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authorPeter Zijlstra <peterz@infradead.org>2011-05-17 16:21:10 -0700
committerIngo Molnar <mingo@elte.hu>2011-05-28 17:02:56 +0200
commit1e876231785d82443a5ac8b6c660e9f51bc5dede (patch)
treecab00c4c8ec3090a41215223dde2f47483287cb7 /kernel/sched_fair.c
parentd6aa8f85f16379d42c147b22b59e33b67f9ff466 (diff)
downloadlinux-linaro-stable-1e876231785d82443a5ac8b6c660e9f51bc5dede.tar.gz
sched: Fix ->min_vruntime calculation in dequeue_entity()
Dima Zavin <dima@android.com> reported: "After pulling the thread off the run-queue during a cgroup change, the cfs_rq.min_vruntime gets recalculated. The dequeued thread's vruntime then gets normalized to this new value. This can then lead to the thread getting an unfair boost in the new group if the vruntime of the next task in the old run-queue was way further ahead." Reported-by: Dima Zavin <dima@android.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Recalls-having-tested-once-upon-a-time-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1305674470-23727-1-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched_fair.c')
-rw-r--r--kernel/sched_fair.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index e32a9b70ee9c..433491c2dc8f 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1076,8 +1076,6 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
se->on_rq = 0;
update_cfs_load(cfs_rq, 0);
account_entity_dequeue(cfs_rq, se);
- update_min_vruntime(cfs_rq);
- update_cfs_shares(cfs_rq);
/*
* Normalize the entity after updating the min_vruntime because the
@@ -1086,6 +1084,9 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
*/
if (!(flags & DEQUEUE_SLEEP))
se->vruntime -= cfs_rq->min_vruntime;
+
+ update_min_vruntime(cfs_rq);
+ update_cfs_shares(cfs_rq);
}
/*