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authorAndré Goddard Rosa <andre.goddard@gmail.com>2009-12-16 03:47:39 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2009-12-16 18:20:12 +0300
commit7be6d991bca63bbcdc5bc3b09789f367a3486537 (patch)
tree79168c345c424ce7b80bfba382c9dc469bdcc70a /kernel/pid.c
parent698ba7b5a3a7be772922340fade365c675b8243f (diff)
downloadlinux-7be6d991bca63bbcdc5bc3b09789f367a3486537.tar.xz
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>
Diffstat (limited to 'kernel/pid.c')
-rw-r--r--kernel/pid.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/kernel/pid.c b/kernel/pid.c
index d3f722d20f9c..55fd5900bac8 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;
}