diff options
Diffstat (limited to 'kernel/sched/fair.c')
| -rw-r--r-- | kernel/sched/fair.c | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 1d6394b9616..383cd134705 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4346,6 +4346,16 @@ unlock: * load-balance). */ #ifdef CONFIG_FAIR_GROUP_SCHED + +#ifdef CONFIG_NO_HZ_COMMON +static int nohz_test_cpu(int cpu); +#else +static inline int nohz_test_cpu(int cpu) +{ + return 0; +} +#endif + /* * 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 @@ -4365,6 +4375,25 @@ migrate_task_rq_fair(struct task_struct *p, int next_cpu) * be negative here since on-rq tasks have decay-count == 0. */ if (se->avg.decay_count) { + /* + * If we migrate a sleeping task away from a CPU + * which has the tick stopped, then both the clock_task + * and decay_counter will be out of date for that CPU + * and we will not decay load correctly. + */ + if (!se->on_rq && nohz_test_cpu(task_cpu(p))) { + struct rq *rq = cpu_rq(task_cpu(p)); + unsigned long flags; + /* + * Current CPU cannot be holding rq->lock in this + * circumstance, but another might be. We must hold + * rq->lock before we go poking around in its clocks + */ + raw_spin_lock_irqsave(&rq->lock, flags); + update_rq_clock(rq); + update_cfs_rq_blocked_load(cfs_rq, 0); + raw_spin_unlock_irqrestore(&rq->lock, flags); + } se->avg.decay_count = -__synchronize_entity_decay(se); atomic64_add(se->avg.load_avg_contrib, &cfs_rq->removed_load); } @@ -6297,6 +6326,18 @@ static struct { unsigned long next_balance; /* in jiffy units */ } nohz ____cacheline_aligned; +/* + * nohz_test_cpu used when load tracking is enabled. FAIR_GROUP_SCHED + * dependency below may be removed when load tracking guards are + * removed. + */ +#ifdef CONFIG_FAIR_GROUP_SCHED +static int nohz_test_cpu(int cpu) +{ + return cpumask_test_cpu(cpu, nohz.idle_cpus_mask); +} +#endif + #ifdef CONFIG_SCHED_HMP_LITTLE_PACKING /* * Decide if the tasks on the busy CPUs in the |