nrg.diff; + + return eenv->nrg.diff; +} + +#ifdef CONFIG_SCHED_TUNE + +struct target_nrg schedtune_target_nrg; + +#ifdef CONFIG_CGROUP_SCHEDTUNE +extern bool schedtune_initialized; +#endif /* CONFIG_CGROUP_SCHEDTUNE */ + +/* + * System energy normalization + * Returns the normalized value, in the range [0..SCHED_CAPACITY_SCALE], + * corresponding to the specified energy variation. + */ +static inline int +normalize_energy(int energy_diff) +{ + u32 normalized_nrg; + +#ifdef CONFIG_CGROUP_SCHEDTUNE + /* during early setup, we don't know the extents */ + if (unlikely(!schedtune_initialized)) + return energy_diff < 0 ? -1 : 1 ; +#endif /* CONFIG_CGROUP_SCHEDTUNE */ + +#ifdef CONFIG_SCHED_DEBUG + { + int max_delta; + + /* Check for boundaries */ + max_delta = schedtune_target_nrg.max_power; + max_delta -= schedtune_target_nrg.min_power; + WARN_ON(abs(energy_diff) >= max_delta); + } +#endif + + /* Do scaling using positive numbers to increase the range */ + normalized_nrg = (energy_diff < 0) ? -energy_diff : energy_diff; + + /* Scale by energy magnitude */ + normalized_nrg <<= SCHED_CAPACITY_SHIFT; + + /* Normalize on max energy for target platform */ + normalized_nrg = reciprocal_divide( + normalized_nrg, schedtune_target_nrg.rdiv); + + return (energy_diff < 0) ? -normalized_nrg : normalized_nrg; +} + +static inline int +energy_diff(struct energy_env *eenv) +{ + int boost = schedtune_task_boost(eenv->task); + int nrg_delta; + + /* Conpute "absolute" energy diff */ + __energy_diff(eenv); + + /* Return energy diff when boost margin is 0 */ + if (boost == 0) { + trace_sched_energy_diff(eenv->task, + eenv->src_cpu, eenv->dst_cpu, eenv->util_delta, + eenv->nrg.before, eenv->nrg.after, eenv->nrg.diff, + eenv->cap.before, eenv->cap.after, eenv->cap.delta, + 0, -eenv->nrg.diff); + return eenv->nrg.diff; + } + + /* Compute normalized energy diff */ + nrg_delta = normalize_energy(eenv->nrg.diff); + eenv->nrg.delta = nrg_delta; + + eenv->payoff = schedtune_accept_deltas( + eenv->nrg.delta, + eenv->cap.delta, + eenv->task); + + trace_sched_energy_diff(eenv->task, + eenv->src_cpu, eenv->dst_cpu, eenv->util_delta, + eenv->nrg.before, eenv->nrg.after, eenv->nrg.diff, + eenv->cap.before, eenv->cap.after, eenv->cap.delta, + eenv->nrg.delta, eenv->payoff); + + /* + * When SchedTune is enabled, the energy_diff() function will return + * the computed energy payoff value. Since the energy_diff() return + * value is expected to be negative by its callers, this evaluation + * function return a negative value each time the evaluation return a + * positive payoff, which is the condition for the acceptance of + * a scheduling decision + */ + return -eenv->payoff; +} +#else /* CONFIG_SCHED_TUNE */ +#define energy_diff(eenv) __energy_diff(eenv) +#endif + +/* + * Detect M:N waker/wakee relationships via a switching-frequency heuristic. + * A waker of many should wake a different task than the one last awakened + * at a frequency roughly N times higher than one of its wakees. In order + * to determine whether we should let the load spread vs consolodating to + * shared cache, we look for a minimum 'flip' frequency of llc_size in one + * partner, and a factor of lls_size higher frequency in the other. With + * both conditions met, we can be relatively sure that the relationship is + * non-monogamous, with partner count exceeding socket size. Waker/wakee + * being client/server, worker/dispatcher, interrupt source or whatever is + * irrelevant, spread criteria is apparent partner count exceeds socket size. + */ +static int wake_wide(struct task_struct *p, int sibling_count_hint) +{ + unsigned int master = current->wakee_flips; + unsigned int slave = p->wakee_flips; + int llc_size = this_cpu_read(sd_llc_size); + + if (sibling_count_hint >= llc_size) + return 1; + + if (master < slave) + swap(master, slave); + if (slave < llc_size || master < slave * llc_size) + return 0; + return 1; +} + +static int wake_affine(struct sched_domain *sd, struct task_struct *p, + int prev_cpu, int sync) +{ + s64 this_load, load; + s64 this_eff_load, prev_eff_load; + int idx, this_cpu; + struct task_group *tg; + unsigned long weight; + int balanced; + + idx = sd->wake_idx; + this_cpu = smp_processor_id(); + load = source_load(prev_cpu, idx); + this_load = target_load(this_cpu, idx); + + /* + * If sync wakeup then subtract the (maximum possible) + * effect of the currently running task from the load + * of the current CPU: + */ + if (sync) { + tg = task_group(current); + weight = current->se.avg.load_avg; + + this_load += effective_load(tg, this_cpu, -weight, -weight); + load += effective_load(tg, prev_cpu, 0, -weight); + } + + tg = task_group(p); + weight = p->se.avg.load_avg; + + /* + * In low-load situations, where prev_cpu is idle and this_cpu is idle + * due to the sync cause above having dropped this_load to 0, we'll + * always have an imbalance, but there's really nothing you can do + * about that, so that's good too. + * + * Otherwise check if either cpus are near enough in load to allow this + * task to be woken on this_cpu. + */ + this_eff_load = 100; + this_eff_load *= capacity_of(prev_cpu); + + prev_eff_load = 100 + (sd->imbalance_pct - 100) / 2; + prev_eff_load *= capacity_of(this_cpu); + + if (this_load > 0) { + this_eff_load *= this_load + + effective_load(tg, this_cpu, weight, weight); + + prev_eff_load *= load + effective_load(tg, prev_cpu, 0, weight); + } + + balanced = this_eff_load <= prev_eff_load; + + schedstat_inc(p, se.statistics.nr_wakeups_affine_attempts); + + if (!balanced) + return 0; + + schedstat_inc(sd, ttwu_move_affine); + schedstat_inc(p, se.statistics.nr_wakeups_affine); + + return 1; +} + +static inline unsigned long task_util(struct task_struct *p) +{ + return p->se.avg.util_avg; +} + +static inline unsigned long boosted_task_util(struct task_struct *task); + +static inline bool __task_fits(struct task_struct *p, int cpu, int util) +{ + unsigned long capacity = capacity_of(cpu); + + util += boosted_task_util(p); + + return (capacity * 1024) > (util * capacity_margin); +} + +static inline bool task_fits_max(struct task_struct *p, int cpu) +{ + unsigned long capacity = capacity_of(cpu); + unsigned long max_capacity = cpu_rq(cpu)->rd->max_cpu_capacity.val; + + if (capacity == max_capacity) + return true; + + if (capacity * capacity_margin > max_capacity * 1024) + return true; + + return __task_fits(p, cpu, 0); +} + +static bool __cpu_overutilized(int cpu, int delta) +{ + return (capacity_of(cpu) * 1024) < ((cpu_util(cpu) + delta) * capacity_margin); +} + +static bool cpu_overutilized(int cpu) +{ + return __cpu_overutilized(cpu, 0); +} + +#ifdef CONFIG_SCHED_TUNE + +struct reciprocal_value schedtune_spc_rdiv; + +static long +schedtune_margin(unsigned long signal, long boost) +{ + long long margin = 0; + + /* + * Signal proportional compensation (SPC) + * + * The Boost (B) value is used to compute a Margin (M) which is + * proportional to the complement of the original Signal (S): + * M = B * (SCHED_CAPACITY_SCALE - S) + * The obtained M could be used by the caller to "boost" S. + */ + if (boost >= 0) { + margin = SCHED_CAPACITY_SCALE - signal; + margin *= boost; + } else + margin = -signal * boost; + + margin = reciprocal_divide(margin, schedtune_spc_rdiv); + + if (boost < 0) + margin *= -1; + return margin; +} + +static inline int +schedtune_cpu_margin(unsigned long util, int cpu) +{ + int boost = schedtune_cpu_boost(cpu); + + if (boost == 0) + return 0; + + return schedtune_margin(util, boost); +} + +static inline long +schedtune_task_margin(struct task_struct *task) +{ + int boost = schedtune_task_boost(task); + unsigned long util; + long margin; + + if (boost == 0) + return 0; + + util = task_util(task); + margin = schedtune_margin(util, boost); + + return margin; +} + +#else /* CONFIG_SCHED_TUNE */ + +static inline int +schedtune_cpu_margin(unsigned long util, int cpu) +{ + return 0; +} + +static inline int +schedtune_task_margin(struct task_struct *task) +{ + return 0; +} + +#endif /* CONFIG_SCHED_TUNE */ + +unsigned long +boosted_cpu_util(int cpu) +{ + unsigned long util = cpu_util_freq(cpu); + long margin = schedtune_cpu_margin(util, cpu); + + trace_sched_boost_cpu(cpu, util, margin); + + return util + margin; +} + +static inline unsigned long +boosted_task_util(struct task_struct *task) +{ + unsigned long util = task_util(task); + long margin = schedtune_task_margin(task); + + trace_sched_boost_task(task, util, margin); + + return util + margin; +} + +static unsigned long capacity_spare_wake(int cpu, struct task_struct *p) +{ + return max_t(long, capacity_of(cpu) - cpu_util_wake(cpu, p), 0); +} + +/* + * find_idlest_group finds and returns the least busy CPU group within the + * domain. + * + * Assumes p is allowed on at least one CPU in sd. + */ +static struct sched_group * +find_idlest_group(struct sched_domain *sd, struct task_struct *p, + int this_cpu, int sd_flag) +{ + struct sched_group *idlest = NULL, *group = sd->groups; + struct sched_group *most_spare_sg = NULL; + unsigned long min_load = ULONG_MAX, this_load = ULONG_MAX; + unsigned long most_spare = 0, this_spare = 0; + int load_idx = sd->forkexec_idx; + int imbalance = 100 + (sd->imbalance_pct-100)/2; + + if (sd_flag & SD_BALANCE_WAKE) + load_idx = sd->wake_idx; + + do { + unsigned long load, avg_load, spare_cap, max_spare_cap; + int local_group; + int i; + + /* Skip over this group if it has no CPUs allowed */ + if (!cpumask_intersects(sched_group_cpus(group), + tsk_cpus_allowed(p))) + continue; + + local_group = cpumask_test_cpu(this_cpu, + sched_group_cpus(group)); + + /* + * Tally up the load of all CPUs in the group and find + * the group containing the CPU with most spare capacity. + */ + avg_load = 0; + max_spare_cap = 0; + + for_each_cpu(i, sched_group_cpus(group)) { + /* Bias balancing toward cpus of our domain */ + if (local_group) + load = source_load(i, load_idx); + else + load = target_load(i, load_idx); + + avg_load += load; + + spare_cap = capacity_spare_wake(i, p); + + if (spare_cap > max_spare_cap) + max_spare_cap = spare_cap; + } + + /* Adjust by relative CPU capacity of the group */ + avg_load = (avg_load * SCHED_CAPACITY_SCALE) / group->sgc->capacity; + + if (local_group) { + this_load = avg_load; + this_spare = max_spare_cap; + } else { + if (avg_load < min_load) { + min_load = avg_load; + idlest = group; + } + + if (most_spare < max_spare_cap) { + most_spare = max_spare_cap; + most_spare_sg = group; + } + } + } while (group = group->next, group != sd->groups); + + /* + * The cross-over point between using spare capacity or least load + * is too conservative for high utilization tasks on partially + * utilized systems if we require spare_capacity > task_util(p), + * so we allow for some task stuffing by using + * spare_capacity > task_util(p)/2. + * + * Spare capacity can't be used for fork because the utilization has + * not been set yet, we must first select a rq to compute the initial + * utilization. + */ + if (sd_flag & SD_BALANCE_FORK) + goto skip_spare; + + if (this_spare > task_util(p) / 2 && + imbalance*this_spare > 100*most_spare) + return NULL; + else if (most_spare > task_util(p) / 2) + return most_spare_sg; + +skip_spare: + if (!idlest || 100*this_load < imbalance*min_load) + return NULL; + return idlest; +} + +/* + * find_idlest_group_cpu - find the idlest cpu among the cpus in group. + */ +static int +find_idlest_group_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) +{ + unsigned long load, min_load = ULONG_MAX; + unsigned int min_exit_latency = UINT_MAX; + u64 latest_idle_timestamp = 0; + int least_loaded_cpu = this_cpu; + int shallowest_idle_cpu = -1; + int i; + + /* Check if we have any choice: */ + if (group->group_weight == 1) + return cpumask_first(sched_group_cpus(group)); + + /* Traverse only the allowed CPUs */ + for_each_cpu_and(i, sched_group_cpus(group), tsk_cpus_allowed(p)) { + if (idle_cpu(i)) { + struct rq *rq = cpu_rq(i); + struct cpuidle_state *idle = idle_get_state(rq); + if (idle && idle->exit_latency < min_exit_latency) { + /* + * We give priority to a CPU whose idle state + * has the smallest exit latency irrespective + * of any idle timestamp. + */ + min_exit_latency = idle->exit_latency; + latest_idle_timestamp = rq->idle_stamp; + shallowest_idle_cpu = i; + } else if ((!idle || idle->exit_latency == min_exit_latency) && + rq->idle_stamp > latest_idle_timestamp) { + /* + * If equal or no active idle state, then + * the most recently idled CPU might have + * a warmer cache. + */ + latest_idle_timestamp = rq->idle_stamp; + shallowest_idle_cpu = i; + } + } else if (shallowest_idle_cpu == -1) { + load = weighted_cpuload(i); + if (load < min_load || (load == min_load && i == this_cpu)) { + min_load = load; + least_loaded_cpu = i; + } + } + } + + return shallowest_idle_cpu != -1 ? shallowest_idle_cpu : least_loaded_cpu; + } + +static inline int find_idlest_cpu(struct sched_domain *sd, struct task_struct *p, + int cpu, int prev_cpu, int sd_flag) +{ + int new_cpu = cpu; + int wu = sd_flag & SD_BALANCE_WAKE; + int cas_cpu = -1; + + if (wu) { + schedstat_inc(p, se.statistics.nr_wakeups_cas_attempts); + schedstat_inc(this_rq(), eas_stats.cas_attempts); + } + + if (!cpumask_intersects(sched_domain_span(sd), &p->cpus_allowed)) + return prev_cpu; + + while (sd) { + struct sched_group *group; + struct sched_domain *tmp; + int weight; + + if (wu) + schedstat_inc(sd, eas_stats.cas_attempts); + + if (!(sd->flags & sd_flag)) { + sd = sd->child; + continue; + } + + group = find_idlest_group(sd, p, cpu, sd_flag); + if (!group) { + sd = sd->child; + continue; + } + + new_cpu = find_idlest_group_cpu(group, p, cpu); + if (new_cpu == cpu) { + /* Now try balancing at a lower domain level of cpu */ + sd = sd->child; + continue; + } + + /* Now try balancing at a lower domain level of new_cpu */ + cpu = cas_cpu = new_cpu; + weight = sd->span_weight; + sd = NULL; + for_each_domain(cpu, tmp) { + if (weight <= tmp->span_weight) + break; + if (tmp->flags & sd_flag) + sd = tmp; + } + /* while loop will break here if sd == NULL */ + } + + if (wu && (cas_cpu >= 0)) { + schedstat_inc(p, se.statistics.nr_wakeups_cas_count); + schedstat_inc(this_rq(), eas_stats.cas_count); + } + + return new_cpu; +} + +/* + * Try and locate an idle CPU in the sched_domain. + */ +static int select_idle_sibling(struct task_struct *p, int prev, int target) +{ + struct sched_domain *sd; + struct sched_group *sg; + int best_idle_cpu = -1; + int best_idle_cstate = INT_MAX; + unsigned long best_idle_capacity = ULONG_MAX; + + schedstat_inc(p, se.statistics.nr_wakeups_sis_attempts); + schedstat_inc(this_rq(), eas_stats.sis_attempts); + + if (!sysctl_sched_cstate_aware) { + if (idle_cpu(target)) { + schedstat_inc(p, se.statistics.nr_wakeups_sis_idle); + schedstat_inc(this_rq(), eas_stats.sis_idle); + return target; + } + + /* + * If the prevous cpu is cache affine and idle, don't be stupid. + */ + if (prev != target && cpus_share_cache(prev, target) && idle_cpu(prev)) { + schedstat_inc(p, se.statistics.nr_wakeups_sis_cache_affine); + schedstat_inc(this_rq(), eas_stats.sis_cache_affine); + return prev; + } + } + + if (!(current->flags & PF_WAKE_UP_IDLE) && + !