Commit f5be2dc0 authored Apr 04, 2011 by Michael Ellerman Committed by Benjamin Herrenschmidt Apr 20, 2011

powerpc/nohash: Allocate stale_map[cpu] on CPU_UP_PREPARE not CPU_ONLINE



Currently we allocate the stale_map for a cpu when it comes online,
this leaves open a small window where a process can be scheduled
on the cpu before the stale_map is allocated. Instead allocate
the stale_map at CPU_UP_PREPARE time, that way it will be always
available before tasks start running.

It is possible the cpu fails to come up, in which case we should free
the stale_map, so add a CPU_UP_CANCELED case to do that.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

parent de300974

arch/powerpc/mm/mmu_context_nohash.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -338,12 +338,14 @@ static int __cpuinit mmu_context_cpu_notify(struct notifier_block *self,
		return NOTIFY_OK;

		switch (action) {
		case CPU_ONLINE:
		case CPU_ONLINE_FROZEN:
		case CPU_UP_PREPARE:
		case CPU_UP_PREPARE_FROZEN:
		pr_devel("MMU: Allocating stale context map for CPU %d\n", cpu);
		stale_map[cpu] = kzalloc(CTX_MAP_SIZE, GFP_KERNEL);
		break;
		#ifdef CONFIG_HOTPLUG_CPU
		case CPU_UP_CANCELED:
		case CPU_UP_CANCELED_FROZEN:
		case CPU_DEAD:
		case CPU_DEAD_FROZEN:
		pr_devel("MMU: Freeing stale context map for CPU %d\n", cpu);

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