From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Fri, 26 Mar 2010 11:22:14 +0000 (+0100)
Subject: sched: Fix nr_uninterruptible count
X-Git-Tag: firefly_0821_release~10186^2~954
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=bea226b8e646ddb0bd262fc666b741134b9e9612;p=firefly-linux-kernel-4.4.55.git

sched: Fix nr_uninterruptible count

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: Mike Galbraith <efault@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/kernel/sched.c b/kernel/sched.c
index 0a2df531b90d..7aed676da071 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2435,8 +2435,12 @@ 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)