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

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Submitter Michael Ellerman
Date April 5, 2011, 6:57 a.m.
Message ID <3cf2e447f50f85da004b145ea87cdace4b4352cc.1301986643.git.michael@ellerman.id.au>
Download mbox | patch
Permalink /patch/89790/
State Accepted, archived
Commit f5be2dc0bd8d27a39d84a89e4ff90ba38cd2b285
Delegated to: Benjamin Herrenschmidt
Headers show

Comments

Michael Ellerman - April 5, 2011, 6:57 a.m.
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>
---
 arch/powerpc/mm/mmu_context_nohash.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

Patch

diff --git a/arch/powerpc/mm/mmu_context_nohash.c b/arch/powerpc/mm/mmu_context_nohash.c
index c0aab52..4d8fa91 100644
--- a/arch/powerpc/mm/mmu_context_nohash.c
+++ b/arch/powerpc/mm/mmu_context_nohash.c
@@ -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);