[tip:sched/core] sched: Fix TASK_WAKING & loadaverage breakage

tip-bot for Ingo Molnar
2009-09-16T19:13:37Z

Commit-ID: bf2add6a0aacf632a71237ac5fc818a82ea12684
Gitweb: http://git.kernel.org/tip/bf2add6a0aacf632a71237ac5fc818a82ea12684
Author: Ingo Molnar <mingo@elte.hu>
AuthorDate: Wed, 16 Sep 2009 21:09:13 +0200
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Wed, 16 Sep 2009 21:09:13 +0200

sched: Fix TASK_WAKING & loadaverage breakage

Fix this:

top - 21:54:00 up 2:59, 1 user, load average: 432512.33, 426421.74, 417432.74

Which happens because we now set TASK_WAKING before activate_task().

Spread out activate_task() in two parts - this is also
a micro-optimization as try_to_wake_up() is one of the
hottest path.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

---
kernel/sched.c | 8 +++++++-
1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/kernel/sched.c b/kernel/sched.c
index 5049d95..e3fbd83 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2343,7 +2343,11 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state,
/*
* In order to handle concurrent wakeups and release the rq->lock
* we put the task in TASK_WAKING state.
+ *
+ * First fix up the nr_uninterruptible count:
*/
+ if (task_contributes_to_load(p))
+ rq->nr_uninterruptible--;
p->state = TASK_WAKING;
task_rq_unlock(rq, &flags);

@@ -2381,7 +2385,9 @@ out_activate:
schedstat_inc(p, se.nr_wakeups_local);
else
schedstat_inc(p, se.nr_wakeups_remote);
- activate_task(rq, p, 1);
+
+ enqueue_task(rq, p, wakeup);
+ inc_nr_running(rq);
success = 1;

/*