From 4a465e3ebbc8004ce4f7f08f6022ee8315a94edf Mon Sep 17 00:00:00 2001 From: Dietmar Eggemann Date: Fri, 3 Aug 2018 15:05:38 +0100 Subject: sched/fair: Remove setting task's se->runnable_weight during PELT update A CFS (SCHED_OTHER, SCHED_BATCH or SCHED_IDLE policy) task's se->runnable_weight must always be in sync with its se->load.weight. se->runnable_weight is set to se->load.weight when the task is forked (init_entity_runnable_average()) or reniced (reweight_entity()). There are two cases in set_load_weight() which since they currently only set se->load.weight could lead to a situation in which se->load.weight is different to se->runnable_weight for a CFS task: (1) A task switches to SCHED_IDLE. (2) A SCHED_FIFO, SCHED_RR or SCHED_DEADLINE task which has been reniced (during which only its static priority gets set) switches to SCHED_OTHER or SCHED_BATCH. Set se->runnable_weight to se->load.weight in these two cases to prevent this. This eliminates the need to explicitly set it to se->load.weight during PELT updates in the CFS scheduler fastpath. Signed-off-by: Dietmar Eggemann Signed-off-by: Peter Zijlstra (Intel) Cc: Joel Fernandes Cc: Linus Torvalds Cc: Morten Rasmussen Cc: Patrick Bellasi Cc: Peter Zijlstra Cc: Quentin Perret Cc: Thomas Gleixner Cc: Vincent Guittot Link: http://lkml.kernel.org/r/20180803140538.1178-1-dietmar.eggemann@arm.com Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 2 ++ kernel/sched/pelt.c | 6 ------ 2 files changed, 2 insertions(+), 6 deletions(-) (limited to 'kernel/sched') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index f2caf1b..56b3c17 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -700,6 +700,7 @@ static void set_load_weight(struct task_struct *p, bool update_load) if (idle_policy(p->policy)) { load->weight = scale_load(WEIGHT_IDLEPRIO); load->inv_weight = WMULT_IDLEPRIO; + p->se.runnable_weight = load->weight; return; } @@ -712,6 +713,7 @@ static void set_load_weight(struct task_struct *p, bool update_load) } else { load->weight = scale_load(sched_prio_to_weight[prio]); load->inv_weight = sched_prio_to_wmult[prio]; + p->se.runnable_weight = load->weight; } } diff --git a/kernel/sched/pelt.c b/kernel/sched/pelt.c index 48a1264..90fb5bc 100644 --- a/kernel/sched/pelt.c +++ b/kernel/sched/pelt.c @@ -269,9 +269,6 @@ ___update_load_avg(struct sched_avg *sa, unsigned long load, unsigned long runna int __update_load_avg_blocked_se(u64 now, int cpu, struct sched_entity *se) { - if (entity_is_task(se)) - se->runnable_weight = se->load.weight; - if (___update_load_sum(now, cpu, &se->avg, 0, 0, 0)) { ___update_load_avg(&se->avg, se_weight(se), se_runnable(se)); return 1; @@ -282,9 +279,6 @@ int __update_load_avg_blocked_se(u64 now, int cpu, struct sched_entity *se) int __update_load_avg_se(u64 now, int cpu, struct cfs_rq *cfs_rq, struct sched_entity *se) { - if (entity_is_task(se)) - se->runnable_weight = se->load.weight; - if (___update_load_sum(now, cpu, &se->avg, !!se->on_rq, !!se->on_rq, cfs_rq->curr == se)) { -- cgit v1.1