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>
This commit is contained in:
André Goddard Rosa 2009-12-15 16:47:39 -08:00 коммит произвёл Linus Torvalds
Родитель 698ba7b5a3
Коммит 7be6d991bc
1 изменённых файлов: 4 добавлений и 3 удалений

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@ -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;
}