Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 393d94d9 authored by Gregory Haskins's avatar Gregory Haskins Committed by Linus Torvalds
Browse files

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: default avatarGregory Haskins <ghaskins@novell.com>
Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6efcae46

kernel/sched.c

+7 −11
Original line number Diff line number Diff line
@@ -5813,6 +5813,13 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) 
		/* 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 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) 
	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 @@ static void rq_attach_root(struct rq *rq, struct root_domain *rd) 
	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)