On 10/27/2010 01:06 AM, Chris Mason wrote: > On Tue, Oct 26, 2010 at 09:36:26AM -0700, Sage Weil wrote: >> On Tue, 26 Oct 2010, liubo wrote: >>> Since wake_up() itself provides a implied wmb, and a wq active check, >>> it is better to drop "if (wq)" in __btrfs_end_transaction(). >> I see. It could also be >> >> smb_mb(); >> if (wq) >> wake_up(); >> >> but just calling wake_up() unconditionally is simpler, and fewer barriers >> in the wake_up case. I'm not attached to the if (wq); I just kept it >> because it was there already. > > wake_up() provides an implied barrier because it takes the lock. I > usually do the smp_mb() + if (wq) dance when I'm working on a relatively > hot waitqueue. Anyway, it is your style. :) thanks, liubo > > -chris > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
