Messages in this thread Patch in this message | | | Date | Wed, 31 Jul 2013 01:55:28 -0700 | From | tip-bot for Peter Zijlstra <> | Subject | [tip:sched/urgent] sched: Ensure update_cfs_shares() is called for parents of continuously-running tasks |
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Commit-ID: bf0bd948d1682e3996adc093b43021ed391983e6 Gitweb: http://git.kernel.org/tip/bf0bd948d1682e3996adc093b43021ed391983e6 Author: Peter Zijlstra <peterz@infradead.org> AuthorDate: Fri, 26 Jul 2013 23:48:42 +0200 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Tue, 30 Jul 2013 22:14:37 +0200
sched: Ensure update_cfs_shares() is called for parents of continuously-running tasks
We typically update a task_group's shares within the dequeue/enqueue path. However, continuously running tasks sharing a CPU are not subject to these updates as they are only put/picked. Unfortunately, when we reverted f269ae046 (in 17bc14b7), we lost the augmenting periodic update that was supposed to account for this; resulting in a potential loss of fairness.
To fix this, re-introduce the explicit update in update_cfs_rq_blocked_load() [called via entity_tick()].
Reported-by: Max Hailperin <max@gustavus.edu> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Reviewed-by: Paul Turner <pjt@google.com> Link: http://lkml.kernel.org/n/tip-9545m3apw5d93ubyrotrj31y@git.kernel.org Cc: <stable@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> --- kernel/sched/fair.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 98d1355..06db94b 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -2032,6 +2032,7 @@ entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued) */ update_entity_load_avg(curr, 1); update_cfs_rq_blocked_load(cfs_rq, 1); + update_cfs_shares(cfs_rq); #ifdef CONFIG_SCHED_HRTICK /*
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