From: Peter Zijlstra <peterz@infradead.org>
Date: Sun, 20 Dec 2009 16:36:27 +0000 (+0100)
Subject: sched: Fix hotplug hang
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=70f1120527797adb31c68bdc6f1b45e182c342c7;p=openwrt%2Fstaging%2Fblogic.git

sched: Fix hotplug hang

The hot-unplug kstopmachine usage does a wakeup after
deactivating the cpu, hence we cannot use cpu_active()
here but must rely on the good olde online.

Reported-by: Sachin Sant <sachinp@in.ibm.com>
Reported-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: Jens Axboe <jens.axboe@oracle.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
LKML-Reference: <1261326987.4314.24.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

diff --git a/kernel/sched.c b/kernel/sched.c
index 7ffde2ae7868..87f1f47beffe 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2346,7 +2346,7 @@ int select_task_rq(struct task_struct *p, int sd_flags, int wake_flags)
 	 *   not worry about this generic constraint ]
 	 */
 	if (unlikely(!cpumask_test_cpu(cpu, &p->cpus_allowed) ||
-		     !cpu_active(cpu)))
+		     !cpu_online(cpu)))
 		cpu = select_fallback_rq(task_cpu(p), p);
 
 	return cpu;