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authorChristoph Lameter <cl@linux.com>2011-03-24 20:51:38 +0100
committerPekka Enberg <penberg@kernel.org>2011-03-24 20:53:07 +0100
commitb8c4c96ed4cdecf5ae51fc6f4c006658e873047f (patch)
treed08a3abe924d54284486839864d73e9d8bba6180
parentslub: Fix debugobjects with lockless fastpath (diff)
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SLUB: Write to per cpu data when allocating it
It turns out that the cmpxchg16b emulation has to access vmalloced percpu memory with interrupts disabled. If the memory has never been touched before then the fault necessary to establish the mapping will not to occur and the kernel will fail on boot. Fix that by reusing the CONFIG_PREEMPT code that writes the cpu number into a field on every cpu. Writing to the per cpu area before causes the mapping to be established before we get to a cmpxchg16b emulation. Tested-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
-rw-r--r--mm/slub.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/slub.c b/mm/slub.c
index a6a783594ad4..f881874843a5 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1604,7 +1604,7 @@ static inline void note_cmpxchg_failure(const char *n,
void init_kmem_cache_cpus(struct kmem_cache *s)
{
-#if defined(CONFIG_CMPXCHG_LOCAL) && defined(CONFIG_PREEMPT)
+#ifdef CONFIG_CMPXCHG_LOCAL
int cpu;
for_each_possible_cpu(cpu)