From b9fa3df33f9166daf81bfa8253d339f5a7726122 Mon Sep 17 00:00:00 2001 From: Srivatsa Vaddagiri Date: Mon, 15 Oct 2007 17:00:12 +0200 Subject: [PATCH] sched: group scheduler, fix latency There is a possibility that because of task of a group moving from one cpu to another, it may gain more cpu time that desired. See http://marc.info/?l=linux-kernel&m=119073197730334 for details. This is an attempt to fix that problem. Basically it simulates dequeue of higher level entities as if they are going to sleep. Similarly it simulate wakeup of higher level entities as if they are waking up from sleep. Signed-off-by: Srivatsa Vaddagiri Signed-off-by: Ingo Molnar Reviewed-by: Thomas Gleixner --- kernel/sched_fair.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 57e7f36..de13a6f 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -727,6 +727,7 @@ static void enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup) break; cfs_rq = cfs_rq_of(se); enqueue_entity(cfs_rq, se, wakeup); + wakeup = 1; } } @@ -746,6 +747,7 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int sleep) /* Don't dequeue parent if it has other entities besides us */ if (cfs_rq->load.weight) break; + sleep = 1; } } -- 2.7.4