(p->flags & PF_WAKE_UP_IDLE)) + return target; + + /* + * Otherwise, iterate the domains and find an elegible idle cpu. + */ + sd = rcu_dereference(per_cpu(sd_llc, target)); + for_each_lower_domain(sd) { + sg = sd->groups; + do { + int i; + if (!cpumask_intersects(sched_group_cpus(sg), + tsk_cpus_allowed(p))) + goto next; + + if (sysctl_sched_cstate_aware) { + for_each_cpu_and(i, tsk_cpus_allowed(p), sched_group_cpus(sg)) { + int idle_idx = idle_get_state_idx(cpu_rq(i)); + unsigned long new_usage = boosted_task_util(p); + unsigned long capacity_orig = capacity_orig_of(i); + + if (new_usage > capacity_orig || !idle_cpu(i)) + goto next; + + if (i == target && new_usage <= capacity_curr_of(target)) { + schedstat_inc(p, se.statistics.nr_wakeups_sis_suff_cap); + schedstat_inc(this_rq(), eas_stats.sis_suff_cap); + schedstat_inc(sd, eas_stats.sis_suff_cap); + return target; + } + + if (idle_idx < best_idle_cstate && + capacity_orig <= best_idle_capacity) { + best_idle_cpu = i; + best_idle_cstate = idle_idx; + best_idle_capacity = capacity_orig; + } + } + } else { + for_each_cpu(i, sched_group_cpus(sg)) { + if (i == target || !idle_cpu(i)) + goto next; + } + + target = cpumask_first_and(sched_group_cpus(sg), + tsk_cpus_allowed(p)); + schedstat_inc(p, se.statistics.nr_wakeups_sis_idle_cpu); + schedstat_inc(this_rq(), eas_stats.sis_idle_cpu); + schedstat_inc(sd, eas_stats.sis_idle_cpu); + goto done; + } +next: + sg = sg->next; + } while (sg != sd->groups); + } + + if (best_idle_cpu >= 0) + target = best_idle_cpu; + +done: + schedstat_inc(p, se.statistics.nr_wakeups_sis_count); + schedstat_inc(this_rq(), eas_stats.sis_count); + + return target; +} + +/* + * cpu_util_wake: Compute cpu utilization with any contributions from + * the waking task p removed. check_for_migration() looks for a better CPU of + * rq->curr. For that case we should return cpu util with contributions from + * currently running task p removed. + */ +static int cpu_util_wake(int cpu, struct task_struct *p) +{ + unsigned long util, capacity; + +#ifdef CONFIG_SCHED_WALT + /* + * WALT does not decay idle tasks in the same manner + * as PELT, so it makes little sense to subtract task + * utilization from cpu utilization. Instead just use + * cpu_util for this case. + */ + if (!walt_disabled && sysctl_sched_use_walt_cpu_util && + p->state == TASK_WAKING) + return cpu_util(cpu); +#endif + /* Task has no contribution or is new */ + if (cpu != task_cpu(p) || !p->se.avg.last_update_time) + return cpu_util(cpu); + + capacity = capacity_orig_of(cpu); + util = max_t(long, cpu_util(cpu) - task_util(p), 0); + + return (util >= capacity) ? capacity : util; +} + +static int start_cpu(bool boosted) +{ + struct root_domain *rd = cpu_rq(smp_processor_id())->rd; + + return boosted ? rd->max_cap_orig_cpu : rd->min_cap_orig_cpu; +} + +static inline int find_best_target(struct task_struct *p, int *backup_cpu, + bool boosted, bool prefer_idle) +{ + unsigned long best_idle_min_cap_orig = ULONG_MAX; + unsigned long min_util = boosted_task_util(p); + unsigned long target_capacity = ULONG_MAX; + unsigned long min_wake_util = ULONG_MAX; + unsigned long target_max_spare_cap = 0; + unsigned long best_active_util = ULONG_MAX; + int best_idle_cstate = INT_MAX; + struct sched_domain *sd; + struct sched_group *sg; + int best_active_cpu = -1; + int best_idle_cpu = -1; + int target_cpu = -1; + int cpu, i; + + *backup_cpu = -1; + + schedstat_inc(p, se.statistics.nr_wakeups_fbt_attempts); + schedstat_inc(this_rq(), eas_stats.fbt_attempts); + + /* Find start CPU based on boost value */ + cpu = start_cpu(boosted); + if (cpu < 0) { + schedstat_inc(p, se.statistics.nr_wakeups_fbt_no_cpu); + schedstat_inc(this_rq(), eas_stats.fbt_no_cpu); + return -1; + } + + /* Find SD for the start CPU */ + sd = rcu_dereference(per_cpu(sd_ea, cpu)); + if (!sd) { + schedstat_inc(p, se.statistics.nr_wakeups_fbt_no_sd); + schedstat_inc(this_rq(), eas_stats.fbt_no_sd); + return -1; + } + + /* Scan CPUs in all SDs */ + sg = sd->groups; + do { + for_each_cpu_and(i, tsk_cpus_allowed(p), sched_group_cpus(sg)) { + unsigned long capacity_curr = capacity_curr_of(i); + unsigned long capacity_orig = capacity_orig_of(i); + unsigned long wake_util, new_util; + + if (!cpu_online(i)) + continue; + + if (walt_cpu_high_irqload(i)) + continue; + + /* + * p's blocked utilization is still accounted for on prev_cpu + * so prev_cpu will receive a negative bias due to the double + * accounting. However, the blocked utilization may be zero. + */ + wake_util = cpu_util_wake(i, p); + new_util = wake_util + task_util(p); + + /* + * Ensure minimum capacity to grant the required boost. + * The target CPU can be already at a capacity level higher + * than the one required to boost the task. + */ + new_util = max(min_util, new_util); + if (new_util > capacity_orig) + continue; + + /* + * Case A) Latency sensitive tasks + * + * Unconditionally favoring tasks that prefer idle CPU to + * improve latency. + * + * Looking for: + * - an idle CPU, whatever its idle_state is, since + * the first CPUs we explore are more likely to be + * reserved for latency sensitive tasks. + * - a non idle CPU where the task fits in its current + * capacity and has the maximum spare capacity. + * - a non idle CPU with lower contention from other + * tasks and running at the lowest possible OPP. + * + * The last two goals tries to favor a non idle CPU + * where the task can run as if it is "almost alone". + * A maximum spare capacity CPU is favoured since + * the task already fits into that CPU's capacity + * without waiting for an OPP chance. + * + * The following code path is the only one in the CPUs + * exploration loop which is always used by + * prefer_idle tasks. It exits the loop with wither a + * best_active_cpu or a target_cpu which should + * represent an optimal choice for latency sensitive + * tasks. + */ + if (prefer_idle) { + + /* + * Case A.1: IDLE CPU + * Return the first IDLE CPU we find. + */ + if (idle_cpu(i)) { + schedstat_inc(p, se.statistics.nr_wakeups_fbt_pref_idle); + schedstat_inc(this_rq(), eas_stats.fbt_pref_idle); + + trace_sched_find_best_target(p, + prefer_idle, min_util, + cpu, best_idle_cpu, + best_active_cpu, i); + + return i; + } + + /* + * Case A.2: Target ACTIVE CPU + * Favor CPUs with max spare capacity. + */ + if ((capacity_curr > new_util) && + (capacity_orig - new_util > target_max_spare_cap)) { + target_max_spare_cap = capacity_orig - new_util; + target_cpu = i; + continue; + } + if (target_cpu != -1) + continue; + + + /* + * Case A.3: Backup ACTIVE CPU + * Favor CPUs with: + * - lower utilization due to other tasks + * - lower utilization with the task in + */ + if (wake_util > min_wake_util) + continue; + if (new_util > best_active_util) + continue; + min_wake_util = wake_util; + best_active_util = new_util; + best_active_cpu = i; + continue; + } + + /* + * Enforce EAS mode + * + * For non latency sensitive tasks, skip CPUs that + * will be overutilized by moving the task there. + * + * The goal here is to remain in EAS mode as long as + * possible at least for !prefer_idle tasks. + */ + if ((new_util * capacity_margin) > + (capacity_orig * SCHED_CAPACITY_SCALE)) + continue; + + /* + * Case B) Non latency sensitive tasks on IDLE CPUs. + * + * Find an optimal backup IDLE CPU for non latency + * sensitive tasks. + * + * Looking for: + * - minimizing the capacity_orig, + * i.e. preferring LITTLE CPUs + * - favoring shallowest idle states + * i.e. avoid to wakeup deep-idle CPUs + * + * The following code path is used by non latency + * sensitive tasks if IDLE CPUs are available. If at + * least one of such CPUs are available it sets the + * best_idle_cpu to the most suitable idle CPU to be + * selected. + * + * If idle CPUs are available, favour these CPUs to + * improve performances by spreading tasks. + * Indeed, the energy_diff() computed by the caller + * will take care to ensure the minimization of energy + * consumptions without affecting performance. + */ + if (idle_cpu(i)) { + int idle_idx = idle_get_state_idx(cpu_rq(i)); + + /* Select idle CPU with lower cap_orig */ + if (capacity_orig > best_idle_min_cap_orig) + continue; + + /* + * Skip CPUs in deeper idle state, but only + * if they are also less energy efficient. + * IOW, prefer a deep IDLE LITTLE CPU vs a + * shallow idle big CPU. + */ + if (sysctl_sched_cstate_aware && + best_idle_cstate <= idle_idx) + continue; + + /* Keep track of best idle CPU */ + best_idle_min_cap_orig = capacity_orig; + best_idle_cstate = idle_idx; + best_idle_cpu = i; + continue; + } + + /* + * Case C) Non latency sensitive tasks on ACTIVE CPUs. + * + * Pack tasks in the most energy efficient capacities. + * + * This task packing strategy prefers more energy + * efficient CPUs (i.e. pack on smaller maximum + * capacity CPUs) while also trying to spread tasks to + * run them all at the lower OPP. + * + * This assumes for example that it's more energy + * efficient to run two tasks on two CPUs at a lower + * OPP than packing both on a single CPU but running + * that CPU at an higher OPP. + * + * Thus, this case keep track of the CPU with the + * smallest maximum capacity and highest spare maximum + * capacity. + */ + + /* Favor CPUs with smaller capacity */ + if (capacity_orig > target_capacity) + continue; + + /* Favor CPUs with maximum spare capacity */ + if ((capacity_orig - new_util) < target_max_spare_cap) + continue; + + target_max_spare_cap = capacity_orig - new_util; + target_capacity = capacity_orig; + target_cpu = i; + } + + } while (sg = sg->next, sg != sd->groups); + + /* + * For non latency sensitive tasks, cases B and C in the previous loop, + * we pick the best IDLE CPU only if we was not able to find a target + * ACTIVE CPU. + * + * Policies priorities: + * + * - prefer_idle tasks: + * + * a) IDLE CPU available, we return immediately + * b) ACTIVE CPU where task fits and has the bigger maximum spare + * capacity (i.e. target_cpu) + * c) ACTIVE CPU with less contention due to other tasks + * (i.e. best_active_cpu) + * + * - NON prefer_idle tasks: + * + * a) ACTIVE CPU: target_cpu + * b) IDLE CPU: best_idle_cpu + */ + if (target_cpu == -1) + target_cpu = prefer_idle + ? best_active_cpu + : best_idle_cpu; + else + *backup_cpu = prefer_idle + ? best_active_cpu + : best_idle_cpu; + + trace_sched_find_best_target(p, prefer_idle, min_util, cpu, + best_idle_cpu, best_active_cpu, + target_cpu); + + schedstat_inc(p, se.statistics.nr_wakeups_fbt_count); + schedstat_inc(this_rq(), eas_stats.fbt_count); + + return target_cpu; +} + +/* + * Disable WAKE_AFFINE in the case where task @p doesn't fit in the + * capacity of either the waking CPU @cpu or the previous CPU @prev_cpu. + * + * In that case WAKE_AFFINE doesn't make sense and we'll let + * BALANCE_WAKE sort things out. + */ +static int wake_cap(struct task_struct *p, int cpu, int prev_cpu) +{ + long min_cap, max_cap; + + min_cap = min(capacity_orig_of(prev_cpu), capacity_orig_of(cpu)); + max_cap = cpu_rq(cpu)->rd->max_cpu_capacity.val; + + /* Minimum capacity is close to max, no need to abort wake_affine */ + if (max_cap - min_cap < max_cap >> 3) + return 0; + + /* Bring task utilization in sync with prev_cpu */ + sync_entity_load_avg(&p->se); + + return min_cap * 1024 < task_util(p) * capacity_margin; +} + +static int select_energy_cpu_brute(struct task_struct *p, int prev_cpu, int sync) +{ + struct sched_domain *sd; + int target_cpu = prev_cpu, tmp_target, tmp_backup; + bool boosted, prefer_idle; + + schedstat_inc(p, se.statistics.nr_wakeups_secb_attempts); + schedstat_inc(this_rq(), eas_stats.secb_attempts); + + if (sysctl_sched_sync_hint_enable && sync) { + int cpu = smp_processor_id(); + + if (cpumask_test_cpu(cpu, tsk_cpus_allowed(p))) { + schedstat_inc(p, se.statistics.nr_wakeups_secb_sync); + schedstat_inc(this_rq(), eas_stats.secb_sync); + return cpu; + } + } + + rcu_read_lock(); +#ifdef CONFIG_CGROUP_SCHEDTUNE + boosted = schedtune_task_boost(p) > 0; + prefer_idle = schedtune_prefer_idle(p) > 0; +#else + boosted = get_sysctl_sched_cfs_boost() > 0; + prefer_idle = 0; +#endif + + sync_entity_load_avg(&p->se); + + sd = rcu_dereference(per_cpu(sd_ea, prev_cpu)); + /* Find a cpu with sufficient capacity */ + tmp_target = find_best_target(p, &tmp_backup, boosted, prefer_idle); + + if (!sd) + goto unlock; + if (tmp_target >= 0) { + target_cpu = tmp_target; + if ((boosted || prefer_idle) && idle_cpu(target_cpu)) { + schedstat_inc(p, se.statistics.nr_wakeups_secb_idle_bt); + schedstat_inc(this_rq(), eas_stats.secb_idle_bt); + goto unlock; + } + } + + if (target_cpu != prev_cpu) { + int delta = 0; + struct energy_env eenv = { + .util_delta = task_util(p), + .src_cpu = prev_cpu, + .dst_cpu = target_cpu, + .task = p, + .trg_cpu = target_cpu, + }; + + +#ifdef CONFIG_SCHED_WALT + if (!walt_disabled && sysctl_sched_use_walt_cpu_util && + p->state == TASK_WAKING) + delta = task_util(p); +#endif + /* Not enough spare capacity on previous cpu */ + if (__cpu_overutilized(prev_cpu, delta)) { + schedstat_inc(p, se.statistics.nr_wakeups_secb_insuff_cap); + schedstat_inc(this_rq(), eas_stats.secb_insuff_cap); + goto unlock; + } + + if (energy_diff(&eenv) >= 0) { + /* No energy saving for target_cpu, try backup */ + target_cpu = tmp_backup; + eenv.dst_cpu = target_cpu; + eenv.trg_cpu = target_cpu; + if (tmp_backup < 0 || + tmp_backup == prev_cpu || + energy_diff(&eenv) >= 0) { + schedstat_inc(p, se.statistics.nr_wakeups_secb_no_nrg_sav); + schedstat_inc(this_rq(), eas_stats.secb_no_nrg_sav); + target_cpu = prev_cpu; + goto unlock; + } + } + + schedstat_inc(p, se.statistics.nr_wakeups_secb_nrg_sav); + schedstat_inc(this_rq(), eas_stats.secb_nrg_sav); + goto unlock; + } + + schedstat_inc(p, se.statistics.nr_wakeups_secb_count); + schedstat_inc(this_rq(), eas_stats.secb_count); + +unlock: + rcu_read_unlock(); + + return target_cpu; +} + +/* + * select_task_rq_fair: Select target runqueue for the waking task in domains + * that have the 'sd_flag' flag set. In practice, this is SD_BALANCE_WAKE, + * SD_BALANCE_FORK, or SD_BALANCE_EXEC. + * + * Balances load by selecting the idlest cpu in the idlest group, or under + * certain conditions an idle sibling cpu if the domain has SD_WAKE_AFFINE set. + * + * Returns the target cpu number. + * + * preempt must be disabled. + */ +static int +select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_flags, + int sibling_count_hint) +{ + struct sched_domain *tmp, *affine_sd = NULL, *sd = NULL; + int cpu = smp_processor_id(); + int new_cpu = prev_cpu; + int want_affine = 0; + int sync = wake_flags & WF_SYNC; + +#ifdef CONFIG_SCHED_HMP + return select_best_cpu(p, prev_cpu, 0, sync); +#endif + + if (sd_flag & SD_BALANCE_WAKE) { + record_wakee(p); + want_affine = !wake_wide(p, sibling_count_hint) && + !wake_cap(p, cpu, prev_cpu) && + cpumask_test_cpu(cpu, &p->cpus_allowed); + } + + if (energy_aware() && !(cpu_rq(prev_cpu)->rd->overutilized)) + return select_energy_cpu_brute(p, prev_cpu, sync); + + rcu_read_lock(); + for_each_domain(cpu, tmp) { + if (!(tmp->flags & SD_LOAD_BALANCE)) + break; + + /* + * If both cpu and prev_cpu are part of this domain, + * cpu is a valid SD_WAKE_AFFINE target. + */ + if (want_affine && (tmp->flags & SD_WAKE_AFFINE) && + cpumask_test_cpu(prev_cpu, sched_domain_span(tmp))) { + affine_sd = tmp; + break; + } + + if (tmp->flags & sd_flag) + sd = tmp; + else if (!want_affine) + break; + } + + if (affine_sd) { + sd = NULL; /* Prefer wake_affine over balance flags */ + if (cpu != prev_cpu && wake_affine(affine_sd, p, prev_cpu, sync)) + new_cpu = cpu; + } + + if (sd && !(sd_flag & SD_BALANCE_FORK)) { + /* + * We're going to need the task's util for capacity_spare_wake + * in find_idlest_group. Sync it up to prev_cpu's + * last_update_time. + */ + sync_entity_load_avg(&p->se); + } + + if (!sd) { + if (sd_flag & SD_BALANCE_WAKE) /* XXX always ? */ + new_cpu = select_idle_sibling(p, prev_cpu, new_cpu); + + } else { + new_cpu = find_idlest_cpu(sd, p, cpu, prev_cpu, sd_flag); + } + rcu_read_unlock(); + + return new_cpu; +} + +/* + * Called immediately before a task is migrated to a new cpu; task_cpu(p) and + * cfs_rq_of(p) references at time of call are still valid and identify the + * previous cpu. However, the caller only guarantees p->pi_lock is held; no + * other assumptions, including the state of rq->lock, should be made. + */ +static void migrate_task_rq_fair(struct task_struct *p) +{ + /* + * We are supposed to update the task to "current" time, then its up to date + * and ready to go to new CPU/cfs_rq. But we have difficulty in getting + * what current time is, so simply throw away the out-of-date time. This + * will result in the wakee task is less decayed, but giving the wakee more + * load sounds not bad. + */ + remove_entity_load_avg(&p->se); + + /* Tell new CPU we are migrated */ + p->se.avg.last_update_time = 0; + + /* We have migrated, no longer consider this task hot */ + p->se.exec_start = 0; +} + +static void task_dead_fair(struct task_struct *p) +{ + remove_entity_load_avg(&p->se); +} +#else +#define task_fits_max(p, cpu) true +#endif /* CONFIG_SMP */ + +static unsigned long +wakeup_gran(struct sched_entity *curr, struct sched_entity *se) +{ + unsigned long gran = sysctl_sched_wakeup_granularity; + + /* + * Since its curr running now, convert the gran from real-time + * to virtual-time in his units. + * + * By using 'se' instead of 'curr' we penalize light tasks, so + * they get preempted easier. That is, if 'se' < 'curr' then + * the resulting gran will be larger, therefore penalizing the + * lighter, if otoh 'se' > 'curr' then the resulting gran will + * be smaller, again penalizing the lighter task. + * + * This is especially important for buddies when the leftmost + * task is higher priority than the buddy. + */ + return calc_delta_fair(gran, se); +} + +/* + * Should 'se' preempt 'curr'. + * + * |s1 + * |s2 + * |s3 + * g + * |<--->|c + * + * w(c, s1) = -1 + * w(c, s2) = 0 + * w(c, s3) = 1 + * + */ +static int +wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se) +{ + s64 gran, vdiff = curr->vruntime - se->vruntime; + + if (vdiff <= 0) + return -1; + + gran = wakeup_gran(curr, se); + if (vdiff > gran) + return 1; + + return 0; +} + +static void set_last_buddy(struct sched_entity *se) +{ + if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE)) + return; + + for_each_sched_entity(se) + cfs_rq_of(se)->last = se; +} + +static void set_next_buddy(struct sched_entity *se) +{ + if (entity_is_task(se) && unlikely(task_of(se)->policy == SCHED_IDLE)) + return; + + for_each_sched_entity(se) + cfs_rq_of(se)->next = se; +} + +static void set_skip_buddy(struct sched_entity *se) +{ + for_each_sched_entity(se) + cfs_rq_of(se)->skip = se; +} + +/* + * Preempt the current task with a newly woken task if needed: + */ +static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) +{ + struct task_struct *curr = rq->curr; + struct sched_entity *se = &curr->se, *pse = &p->se; + struct cfs_rq *cfs_rq = task_cfs_rq(curr); + int scale = cfs_rq->nr_running >= sched_nr_latency; + int next_buddy_marked = 0; + + if (unlikely(se == pse)) + return; + + /* + * This is possible from callers such as attach_tasks(), in which we + * unconditionally check_prempt_curr() after an enqueue (which may have + * lead to a throttle). This both saves work and prevents false + * next-buddy nomination below. + */ + if (unlikely(throttled_hierarchy(cfs_rq_of(pse)))) + return; + + if (sched_feat(NEXT_BUDDY) && scale && !