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authorAndré Goddard Rosa <andre.goddard@gmail.com>2009-12-15 16:47:39 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-12-16 07:20:12 -0800
commit7be6d991bca63bbcdc5bc3b09789f367a3486537 (patch)
tree79168c345c424ce7b80bfba382c9dc469bdcc70a
parent698ba7b5a3a7be772922340fade365c675b8243f (diff)
downloadop-kernel-dev-7be6d991bca63bbcdc5bc3b09789f367a3486537.zip
op-kernel-dev-7be6d991bca63bbcdc5bc3b09789f367a3486537.tar.gz
pid: tighten pidmap spinlock critical section by removing kfree()
Avoid calling kfree() under pidmap spinlock, calling it afterwards. Normally kfree() is fast, but sometimes it can be slow, so avoid calling it under the spinlock if we can do it. Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--kernel/pid.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/kernel/pid.c b/kernel/pid.c
index d3f722d..55fd590 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -141,11 +141,12 @@ static int alloc_pidmap(struct pid_namespace *pid_ns)
* installing it:
*/
spin_lock_irq(&pidmap_lock);
- if (map->page)
- kfree(page);
- else
+ if (!map->page) {
map->page = page;
+ page = NULL;
+ }
spin_unlock_irq(&pidmap_lock);
+ kfree(page);
if (unlikely(!map->page))
break;
}
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