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authorChristoph Lameter <clameter@sgi.com>2006-12-10 02:20:13 -0800
committerLinus Torvalds <torvalds@woody.osdl.org>2006-12-10 09:55:42 -0800
commit571f6d2fb0b1c04798df783db2ba85e96bcce43d (patch)
tree09e90a5f4976ddfa35e93e90372413e2ef87060a
parentac7d550499e225efb51a53d0b00667f26b93bdff (diff)
[PATCH] sched: avoid taking rq lock in wake_priority_sleeper
Avoid taking the request queue lock in wake_priority_sleeper if there are no running processes. Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Peter Williams <pwil3058@bigpond.net.au> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Christoph Lameter <clameter@sgi.com> Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com> Cc: "Chen, Kenneth W" <kenneth.w.chen@intel.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--kernel/sched.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index f04add905bd..fdd26fffaa2 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2915,6 +2915,9 @@ static inline int wake_priority_sleeper(struct rq *rq)
int ret = 0;
#ifdef CONFIG_SCHED_SMT
+ if (!rq->nr_running)
+ return 0;
+
spin_lock(&rq->lock);
/*
* If an SMT sibling task has been put to sleep for priority