(wake_flags & WF_FORK)) { + set_next_buddy(pse); + next_buddy_marked = 1; + } + + /* + * We can come here with TIF_NEED_RESCHED already set from new task + * wake up path. + * + * Note: this also catches the edge-case of curr being in a throttled + * group (e.g. via set_curr_task), since update_curr() (in the + * enqueue of curr) will have resulted in resched being set. This + * prevents us from potentially nominating it as a false LAST_BUDDY + * below. + */ + if (test_tsk_need_resched(curr)) + return; + + /* Idle tasks are by definition preempted by non-idle tasks. */ + if (unlikely(curr->policy == SCHED_IDLE) && + likely(p->policy != SCHED_IDLE)) + goto preempt; + + /* + * Batch and idle tasks do not preempt non-idle tasks (their preemption + * is driven by the tick): + */ + if (unlikely(p->policy != SCHED_NORMAL) || !sched_feat(WAKEUP_PREEMPTION)) + return; + + find_matching_se(&se, &pse); + update_curr(cfs_rq_of(se)); + BUG_ON(!pse); + if (wakeup_preempt_entity(se, pse) == 1) { + /* + * Bias pick_next to pick the sched entity that is + * triggering this preemption. + */ + if (!next_buddy_marked) + set_next_buddy(pse); + goto preempt; + } + + return; + +preempt: + resched_curr(rq); + /* + * Only set the backward buddy when the current task is still + * on the rq. This can happen when a wakeup gets interleaved + * with schedule on the ->pre_schedule() or idle_balance() + * point, either of which can * drop the rq lock. + * + * Also, during early boot the idle thread is in the fair class, + * for obvious reasons its a bad idea to schedule back to it. + */ + if (unlikely(!se->on_rq || curr == rq->idle)) + return; + + if (sched_feat(LAST_BUDDY) && scale && entity_is_task(se)) + set_last_buddy(se); +} + +static struct task_struct * +pick_next_task_fair(struct rq *rq, struct task_struct *prev) +{ + struct cfs_rq *cfs_rq = &rq->cfs; + struct sched_entity *se; + struct task_struct *p; + int new_tasks; + +again: +#ifdef CONFIG_FAIR_GROUP_SCHED + if (!cfs_rq->nr_running) + goto idle; + + if (prev->sched_class != &fair_sched_class) + goto simple; + + /* + * Because of the set_next_buddy() in dequeue_task_fair() it is rather + * likely that a next task is from the same cgroup as the current. + * + * Therefore attempt to avoid putting and setting the entire cgroup + * hierarchy, only change the part that actually changes. + */ + + do { + struct sched_entity *curr = cfs_rq->curr; + + /* + * Since we got here without doing put_prev_entity() we also + * have to consider cfs_rq->curr. If it is still a runnable + * entity, update_curr() will update its vruntime, otherwise + * forget we've ever seen it. + */ + if (curr) { + if (curr->on_rq) + update_curr(cfs_rq); + else + curr = NULL; + + /* + * This call to check_cfs_rq_runtime() will do the + * throttle and dequeue its entity in the parent(s). + * Therefore the 'simple' nr_running test will indeed + * be correct. + */ + if (unlikely(check_cfs_rq_runtime(cfs_rq))) + goto simple; + } + + se = pick_next_entity(cfs_rq, curr); + cfs_rq = group_cfs_rq(se); + } while (cfs_rq); + + p = task_of(se); + + /* + * Since we haven't yet done put_prev_entity and if the selected task + * is a different task than we started out with, try and touch the + * least amount of cfs_rqs. + */ + if (prev != p) { + struct sched_entity *pse = &prev->se; + + while (!(cfs_rq = is_same_group(se, pse))) { + int se_depth = se->depth; + int pse_depth = pse->depth; + + if (se_depth <= pse_depth) { + put_prev_entity(cfs_rq_of(pse), pse); + pse = parent_entity(pse); + } + if (se_depth >= pse_depth) { + set_next_entity(cfs_rq_of(se), se); + se = parent_entity(se); + } + } + + put_prev_entity(cfs_rq, pse); + set_next_entity(cfs_rq, se); + } + + if (hrtick_enabled(rq)) + hrtick_start_fair(rq, p); + + rq->misfit_task = !task_fits_max(p, rq->cpu); + + return p; +simple: + cfs_rq = &rq->cfs; +#endif + + if (!cfs_rq->nr_running) + goto idle; + + put_prev_task(rq, prev); + + do { + se = pick_next_entity(cfs_rq, NULL); + set_next_entity(cfs_rq, se); + cfs_rq = group_cfs_rq(se); + } while (cfs_rq); + + p = task_of(se); + + if (hrtick_enabled(rq)) + hrtick_start_fair(rq, p); + + rq->misfit_task = !task_fits_max(p, rq->cpu); + + return p; + +idle: + rq->misfit_task = 0; + /* + * This is OK, because current is on_cpu, which avoids it being picked + * for load-balance and preemption/IRQs are still disabled avoiding + * further scheduler activity on it and we're being very careful to + * re-start the picking loop. + */ + lockdep_unpin_lock(&rq->lock); + new_tasks = idle_balance(rq); + lockdep_pin_lock(&rq->lock); + /* + * Because idle_balance() releases (and re-acquires) rq->lock, it is + * possible for any higher priority task to appear. In that case we + * must re-start the pick_next_entity() loop. + */ + if (new_tasks < 0) + return RETRY_TASK; + + if (new_tasks > 0) + goto again; + + return NULL; +} + +/* + * Account for a descheduled task: + */ +static void put_prev_task_fair(struct rq *rq, struct task_struct *prev) +{ + struct sched_entity *se = &prev->se; + struct cfs_rq *cfs_rq; + + for_each_sched_entity(se) { + cfs_rq = cfs_rq_of(se); + put_prev_entity(cfs_rq, se); + } +} + +/* + * sched_yield() is very simple + * + * The magic of dealing with the ->skip buddy is in pick_next_entity. + */ +static void yield_task_fair(struct rq *rq) +{ + struct task_struct *curr = rq->curr; + struct cfs_rq *cfs_rq = task_cfs_rq(curr); + struct sched_entity *se = &curr->se; + + /* + * Are we the only task in the tree? + */ + if (unlikely(rq->nr_running == 1)) + return; + + clear_buddies(cfs_rq, se); + + if (curr->policy != SCHED_BATCH) { + update_rq_clock(rq); + /* + * Update run-time statistics of the 'current'. + */ + update_curr(cfs_rq); + /* + * Tell update_rq_clock() that we've just updated, + * so we don't do microscopic update in schedule() + * and double the fastpath cost. + */ + rq_clock_skip_update(rq, true); + } + + set_skip_buddy(se); +} + +static bool yield_to_task_fair(struct rq *rq, struct task_struct *p, bool preempt) +{ + struct sched_entity *se = &p->se; + + /* throttled hierarchies are not runnable */ + if (!se->on_rq || throttled_hierarchy(cfs_rq_of(se))) + return false; + + /* Tell the scheduler that we'd really like pse to run next. */ + set_next_buddy(se); + + yield_task_fair(rq); + + return true; +} + +#ifdef CONFIG_SMP +/************************************************** + * Fair scheduling class load-balancing methods. + * + * BASICS + * + * The purpose of load-balancing is to achieve the same basic fairness the + * per-cpu scheduler provides, namely provide a proportional amount of compute + * time to each task. This is expressed in the following equation: + * + * W_i,n/P_i == W_j,n/P_j for all i,j (1) + * + * Where W_i,n is the n-th weight average for cpu i. The instantaneous weight + * W_i,0 is defined as: + * + * W_i,0 = \Sum_j w_i,j (2) + * + * Where w_i,j is the weight of the j-th runnable task on cpu i. This weight + * is derived from the nice value as per prio_to_weight[]. + * + * The weight average is an exponential decay average of the instantaneous + * weight: + * + * W'_i,n = (2^n - 1) / 2^n * W_i,n + 1 / 2^n * W_i,0 (3) + * + * C_i is the compute capacity of cpu i, typically it is the + * fraction of 'recent' time available for SCHED_OTHER task execution. But it + * can also include other factors [XXX]. + * + * To achieve this balance we define a measure of imbalance which follows + * directly from (1): + * + * imb_i,j = max{ avg(W/C), W_i/C_i } - min{ avg(W/C), W_j/C_j } (4) + * + * We them move tasks around to minimize the imbalance. In the continuous + * function space it is obvious this converges, in the discrete case we get + * a few fun cases generally called infeasible weight scenarios. + * + * [XXX expand on: + * - infeasible weights; + * - local vs global optima in the discrete case. ] + * + * + * SCHED DOMAINS + * + * In order to solve the imbalance equation (4), and avoid the obvious O(n^2) + * for all i,j solution, we create a tree of cpus that follows the hardware + * topology where each level pairs two lower groups (or better). This results + * in O(log n) layers. Furthermore we reduce the number of cpus going up the + * tree to only the first of the previous level and we decrease the frequency + * of load-balance at each level inv. proportional to the number of cpus in + * the groups. + * + * This yields: + * + * log_2 n 1 n + * \Sum { --- * --- * 2^i } = O(n) (5) + * i = 0 2^i 2^i + * `- size of each group + * | | `- number of cpus doing load-balance + * | `- freq + * `- sum over all levels + * + * Coupled with a limit on how many tasks we can migrate every balance pass, + * this makes (5) the runtime complexity of the balancer. + * + * An important property here is that each CPU is still (indirectly) connected + * to every other cpu in at most O(log n) steps: + * + * The adjacency matrix of the resulting graph is given by: + * + * log_2 n + * A_i,j = \Union (i % 2^k == 0) && i / 2^(k+1) == j / 2^(k+1) (6) + * k = 0 + * + * And you'll find that: + * + * A^(log_2 n)_i,j != 0 for all i,j (7) + * + * Showing there's indeed a path between every cpu in at most O(log n) steps. + * The task movement gives a factor of O(m), giving a convergence complexity + * of: + * + * O(nm log n), n := nr_cpus, m := nr_tasks (8) + * + * + * WORK CONSERVING + * + * In order to avoid CPUs going idle while there's still work to do, new idle + * balancing is more aggressive and has the newly idle cpu iterate up the domain + * tree itself instead of relying on other CPUs to bring it work. + * + * This adds some complexity to both (5) and (8) but it reduces the total idle + * time. + * + * [XXX more?] + * + * + * CGROUPS + * + * Cgroups make a horror show out of (2), instead of a simple sum we get: + * + * s_k,i + * W_i,0 = \Sum_j \Prod_k w_k * ----- (9) + * S_k + * + * Where + * + * s_k,i = \Sum_j w_i,j,k and S_k = \Sum_i s_k,i (10) + * + * w_i,j,k is the weight of the j-th runnable task in the k-th cgroup on cpu i. + * + * The big problem is S_k, its a global sum needed to compute a local (W_i) + * property. + * + * [XXX write more on how we solve this.. _after_ merging pjt's patches that + * rewrite all of this once again.] + */ + +static unsigned long __read_mostly max_load_balance_interval = HZ/10; + +enum fbq_type { regular, remote, all }; + +enum group_type { + group_other = 0, + group_misfit_task, + group_imbalanced, + group_overloaded, +}; + +#define LBF_ALL_PINNED 0x01 +#define LBF_NEED_BREAK 0x02 +#define LBF_DST_PINNED 0x04 +#define LBF_SOME_PINNED 0x08 +#define LBF_BIG_TASK_ACTIVE_BALANCE 0x80 +#define LBF_IGNORE_BIG_TASKS 0x100 +#define LBF_IGNORE_PREFERRED_CLUSTER_TASKS 0x200 +#define LBF_MOVED_RELATED_THREAD_GROUP_TASK 0x400 + +struct lb_env { + struct sched_domain *sd; + + struct rq *src_rq; + int src_cpu; + + int dst_cpu; + struct rq *dst_rq; + + struct cpumask *dst_grpmask; + int new_dst_cpu; + enum cpu_idle_type idle; + long imbalance; + unsigned int src_grp_nr_running; + /* The set of CPUs under consideration for load-balancing */ + struct cpumask *cpus; + unsigned int busiest_grp_capacity; + unsigned int busiest_nr_running; + + unsigned int flags; + + unsigned int loop; + unsigned int loop_break; + unsigned int loop_max; + + enum fbq_type fbq_type; + enum group_type busiest_group_type; + struct list_head tasks; + enum sched_boost_policy boost_policy; +}; + +/* + * Is this task likely cache-hot: + */ +static int task_hot(struct task_struct *p, struct lb_env *env) +{ + s64 delta; + + lockdep_assert_held(&env->src_rq->lock); + + if (p->sched_class != &fair_sched_class) + return 0; + + if (unlikely(p->policy == SCHED_IDLE)) + return 0; + + /* + * Buddy candidates are cache hot: + */ + if (sched_feat(CACHE_HOT_BUDDY) && env->dst_rq->nr_running && + (&p->se == cfs_rq_of(&p->se)->next || + &p->se == cfs_rq_of(&p->se)->last)) + return 1; + + if (sysctl_sched_migration_cost == -1) + return 1; + if (sysctl_sched_migration_cost == 0) + return 0; + + delta = rq_clock_task(env->src_rq) - p->se.exec_start; + + return delta < (s64)sysctl_sched_migration_cost; +} + +#ifdef CONFIG_NUMA_BALANCING +/* + * Returns 1, if task migration degrades locality + * Returns 0, if task migration improves locality i.e migration preferred. + * Returns -1, if task migration is not affected by locality. + */ +static int migrate_degrades_locality(struct task_struct *p, struct lb_env *env) +{ + struct numa_group *numa_group = rcu_dereference(p->numa_group); + unsigned long src_faults, dst_faults; + int src_nid, dst_nid; + + if (!static_branch_likely(&sched_numa_balancing)) + return -1; + + if (!p->numa_faults || !(env->sd->flags & SD_NUMA)) + return -1; + + src_nid = cpu_to_node(env->src_cpu); + dst_nid = cpu_to_node(env->dst_cpu); + + if (src_nid == dst_nid) + return -1; + + /* Migrating away from the preferred node is always bad. */ + if (src_nid == p->numa_preferred_nid) { + if (env->src_rq->nr_running > env->src_rq->nr_preferred_running) + return 1; + else + return -1; + } + + /* Encourage migration to the preferred node. */ + if (dst_nid == p->numa_preferred_nid) + return 0; + + if (numa_group) { + src_faults = group_faults(p, src_nid); + dst_faults = group_faults(p, dst_nid); + } else { + src_faults = task_faults(p, src_nid); + dst_faults = task_faults(p, dst_nid); + } + + return dst_faults < src_faults; +} + +#else +static inline int migrate_degrades_locality(struct task_struct *p, + struct lb_env *env) +{ + return -1; +} +#endif + +/* + * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? + */ +static +int can_migrate_task(struct task_struct *p, struct lb_env *env) +{ + int tsk_cache_hot; + int twf, group_cpus; + + lockdep_assert_held(&env->src_rq->lock); + + /* + * We do not migrate tasks that are: + * 1) throttled_lb_pair, or + * 2) cannot be migrated to this CPU due to cpus_allowed, or + * 3) running (obviously), or + * 4) are cache-hot on their current CPU. + */ + if (throttled_lb_pair(task_group(p), env->src_cpu, env->dst_cpu)) + return 0; + + if (!cpumask_test_cpu(env->dst_cpu, tsk_cpus_allowed(p))) { + int cpu; + + schedstat_inc(p, se.statistics.nr_failed_migrations_affine); + + env->flags |= LBF_SOME_PINNED; + + /* + * Remember if this task can be migrated to any other cpu in + * our sched_group. We may want to revisit it if we couldn't + * meet load balance goals by pulling other tasks on src_cpu. + * + * Also avoid computing new_dst_cpu if we have already computed + * one in current iteration. + */ + if (!env->dst_grpmask || (env->flags & LBF_DST_PINNED)) + return 0; + + /* Prevent to re-select dst_cpu via env's cpus */ + for_each_cpu_and(cpu, env->dst_grpmask, env->cpus) { + if (cpumask_test_cpu(cpu, tsk_cpus_allowed(p))) { + env->flags |= LBF_DST_PINNED; + env->new_dst_cpu = cpu; + break; + } + } + + return 0; + } + + /* Record that we found atleast one task that could run on dst_cpu */ + env->flags &= ~LBF_ALL_PINNED; + + if (cpu_capacity(env->dst_cpu) > cpu_capacity(env->src_cpu)) { + if (nr_big_tasks(env->src_rq) && !is_big_task(p)) + return 0; + + if (env->boost_policy == SCHED_BOOST_ON_BIG && + !task_sched_boost(p)) + return 0; + } + + twf = task_will_fit(p, env->dst_cpu); + + /* + * Attempt to not pull tasks that don't fit. We may get lucky and find + * one that actually fits. + */ + if (env->flags & LBF_IGNORE_BIG_TASKS && !twf) + return 0; + + if (env->flags & LBF_IGNORE_PREFERRED_CLUSTER_TASKS && + !preferred_cluster(rq_cluster(cpu_rq(env->dst_cpu)), p)) + return 0; + + /* + * Group imbalance can sometimes cause work to be pulled across groups + * even though the group could have managed the imbalance on its own. + * Prevent inter-cluster migrations for big tasks when the number of + * tasks is lower than the capacity of the group. + */ + group_cpus = DIV_ROUND_UP(env->busiest_grp_capacity, + SCHED_CAPACITY_SCALE); + if (!twf && env->busiest_nr_running <= group_cpus) + return 0; + + if (task_running(env->src_rq, p)) { + schedstat_inc(p, se.statistics.nr_failed_migrations_running); + return 0; + } + + /* + * Aggressive migration if: + * 1) IDLE or NEWLY_IDLE balance. + * 2) destination numa is preferred + * 3) task is cache cold, or + * 4) too many balance attempts have failed. + */ + tsk_cache_hot = migrate_degrades_locality(p, env); + if (tsk_cache_hot == -1) + tsk_cache_hot = task_hot(p, env); + + if (env->idle != CPU_NOT_IDLE || tsk_cache_hot <= 0 || + env->sd->nr_balance_failed > env->sd->cache_nice_tries) { + if (tsk_cache_hot == 1) { + schedstat_inc(env->sd, lb_hot_gained[env->idle]); + schedstat_inc(p, se.statistics.nr_forced_migrations); + } + return 1; + } + + schedstat_inc(p, se.statistics.nr_failed_migrations_hot); + return 0; +} + +/* + * detach_task() -- detach the task for the migration specified in env + */ +static void detach_task(struct task_struct *p, struct lb_env *env) +{ + lockdep_assert_held(&env->src_rq->lock); + + p->on_rq = TASK_ON_RQ_MIGRATING; + deactivate_task(env->src_rq, p, 0); + double_lock_balance(env->src_rq, env->dst_rq); + set_task_cpu(p, env->dst_cpu); + if (task_in_related_thread_group(p)) + env->flags |= LBF_MOVED_RELATED_THREAD_GROUP_TASK; + double_unlock_balance(env->src_rq, env->dst_rq); +} + +/* + * detach_one_task() -- tries to dequeue exactly one task from env->src_rq, as + * part of active balancing operations within "domain". + * + * Returns a task if successful and NULL otherwise. + */ +static struct task_struct *detach_one_task(struct lb_env *env) +{ + struct task_struct *p, *n; + + lockdep_assert_held(&env->src_rq->lock); + + list_for_each_entry_safe(p, n, &env->src_rq->cfs_tasks, se.group_node) { + if (!can_migrate_task(p, env)) + continue; + + detach_task(p, env); + + /* + * Right now, this is only the second place where + * lb_gained[env->idle] is updated (other is detach_tasks) + * so we can safely collect stats here rather than + * inside detach_tasks(). + */ + schedstat_inc(env->sd, lb_gained[env->idle]); + + return p; + } + return NULL; +} + +static const unsigned int sched_nr_migrate_break = 32; + +/* + * detach_tasks() -- tries to detach up to imbalance weighted load from + * busiest_rq, as part of a balancing operation within domain "sd". + * + * Returns number of detached tasks if successful and 0 otherwise. + */ +static int detach_tasks(struct lb_env *env) +{ + struct list_head *tasks = &env->src_rq->cfs_tasks; + struct task_struct *p; + unsigned long load; + int detached = 0; + int orig_loop = env->loop; + + lockdep_assert_held(&env->src_rq->lock); + + if (env->imbalance <= 0) + return 0; + + if (!same_cluster(env->dst_cpu, env->src_cpu)) + env->flags |= LBF_IGNORE_PREFERRED_CLUSTER_TASKS; + + if (cpu_capacity(env->dst_cpu) < cpu_capacity(env->src_cpu)) + env->flags |= LBF_IGNORE_BIG_TASKS; + +redo: + while (!list_empty(tasks)) { + /* + * We don't want to steal all, otherwise we may be treated likewise, + * which could at worst lead to a livelock crash. + */ + if (env->idle != CPU_NOT_IDLE && env->src_rq->nr_running <= 1) + break; + + p = list_first_entry(tasks, struct task_struct, se.group_node); + + env->loop++; + /* We've more or less seen every task there is, call it quits */ + if (env->loop > env->loop_max) + break; + + /* take a breather every nr_migrate tasks */ + if (env->loop > env->loop_break) { + env->loop_break += sched_nr_migrate_break; + env->flags |= LBF_NEED_BREAK; + break; + } + + if (!can_migrate_task(p, env)) + goto next; + + /* + * Depending of the number of CPUs and tasks and the + * cgroup hierarchy, task_h_load() can return a null + * value. Make sure that env->imbalance decreases + * otherwise detach_tasks() will stop only after + * detaching up to loop_max tasks. + */ + load = max_t(unsigned long, task_h_load(p), 1); + + + if (sched_feat(LB_MIN) && load < 16 && !env->sd->nr_balance_failed) + goto next; + + if ((load / 2) > env->imbalance) + goto next; + + detach_task(p, env); + list_add(&p->se.group_node, &env->tasks); + + detached++; + env->imbalance -= load; + +#ifdef CONFIG_PREEMPT + /* + * NEWIDLE balancing is a source of latency, so preemptible + * kernels will stop after the first task is detached to minimize + * the critical section. + */ + if (env->idle == CPU_NEWLY_IDLE) + break; +#endif + + /* + * We only want to steal up to the prescribed amount of + * weighted load. + */ + if (env->imbalance <= 0) + break; + + continue; +next: + list_move_tail(&p->se.group_node, tasks); + } + + if (env->flags & (LBF_IGNORE_BIG_TASKS | + LBF_IGNORE_PREFERRED_CLUSTER_TASKS) && !detached) { + tasks = &env->src_rq->cfs_tasks; + env->flags &= ~(LBF_IGNORE_BIG_TASKS | + LBF_IGNORE_PREFERRED_CLUSTER_TASKS); + env->loop = orig_loop; + goto redo; + } + + /* + * Right now, this is one of only two places we collect this stat + * so we can safely collect detach_one_task() stats here rather + * than inside detach_one_task(). + */ + schedstat_add(env->sd, lb_gained[env->idle], detached); + + return detached; +} + +/* + * attach_task() -- attach the task detached by detach_task() to its new rq. + */ +static void attach_task(struct rq *rq, struct task_struct *p) +{ + lockdep_assert_held(&rq->lock); + + BUG_ON(task_rq(p) != rq); + activate_task(rq, p, 0); + p->on_rq = TASK_ON_RQ_QUEUED; + check_preempt_curr(rq, p, 0); +} + +/* + * attach_one_task() -- attaches the task returned from detach_one_task() to + * its new rq. + */ +static void attach_one_task(struct rq *rq, struct task_struct *p) +{ + raw_spin_lock(&rq->lock); + attach_task(rq, p); + raw_spin_unlock(&rq->lock); +} + +/* + * attach_tasks() -- attaches all tasks detached by detach_tasks() to their + * new rq. + */ +static void attach_tasks(struct lb_env *env) +{ + struct list_head *tasks = &env->tasks; + struct task_struct *p; + + raw_spin_lock(&env->dst_rq->lock); + + while (!list_empty(tasks)) { + p = list_first_entry(tasks, struct task_struct, se.group_node); + list_del_init(&p->se.group_node); + + attach_task(env->dst_rq, p); + } + + raw_spin_unlock(&env->dst_rq->lock); +} + +#ifdef CONFIG_FAIR_GROUP_SCHED +static void update_blocked_averages(int cpu) +{ + struct rq *rq = cpu_rq(cpu); + struct cfs_rq *cfs_rq; + unsigned long flags; + + raw_spin_lock_irqsave(&rq->lock, flags); + update_rq_clock(rq); + + /* + * Iterates the task_group tree in a bottom up fashion, see + * list_add_leaf_cfs_rq() for details. + */ + for_each_leaf_cfs_rq(rq, cfs_rq) { + /* throttled entities do not contribute to load */ + if (throttled_hierarchy(cfs_rq)) + continue; + + if (update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq, + true)) + update_tg_load_avg(cfs_rq, 0); + + /* Propagate pending load changes to the parent */ + if (cfs_rq->tg->se[cpu]) + update_load_avg(cfs_rq->tg->se[cpu], 0); + } + raw_spin_unlock_irqrestore(&rq->lock, flags); +} + +/* + * Compute the hierarchical load factor for cfs_rq and all its ascendants. + * This needs to be done in a top-down fashion because the load of a child + * group is a fraction of its parents load. + */ +static void update_cfs_rq_h_load(struct cfs_rq *cfs_rq) +{ + struct rq *rq = rq_of(cfs_rq); + struct sched_entity *se = cfs_rq->tg->se[cpu_of(rq)]; + unsigned long now = jiffies; + unsigned long load; + + if (cfs_rq->last_h_load_update == now) + return; + + WRITE_ONCE(cfs_rq->h_load_next, NULL); + for_each_sched_entity(se) { + cfs_rq = cfs_rq_of(se); + WRITE_ONCE(cfs_rq->h_load_next, se); + if (cfs_rq->last_h_load_update == now) + break; + } + + if (!se) { + cfs_rq->h_load = cfs_rq_load_avg(cfs_rq); + cfs_rq->last_h_load_update = now; + } + + while ((se = READ_ONCE(cfs_rq->h_load_next)) != NULL) { + load = cfs_rq->h_load; + load = div64_ul(load * se->avg.load_avg, + cfs_rq_load_avg(cfs_rq) + 1); + cfs_rq = group_cfs_rq(se); + cfs_rq->h_load = load; + cfs_rq->last_h_load_update = now; + } +} + +static unsigned long task_h_load(struct task_struct *p) +{ + struct cfs_rq *cfs_rq = task_cfs_rq(p); + + update_cfs_rq_h_load(cfs_rq); + return div64_ul(p->se.avg.load_avg * cfs_rq->h_load, + cfs_rq_load_avg(cfs_rq) + 1); +} +#else +static inline void update_blocked_averages(int cpu) +{ + struct rq *rq = cpu_rq(cpu); + struct cfs_rq *cfs_rq = &rq->cfs; + unsigned long flags; + + raw_spin_lock_irqsave(&rq->lock, flags); + update_rq_clock(rq); + update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq, true); + raw_spin_unlock_irqrestore(&rq->lock, flags); +} + +static unsigned long task_h_load(struct task_struct *p) +{ + return p->se.avg.load_avg; +} +#endif + +/********** Helpers for find_busiest_group ************************/ + +/* + * sg_lb_stats - stats of a sched_group required for load_balancing + */ +struct sg_lb_stats { + unsigned long avg_load; /*Avg load across the CPUs of the group */ + unsigned long group_load; /* Total load over the CPUs of the group */ + unsigned long sum_weighted_load; /* Weighted load of group's tasks */ + unsigned long load_per_task; + unsigned long group_capacity; + unsigned long group_util; /* Total utilization of the group */ + unsigned int sum_nr_running; /* Nr tasks running in the group */ +#ifdef CONFIG_SCHED_HMP + unsigned long sum_nr_big_tasks; + u64 group_cpu_load; /* Scaled load of all CPUs of the group */ +#endif + unsigned int idle_cpus; + unsigned int group_weight; + enum group_type group_type; + int group_no_capacity; + int group_misfit_task; /* A cpu has a task too big for its capacity */ +#ifdef CONFIG_NUMA_BALANCING + unsigned int nr_numa_running; + unsigned int nr_preferred_running; +#endif +}; + +/* + * sd_lb_stats - Structure to store the statistics of a sched_domain + * during load balancing. + */ +struct sd_lb_stats { + struct sched_group *busiest; /* Busiest group in this sd */ + struct sched_group *local; /* Local group in this sd */ + unsigned long total_load; /* Total load of all groups in sd */ + unsigned long total_capacity; /* Total capacity of all groups in sd */ + unsigned long avg_load; /* Average load across all groups in sd */ + + struct sg_lb_stats busiest_stat;/* Statistics of the busiest group */ + struct sg_lb_stats local_stat; /* Statistics of the local group */ +}; + +static inline void init_sd_lb_stats(struct sd_lb_stats *sds) +{ + /* + * Skimp on the clearing to avoid duplicate work. We can avoid clearing + * local_stat because update_sg_lb_stats() does a full clear/assignment. + * We must however clear busiest_stat::avg_load because + * update_sd_pick_busiest() reads this before assignment. + */ + *sds = (struct sd_lb_stats){ + .busiest = NULL, + .local = NULL, + .total_load = 0UL, + .total_capacity = 0UL, + .busiest_stat = { + .avg_load = 0UL, + .sum_nr_running = 0, + .group_type = group_other, +#ifdef CONFIG_SCHED_HMP + .sum_nr_big_tasks = 0UL, + .group_cpu_load = 0ULL, +#endif + }, + }; +} + +#ifdef CONFIG_SCHED_HMP + +static int +bail_inter_cluster_balance(struct lb_env *env, struct sd_lb_stats *sds) +{ + int local_cpu, busiest_cpu; + int local_capacity, busiest_capacity; + int local_pwr_cost, busiest_pwr_cost; + int nr_cpus; + int boost = sched_boost(); + + if (!sysctl_sched_restrict_cluster_spill || + boost == FULL_THROTTLE_BOOST || boost == CONSERVATIVE_BOOST) + return 0; + + local_cpu = group_first_cpu(sds->local); + busiest_cpu = group_first_cpu(sds->busiest); + + local_capacity = cpu_max_possible_capacity(local_cpu); + busiest_capacity = cpu_max_possible_capacity(busiest_cpu); + + local_pwr_cost = cpu_max_power_cost(local_cpu); + busiest_pwr_cost = cpu_max_power_cost(busiest_cpu); + + if (local_pwr_cost <= busiest_pwr_cost) + return 0; + + if (local_capacity > busiest_capacity && + sds->busiest_stat.sum_nr_big_tasks) + return 0; + + nr_cpus = cpumask_weight(sched_group_cpus(sds->busiest)); + if ((sds->busiest_stat.group_cpu_load < nr_cpus * sched_spill_load) && + (sds->busiest_stat.sum_nr_running < + nr_cpus * sysctl_sched_spill_nr_run)) + return 1; + + return 0; +} + +#else /* CONFIG_SCHED_HMP */ + +static inline int +bail_inter_cluster_balance(struct lb_env *env, struct sd_lb_stats *sds) +{ + return 0; +} + +#endif /* CONFIG_SCHED_HMP */ + +/** + * get_sd_load_idx - Obtain the load index for a given sched domain. + * @sd: The sched_domain whose load_idx is to be obtained. + * @idle: The idle status of the CPU for whose sd load_idx is obtained. + * + * Return: The load index. + */ +static inline int get_sd_load_idx(struct sched_domain *sd, + enum cpu_idle_type idle) +{ + int load_idx; + + switch (idle) { + case CPU_NOT_IDLE: + load_idx = sd->busy_idx; + break; + + case CPU_NEWLY_IDLE: + load_idx = sd->newidle_idx; + break; + default: + load_idx = sd->idle_idx; + break; + } + + return load_idx; +} + +static unsigned long scale_rt_capacity(int cpu) +{ + struct rq *rq = cpu_rq(cpu); + u64 total, used, age_stamp, avg; + s64 delta; + + /* + * Since we're reading these variables without serialization make sure + * we read them once before doing sanity checks on them. + */ + age_stamp = READ_ONCE(rq->age_stamp); + avg = READ_ONCE(rq->rt_avg); + delta = __rq_clock_broken(rq) - age_stamp; + + if (unlikely(delta < 0)) + delta = 0; + + total = sched_avg_period() + delta; + + used = div_u64(avg, total); + + /* + * deadline bandwidth is defined at system level so we must + * weight this bandwidth with the max capacity of the system. + * As a reminder, avg_bw is 20bits width and + * scale_cpu_capacity is 10 bits width + */ + used += div_u64(rq->dl.avg_bw, arch_scale_cpu_capacity(NULL, cpu)); + + if (likely(used < SCHED_CAPACITY_SCALE)) + return SCHED_CAPACITY_SCALE - used; + + return 1; +} + +void init_max_cpu_capacity(struct max_cpu_capacity *mcc) +{ + raw_spin_lock_init(&mcc->lock); + mcc->val = 0; + mcc->cpu = -1; +} + +static void update_cpu_capacity(struct sched_domain *sd, int cpu) +{ + unsigned long capacity = arch_scale_cpu_capacity(sd, cpu); + struct sched_group *sdg = sd->groups; + struct max_cpu_capacity *mcc; + unsigned long max_capacity; + int max_cap_cpu; + unsigned long flags; + + cpu_rq(cpu)->cpu_capacity_orig = capacity; + + mcc = &cpu_rq(cpu)->rd->max_cpu_capacity; + + raw_spin_lock_irqsave(&mcc->lock, flags); + max_capacity = mcc->val; + max_cap_cpu = mcc->cpu; + + if ((max_capacity > capacity && max_cap_cpu == cpu) || + (max_capacity < capacity)) { + mcc->val = capacity; + mcc->cpu = cpu; +#ifdef CONFIG_SCHED_DEBUG + raw_spin_unlock_irqrestore(&mcc->lock, flags); + printk_deferred(KERN_INFO "CPU%d: update max cpu_capacity %lu\n", + cpu, capacity); + goto skip_unlock; +#endif + } + raw_spin_unlock_irqrestore(&mcc->lock, flags); + +skip_unlock: __attribute__ ((unused)); + capacity *= scale_rt_capacity(cpu); + capacity >>= SCHED_CAPACITY_SHIFT; + + if (!capacity) + capacity = 1; + + cpu_rq(cpu)->cpu_capacity = capacity; + sdg->sgc->capacity = capacity; + sdg->sgc->max_capacity = capacity; + sdg->sgc->min_capacity = capacity; +} + +void update_group_capacity(struct sched_domain *sd, int cpu) +{ + struct sched_domain *child = sd->child; + struct sched_group *group, *sdg = sd->groups; + unsigned long capacity, max_capacity, min_capacity; + unsigned long interval; + + interval = msecs_to_jiffies(sd->balance_interval); + interval = clamp(interval, 1UL, max_load_balance_interval); + sdg->sgc->next_update = jiffies + interval; + + if (!child) { + update_cpu_capacity(sd, cpu); + return; + } + + capacity = 0; + max_capacity = 0; + min_capacity = ULONG_MAX; + + if (child->flags & SD_OVERLAP) { + /* + * SD_OVERLAP domains cannot assume that child groups + * span the current group. + */ + + for_each_cpu(cpu, sched_group_cpus(sdg)) { + struct sched_group_capacity *sgc; + struct rq *rq = cpu_rq(cpu); + + if (cpumask_test_cpu(cpu, cpu_isolated_mask)) + continue; + /* + * build_sched_domains() -> init_sched_groups_capacity() + * gets here before we've attached the domains to the + * runqueues. + * + * Use capacity_of(), which is set irrespective of domains + * in update_cpu_capacity(). + * + * This avoids capacity from being 0 and + * causing divide-by-zero issues on boot. + */ + if (unlikely(!rq->sd)) { + capacity += capacity_of(cpu); + } else { + sgc = rq->sd->groups->sgc; + capacity += sgc->capacity; + } + + max_capacity = max(capacity, max_capacity); + min_capacity = min(capacity, min_capacity); + } + } else { + /* + * !SD_OVERLAP domains can assume that child groups + * span the current group. + */ + + group = child->groups; + do { + struct sched_group_capacity *sgc = group->sgc; + + cpumask_t *cpus = sched_group_cpus(group); + + /* Revisit this later. This won't work for MT domain */ + if (!cpu_isolated(cpumask_first(cpus))) { + capacity += sgc->capacity; + max_capacity = max(sgc->max_capacity, max_capacity); + min_capacity = min(sgc->min_capacity, min_capacity); + } + group = group->next; + } while (group != child->groups); + } + + sdg->sgc->capacity = capacity; + sdg->sgc->max_capacity = max_capacity; + sdg->sgc->min_capacity = min_capacity; +} + +/* + * Check whether the capacity of the rq has been noticeably reduced by side + * activity. The imbalance_pct is used for the threshold. + * Return true is the capacity is reduced + */ +static inline int +check_cpu_capacity(struct rq *rq, struct sched_domain *sd) +{ + return ((rq->cpu_capacity * sd->imbalance_pct) < + (rq->cpu_capacity_orig * 100)); +} + +/* + * Group imbalance indicates (and tries to solve) the problem where balancing + * groups is inadequate due to tsk_cpus_allowed() constraints. + * + * Imagine a situation of two groups of 4 cpus each and 4 tasks each with a + * cpumask covering 1 cpu of the first group and 3 cpus of the second group. + * Something like: + * + * { 0 1 2 3 } { 4 5 6 7 } + * * * * * + * + * If we were to balance group-wise we'd place two tasks in the first group and + * two tasks in the second group. Clearly this is undesired as it will overload + * cpu 3 and leave one of the cpus in the second group unused. + * + * The current solution to this issue is detecting the skew in the first group + * by noticing the lower domain failed to reach balance and had difficulty + * moving tasks due to affinity constraints. + * + * When this is so detected; this group becomes a candidate for busiest; see + * update_sd_pick_busiest(). And calculate_imbalance() and + * find_busiest_group() avoid some of the usual balance conditions to allow it + * to create an effective group imbalance. + * + * This is a somewhat tricky proposition since the next run might not find the + * group imbalance and decide the groups need to be balanced again. A most + * subtle and fragile situation. + */ + +static inline int sg_imbalanced(struct sched_group *group) +{ + return group->sgc->imbalance; +} + +/* + * group_has_capacity returns true if the group has spare capacity that could + * be used by some tasks. + * We consider that a group has spare capacity if the * number of task is + * smaller than the number of CPUs or if the utilization is lower than the + * available capacity for CFS tasks. + * For the latter, we use a threshold to stabilize the state, to take into + * account the variance of the tasks' load and to return true if the available + * capacity in meaningful for the load balancer. + * As an example, an available capacity of 1% can appear but it doesn't make + * any benefit for the load balance. + */ +static inline bool +group_has_capacity(struct lb_env *env, struct sg_lb_stats *sgs) +{ + if (sgs->sum_nr_running < sgs->group_weight) + return true; + + if ((sgs->group_capacity * 100) > + (sgs->group_util * env->sd->imbalance_pct)) + return true; + + return false; +} + +/* + * group_is_overloaded returns true if the group has more tasks than it can + * handle. + * group_is_overloaded is not equals to !group_has_capacity because a group + * with the exact right number of tasks, has no more spare capacity but is not + * overloaded so both group_has_capacity and group_is_overloaded return + * false. + */ +static inline bool +group_is_overloaded(struct lb_env *env, struct