From ea14b57e8a181ac0561eba7a787e088f8c89f822 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 2 Feb 2018 10:27:00 +0100 Subject: [PATCH] sched/cpufreq: Provide migration hint It was suggested that a migration hint might be usefull for the CPU-freq governors. Signed-off-by: Peter Zijlstra (Intel) Cc: Juri Lelli Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Rafael J. Wysocki Cc: Thomas Gleixner Cc: Viresh Kumar Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- include/linux/sched/cpufreq.h | 1 + kernel/sched/fair.c | 31 +++++++++++++++++++------------ 2 files changed, 20 insertions(+), 12 deletions(-) diff --git a/include/linux/sched/cpufreq.h b/include/linux/sched/cpufreq.h index b48f2fb3b316..59667444669f 100644 --- a/include/linux/sched/cpufreq.h +++ b/include/linux/sched/cpufreq.h @@ -9,6 +9,7 @@ */ #define SCHED_CPUFREQ_IOWAIT (1U << 0) +#define SCHED_CPUFREQ_MIGRATION (1U << 1) #ifdef CONFIG_CPU_FREQ struct update_util_data { diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 494d5db9a6cd..e8f5efe2936c 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -772,7 +772,7 @@ void post_init_entity_util_avg(struct sched_entity *se) * For !fair tasks do: * update_cfs_rq_load_avg(now, cfs_rq); - attach_entity_load_avg(cfs_rq, se); + attach_entity_load_avg(cfs_rq, se, 0); switched_from_fair(rq, p); * * such that the next switched_to_fair() has the @@ -3009,11 +3009,11 @@ static inline void update_cfs_group(struct sched_entity *se) } #endif /* CONFIG_FAIR_GROUP_SCHED */ -static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq) +static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq, int flags) { struct rq *rq = rq_of(cfs_rq); - if (&rq->cfs == cfs_rq) { + if (&rq->cfs == cfs_rq || (flags & SCHED_CPUFREQ_MIGRATION)) { /* * There are a few boundary cases this might miss but it should * get called often enough that that should (hopefully) not be @@ -3028,7 +3028,7 @@ static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq) * * See cpu_util(). */ - cpufreq_update_util(rq, 0); + cpufreq_update_util(rq, flags); } } @@ -3686,7 +3686,7 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq) #endif if (decayed) - cfs_rq_util_change(cfs_rq); + cfs_rq_util_change(cfs_rq, 0); return decayed; } @@ -3699,7 +3699,7 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq) * 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) +static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) { u32 divider = LOAD_AVG_MAX - 1024 + cfs_rq->avg.period_contrib; @@ -3735,7 +3735,7 @@ static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s add_tg_cfs_propagate(cfs_rq, se->avg.load_sum); - cfs_rq_util_change(cfs_rq); + cfs_rq_util_change(cfs_rq, flags); } /** @@ -3754,7 +3754,7 @@ static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s add_tg_cfs_propagate(cfs_rq, -se->avg.load_sum); - cfs_rq_util_change(cfs_rq); + cfs_rq_util_change(cfs_rq, 0); } /* @@ -3784,7 +3784,14 @@ static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s if (!se->avg.last_update_time && (flags & DO_ATTACH)) { - attach_entity_load_avg(cfs_rq, se); + /* + * DO_ATTACH means we're here from enqueue_entity(). + * !last_update_time means we've passed through + * migrate_task_rq_fair() indicating we migrated. + * + * IOW we're enqueueing a task on a new CPU. + */ + attach_entity_load_avg(cfs_rq, se, SCHED_CPUFREQ_MIGRATION); update_tg_load_avg(cfs_rq, 0); } else if (decayed && (flags & UPDATE_TG)) @@ -3880,13 +3887,13 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq) static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int not_used1) { - cfs_rq_util_change(cfs_rq); + cfs_rq_util_change(cfs_rq, 0); } 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) {} +attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) {} static inline void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {} @@ -9726,7 +9733,7 @@ static void attach_entity_cfs_rq(struct sched_entity *se) /* Synchronize entity with its cfs_rq */ update_load_avg(cfs_rq, se, sched_feat(ATTACH_AGE_LOAD) ? 0 : SKIP_AGE_LOAD); - attach_entity_load_avg(cfs_rq, se); + attach_entity_load_avg(cfs_rq, se, 0); update_tg_load_avg(cfs_rq, false); propagate_entity_cfs_rq(se); }