diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/core.c | 41 |
1 files changed, 29 insertions, 12 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index e83959592d6c..f73831486c2f 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1085,6 +1085,33 @@ void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags) } #ifdef CONFIG_SMP + +static inline bool is_per_cpu_kthread(struct task_struct *p) +{ + if (!(p->flags & PF_KTHREAD)) + return false; + + if (p->nr_cpus_allowed != 1) + return false; + + return true; +} + +/* + * Per-CPU kthreads are allowed to run on !actie && online CPUs, see + * __set_cpus_allowed_ptr() and select_fallback_rq(). + */ +static inline bool is_cpu_allowed(struct task_struct *p, int cpu) +{ + if (!cpumask_test_cpu(cpu, &p->cpus_allowed)) + return false; + + if (is_per_cpu_kthread(p)) + return cpu_online(cpu); + + return cpu_active(cpu); +} + /* * This is how migration works: * @@ -1144,16 +1171,8 @@ static struct rq *__migrate_task(struct rq *rq, struct task_struct *p, int dest_ { int src_cpu; - if (p->flags & PF_KTHREAD) { - if (unlikely(!cpu_online(dest_cpu))) - return ret; - } else { - if (unlikely(!cpu_active(dest_cpu))) - return ret; - } - /* Affinity changed (again). */ - if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) + if (!is_cpu_allowed(p, dest_cpu)) return rq; src_cpu = cpu_of(rq); @@ -1654,9 +1673,7 @@ static int select_fallback_rq(int cpu, struct task_struct *p, bool allow_iso) for (;;) { /* Any allowed, online CPU? */ for_each_cpu(dest_cpu, tsk_cpus_allowed(p)) { - if (!(p->flags & PF_KTHREAD) && !cpu_active(dest_cpu)) - continue; - if (!cpu_online(dest_cpu)) + if (!is_cpu_allowed(p, dest_cpu)) continue; if (cpu_isolated(dest_cpu)) { if (allow_iso) |