sg_lb_stats *sgs) +{ + if (sgs->sum_nr_running <= sgs->group_weight) + return false; + + if ((sgs->group_capacity * 100) < + (sgs->group_util * env->sd->imbalance_pct)) + return true; + + return false; +} + + +/* + * group_smaller_cpu_capacity: Returns true if sched_group sg has smaller + * per-cpu capacity than sched_group ref. + */ +static inline bool +group_smaller_cpu_capacity(struct sched_group *sg, struct sched_group *ref) +{ + return sg->sgc->max_capacity + capacity_margin - SCHED_LOAD_SCALE < + ref->sgc->max_capacity; +} + +static inline enum +group_type group_classify(struct sched_group *group, + struct sg_lb_stats *sgs, struct lb_env *env) +{ + if (sgs->group_no_capacity) + return group_overloaded; + + if (sg_imbalanced(group)) + return group_imbalanced; + + if (sgs->group_misfit_task) + return group_misfit_task; + + return group_other; +} + +#ifdef CONFIG_NO_HZ_COMMON +/* + * idle load balancing data + * - used by the nohz balance, but we want it available here + * so that we can see which CPUs have no tick. + */ +static struct { + cpumask_var_t idle_cpus_mask; + atomic_t nr_cpus; + unsigned long next_balance; /* in jiffy units */ +} nohz ____cacheline_aligned; + +static inline void update_cpu_stats_if_tickless(struct rq *rq) +{ + /* only called from update_sg_lb_stats when irqs are disabled */ + if (cpumask_test_cpu(rq->cpu, nohz.idle_cpus_mask)) { + /* rate limit updates to once-per-jiffie at most */ + if (READ_ONCE(jiffies) <= rq->last_load_update_tick) + return; + + raw_spin_lock(&rq->lock); + update_rq_clock(rq); + update_idle_cpu_load(rq); + update_cfs_rq_load_avg(rq->clock_task, &rq->cfs, false); + raw_spin_unlock(&rq->lock); + } +} + +#else +static inline void update_cpu_stats_if_tickless(struct rq *rq) { } +#endif + +/** + * update_sg_lb_stats - Update sched_group's statistics for load balancing. + * @env: The load balancing environment. + * @group: sched_group whose statistics are to be updated. + * @load_idx: Load index of sched_domain of this_cpu for load calc. + * @local_group: Does group contain this_cpu. + * @sgs: variable to hold the statistics for this group. + * @overload: Indicate more than one runnable task for any CPU. + * @overutilized: Indicate overutilization for any CPU. + */ +static inline void update_sg_lb_stats(struct lb_env *env, + struct sched_group *group, int load_idx, + int local_group, struct sg_lb_stats *sgs, + bool *overload, bool *overutilized) +{ + unsigned long load; + int i, nr_running; + + memset(sgs, 0, sizeof(*sgs)); + + for_each_cpu_and(i, sched_group_cpus(group), env->cpus) { + struct rq *rq = cpu_rq(i); + + trace_sched_cpu_load_lb(cpu_rq(i), idle_cpu(i), + sched_irqload(i), + power_cost(i, 0), + cpu_temp(i)); + + if (cpu_isolated(i)) + continue; + + /* if we are entering idle and there are CPUs with + * their tick stopped, do an update for them + */ + if (env->idle == CPU_NEWLY_IDLE) + update_cpu_stats_if_tickless(rq); + + /* Bias balancing toward cpus of our domain */ + if (local_group) + load = target_load(i, load_idx); + else + load = source_load(i, load_idx); + + sgs->group_load += load; + sgs->group_util += cpu_util(i); + sgs->sum_nr_running += rq->cfs.h_nr_running; + + nr_running = rq->nr_running; + if (nr_running > 1) + *overload = true; + +#ifdef CONFIG_SCHED_HMP + sgs->sum_nr_big_tasks += rq->hmp_stats.nr_big_tasks; + sgs->group_cpu_load += cpu_load(i); +#endif + +#ifdef CONFIG_NUMA_BALANCING + sgs->nr_numa_running += rq->nr_numa_running; + sgs->nr_preferred_running += rq->nr_preferred_running; +#endif + sgs->sum_weighted_load += weighted_cpuload(i); + /* + * No need to call idle_cpu() if nr_running is not 0 + */ + if (!nr_running && idle_cpu(i)) + sgs->idle_cpus++; + + if (energy_aware() && cpu_overutilized(i)) { + *overutilized = true; + if (!sgs->group_misfit_task && rq->misfit_task) + sgs->group_misfit_task = capacity_of(i); + } + } + + /* Isolated CPU has no weight */ + if (!group->group_weight) { + sgs->group_capacity = 0; + sgs->avg_load = 0; + sgs->group_no_capacity = 1; + sgs->group_type = group_other; + sgs->group_weight = group->group_weight; + } else { + /* Adjust by relative CPU capacity of the group */ + sgs->group_capacity = group->sgc->capacity; + sgs->avg_load = (sgs->group_load*SCHED_CAPACITY_SCALE) / + sgs->group_capacity; + + sgs->group_weight = group->group_weight; + + sgs->group_no_capacity = group_is_overloaded(env, sgs); + sgs->group_type = group_classify(group, sgs, env); + } + + if (sgs->sum_nr_running) + sgs->load_per_task = sgs->sum_weighted_load / sgs->sum_nr_running; +} + +#ifdef CONFIG_SCHED_HMP +static bool update_sd_pick_busiest_active_balance(struct lb_env *env, + struct sd_lb_stats *sds, + struct sched_group *sg, + struct sg_lb_stats *sgs) +{ + if (env->idle != CPU_NOT_IDLE && + cpu_capacity(env->dst_cpu) > group_rq_capacity(sg)) { + if (sgs->sum_nr_big_tasks > + sds->busiest_stat.sum_nr_big_tasks) { + env->flags |= LBF_BIG_TASK_ACTIVE_BALANCE; + return true; + } + } + + return false; +} +#else +static bool update_sd_pick_busiest_active_balance(struct lb_env *env, + struct sd_lb_stats *sds, + struct sched_group *sg, + struct sg_lb_stats *sgs) +{ + return false; +} +#endif + +/** + * update_sd_pick_busiest - return 1 on busiest group + * @env: The load balancing environment. + * @sds: sched_domain statistics + * @sg: sched_group candidate to be checked for being the busiest + * @sgs: sched_group statistics + * + * Determine if @sg is a busier group than the previously selected + * busiest group. + * + * Return: %true if @sg is a busier group than the previously selected + * busiest group. %false otherwise. + */ +static bool update_sd_pick_busiest(struct lb_env *env, + struct sd_lb_stats *sds, + struct sched_group *sg, + struct sg_lb_stats *sgs) +{ + struct sg_lb_stats *busiest = &sds->busiest_stat; + + if (update_sd_pick_busiest_active_balance(env, sds, sg, sgs)) + return true; + + if (sgs->group_type > busiest->group_type) + return true; + + if (sgs->group_type < busiest->group_type) + return false; + + if (energy_aware()) { + /* + * Candidate sg doesn't face any serious load-balance problems + * so don't pick it if the local sg is already filled up. + */ + if (sgs->group_type == group_other && + !group_has_capacity(env, &sds->local_stat)) + return false; + + if (sgs->avg_load <= busiest->avg_load) + return false; + + if (!(env->sd->flags & SD_ASYM_CPUCAPACITY)) + goto asym_packing; + + /* + * Candidate sg has no more than one task per CPU and + * has higher per-CPU capacity. Migrating tasks to less + * capable CPUs may harm throughput. Maximize throughput, + * power/energy consequences are not considered. + */ + if (sgs->sum_nr_running <= sgs->group_weight && + group_smaller_cpu_capacity(sds->local, sg)) + return false; + } + +asym_packing: + /* This is the busiest node in its class. */ + if (!(env->sd->flags & SD_ASYM_PACKING)) + return true; + + /* + * ASYM_PACKING needs to move all the work to the lowest + * numbered CPUs in the group, therefore mark all groups + * higher than ourself as busy. + */ + if (sgs->sum_nr_running && env->dst_cpu < group_first_cpu(sg)) { + if (!sds->busiest) + return true; + + if (group_first_cpu(sds->busiest) > group_first_cpu(sg)) + return true; + } + + return false; +} + +#ifdef CONFIG_NUMA_BALANCING +static inline enum fbq_type fbq_classify_group(struct sg_lb_stats *sgs) +{ + if (sgs->sum_nr_running > sgs->nr_numa_running) + return regular; + if (sgs->sum_nr_running > sgs->nr_preferred_running) + return remote; + return all; +} + +static inline enum fbq_type fbq_classify_rq(struct rq *rq) +{ + if (rq->nr_running > rq->nr_numa_running) + return regular; + if (rq->nr_running > rq->nr_preferred_running) + return remote; + return all; +} +#else +static inline enum fbq_type fbq_classify_group(struct sg_lb_stats *sgs) +{ + return all; +} + +static inline enum fbq_type fbq_classify_rq(struct rq *rq) +{ + return regular; +} +#endif /* CONFIG_NUMA_BALANCING */ + +#define lb_sd_parent(sd) \ + (sd->parent && sd->parent->groups != sd->parent->groups->next) + +/** + * update_sd_lb_stats - Update sched_domain's statistics for load balancing. + * @env: The load balancing environment. + * @sds: variable to hold the statistics for this sched_domain. + */ +static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sds) +{ + struct sched_domain *child = env->sd->child; + struct sched_group *sg = env->sd->groups; + struct sg_lb_stats tmp_sgs; + int load_idx, prefer_sibling = 0; + bool overload = false, overutilized = false; + + if (child && child->flags & SD_PREFER_SIBLING) + prefer_sibling = 1; + + load_idx = get_sd_load_idx(env->sd, env->idle); + + do { + struct sg_lb_stats *sgs = &tmp_sgs; + int local_group; + + local_group = cpumask_test_cpu(env->dst_cpu, sched_group_cpus(sg)); + if (local_group) { + sds->local = sg; + sgs = &sds->local_stat; + + if (env->idle != CPU_NEWLY_IDLE || + time_after_eq(jiffies, sg->sgc->next_update)) + update_group_capacity(env->sd, env->dst_cpu); + } + + update_sg_lb_stats(env, sg, load_idx, local_group, sgs, + &overload, &overutilized); + + if (local_group) + goto next_group; + + /* + * In case the child domain prefers tasks go to siblings + * first, lower the sg capacity so that we'll try + * and move all the excess tasks away. We lower the capacity + * of a group only if the local group has the capacity to fit + * these excess tasks. The extra check prevents the case where + * you always pull from the heaviest group when it is already + * under-utilized (possible with a large weight task outweighs + * the tasks on the system). + */ + if (prefer_sibling && sds->local && + group_has_capacity(env, &sds->local_stat) && + (sgs->sum_nr_running > 1)) { + sgs->group_no_capacity = 1; + sgs->group_type = group_classify(sg, sgs, env); + } + + /* + * Ignore task groups with misfit tasks if local group has no + * capacity or if per-cpu capacity isn't higher. + */ + if (energy_aware() && + sgs->group_type == group_misfit_task && + (!group_has_capacity(env, &sds->local_stat) || + !group_smaller_cpu_capacity(sg, sds->local))) + sgs->group_type = group_other; + + if (update_sd_pick_busiest(env, sds, sg, sgs)) { + sds->busiest = sg; + sds->busiest_stat = *sgs; + env->busiest_nr_running = sgs->sum_nr_running; + env->busiest_grp_capacity = sgs->group_capacity; + } + +next_group: + /* Now, start updating sd_lb_stats */ + sds->total_load += sgs->group_load; + sds->total_capacity += sgs->group_capacity; + + sg = sg->next; + } while (sg != env->sd->groups); + + if (env->sd->flags & SD_NUMA) + env->fbq_type = fbq_classify_group(&sds->busiest_stat); + + env->src_grp_nr_running = sds->busiest_stat.sum_nr_running; + + if (!lb_sd_parent(env->sd)) { + /* update overload indicator if we are at root domain */ + if (env->dst_rq->rd->overload != overload) + env->dst_rq->rd->overload = overload; + + /* Update over-utilization (tipping point, U >= 0) indicator */ + if (energy_aware() && env->dst_rq->rd->overutilized != overutilized) { + env->dst_rq->rd->overutilized = overutilized; + trace_sched_overutilized(overutilized); + } + } else { + if (energy_aware() && !env->dst_rq->rd->overutilized && overutilized) { + env->dst_rq->rd->overutilized = true; + trace_sched_overutilized(true); + } + } + +} + +/** + * check_asym_packing - Check to see if the group is packed into the + * sched doman. + * + * This is primarily intended to used at the sibling level. Some + * cores like POWER7 prefer to use lower numbered SMT threads. In the + * case of POWER7, it can move to lower SMT modes only when higher + * threads are idle. When in lower SMT modes, the threads will + * perform better since they share less core resources. Hence when we + * have idle threads, we want them to be the higher ones. + * + * This packing function is run on idle threads. It checks to see if + * the busiest CPU in this domain (core in the P7 case) has a higher + * CPU number than the packing function is being run on. Here we are + * assuming lower CPU number will be equivalent to lower a SMT thread + * number. + * + * Return: 1 when packing is required and a task should be moved to + * this CPU. The amount of the imbalance is returned in *imbalance. + * + * @env: The load balancing environment. + * @sds: Statistics of the sched_domain which is to be packed + */ +static int check_asym_packing(struct lb_env *env, struct sd_lb_stats *sds) +{ + int busiest_cpu; + + if (!(env->sd->flags & SD_ASYM_PACKING)) + return 0; + + if (!sds->busiest) + return 0; + + busiest_cpu = group_first_cpu(sds->busiest); + if (env->dst_cpu > busiest_cpu) + return 0; + + env->imbalance = DIV_ROUND_CLOSEST( + sds->busiest_stat.avg_load * sds->busiest_stat.group_capacity, + SCHED_CAPACITY_SCALE); + + return 1; +} + +/** + * fix_small_imbalance - Calculate the minor imbalance that exists + * amongst the groups of a sched_domain, during + * load balancing. + * @env: The load balancing environment. + * @sds: Statistics of the sched_domain whose imbalance is to be calculated. + */ +static inline +void fix_small_imbalance(struct lb_env *env, struct sd_lb_stats *sds) +{ + unsigned long tmp, capa_now = 0, capa_move = 0; + unsigned int imbn = 2; + unsigned long scaled_busy_load_per_task; + struct sg_lb_stats *local, *busiest; + + local = &sds->local_stat; + busiest = &sds->busiest_stat; + + if (!local->sum_nr_running) + local->load_per_task = cpu_avg_load_per_task(env->dst_cpu); + else if (busiest->load_per_task > local->load_per_task) + imbn = 1; + + scaled_busy_load_per_task = + (busiest->load_per_task * SCHED_CAPACITY_SCALE) / + busiest->group_capacity; + + if (busiest->avg_load + scaled_busy_load_per_task >= + local->avg_load + (scaled_busy_load_per_task * imbn)) { + env->imbalance = busiest->load_per_task; + return; + } + + /* + * OK, we don't have enough imbalance to justify moving tasks, + * however we may be able to increase total CPU capacity used by + * moving them. + */ + + capa_now += busiest->group_capacity * + min(busiest->load_per_task, busiest->avg_load); + capa_now += local->group_capacity * + min(local->load_per_task, local->avg_load); + capa_now /= SCHED_CAPACITY_SCALE; + + /* Amount of load we'd subtract */ + if (busiest->avg_load > scaled_busy_load_per_task) { + capa_move += busiest->group_capacity * + min(busiest->load_per_task, + busiest->avg_load - scaled_busy_load_per_task); + } + + /* Amount of load we'd add */ + if (busiest->avg_load * busiest->group_capacity < + busiest->load_per_task * SCHED_CAPACITY_SCALE) { + tmp = (busiest->avg_load * busiest->group_capacity) / + local->group_capacity; + } else { + tmp = (busiest->load_per_task * SCHED_CAPACITY_SCALE) / + local->group_capacity; + } + capa_move += local->group_capacity * + min(local->load_per_task, local->avg_load + tmp); + capa_move /= SCHED_CAPACITY_SCALE; + + /* Move if we gain throughput */ + if (capa_move > capa_now) + env->imbalance = busiest->load_per_task; +} + +/** + * calculate_imbalance - Calculate the amount of imbalance present within the + * groups of a given sched_domain during load balance. + * @env: load balance environment + * @sds: statistics of the sched_domain whose imbalance is to be calculated. + */ +static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *sds) +{ + unsigned long max_pull, load_above_capacity = ~0UL; + struct sg_lb_stats *local, *busiest; + + local = &sds->local_stat; + busiest = &sds->busiest_stat; + + if (busiest->group_type == group_imbalanced) { + /* + * In the group_imb case we cannot rely on group-wide averages + * to ensure cpu-load equilibrium, look at wider averages. XXX + */ + busiest->load_per_task = + min(busiest->load_per_task, sds->avg_load); + } + + /* + * In the presence of smp nice balancing, certain scenarios can have + * max load less than avg load(as we skip the groups at or below + * its cpu_capacity, while calculating max_load..) + */ + if (busiest->avg_load <= sds->avg_load || + local->avg_load >= sds->avg_load) { + if (energy_aware()) { + /* Misfitting tasks should be migrated in any case */ + if (busiest->group_type == group_misfit_task) { + env->imbalance = busiest->group_misfit_task; + return; + } + + /* + * Busiest group is overloaded, local is not, use the spare + * cycles to maximize throughput + */ + if (busiest->group_type == group_overloaded && + local->group_type <= group_misfit_task) { + env->imbalance = busiest->load_per_task; + return; + } + } + + env->imbalance = 0; + return fix_small_imbalance(env, sds); + } + + /* + * If there aren't any idle cpus, avoid creating some. + */ + if (busiest->group_type == group_overloaded && + local->group_type == group_overloaded) { + load_above_capacity = busiest->sum_nr_running * + SCHED_LOAD_SCALE; + if (load_above_capacity > busiest->group_capacity) + load_above_capacity -= busiest->group_capacity; + else + load_above_capacity = ~0UL; + } + + /* + * We're trying to get all the cpus to the average_load, so we don't + * want to push ourselves above the average load, nor do we wish to + * reduce the max loaded cpu below the average load. At the same time, + * we also don't want to reduce the group load below the group capacity + * (so that we can implement power-savings policies etc). Thus we look + * for the minimum possible imbalance. + */ + max_pull = min(busiest->avg_load - sds->avg_load, load_above_capacity); + + /* How much load to actually move to equalise the imbalance */ + env->imbalance = min( + max_pull * busiest->group_capacity, + (sds->avg_load - local->avg_load) * local->group_capacity + ) / SCHED_CAPACITY_SCALE; + + /* Boost imbalance to allow misfit task to be balanced. */ + if (energy_aware() && busiest->group_type == group_misfit_task) + env->imbalance = max_t(long, env->imbalance, + busiest->group_misfit_task); + + /* + * if *imbalance is less than the average load per runnable task + * there is no guarantee that any tasks will be moved so we'll have + * a think about bumping its value to force at least one task to be + * moved + */ + if (env->imbalance < busiest->load_per_task) + return fix_small_imbalance(env, sds); +} + +/******* find_busiest_group() helpers end here *********************/ + +/** + * find_busiest_group - Returns the busiest group within the sched_domain + * if there is an imbalance. If there isn't an imbalance, and + * the user has opted for power-savings, it returns a group whose + * CPUs can be put to idle by rebalancing those tasks elsewhere, if + * such a group exists. + * + * Also calculates the amount of weighted load which should be moved + * to restore balance. + * + * @env: The load balancing environment. + * + * Return: - The busiest group if imbalance exists. + * - If no imbalance and user has opted for power-savings balance, + * return the least loaded group whose CPUs can be + * put to idle by rebalancing its tasks onto our group. + */ +static struct sched_group *find_busiest_group(struct lb_env *env) +{ + struct sg_lb_stats *local, *busiest; + struct sd_lb_stats sds; + + init_sd_lb_stats(&sds); + + /* + * Compute the various statistics relavent for load balancing at + * this level. + */ + update_sd_lb_stats(env, &sds); + + if (energy_aware() && !env->dst_rq->rd->overutilized) + goto out_balanced; + + local = &sds.local_stat; + busiest = &sds.busiest_stat; + + /* ASYM feature bypasses nice load balance check */ + if ((env->idle == CPU_IDLE || env->idle == CPU_NEWLY_IDLE) && + check_asym_packing(env, &sds)) + return sds.busiest; + + /* There is no busy sibling group to pull tasks from */ + if (!sds.busiest || busiest->sum_nr_running == 0) + goto out_balanced; + + if (env->flags & LBF_BIG_TASK_ACTIVE_BALANCE) + goto force_balance; + + if (bail_inter_cluster_balance(env, &sds)) + goto out_balanced; + + sds.avg_load = (SCHED_CAPACITY_SCALE * sds.total_load) + / sds.total_capacity; + + /* + * If the busiest group is imbalanced the below checks don't + * work because they assume all things are equal, which typically + * isn't true due to cpus_allowed constraints and the like. + */ + if (busiest->group_type == group_imbalanced) + goto force_balance; + + /* + * When dst_cpu is idle, prevent SMP nice and/or asymmetric group + * capacities from resulting in underutilization due to avg_load. + */ + if (env->idle != CPU_NOT_IDLE && group_has_capacity(env, local) && + busiest->group_no_capacity) + goto force_balance; + + /* Misfitting tasks should be dealt with regardless of the avg load */ + if (energy_aware() && busiest->group_type == group_misfit_task) { + goto force_balance; + } + + /* + * If the local group is busier than the selected busiest group + * don't try and pull any tasks. + */ + if (local->avg_load >= busiest->avg_load) + goto out_balanced; + + /* + * Don't pull any tasks if this group is already above the domain + * average load. + */ + if (local->avg_load >= sds.avg_load) + goto out_balanced; + + if (env->idle == CPU_IDLE) { + /* + * This cpu is idle. If the busiest group is not overloaded + * and there is no imbalance between this and busiest group + * wrt idle cpus, it is balanced. The imbalance becomes + * significant if the diff is greater than 1 otherwise we + * might end up to just move the imbalance on another group + */ + if ((busiest->group_type != group_overloaded) && + (local->idle_cpus <= (busiest->idle_cpus + 1)) && + !group_smaller_cpu_capacity(sds.busiest, sds.local)) + goto out_balanced; + } else { + /* + * In the CPU_NEWLY_IDLE, CPU_NOT_IDLE cases, use + * imbalance_pct to be conservative. + */ + if (100 * busiest->avg_load <= + env->sd->imbalance_pct * local->avg_load) + goto out_balanced; + } + +force_balance: + env->busiest_group_type = busiest->group_type; + /* Looks like there is an imbalance. Compute it */ + calculate_imbalance(env, &sds); + return sds.busiest; + +out_balanced: + env->imbalance = 0; + return NULL; +} + +#ifdef CONFIG_SCHED_HMP +static struct rq *find_busiest_queue_hmp(struct lb_env *env, + struct sched_group *group) +{ + struct rq *busiest = NULL, *busiest_big = NULL; + u64 max_runnable_avg = 0, max_runnable_avg_big = 0; + int max_nr_big = 0, nr_big; + bool find_big = !!(env->flags & LBF_BIG_TASK_ACTIVE_BALANCE); + int i; + cpumask_t cpus; + + cpumask_andnot(&cpus, sched_group_cpus(group), cpu_isolated_mask); + + for_each_cpu(i, &cpus) { + struct rq *rq = cpu_rq(i); + u64 cumulative_runnable_avg = + rq->hmp_stats.cumulative_runnable_avg; + + if (!cpumask_test_cpu(i, env->cpus)) + continue; + + + if (find_big) { + nr_big = nr_big_tasks(rq); + if (nr_big > max_nr_big || + (nr_big > 0 && nr_big == max_nr_big && + cumulative_runnable_avg > max_runnable_avg_big)) { + max_runnable_avg_big = cumulative_runnable_avg; + busiest_big = rq; + max_nr_big = nr_big; + continue; + } + } + + if (cumulative_runnable_avg > max_runnable_avg) { + max_runnable_avg = cumulative_runnable_avg; + busiest = rq; + } + } + + if (busiest_big) + return busiest_big; + + env->flags &= ~LBF_BIG_TASK_ACTIVE_BALANCE; + return busiest; +} +#else +static inline struct rq *find_busiest_queue_hmp(struct lb_env *env, + struct sched_group *group) +{ + return NULL; +} +#endif + +/* + * find_busiest_queue - find the busiest runqueue among the cpus in group. + */ +static struct rq *find_busiest_queue(struct lb_env *env, + struct sched_group *group) +{ + struct rq *busiest = NULL, *rq; + unsigned long busiest_load = 0, busiest_capacity = 1; + int i; + +#ifdef CONFIG_SCHED_HMP + return find_busiest_queue_hmp(env, group); +#endif + + for_each_cpu_and(i, sched_group_cpus(group), env->cpus) { + unsigned long capacity, wl; + enum fbq_type rt; + + rq = cpu_rq(i); + rt = fbq_classify_rq(rq); + + /* + * We classify groups/runqueues into three groups: + * - regular: there are !numa tasks + * - remote: there are numa tasks that run on the 'wrong' node + * - all: there is no distinction + * + * In order to avoid migrating ideally placed numa tasks, + * ignore those when there's better options. + * + * If we ignore the actual busiest queue to migrate another + * task, the next balance pass can still reduce the busiest + * queue by moving tasks around inside the node. + * + * If we cannot move enough load due to this classification + * the next pass will adjust the group classification and + * allow migration of more tasks. + * + * Both cases only affect the total convergence complexity. + */ + if (rt > env->fbq_type) + continue; + + capacity = capacity_of(i); + + wl = weighted_cpuload(i); + + /* + * When comparing with imbalance, use weighted_cpuload() + * which is not scaled with the cpu capacity. + */ + + if (rq->nr_running == 1 && wl > env->imbalance && + !check_cpu_capacity(rq, env->sd) && + env->busiest_group_type != group_misfit_task) + continue; + + /* + * For the load comparisons with the other cpu's, consider + * the weighted_cpuload() scaled with the cpu capacity, so + * that the load can be moved away from the cpu that is + * potentially running at a lower capacity. + * + * Thus we're looking for max(wl_i / capacity_i), crosswise + * multiplication to rid ourselves of the division works out + * to: wl_i * capacity_j > wl_j * capacity_i; where j is + * our previous maximum. + */ + if (wl * busiest_capacity > busiest_load * capacity) { + busiest_load = wl; + busiest_capacity = capacity; + busiest = rq; + } + } + + return busiest; +} + +/* + * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but + * so long as it is large enough. + */ +#define MAX_PINNED_INTERVAL 16 + +/* Working cpumask for load_balance and load_balance_newidle. */ +DEFINE_PER_CPU(cpumask_var_t, load_balance_mask); + +#define NEED_ACTIVE_BALANCE_THRESHOLD 10 + +static int need_active_balance(struct lb_env *env) +{ + struct sched_domain *sd = env->sd; + + if (env->flags & LBF_BIG_TASK_ACTIVE_BALANCE) + return 1; + + if (env->idle == CPU_NEWLY_IDLE) { + + /* + * ASYM_PACKING needs to force migrate tasks from busy but + * higher numbered CPUs in order to pack all tasks in the + * lowest numbered CPUs. + */ + if ((sd->flags & SD_ASYM_PACKING) && env->src_cpu > env->dst_cpu) + return 1; + } + + /* + * The dst_cpu is idle and the src_cpu CPU has only 1 CFS task. + * It's worth migrating the task if the src_cpu's capacity is reduced + * because of other sched_class or IRQs if more capacity stays + * available on dst_cpu. + */ + if ((env->idle != CPU_NOT_IDLE) && + (env->src_rq->cfs.h_nr_running == 1)) { + if ((check_cpu_capacity(env->src_rq, sd)) && + (capacity_of(env->src_cpu)*sd->imbalance_pct < capacity_of(env->dst_cpu)*100)) + return 1; + } + + if (energy_aware() && + (capacity_of(env->src_cpu) < capacity_of(env->dst_cpu)) && + ((capacity_orig_of(env->src_cpu) < capacity_orig_of(env->dst_cpu))) && + env->src_rq->cfs.h_nr_running == 1 && + cpu_overutilized(env->src_cpu) && + !cpu_overutilized(env->dst_cpu)) { + return 1; + } + + return unlikely(sd->nr_balance_failed > + sd->cache_nice_tries + NEED_ACTIVE_BALANCE_THRESHOLD); +} + +static int group_balance_cpu_not_isolated(struct sched_group *sg) +{ + cpumask_t cpus; + + cpumask_and(&cpus, sched_group_cpus(sg), sched_group_mask(sg)); + cpumask_andnot(&cpus, &cpus, cpu_isolated_mask); + return cpumask_first(&cpus); +} + +static int should_we_balance(struct lb_env *env) +{ + struct sched_group *sg = env->sd->groups; + struct cpumask *sg_cpus, *sg_mask; + int cpu, balance_cpu = -1; + + /* + * In the newly idle case, we will allow all the cpu's + * to do the newly idle load balance. + */ + if (env->idle == CPU_NEWLY_IDLE) + return 1; + + sg_cpus = sched_group_cpus(sg); + sg_mask = sched_group_mask(sg); + /* Try to find first idle cpu */ + for_each_cpu_and(cpu, sg_cpus, env->cpus) { + if (!cpumask_test_cpu(cpu, sg_mask) || !idle_cpu(cpu) || + cpu_isolated(cpu)) + continue; + + balance_cpu = cpu; + break; + } + + if (balance_cpu == -1) + balance_cpu = group_balance_cpu_not_isolated(sg); + + /* + * First idle cpu or the first cpu(busiest) in this sched group + * is eligible for doing load balancing at this and above domains. + */ + return balance_cpu == env->dst_cpu; +} + +/* + * Check this_cpu to ensure it is balanced within domain. Attempt to move + * tasks if there is an imbalance. + */ +static int load_balance(int this_cpu, struct rq *this_rq, + struct sched_domain *sd, enum cpu_idle_type idle, + int *continue_balancing) +{ + int ld_moved = 0, cur_ld_moved, active_balance = 0; + struct sched_domain *sd_parent = lb_sd_parent(sd) ? sd->parent : NULL; + struct sched_group *group = NULL; + struct rq *busiest = NULL; + unsigned long flags; + struct cpumask *cpus = this_cpu_cpumask_var_ptr(load_balance_mask); + + struct lb_env env = { + .sd = sd, + .dst_cpu = this_cpu, + .dst_rq = this_rq, + .dst_grpmask = sched_group_cpus(sd->groups), + .idle = idle, + .loop_break = sched_nr_migrate_break, + .cpus = cpus, + .fbq_type = all, + .tasks = LIST_HEAD_INIT(env.tasks), + .imbalance = 0, + .flags = 0, + .loop = 0, + .busiest_nr_running = 0, + .busiest_grp_capacity = 0, + .boost_policy = sched_boost_policy(), + }; + + /* + * For NEWLY_IDLE load_balancing, we don't need to consider + * other cpus in our group + */ + if (idle == CPU_NEWLY_IDLE) + env.dst_grpmask = NULL; + + cpumask_copy(cpus, cpu_active_mask); + + schedstat_inc(sd, lb_count[idle]); + +redo: + if (!should_we_balance(&env)) { + *continue_balancing = 0; + goto out_balanced; + } + + group = find_busiest_group(&env); + if (!group) { + schedstat_inc(sd, lb_nobusyg[idle]); + goto out_balanced; + } + + busiest = find_busiest_queue(&env, group); + if (!busiest) { + schedstat_inc(sd, lb_nobusyq[idle]); + goto out_balanced; + } + + BUG_ON(busiest == env.dst_rq); + + schedstat_add(sd, lb_imbalance[idle], env.imbalance); + + env.src_cpu = busiest->cpu; + env.src_rq = busiest; + + ld_moved = 0; + if (busiest->nr_running > 1) { + /* + * Attempt to move tasks. If find_busiest_group has found + * an imbalance but busiest->nr_running <= 1, the group is + * still unbalanced. ld_moved simply stays zero, so it is + * correctly treated as an imbalance. + */ + env.flags |= LBF_ALL_PINNED; + +more_balance: + raw_spin_lock_irqsave(&busiest->lock, flags); + update_rq_clock(busiest); + + /* The world might have changed. Validate assumptions */ + if (busiest->nr_running <= 1) { + raw_spin_unlock_irqrestore(&busiest->lock, flags); + env.flags &= ~LBF_ALL_PINNED; + goto no_move; + } + + /* + * Set loop_max when rq's lock is taken to prevent a race. + */ + env.loop_max = min(sysctl_sched_nr_migrate, + busiest->nr_running); + + /* + * cur_ld_moved - load moved in current iteration + * ld_moved - cumulative load moved across iterations + */ + cur_ld_moved = detach_tasks(&env); + + /* + * We've detached some tasks from busiest_rq. Every + * task is masked "TASK_ON_RQ_MIGRATING", so we can safely + * unlock busiest->lock, and we are able to be sure + * that nobody can manipulate the tasks in parallel. + * See task_rq_lock() family for the details. + */ + + raw_spin_unlock(&busiest->lock); + + if (cur_ld_moved) { + attach_tasks(&env); + ld_moved += cur_ld_moved; + } + + local_irq_restore(flags); + + if (env.flags & LBF_NEED_BREAK) { + env.flags &= ~LBF_NEED_BREAK; + goto more_balance; + } + + /* + * Revisit (affine) tasks on src_cpu that couldn't be moved to + * us and move them to an alternate dst_cpu in our sched_group + * where they can run. The upper limit on how many times we + * iterate on same src_cpu is dependent on number of cpus in our + * sched_group. + * + * This changes load balance semantics a bit on who can move + * load to a given_cpu. In addition to the given_cpu itself + * (or a ilb_cpu acting on its behalf where given_cpu is + * nohz-idle), we now have balance_cpu in a position to move + * load to given_cpu. In rare situations, this may cause + * conflicts (balance_cpu and given_cpu/ilb_cpu deciding + * _independently_ and at _same_ time to move some load to + * given_cpu) causing exceess load to be moved to given_cpu. + * This however should not happen so much in practice and + * moreover subsequent load balance cycles should correct the + * excess load moved. + */ + if ((env.flags & LBF_DST_PINNED) && env.imbalance > 0) { + + /* Prevent to re-select dst_cpu via env's cpus */ + cpumask_clear_cpu(env.dst_cpu, env.cpus); + + env.dst_rq = cpu_rq(env.new_dst_cpu); + env.dst_cpu = env.new_dst_cpu; + env.flags &= ~LBF_DST_PINNED; + env.loop = 0; + env.loop_break = sched_nr_migrate_break; + + /* + * Go back to "more_balance" rather than "redo" since we + * need to continue with same src_cpu. + */ + goto more_balance; + } + + /* + * We failed to reach balance because of affinity. + */ + if (sd_parent) { + int *group_imbalance = &sd_parent->groups->sgc->imbalance; + + if ((env.flags & LBF_SOME_PINNED) && env.imbalance > 0) + *group_imbalance = 1; + } + + /* All tasks on this runqueue were pinned by CPU affinity */ + if (unlikely(env.flags & LBF_ALL_PINNED)) { + cpumask_clear_cpu(cpu_of(busiest), cpus); + if (!cpumask_empty(cpus)) { + env.loop = 0; + env.loop_break = sched_nr_migrate_break; + goto redo; + } + goto out_all_pinned; + } + } + +no_move: + if (!ld_moved) { + if (!(env.flags & LBF_BIG_TASK_ACTIVE_BALANCE)) + schedstat_inc(sd, lb_failed[idle]); + + /* + * Increment the failure counter only on periodic balance. + * We do not want newidle balance, which can be very + * frequent, pollute the failure counter causing + * excessive cache_hot migrations and active balances. + */ + if (idle != CPU_NEWLY_IDLE && + !(env.flags & LBF_BIG_TASK_ACTIVE_BALANCE)) { + if (env.src_grp_nr_running > 1) + sd->nr_balance_failed++; + } + + if (need_active_balance(&env)) { + raw_spin_lock_irqsave(&busiest->lock, flags); + + /* don't kick the active_load_balance_cpu_stop, + * if the curr task on busiest cpu can't be + * moved to this_cpu + */ + if (!cpumask_test_cpu(this_cpu, + tsk_cpus_allowed(busiest->curr))) { + raw_spin_unlock_irqrestore(&busiest->lock, + flags); + env.flags |= LBF_ALL_PINNED; + goto out_one_pinned; + } + + /* + * ->active_balance synchronizes accesses to + * ->active_balance_work. Once set, it's cleared + * only after active load balance is finished. + */ + if (!busiest->active_balance && + !cpu_isolated(cpu_of(busiest))) { + busiest->active_balance = 1; + busiest->push_cpu = this_cpu; + active_balance = 1; + } + raw_spin_unlock_irqrestore(&busiest->lock, flags); + + if (active_balance) { + stop_one_cpu_nowait(cpu_of(busiest), + active_load_balance_cpu_stop, busiest, + &busiest->active_balance_work); + *continue_balancing = 0; + } + + /* + * We've kicked active balancing, reset the failure + * counter. + */ + sd->nr_balance_failed = + sd->cache_nice_tries + + NEED_ACTIVE_BALANCE_THRESHOLD - 1; + } + } else { + sd->nr_balance_failed = 0; + + /* Assumes one 'busiest' cpu that we pulled tasks from */ + if (!same_freq_domain(this_cpu, cpu_of(busiest))) { + int check_groups = !!(env.flags & + LBF_MOVED_RELATED_THREAD_GROUP_TASK); + + check_for_freq_change(this_rq, false, check_groups); + check_for_freq_change(busiest, false, check_groups); + } else { + check_for_freq_change(this_rq, true, false); + } + } + if (likely(!active_balance)) { + /* We were unbalanced, so reset the balancing interval */ + sd->balance_interval = sd->min_interval; + } else { + /* + * If we've begun active balancing, start to back off. This + * case may not be covered by the all_pinned logic if there + * is only 1 task on the busy runqueue (because we don't call + * detach_tasks). + */ + if (sd->balance_interval < sd->max_interval) + sd->balance_interval *= 2; + } + + goto out; + +out_balanced: + /* + * We reach balance although we may have faced some affinity + * constraints. Clear the imbalance flag only if other tasks got + * a chance to move and fix the imbalance. + */ + if (sd_parent && !