diff options
| -rw-r--r-- | include/linux/sched/smt.h | 18 | ||||
| -rw-r--r-- | kernel/sched/core.c | 24 | ||||
| -rw-r--r-- | kernel/sched/sched.h | 1 |
3 files changed, 43 insertions, 0 deletions
diff --git a/include/linux/sched/smt.h b/include/linux/sched/smt.h new file mode 100644 index 000000000000..5209c268c6fd --- /dev/null +++ b/include/linux/sched/smt.h @@ -0,0 +1,18 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_SCHED_SMT_H +#define _LINUX_SCHED_SMT_H + +#include <linux/atomic.h> + +#ifdef CONFIG_SCHED_SMT +extern atomic_t sched_smt_present; + +static __always_inline bool sched_smt_active(void) +{ + return atomic_read(&sched_smt_present); +} +#else +static inline bool sched_smt_active(void) { return false; } +#endif + +#endif diff --git a/kernel/sched/core.c b/kernel/sched/core.c index d0618951014b..d35a7d528ea6 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5610,6 +5610,10 @@ static void set_cpu_rq_start_time(void) rq->age_stamp = sched_clock_cpu(cpu); } +#ifdef CONFIG_SCHED_SMT +atomic_t sched_smt_present = ATOMIC_INIT(0); +#endif + static int sched_cpu_active(struct notifier_block *nfb, unsigned long action, void *hcpu) { @@ -5626,11 +5630,23 @@ static int sched_cpu_active(struct notifier_block *nfb, * set_cpu_online(). But it might not yet have marked itself * as active, which is essential from here on. */ +#ifdef CONFIG_SCHED_SMT + /* + * When going up, increment the number of cores with SMT present. + */ + if (cpumask_weight(cpu_smt_mask(cpu)) == 2) + atomic_inc(&sched_smt_present); +#endif set_cpu_active(cpu, true); stop_machine_unpark(cpu); return NOTIFY_OK; case CPU_DOWN_FAILED: +#ifdef CONFIG_SCHED_SMT + /* Same as for CPU_ONLINE */ + if (cpumask_weight(cpu_smt_mask(cpu)) == 2) + atomic_inc(&sched_smt_present); +#endif set_cpu_active(cpu, true); return NOTIFY_OK; @@ -5645,7 +5661,15 @@ static int sched_cpu_inactive(struct notifier_block *nfb, switch (action & ~CPU_TASKS_FROZEN) { case CPU_DOWN_PREPARE: set_cpu_active((long)hcpu, false); +#ifdef CONFIG_SCHED_SMT + /* + * When going down, decrement the number of cores with SMT present. + */ + if (cpumask_weight(cpu_smt_mask((long)hcpu)) == 2) + atomic_dec(&sched_smt_present); +#endif return NOTIFY_OK; + default: return NOTIFY_DONE; } diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 6893ee31df4d..8b96df04ba78 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2,6 +2,7 @@ #include <linux/sched.h> #include <linux/sched/sysctl.h> #include <linux/sched/rt.h> +#include <linux/sched/smt.h> #include <linux/sched/deadline.h> #include <linux/mutex.h> #include <linux/spinlock.h> |