[PATCH 3/3] Fix other possible sources of latency issues

From: Srivatsa Vaddagiri
Date: Tue Sep 25 2007 - 12:27:23 EST

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

Signed-off-by : Srivatsa Vaddagiri <vatsa@xxxxxxxxxxxxxxxxxx>

kernel/sched_fair.c | 2 ++
1 files changed, 2 insertions(+)

Index: current/kernel/sched_fair.c
--- current.orig/kernel/sched_fair.c
+++ current/kernel/sched_fair.c
@@ -715,6 +715,7 @@ static void enqueue_task_fair(struct rq
cfs_rq = cfs_rq_of(se);
enqueue_entity(cfs_rq, se, wakeup);
+ wakeup = 1;

@@ -734,6 +735,7 @@ static void dequeue_task_fair(struct rq
/* Don't dequeue parent if it has other entities besides us */
if (cfs_rq->load.weight)
+ sleep = 1;

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