(env.flags & LBF_ALL_PINNED)) { + int *group_imbalance = &sd_parent->groups->sgc->imbalance; + + if (*group_imbalance) + *group_imbalance = 0; + } + +out_all_pinned: + /* + * We reach balance because all tasks are pinned at this level so + * we can't migrate them. Let the imbalance flag set so parent level + * can try to migrate them. + */ + schedstat_inc(sd, lb_balanced[idle]); + + sd->nr_balance_failed = 0; + +out_one_pinned: + ld_moved = 0; + + /* + * idle_balance() disregards balance intervals, so we could repeatedly + * reach this code, which would lead to balance_interval skyrocketting + * in a short amount of time. Skip the balance_interval increase logic + * to avoid that. + */ + if (env.idle == CPU_NEWLY_IDLE) + goto out; + + /* tune up the balancing interval */ + if (((env.flags & LBF_ALL_PINNED) && + sd->balance_interval < MAX_PINNED_INTERVAL) || + (sd->balance_interval < sd->max_interval)) + sd->balance_interval *= 2; +out: + trace_sched_load_balance(this_cpu, idle, *continue_balancing, + group ? group->cpumask[0] : 0, + busiest ? busiest->nr_running : 0, + env.imbalance, env.flags, ld_moved, + sd->balance_interval); + return ld_moved; +} + +static inline unsigned long +get_sd_balance_interval(struct sched_domain *sd, int cpu_busy) +{ + unsigned long interval = sd->balance_interval; + + if (cpu_busy) + interval *= sd->busy_factor; + + /* scale ms to jiffies */ + interval = msecs_to_jiffies(interval); + interval = clamp(interval, 1UL, max_load_balance_interval); + + return interval; +} + +static inline void +update_next_balance(struct sched_domain *sd, int cpu_busy, unsigned long *next_balance) +{ + unsigned long interval, next; + + interval = get_sd_balance_interval(sd, cpu_busy); + next = sd->last_balance + interval; + + if (time_after(*next_balance, next)) + *next_balance = next; +} + +/* + * idle_balance is called by schedule() if this_cpu is about to become + * idle. Attempts to pull tasks from other CPUs. + */ +static int idle_balance(struct rq *this_rq) +{ + unsigned long next_balance = jiffies + HZ; + int this_cpu = this_rq->cpu; + struct sched_domain *sd; + int pulled_task = 0; + u64 curr_cost = 0; + + if (cpu_isolated(this_cpu)) + return 0; + + idle_enter_fair(this_rq); + + /* + * We must set idle_stamp _before_ calling idle_balance(), such that we + * measure the duration of idle_balance() as idle time. + */ + this_rq->idle_stamp = rq_clock(this_rq); + + if (!energy_aware() && + (this_rq->avg_idle < sysctl_sched_migration_cost || + !this_rq->rd->overload)) { + rcu_read_lock(); + sd = rcu_dereference_check_sched_domain(this_rq->sd); + if (sd) + update_next_balance(sd, 0, &next_balance); + rcu_read_unlock(); + + goto out; + } + + raw_spin_unlock(&this_rq->lock); + + update_blocked_averages(this_cpu); + rcu_read_lock(); + for_each_domain(this_cpu, sd) { + int continue_balancing = 1; + u64 t0, domain_cost; + + if (!(sd->flags & SD_LOAD_BALANCE)) + continue; + + if (this_rq->avg_idle < curr_cost + sd->max_newidle_lb_cost) { + update_next_balance(sd, 0, &next_balance); + break; + } + + if (sd->flags & SD_BALANCE_NEWIDLE) { + t0 = sched_clock_cpu(this_cpu); + + pulled_task = load_balance(this_cpu, this_rq, + sd, CPU_NEWLY_IDLE, + &continue_balancing); + + domain_cost = sched_clock_cpu(this_cpu) - t0; + if (domain_cost > sd->max_newidle_lb_cost) + sd->max_newidle_lb_cost = domain_cost; + + curr_cost += domain_cost; + } + + update_next_balance(sd, 0, &next_balance); + + /* + * Stop searching for tasks to pull if there are + * now runnable tasks on the balance rq or if + * continue_balancing has been unset (only possible + * due to active migration). + */ + if (pulled_task || this_rq->nr_running > 0 || + !continue_balancing) + break; + } + rcu_read_unlock(); + + raw_spin_lock(&this_rq->lock); + + if (curr_cost > this_rq->max_idle_balance_cost) + this_rq->max_idle_balance_cost = curr_cost; + + /* + * While browsing the domains, we released the rq lock, a task could + * have been enqueued in the meantime. Since we're not going idle, + * pretend we pulled a task. + */ + if (this_rq->cfs.h_nr_running && !pulled_task) + pulled_task = 1; + +out: + /* Move the next balance forward */ + if (time_after(this_rq->next_balance, next_balance)) + this_rq->next_balance = next_balance; + + /* Is there a task of a high priority class? */ + if (this_rq->nr_running != this_rq->cfs.h_nr_running) + pulled_task = -1; + + if (pulled_task) { + idle_exit_fair(this_rq); + this_rq->idle_stamp = 0; + } + + return pulled_task; +} + +/* + * active_load_balance_cpu_stop is run by cpu stopper. It pushes + * running tasks off the busiest CPU onto idle CPUs. It requires at + * least 1 task to be running on each physical CPU where possible, and + * avoids physical / logical imbalances. + */ +static int active_load_balance_cpu_stop(void *data) +{ + struct rq *busiest_rq = data; + int busiest_cpu = cpu_of(busiest_rq); + int target_cpu = busiest_rq->push_cpu; + struct rq *target_rq = cpu_rq(target_cpu); + struct sched_domain *sd = NULL; + struct task_struct *p = NULL; + struct task_struct *push_task = NULL; + int push_task_detached = 0; + struct lb_env env = { + .sd = sd, + .dst_cpu = target_cpu, + .dst_rq = target_rq, + .src_cpu = busiest_rq->cpu, + .src_rq = busiest_rq, + .idle = CPU_IDLE, + .busiest_nr_running = 0, + .busiest_grp_capacity = 0, + .flags = 0, + .loop = 0, + .boost_policy = sched_boost_policy(), + }; + bool moved = false; + + raw_spin_lock_irq(&busiest_rq->lock); + + /* make sure the requested cpu hasn't gone down in the meantime */ + if (unlikely(busiest_cpu != smp_processor_id() || + !busiest_rq->active_balance)) + goto out_unlock; + + /* Is there any task to move? */ + if (busiest_rq->nr_running <= 1) + goto out_unlock; + + /* + * This condition is "impossible", if it occurs + * we need to fix it. Originally reported by + * Bjorn Helgaas on a 128-cpu setup. + */ + BUG_ON(busiest_rq == target_rq); + + push_task = busiest_rq->push_task; + target_cpu = busiest_rq->push_cpu; + if (push_task) { + if (task_on_rq_queued(push_task) && + push_task->state == TASK_RUNNING && + task_cpu(push_task) == busiest_cpu && + cpu_online(target_cpu)) { + detach_task(push_task, &env); + push_task_detached = 1; + moved = true; + } + goto out_unlock; + } + + /* Search for an sd spanning us and the target CPU. */ + rcu_read_lock(); + for_each_domain(target_cpu, sd) { + if ((sd->flags & SD_LOAD_BALANCE) && + cpumask_test_cpu(busiest_cpu, sched_domain_span(sd))) + break; + } + + if (likely(sd)) { + env.sd = sd; + schedstat_inc(sd, alb_count); + update_rq_clock(busiest_rq); + + p = detach_one_task(&env); + if (p) { + schedstat_inc(sd, alb_pushed); + moved = true; + } else { + schedstat_inc(sd, alb_failed); + } + } + rcu_read_unlock(); +out_unlock: + busiest_rq->active_balance = 0; + push_task = busiest_rq->push_task; + target_cpu = busiest_rq->push_cpu; + + if (push_task) + busiest_rq->push_task = NULL; + + raw_spin_unlock(&busiest_rq->lock); + + if (push_task) { + if (push_task_detached) + attach_one_task(target_rq, push_task); + put_task_struct(push_task); + clear_reserved(target_cpu); + } + + if (p) + attach_one_task(target_rq, p); + + local_irq_enable(); + + if (moved && !same_freq_domain(busiest_cpu, target_cpu)) { + int check_groups = !!(env.flags & + LBF_MOVED_RELATED_THREAD_GROUP_TASK); + check_for_freq_change(busiest_rq, false, check_groups); + check_for_freq_change(target_rq, false, check_groups); + } else if (moved) { + check_for_freq_change(target_rq, true, false); + } + + return 0; +} + +static inline int on_null_domain(struct rq *rq) +{ + return unlikely(!rcu_dereference_sched(rq->sd)); +} + +#ifdef CONFIG_NO_HZ_COMMON +/* + * idle load balancing details + * - When one of the busy CPUs notice that there may be an idle rebalancing + * needed, they will kick the idle load balancer, which then does idle + * load balancing for all the idle CPUs. + */ + +#ifdef CONFIG_SCHED_HMP +static inline int find_new_hmp_ilb(int type) +{ + int call_cpu = raw_smp_processor_id(); + struct sched_domain *sd; + int ilb; + + rcu_read_lock(); + + /* Pick an idle cpu "closest" to call_cpu */ + for_each_domain(call_cpu, sd) { + for_each_cpu_and(ilb, nohz.idle_cpus_mask, + sched_domain_span(sd)) { + if (idle_cpu(ilb) && (type != NOHZ_KICK_RESTRICT || + cpu_max_power_cost(ilb) <= + cpu_max_power_cost(call_cpu))) { + rcu_read_unlock(); + reset_balance_interval(ilb); + return ilb; + } + } + } + + rcu_read_unlock(); + return nr_cpu_ids; +} +#else /* CONFIG_SCHED_HMP */ +static inline int find_new_hmp_ilb(int type) +{ + return 0; +} +#endif /* CONFIG_SCHED_HMP */ + +static inline int find_new_ilb(int type) +{ + int ilb; + +#ifdef CONFIG_SCHED_HMP + return find_new_hmp_ilb(type); +#endif + + ilb = cpumask_first(nohz.idle_cpus_mask); + + if (ilb < nr_cpu_ids && idle_cpu(ilb)) + return ilb; + + return nr_cpu_ids; +} + +/* + * Kick a CPU to do the nohz balancing, if it is time for it. We pick the + * nohz_load_balancer CPU (if there is one) otherwise fallback to any idle + * CPU (if there is one). + */ +static void nohz_balancer_kick(int type) +{ + int ilb_cpu; + + nohz.next_balance++; + + ilb_cpu = find_new_ilb(type); + + if (ilb_cpu >= nr_cpu_ids) + return; + + if (test_and_set_bit(NOHZ_BALANCE_KICK, nohz_flags(ilb_cpu))) + return; + /* + * Use smp_send_reschedule() instead of resched_cpu(). + * This way we generate a sched IPI on the target cpu which + * is idle. And the softirq performing nohz idle load balance + * will be run before returning from the IPI. + */ + smp_send_reschedule(ilb_cpu); + return; +} + +void nohz_balance_clear_nohz_mask(int cpu) +{ + if (likely(cpumask_test_cpu(cpu, nohz.idle_cpus_mask))) { + cpumask_clear_cpu(cpu, nohz.idle_cpus_mask); + atomic_dec(&nohz.nr_cpus); + } +} + +static inline void nohz_balance_exit_idle(int cpu) +{ + if (unlikely(test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)))) { + /* + * Completely isolated CPUs don't ever set, so we must test. + */ + nohz_balance_clear_nohz_mask(cpu); + clear_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)); + } +} + +static inline void set_cpu_sd_state_busy(void) +{ + struct sched_domain *sd; + int cpu = smp_processor_id(); + + rcu_read_lock(); + sd = rcu_dereference(per_cpu(sd_busy, cpu)); + + if (!sd || !sd->nohz_idle) + goto unlock; + sd->nohz_idle = 0; + + atomic_inc(&sd->groups->sgc->nr_busy_cpus); +unlock: + rcu_read_unlock(); +} + +void set_cpu_sd_state_idle(void) +{ + struct sched_domain *sd; + int cpu = smp_processor_id(); + + rcu_read_lock(); + sd = rcu_dereference(per_cpu(sd_busy, cpu)); + + if (!sd || sd->nohz_idle) + goto unlock; + sd->nohz_idle = 1; + + atomic_dec(&sd->groups->sgc->nr_busy_cpus); +unlock: + rcu_read_unlock(); +} + +/* + * This routine will record that the cpu is going idle with tick stopped. + * This info will be used in performing idle load balancing in the future. + */ +void nohz_balance_enter_idle(int cpu) +{ + /* + * If this cpu is going down, then nothing needs to be done. + */ + if (!cpu_active(cpu)) + return; + + if (test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu))) + return; + + /* + * If we're a completely isolated CPU, we don't play. + */ + if (on_null_domain(cpu_rq(cpu)) || cpu_isolated(cpu)) + return; + + cpumask_set_cpu(cpu, nohz.idle_cpus_mask); + atomic_inc(&nohz.nr_cpus); + set_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)); +} + +static int sched_ilb_notifier(struct notifier_block *nfb, + unsigned long action, void *hcpu) +{ + switch (action & ~CPU_TASKS_FROZEN) { + case CPU_DYING: + nohz_balance_exit_idle(smp_processor_id()); + return NOTIFY_OK; + default: + return NOTIFY_DONE; + } +} +#endif + +static DEFINE_SPINLOCK(balancing); + +/* + * Scale the max load_balance interval with the number of CPUs in the system. + * This trades load-balance latency on larger machines for less cross talk. + */ +void update_max_interval(void) +{ + cpumask_t avail_mask; + unsigned int available_cpus; + + cpumask_andnot(&avail_mask, cpu_online_mask, cpu_isolated_mask); + available_cpus = cpumask_weight(&avail_mask); + + max_load_balance_interval = HZ*available_cpus/10; +} + +/* + * It checks each scheduling domain to see if it is due to be balanced, + * and initiates a balancing operation if so. + * + * Balancing parameters are set up in init_sched_domains. + */ +static void rebalance_domains(struct rq *rq, enum cpu_idle_type idle) +{ + int continue_balancing = 1; + int cpu = rq->cpu; + unsigned long interval; + struct sched_domain *sd; + /* Earliest time when we have to do rebalance again */ + unsigned long next_balance = jiffies + 60*HZ; + int update_next_balance = 0; + int need_serialize, need_decay = 0; + u64 max_cost = 0; + + update_blocked_averages(cpu); + + rcu_read_lock(); + for_each_domain(cpu, sd) { + /* + * Decay the newidle max times here because this is a regular + * visit to all the domains. Decay ~1% per second. + */ + if (time_after(jiffies, sd->next_decay_max_lb_cost)) { + sd->max_newidle_lb_cost = + (sd->max_newidle_lb_cost * 253) / 256; + sd->next_decay_max_lb_cost = jiffies + HZ; + need_decay = 1; + } + max_cost += sd->max_newidle_lb_cost; + + if (!(sd->flags & SD_LOAD_BALANCE)) + continue; + + /* + * Stop the load balance at this level. There is another + * CPU in our sched group which is doing load balancing more + * actively. + */ + if (!continue_balancing) { + if (need_decay) + continue; + break; + } + + interval = get_sd_balance_interval(sd, idle != CPU_IDLE); + + need_serialize = sd->flags & SD_SERIALIZE; + if (need_serialize) { + if (!spin_trylock(&balancing)) + goto out; + } + + if (time_after_eq(jiffies, sd->last_balance + interval)) { + if (load_balance(cpu, rq, sd, idle, &continue_balancing)) { + /* + * The LBF_DST_PINNED logic could have changed + * env->dst_cpu, so we can't know our idle + * state even if we migrated tasks. Update it. + */ + idle = idle_cpu(cpu) ? CPU_IDLE : CPU_NOT_IDLE; + } + sd->last_balance = jiffies; + interval = get_sd_balance_interval(sd, idle != CPU_IDLE); + } + if (need_serialize) + spin_unlock(&balancing); +out: + if (time_after(next_balance, sd->last_balance + interval)) { + next_balance = sd->last_balance + interval; + update_next_balance = 1; + } + } + if (need_decay) { + /* + * Ensure the rq-wide value also decays but keep it at a + * reasonable floor to avoid funnies with rq->avg_idle. + */ + rq->max_idle_balance_cost = + max((u64)sysctl_sched_migration_cost, max_cost); + } + rcu_read_unlock(); + + /* + * next_balance will be updated only when there is a need. + * When the cpu is attached to null domain for ex, it will not be + * updated. + */ + if (likely(update_next_balance)) { + rq->next_balance = next_balance; + +#ifdef CONFIG_NO_HZ_COMMON + /* + * If this CPU has been elected to perform the nohz idle + * balance. Other idle CPUs have already rebalanced with + * nohz_idle_balance() and nohz.next_balance has been + * updated accordingly. This CPU is now running the idle load + * balance for itself and we need to update the + * nohz.next_balance accordingly. + */ + if ((idle == CPU_IDLE) && time_after(nohz.next_balance, rq->next_balance)) + nohz.next_balance = rq->next_balance; +#endif + } +} + +#ifdef CONFIG_NO_HZ_COMMON +/* + * In CONFIG_NO_HZ_COMMON case, the idle balance kickee will do the + * rebalancing for all the cpus for whom scheduler ticks are stopped. + */ +static void nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle) +{ + int this_cpu = this_rq->cpu; + struct rq *rq; + int balance_cpu; + /* Earliest time when we have to do rebalance again */ + unsigned long next_balance = jiffies + 60*HZ; + int update_next_balance = 0; + cpumask_t cpus; + + if (idle != CPU_IDLE || + !test_bit(NOHZ_BALANCE_KICK, nohz_flags(this_cpu))) + goto end; + + cpumask_andnot(&cpus, nohz.idle_cpus_mask, cpu_isolated_mask); + + for_each_cpu(balance_cpu, &cpus) { + if (balance_cpu == this_cpu || !idle_cpu(balance_cpu)) + continue; + + /* + * If this cpu gets work to do, stop the load balancing + * work being done for other cpus. Next load + * balancing owner will pick it up. + */ + if (need_resched()) + break; + + rq = cpu_rq(balance_cpu); + + /* + * If time for next balance is due, + * do the balance. + */ + if (time_after_eq(jiffies, rq->next_balance)) { + raw_spin_lock_irq(&rq->lock); + update_rq_clock(rq); + update_idle_cpu_load(rq); + raw_spin_unlock_irq(&rq->lock); + rebalance_domains(rq, CPU_IDLE); + } + + if (time_after(next_balance, rq->next_balance)) { + next_balance = rq->next_balance; + update_next_balance = 1; + } + } + + /* + * next_balance will be updated only when there is a need. + * When the CPU is attached to null domain for ex, it will not be + * updated. + */ + if (likely(update_next_balance)) + nohz.next_balance = next_balance; +end: + clear_bit(NOHZ_BALANCE_KICK, nohz_flags(this_cpu)); +} + +#ifdef CONFIG_SCHED_HMP +static inline int _nohz_kick_needed_hmp(struct rq *rq, int cpu, int *type) +{ + struct sched_domain *sd; + int i; + + if (rq->nr_running < 2) + return 0; + + if (!sysctl_sched_restrict_cluster_spill || + sched_boost_policy() == SCHED_BOOST_ON_ALL) + return 1; + + if (cpu_max_power_cost(cpu) == max_power_cost) + return 1; + + rcu_read_lock(); + sd = rcu_dereference_check_sched_domain(rq->sd); + if (!sd) { + rcu_read_unlock(); + return 