From: tip-bot for Peter Zijlstra <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org,
pjt@google.com, peterz@infradead.org, max@gustavus.edu,
stable@kernel.org, tglx@linutronix.de
Subject: [tip:sched/urgent] sched: Ensure update_cfs_shares() is called for parents of continuously-running tasks
Date: Wed, 31 Jul 2013 01:55:28 -0700 [thread overview]
Message-ID: <tip-9545m3apw5d93ubyrotrj31y@git.kernel.org> (raw)
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
/*
reply other threads:[~2013-07-31 8:56 UTC|newest]
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