From 17bc14b767cf0692420c43dbe5310ae98a5a7836 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Fri, 14 Dec 2012 07:20:43 -0800 Subject: [PATCH] Revert "sched: Update_cfs_shares at period edge" This reverts commit f269ae0469fc882332bdfb5db15d3c1315fe2a10. It turns out it causes a very noticeable interactivity regression with CONFIG_SCHED_AUTOGROUP (test-case: "make -j32" of the kernel in a terminal window, while scrolling in a browser - the autogrouping means that the two end up in separate cgroups, and the browser should be smooth as silk despite the high load). Says Paul Turner: "It seems that the update-throttling on the wake-side is reducing the interactive tasks' ability to preempt. While I suspect the right longer term answer here is force these updates only in the cross-cgroup case; this is less trivial. For this release I believe the right answer is either going to be a revert or restore the updates on the enqueue-side." Reported-by: Linus Torvalds Bisected-by: Mike Galbraith Acked-by: Paul Turner Acked-by: Ingo Molnar Signed-off-by: Linus Torvalds --- kernel/sched/fair.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 59e072b2db97..756f9f9e8542 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1265,7 +1265,6 @@ static void update_cfs_rq_blocked_load(struct cfs_rq *cfs_rq, int force_update) } __update_cfs_rq_tg_load_contrib(cfs_rq, force_update); - update_cfs_shares(cfs_rq); } static inline void update_rq_runnable_avg(struct rq *rq, int runnable) @@ -1475,8 +1474,9 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) * Update run-time statistics of the 'current'. */ update_curr(cfs_rq); - account_entity_enqueue(cfs_rq, se); enqueue_entity_load_avg(cfs_rq, se, flags & ENQUEUE_WAKEUP); + account_entity_enqueue(cfs_rq, se); + update_cfs_shares(cfs_rq); if (flags & ENQUEUE_WAKEUP) { place_entity(cfs_rq, se, 0); @@ -1549,6 +1549,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) * Update run-time statistics of the 'current'. */ update_curr(cfs_rq); + dequeue_entity_load_avg(cfs_rq, se, flags & DEQUEUE_SLEEP); update_stats_dequeue(cfs_rq, se); if (flags & DEQUEUE_SLEEP) { @@ -1568,8 +1569,8 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) if (se != cfs_rq->curr) __dequeue_entity(cfs_rq, se); + se->on_rq = 0; account_entity_dequeue(cfs_rq, se); - dequeue_entity_load_avg(cfs_rq, se, flags & DEQUEUE_SLEEP); /* * Normalize the entity after updating the min_vruntime because the @@ -1583,7 +1584,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) return_cfs_rq_runtime(cfs_rq); update_min_vruntime(cfs_rq); - se->on_rq = 0; + update_cfs_shares(cfs_rq); } /* @@ -2595,8 +2596,8 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) if (cfs_rq_throttled(cfs_rq)) break; + update_cfs_shares(cfs_rq); update_entity_load_avg(se, 1); - update_cfs_rq_blocked_load(cfs_rq, 0); } if (!se) { @@ -2656,8 +2657,8 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) if (cfs_rq_throttled(cfs_rq)) break; + update_cfs_shares(cfs_rq); update_entity_load_avg(se, 1); - update_cfs_rq_blocked_load(cfs_rq, 0); } if (!se) { @@ -5837,11 +5838,8 @@ int sched_group_set_shares(struct task_group *tg, unsigned long shares) se = tg->se[i]; /* Propagate contribution to hierarchy */ raw_spin_lock_irqsave(&rq->lock, flags); - for_each_sched_entity(se) { + for_each_sched_entity(se) update_cfs_shares(group_cfs_rq(se)); - /* update contribution to parent */ - update_entity_load_avg(se, 1); - } raw_spin_unlock_irqrestore(&rq->lock, flags); } -- 2.20.1