From: Byungchul Park <[email protected]> This patch removes a weird coupling between se->avg.last_update_time and the condition checking for migration, and introduce a new migration flag. Now, scheduler can use the flag instead of se->avg.last_update_time to check if migration already happened or not.
Signed-off-by: Byungchul Park <[email protected]> --- include/linux/sched.h | 3 +++ kernel/sched/core.c | 1 + kernel/sched/fair.c | 22 ++++++++++++---------- kernel/sched/sched.h | 1 + 4 files changed, 17 insertions(+), 10 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 699228b..a104c72 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1379,6 +1379,9 @@ struct task_struct { #endif int on_rq; + /* For indicating if a migration has happened. */ + int migrated; + int prio, static_prio, normal_prio; unsigned int rt_priority; const struct sched_class *sched_class; diff --git a/kernel/sched/core.c b/kernel/sched/core.c index a91df61..57f4300 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2068,6 +2068,7 @@ void __dl_clear_params(struct task_struct *p) static void __sched_fork(unsigned long clone_flags, struct task_struct *p) { p->on_rq = 0; + p->migrated = 0; p->se.on_rq = 0; p->se.exec_start = 0; diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 077076f..0f76903 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2771,14 +2771,15 @@ static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s /* 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) +enqueue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) { struct sched_avg *sa = &se->avg; u64 now = cfs_rq_clock_task(cfs_rq); - int migrated, decayed; + int decayed; + int migrated = flags & ENQUEUE_MIGRATED; + int created = !sa->last_update_time; - migrated = !sa->last_update_time; - if (!migrated) { + if (!migrated && !created) { __update_load_avg(now, cpu_of(rq_of(cfs_rq)), sa, se->on_rq * scale_load_down(se->load.weight), cfs_rq->curr == se, NULL); @@ -2789,10 +2790,10 @@ enqueue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) cfs_rq->runnable_load_avg += sa->load_avg; cfs_rq->runnable_load_sum += sa->load_sum; - if (migrated) + if (migrated || created) attach_entity_load_avg(cfs_rq, se); - if (decayed || migrated) + if (decayed || migrated || created) update_tg_load_avg(cfs_rq, 0); } @@ -2868,7 +2869,7 @@ static int idle_balance(struct rq *this_rq); static inline void update_load_avg(struct sched_entity *se, int update_tg) {} static inline void -enqueue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {} +enqueue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) {} 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) {} @@ -3008,7 +3009,7 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) * Update run-time statistics of the 'current'. */ update_curr(cfs_rq); - enqueue_entity_load_avg(cfs_rq, se); + enqueue_entity_load_avg(cfs_rq, se, flags); account_entity_enqueue(cfs_rq, se); update_cfs_shares(cfs_rq); @@ -4136,6 +4137,7 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) struct cfs_rq *cfs_rq; struct sched_entity *se = &p->se; + flags = flags | (xchg(&p->migrated, 0) ? ENQUEUE_MIGRATED : 0); for_each_sched_entity(se) { if (se->on_rq) break; @@ -5021,7 +5023,7 @@ static void migrate_task_rq_fair(struct task_struct *p, int next_cpu) remove_entity_load_avg(&p->se); /* Tell new CPU we are migrated */ - p->se.avg.last_update_time = 0; + p->migrated = 1; /* We have migrated, no longer consider this task hot */ p->se.exec_start = 0; @@ -8082,7 +8084,7 @@ static void task_move_group_fair(struct task_struct *p) set_task_rq(p, task_cpu(p)); #ifdef CONFIG_SMP - /* Tell se's cfs_rq has been changed -- migrated */ + /* Tell se's cfs_rq has been changed */ p->se.avg.last_update_time = 0; #endif attach_task_cfs_rq(p); diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index af6f252..66d0552 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1158,6 +1158,7 @@ static const u32 prio_to_wmult[40] = { #define ENQUEUE_WAKING 0 #endif #define ENQUEUE_REPLENISH 8 +#define ENQUEUE_MIGRATED 16 #define DEQUEUE_SLEEP 1 -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