0; + } + + for_each_cpu(i, sched_domain_span(sd)) { + if (cpu_load(i) < sched_spill_load && + cpu_rq(i)->nr_running < + sysctl_sched_spill_nr_run) { + /* Change the kick type to limit to CPUs that + * are of equal or lower capacity. + */ + *type = NOHZ_KICK_RESTRICT; + break; + } + } + rcu_read_unlock(); + return 1; +} +#else +static inline int _nohz_kick_needed_hmp(struct rq *rq, int cpu, int *type) +{ + return 0; +} +#endif + +static inline int _nohz_kick_needed(struct rq *rq, int cpu, int *type) +{ + unsigned long now = jiffies; + + /* + * None are in tickless mode and hence no need for NOHZ idle load + * balancing. + */ + if (likely(!atomic_read(&nohz.nr_cpus))) + return 0; + +#ifdef CONFIG_SCHED_HMP + return _nohz_kick_needed_hmp(rq, cpu, type); +#endif + + if (time_before(now, nohz.next_balance)) + return 0; + + if (rq->nr_running >= 2 && + (!energy_aware() || cpu_overutilized(cpu))) + return true; + + /* Do idle load balance if there have misfit task */ + if (energy_aware()) + return rq->misfit_task; + + return (rq->nr_running >= 2); +} + +/* + * Current heuristic for kicking the idle load balancer in the presence + * of an idle cpu in the system. + * - This rq has more than one task. + * - This rq has at least one CFS task and the capacity of the CPU is + * significantly reduced because of RT tasks or IRQs. + * - At parent of LLC scheduler domain level, this cpu's scheduler group has + * multiple busy cpu. + * - For SD_ASYM_PACKING, if the lower numbered cpu's in the scheduler + * domain span are idle. + */ +static inline bool nohz_kick_needed(struct rq *rq, int *type) +{ +#ifndef CONFIG_SCHED_HMP + struct sched_domain *sd; + struct sched_group_capacity *sgc; + int nr_busy; +#endif + int cpu = rq->cpu; + bool kick = false; + + if (unlikely(rq->idle_balance)) + return false; + + /* + * We may be recently in ticked or tickless idle mode. At the first + * busy tick after returning from idle, we will update the busy stats. + */ + set_cpu_sd_state_busy(); + nohz_balance_exit_idle(cpu); + + if (_nohz_kick_needed(rq, cpu, type)) + return true; + +#ifndef CONFIG_SCHED_HMP + rcu_read_lock(); + sd = rcu_dereference(per_cpu(sd_busy, cpu)); + if (sd) { + sgc = sd->groups->sgc; + nr_busy = atomic_read(&sgc->nr_busy_cpus); + + if (nr_busy > 1) { + kick = true; + goto unlock; + } + + } + + sd = rcu_dereference(rq->sd); + if (sd) { + if ((rq->cfs.h_nr_running >= 1) && + check_cpu_capacity(rq, sd)) { + kick = true; + goto unlock; + } + } + + sd = rcu_dereference(per_cpu(sd_asym, cpu)); + if (sd && (cpumask_first_and(nohz.idle_cpus_mask, + sched_domain_span(sd)) < cpu)) { + kick = true; + goto unlock; + } + +unlock: + rcu_read_unlock(); +#endif + return kick; +} +#else +static void nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle) { } +#endif + +/* + * run_rebalance_domains is triggered when needed from the scheduler tick. + * Also triggered for nohz idle balancing (with nohz_balancing_kick set). + */ +static void run_rebalance_domains(struct softirq_action *h) +{ + struct rq *this_rq = this_rq(); + enum cpu_idle_type idle = this_rq->idle_balance ? + CPU_IDLE : CPU_NOT_IDLE; + + /* + * If this cpu has a pending nohz_balance_kick, then do the + * balancing on behalf of the other idle cpus whose ticks are + * stopped. Do nohz_idle_balance *before* rebalance_domains to + * give the idle cpus a chance to load balance. Else we may + * load balance only within the local sched_domain hierarchy + * and abort nohz_idle_balance altogether if we pull some load. + */ + nohz_idle_balance(this_rq, idle); + rebalance_domains(this_rq, idle); +} + +/* + * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing. + */ +void trigger_load_balance(struct rq *rq) +{ + int type = NOHZ_KICK_ANY; + + /* Don't need to rebalance while attached to NULL domain or + * cpu is isolated. + */ + if (unlikely(on_null_domain(rq)) || cpu_isolated(cpu_of(rq))) + return; + + if (time_after_eq(jiffies, rq->next_balance)) + raise_softirq(SCHED_SOFTIRQ); +#ifdef CONFIG_NO_HZ_COMMON + if (nohz_kick_needed(rq, &type)) + nohz_balancer_kick(type); +#endif +} + +static void rq_online_fair(struct rq *rq) +{ + update_sysctl(); + + update_runtime_enabled(rq); +} + +static void rq_offline_fair(struct rq *rq) +{ + update_sysctl(); + + /* Ensure any throttled groups are reachable by pick_next_task */ + unthrottle_offline_cfs_rqs(rq); +} + +#endif /* CONFIG_SMP */ + +/* + * scheduler tick hitting a task of our scheduling class: + */ +static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued) +{ + struct cfs_rq *cfs_rq; + struct sched_entity *se = &curr->se; + + for_each_sched_entity(se) { + cfs_rq = cfs_rq_of(se); + entity_tick(cfs_rq, se, queued); + } + + if (static_branch_unlikely(&sched_numa_balancing)) + task_tick_numa(rq, curr); + +#ifdef CONFIG_SMP + if (energy_aware() && + !rq->rd->overutilized && cpu_overutilized(task_cpu(curr))) { + rq->rd->overutilized = true; + trace_sched_overutilized(true); + } + + rq->misfit_task = !task_fits_max(curr, rq->cpu); +#endif + +} + +/* + * called on fork with the child task as argument from the parent's context + * - child not yet on the tasklist + * - preemption disabled + */ +static void task_fork_fair(struct task_struct *p) +{ + struct cfs_rq *cfs_rq; + struct sched_entity *se = &p->se, *curr; + struct rq *rq = this_rq(); + + raw_spin_lock(&rq->lock); + update_rq_clock(rq); + + cfs_rq = task_cfs_rq(current); + curr = cfs_rq->curr; + if (curr) { + update_curr(cfs_rq); + se->vruntime = curr->vruntime; + } + place_entity(cfs_rq, se, 1); + + if (sysctl_sched_child_runs_first && curr && entity_before(curr, se)) { + /* + * Upon rescheduling, sched_class::put_prev_task() will place + * 'current' within the tree based on its new key value. + */ + swap(curr->vruntime, se->vruntime); + resched_curr(rq); + } + + se->vruntime -= cfs_rq->min_vruntime; + raw_spin_unlock(&rq->lock); +} + +/* + * Priority of the task has changed. Check to see if we preempt + * the current task. + */ +static void +prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio) +{ + if (!task_on_rq_queued(p)) + return; + + /* + * Reschedule if we are currently running on this runqueue and + * our priority decreased, or if we are not currently running on + * this runqueue and our priority is higher than the current's + */ + if (rq->curr == p) { + if (p->prio > oldprio) + resched_curr(rq); + } else + check_preempt_curr(rq, p, 0); +} + +static inline bool vruntime_normalized(struct task_struct *p) +{ + struct sched_entity *se = &p->se; + + /* + * In both the TASK_ON_RQ_QUEUED and TASK_ON_RQ_MIGRATING cases, + * the dequeue_entity(.flags=0) will already have normalized the + * vruntime. + */ + if (p->on_rq) + return true; + + /* + * When !on_rq, vruntime of the task has usually NOT been normalized. + * But there are some cases where it has already been normalized: + * + * - A forked child which is waiting for being woken up by + * wake_up_new_task(). + * - A task which has been woken up by try_to_wake_up() and + * waiting for actually being woken up by sched_ttwu_pending(). + */ + if (!se->sum_exec_runtime || p->state == TASK_WAKING) + return true; + + return false; +} + +#ifdef CONFIG_FAIR_GROUP_SCHED +/* + * Propagate the changes of the sched_entity across the tg tree to make it + * visible to the root + */ +static void propagate_entity_cfs_rq(struct sched_entity *se) +{ + struct cfs_rq *cfs_rq; + + /* Start to propagate at parent */ + se = se->parent; + + for_each_sched_entity(se) { + cfs_rq = cfs_rq_of(se); + + if (cfs_rq_throttled(cfs_rq)) + break; + + update_load_avg(se, UPDATE_TG); + } +} +#else +static void propagate_entity_cfs_rq(struct sched_entity *se) { } +#endif + +static void detach_entity_cfs_rq(struct sched_entity *se) +{ + struct cfs_rq *cfs_rq = cfs_rq_of(se); + + /* Catch up with the cfs_rq and remove our load when we leave */ + update_load_avg(se, 0); + detach_entity_load_avg(cfs_rq, se); + update_tg_load_avg(cfs_rq, false); + propagate_entity_cfs_rq(se); +} + +static void attach_entity_cfs_rq(struct sched_entity *se) +{ + struct cfs_rq *cfs_rq = cfs_rq_of(se); + +#ifdef CONFIG_FAIR_GROUP_SCHED + /* + * Since the real-depth could have been changed (only FAIR + * class maintain depth value), reset depth properly. + */ + se->depth = se->parent ? se->parent->depth + 1 : 0; +#endif + + /* Synchronize entity with its cfs_rq */ + update_load_avg(se, sched_feat(ATTACH_AGE_LOAD) ? 0 : SKIP_AGE_LOAD); + attach_entity_load_avg(cfs_rq, se); + update_tg_load_avg(cfs_rq, false); + propagate_entity_cfs_rq(se); +} + +static void detach_task_cfs_rq(struct task_struct *p) +{ + struct sched_entity *se = &p->se; + struct cfs_rq *cfs_rq = cfs_rq_of(se); + + if (!vruntime_normalized(p)) { + /* + * Fix up our vruntime so that the current sleep doesn't + * cause 'unlimited' sleep bonus. + */ + place_entity(cfs_rq, se, 0); + se->vruntime -= cfs_rq->min_vruntime; + } + + detach_entity_cfs_rq(se); +} + +static void attach_task_cfs_rq(struct task_struct *p) +{ + struct sched_entity *se = &p->se; + struct cfs_rq *cfs_rq = cfs_rq_of(se); + + attach_entity_cfs_rq(se); + + if (!vruntime_normalized(p)) + se->vruntime += cfs_rq->min_vruntime; +} + +static void switched_from_fair(struct rq *rq, struct task_struct *p) +{ + detach_task_cfs_rq(p); +} + +static void switched_to_fair(struct rq *rq, struct task_struct *p) +{ + attach_task_cfs_rq(p); + + if (task_on_rq_queued(p)) { + /* + * We were most likely switched from sched_rt, so + * kick off the schedule if running, otherwise just see + * if we can still preempt the current task. + */ + if (rq->curr == p) + resched_curr(rq); + else + check_preempt_curr(rq, p, 0); + } +} + +/* Account for a task changing its policy or group. + * + * This routine is mostly called to set cfs_rq->curr field when a task + * migrates between groups/classes. + */ +static void set_curr_task_fair(struct rq *rq) +{ + struct sched_entity *se = &rq->curr->se; + + for_each_sched_entity(se) { + struct cfs_rq *cfs_rq = cfs_rq_of(se); + + set_next_entity(cfs_rq, se); + /* ensure bandwidth has been allocated on our new cfs_rq */ + account_cfs_rq_runtime(cfs_rq, 0); + } +} + +void init_cfs_rq(struct cfs_rq *cfs_rq) +{ + cfs_rq->tasks_timeline = RB_ROOT; + cfs_rq->min_vruntime = (u64)(-(1LL << 20)); +#ifndef CONFIG_64BIT + cfs_rq->min_vruntime_copy = cfs_rq->min_vruntime; +#endif +#ifdef CONFIG_SMP +#ifdef CONFIG_FAIR_GROUP_SCHED + cfs_rq->propagate_avg = 0; +#endif + atomic_long_set(&cfs_rq->removed_load_avg, 0); + atomic_long_set(&cfs_rq->removed_util_avg, 0); +#endif +} + +#ifdef CONFIG_FAIR_GROUP_SCHED +static void task_set_group_fair(struct task_struct *p) +{ + struct sched_entity *se = &p->se; + + set_task_rq(p, task_cpu(p)); + se->depth = se->parent ? se->parent->depth + 1 : 0; +} + +static void task_move_group_fair(struct task_struct *p) +{ + detach_task_cfs_rq(p); + set_task_rq(p, task_cpu(p)); + +#ifdef CONFIG_SMP + /* Tell se's cfs_rq has been changed -- migrated */ + p->se.avg.last_update_time = 0; +#endif + attach_task_cfs_rq(p); +} + +static void task_change_group_fair(struct task_struct *p, int type) +{ + switch (type) { + case TASK_SET_GROUP: + task_set_group_fair(p); + break; + + case TASK_MOVE_GROUP: + task_move_group_fair(p); + break; + } +} + +void free_fair_sched_group(struct task_group *tg) +{ + int i; + + destroy_cfs_bandwidth(tg_cfs_bandwidth(tg)); + + for_each_possible_cpu(i) { + if (tg->cfs_rq) + kfree(tg->cfs_rq[i]); + if (tg->se) + kfree(tg->se[i]); + } + + kfree(tg->cfs_rq); + kfree(tg->se); +} + +int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent) +{ + struct sched_entity *se; + struct cfs_rq *cfs_rq; + struct rq *rq; + int i; + + tg->cfs_rq = kzalloc(sizeof(cfs_rq) * nr_cpu_ids, GFP_KERNEL); + if (!tg->cfs_rq) + goto err; + tg->se = kzalloc(sizeof(se) * nr_cpu_ids, GFP_KERNEL); + if (!tg->se) + goto err; + + tg->shares = NICE_0_LOAD; + + init_cfs_bandwidth(tg_cfs_bandwidth(tg)); + + for_each_possible_cpu(i) { + rq = cpu_rq(i); + + cfs_rq = kzalloc_node(sizeof(struct cfs_rq), + GFP_KERNEL, cpu_to_node(i)); + if (!cfs_rq) + goto err; + + se = kzalloc_node(sizeof(struct sched_entity), + GFP_KERNEL, cpu_to_node(i)); + if (!se) + goto err_free_rq; + + init_cfs_rq(cfs_rq); + init_tg_cfs_entry(tg, cfs_rq, se, i, parent->se[i]); + init_entity_runnable_average(se); + + raw_spin_lock_irq(&rq->lock); + post_init_entity_util_avg(se); + raw_spin_unlock_irq(&rq->lock); + } + + return 1; + +err_free_rq: + kfree(cfs_rq); +err: + return 0; +} + +void unregister_fair_sched_group(struct task_group *tg) +{ + unsigned long flags; + struct rq *rq; + int cpu; + + for_each_possible_cpu(cpu) { + if (tg->se[cpu]) + remove_entity_load_avg(tg->se[cpu]); + + /* + * Only empty task groups can be destroyed; so we can speculatively + * check on_list without danger of it being re-added. + */ + if (!tg->cfs_rq[cpu]->on_list) + continue; + + rq = cpu_rq(cpu); + + raw_spin_lock_irqsave(&rq->lock, flags); + list_del_leaf_cfs_rq(tg->cfs_rq[cpu]); + raw_spin_unlock_irqrestore(&rq->lock, flags); + } +} + +void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq, + struct sched_entity *se, int cpu, + struct sched_entity *parent) +{ + struct rq *rq = cpu_rq(cpu); + + cfs_rq->tg = tg; + cfs_rq->rq = rq; + init_cfs_rq_runtime(cfs_rq); + + tg->cfs_rq[cpu] = cfs_rq; + tg->se[cpu] = se; + + /* se could be NULL for root_task_group */ + if (!se) + return; + + if (!parent) { + se->cfs_rq = &rq->cfs; + se->depth = 0; + } else { + se->cfs_rq = parent->my_q; + se->depth = parent->depth + 1; + } + + se->my_q = cfs_rq; + /* guarantee group entities always have weight */ + update_load_set(&se->load, NICE_0_LOAD); + se->parent = parent; +} + +static DEFINE_MUTEX(shares_mutex); + +int sched_group_set_shares(struct task_group *tg, unsigned long shares) +{ + int i; + unsigned long flags; + + /* + * We can't change the weight of the root cgroup. + */ + if (!tg->se[0]) + return -EINVAL; + + shares = clamp(shares, scale_load(MIN_SHARES), scale_load(MAX_SHARES)); + + mutex_lock(&shares_mutex); + if (tg->shares == shares) + goto done; + + tg->shares = shares; + for_each_possible_cpu(i) { + struct rq *rq = cpu_rq(i); + struct sched_entity *se; + + se = tg->se[i]; + /* Propagate contribution to hierarchy */ + raw_spin_lock_irqsave(&rq->lock, flags); + + /* Possible calls to update_curr() need rq clock */ + update_rq_clock(rq); + for_each_sched_entity(se) { + update_load_avg(se, UPDATE_TG); + update_cfs_shares(se); + } + raw_spin_unlock_irqrestore(&rq->lock, flags); + } + +done: + mutex_unlock(&shares_mutex); + return 0; +} +#else /* CONFIG_FAIR_GROUP_SCHED */ + +void free_fair_sched_group(struct task_group *tg) { } + +int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent) +{ + return 1; +} + +void unregister_fair_sched_group(struct task_group *tg) { } + +#endif /* CONFIG_FAIR_GROUP_SCHED */ + + +static unsigned int get_rr_interval_fair(struct rq *rq, struct task_struct *task) +{ + struct sched_entity *se = &task->se; + unsigned int rr_interval = 0; + + /* + * Time slice is 0 for SCHED_OTHER tasks that are on an otherwise + * idle runqueue: + */ + if (rq->cfs.load.weight) + rr_interval = NS_TO_JIFFIES(sched_slice(cfs_rq_of(se), se)); + + return rr_interval; +} + +/* + * All the scheduling class methods: + */ +const struct sched_class fair_sched_class = { + .next = &idle_sched_class, + .enqueue_task = enqueue_task_fair, + .dequeue_task = dequeue_task_fair, + .yield_task = yield_task_fair, + .yield_to_task = yield_to_task_fair, + + .check_preempt_curr = check_preempt_wakeup, + + .pick_next_task = pick_next_task_fair, + .put_prev_task = put_prev_task_fair, + +#ifdef CONFIG_SMP + .select_task_rq = select_task_rq_fair, + .migrate_task_rq = migrate_task_rq_fair, + + .rq_online = rq_online_fair, + .rq_offline = rq_offline_fair, + + .task_waking = task_waking_fair, + .task_dead = task_dead_fair, + .set_cpus_allowed = set_cpus_allowed_common, +#endif + + .set_curr_task = set_curr_task_fair, + .task_tick = task_tick_fair, + .task_fork = task_fork_fair, + + .prio_changed = prio_changed_fair, + .switched_from = switched_from_fair, + .switched_to = switched_to_fair, + + .get_rr_interval = get_rr_interval_fair, + + .update_curr = update_curr_fair, + +#ifdef CONFIG_FAIR_GROUP_SCHED + .task_change_group = task_change_group_fair, +#endif +#ifdef CONFIG_SCHED_HMP + .inc_hmp_sched_stats = inc_hmp_sched_stats_fair, + .dec_hmp_sched_stats = dec_hmp_sched_stats_fair, + .fixup_hmp_sched_stats = fixup_hmp_sched_stats_fair, +#endif +}; + +#ifdef CONFIG_SCHED_DEBUG +void print_cfs_stats(struct seq_file *m, int cpu) +{ + struct cfs_rq *cfs_rq; + + rcu_read_lock(); + for_each_leaf_cfs_rq(cpu_rq(cpu), cfs_rq) + print_cfs_rq(m, cpu, cfs_rq); + rcu_read_unlock(); +} + +#ifdef CONFIG_NUMA_BALANCING +void show_numa_stats(struct task_struct *p, struct seq_file *m) +{ + int node; + unsigned long tsf = 0, tpf = 0, gsf = 0, gpf = 0; + + for_each_online_node(node) { + if (p->numa_faults) { + tsf = p->numa_faults[task_faults_idx(NUMA_MEM, node, 0)]; + tpf = p->numa_faults[task_faults_idx(NUMA_MEM, node, 1)]; + } + if (p->numa_group) { + gsf = p->numa_group->faults[task_faults_idx(NUMA_MEM, node, 0)], + gpf = p->numa_group->faults[task_faults_idx(NUMA_MEM, node, 1)]; + } + print_numa_stats(m, node, tsf, tpf, gsf, gpf); + } +} +#endif /* CONFIG_NUMA_BALANCING */ +#endif /* CONFIG_SCHED_DEBUG */ + +__init void init_sched_fair_class(void) +{ +#ifdef CONFIG_SMP + open_softirq(SCHED_SOFTIRQ, run_rebalance_domains); + +#ifdef CONFIG_NO_HZ_COMMON + nohz.next_balance = jiffies; + zalloc_cpumask_var(&nohz.idle_cpus_mask, GFP_NOWAIT); + cpu_notifier(sched_ilb_notifier, 0); +#endif +#endif /* SMP */ + +} |