[34-longterm 090/260] sched: Fix nr_uninterruptible count

Paul Gortmaker
2011-01-02T07:58:32Z

From: Peter Zijlstra <a.p.zijlstra@chello.nl>

commit cc87f76a601d2d256118f7bab15e35254356ae21 upstream.

The cpuload calculation in calc_load_account_active() assumes
rq->nr_uninterruptible will not change on an offline cpu after
migrate_nr_uninterruptible(). However the recent migrate on wakeup
changes broke that and would result in decrementing the offline cpu's
rq->nr_uninterruptible.

Fix this by accounting the nr_uninterruptible on the waking cpu.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
kernel/sched.c | 8 ++++++--
1 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/kernel/sched.c b/kernel/sched.c
index e542c1e..074c4d8 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2388,8 +2388,12 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state,
*
* First fix up the nr_uninterruptible count:
*/
- if (task_contributes_to_load(p))
- rq->nr_uninterruptible--;
+ if (task_contributes_to_load(p)) {
+ if (likely(cpu_online(orig_cpu)))
+ rq->nr_uninterruptible--;
+ else
+ this_rq()->nr_uninterruptible--;
+ }
p->state = TASK_WAKING;

if (p->sched_class->task_waking)
--
1.7.3.3