| From | Greg Kroah-Hartman <> | Subject | [ 07/45] sched: Ensure update_cfs_shares() is called for parents of continuously-running tasks | Date | Sun, 18 Aug 2013 13:35:56 -0700 |
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3.10-stable review patch. If anyone has any objections, please let me know.
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From: Peter Zijlstra <peterz@infradead.org>
commit bf0bd948d1682e3996adc093b43021ed391983e6 upstream.
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 Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- kernel/sched/fair.c | 1 + 1 file changed, 1 insertion(+)
--- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1984,6 +1984,7 @@ entity_tick(struct cfs_rq *cfs_rq, struc */ 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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