tree c6190bdcc6e15fd8b5657a5932313e296b475577
parent 48db57f8ff10eb09ab887ccb6150b0da0c7be24e
author Christoph Lameter <clameter@engr.sgi.com> 1136710843 -0800
committer Linus Torvalds <torvalds@g5.osdl.org> 1136779960 -0800

[PATCH] add schedule_on_each_cpu()

swap migration's isolate_lru_page() currently uses an IPI to notify other
processors that the lru caches need to be drained if the page cannot be
found on the LRU.  The IPI interrupt may interrupt a processor that is just
processing lru requests and cause a race condition.

This patch introduces a new function run_on_each_cpu() that uses the
keventd() to run the LRU draining on each processor.  Processors disable
preemption when dealing the LRU caches (these are per processor) and thus
executing LRU draining from another process is safe.

Thanks to Lee Schermerhorn <lee.schermerhorn@hp.com> for finding this race
condition.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>