tree d08a3abe924d54284486839864d73e9d8bba6180
parent f9b615de4663c4b852e07257e9f967df6a0161c0
author Christoph Lameter <cl@linux.com> 1300996298 -0500
committer Pekka Enberg <penberg@kernel.org> 1300996387 +0200

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>