Re: Linus rollup
From: Andrea Arcangeli <hidden>
Date: 2003-01-30 01:35:22
On Wed, Jan 29, 2003 at 05:27:43PM -0800, Andrew Morton wrote:
quoted hunk ↗ jump to hunk
@@ -82,11 +85,12 @@ static inline int fr_write_trylock(frloc if (ret) { ++rw->pre_sequence; - wmb(); + mb(); }
this isn't needed if we hold the spinlock, the serialized memory can't be change under us, so there's no need to put a read barrier, we only care that pre_sequence is visible before the chagnes are visible and before post_sequence is visible, hence only wmb() (after spin_lock and pre_sequence++) is needed there and only rmb() is needed in the read-side. Andrea -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/