From 776dd2c87482de547f1ebf06e2d496ade39d1e1a Mon Sep 17 00:00:00 2001 From: Dima Zavin Date: Tue, 28 Sep 2010 17:35:31 -0700 Subject: sched: use the old min_vruntime when normalizing on dequeue MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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. Cc: Arve Hjønnevåg Signed-off-by: Dima Zavin --- kernel/sched_fair.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'kernel/sched_fair.c') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 6ded59f453c0..1bb879013173 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -802,6 +802,8 @@ static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se) static void dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) { + u64 min_vruntime; + /* * Update run-time statistics of the 'current'. */ @@ -826,6 +828,8 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) if (se != cfs_rq->curr) __dequeue_entity(cfs_rq, se); account_entity_dequeue(cfs_rq, se); + + min_vruntime = cfs_rq->min_vruntime; update_min_vruntime(cfs_rq); /* @@ -834,7 +838,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) * movement in our normalized position. */ if (!(flags & DEQUEUE_SLEEP)) - se->vruntime -= cfs_rq->min_vruntime; + se->vruntime -= min_vruntime; } /* -- cgit v1.2.3