cpu hotplug: adjust root-domain->online span in response to hotplug event
We currently set the root-domain online span automatically when the
domain is added to the cpu if the cpu is already a member of
cpu_online_map.
This was done as a hack/bug-fix for s2ram, but it also causes a problem
with hotplug CPU_DOWN transitioning. The right way to fix the original
problem is to actually respond to CPU_UP events, instead of CPU_ONLINE,
which is already too late.
This solves the hung reboot regression reported by Andrew Morton and
others.
Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/sched.c b/kernel/sched.c
index 52b9867..b02e4fc 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -5813,6 +5813,13 @@
/* Must be high prio: stop_machine expects to yield to it. */
rq = task_rq_lock(p, &flags);
__setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
+
+ /* Update our root-domain */
+ if (rq->rd) {
+ BUG_ON(!cpu_isset(cpu, rq->rd->span));
+ cpu_set(cpu, rq->rd->online);
+ }
+
task_rq_unlock(rq, &flags);
cpu_rq(cpu)->migration_thread = p;
break;
@@ -5821,15 +5828,6 @@
case CPU_ONLINE_FROZEN:
/* Strictly unnecessary, as first user will wake it. */
wake_up_process(cpu_rq(cpu)->migration_thread);
-
- /* Update our root-domain */
- rq = cpu_rq(cpu);
- spin_lock_irqsave(&rq->lock, flags);
- if (rq->rd) {
- BUG_ON(!cpu_isset(cpu, rq->rd->span));
- cpu_set(cpu, rq->rd->online);
- }
- spin_unlock_irqrestore(&rq->lock, flags);
break;
#ifdef CONFIG_HOTPLUG_CPU
@@ -6105,8 +6103,6 @@
rq->rd = rd;
cpu_set(rq->cpu, rd->span);
- if (cpu_isset(rq->cpu, cpu_online_map))
- cpu_set(rq->cpu, rd->online);
for (class = sched_class_highest; class; class = class->next) {
if (class->join_domain)