Commit-ID: 1936c53ce8c8d4555e9ccad2dc8d98e0637b11f7 Gitweb: https://git.kernel.org/tip/1936c53ce8c8d4555e9ccad2dc8d98e0637b11f7 Author: Vincent Guittot <vincent.guit...@linaro.org> AuthorDate: Tue, 13 Feb 2018 11:31:18 +0100 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Fri, 9 Mar 2018 07:59:22 +0100
sched/fair: Reduce the periodic update duration Instead of using the cfs_rq_is_decayed() which monitors all *_avg and *_sum, we create a cfs_rq_has_blocked() which only takes care of util_avg and load_avg. We are only interested by these 2 values which are decaying faster than the *_sum so we can stop the periodic update earlier. Signed-off-by: Vincent Guittot <vincent.guit...@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Cc: brendan.jack...@arm.com Cc: dietmar.eggem...@arm.com Cc: morten.rasmus...@foss.arm.com Cc: valentin.schnei...@arm.com Link: http://lkml.kernel.org/r/1518517879-2280-3-git-send-email-vincent.guit...@linaro.org Signed-off-by: Ingo Molnar <mi...@kernel.org> --- kernel/sched/fair.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 78b06a0814d1..aad7c03dbad8 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7424,6 +7424,19 @@ static void attach_tasks(struct lb_env *env) rq_unlock(env->dst_rq, &rf); } +static inline bool cfs_rq_has_blocked(struct cfs_rq *cfs_rq) +{ + if (cfs_rq->avg.load_avg) + return true; + + if (cfs_rq->avg.util_avg) + return true; + + return false; +} + +#ifdef CONFIG_FAIR_GROUP_SCHED + static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq) { if (cfs_rq->load.weight) @@ -7441,8 +7454,6 @@ static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq) return true; } -#ifdef CONFIG_FAIR_GROUP_SCHED - static void update_blocked_averages(int cpu) { struct rq *rq = cpu_rq(cpu); @@ -7478,7 +7489,9 @@ static void update_blocked_averages(int cpu) */ if (cfs_rq_is_decayed(cfs_rq)) list_del_leaf_cfs_rq(cfs_rq); - else + + /* Don't need periodic decay once load/util_avg are null */ + if (cfs_rq_has_blocked(cfs_rq)) done = false; } @@ -7548,7 +7561,7 @@ static inline void update_blocked_averages(int cpu) update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq); #ifdef CONFIG_NO_HZ_COMMON rq->last_blocked_load_update_tick = jiffies; - if (cfs_rq_is_decayed(cfs_rq)) + if (!cfs_rq_has_blocked(cfs_rq)) rq->has_blocked_load = 0; #endif rq_unlock_irqrestore(rq, &rf);
