On Thu, Aug 2, 2012 at 4:46 AM, Liu Bo <liub.liubo@xxxxxxxxx> wrote: > On 08/02/2012 04:25 AM, Josef Bacik wrote: >> We need an smb_mb() before waitqueue_active to avoid missing wakeups. >> Before Mitch was hitting a deadlock between the ordered flushers and the >> transaction commit because the ordered flushers were waiting for more refs >> and were never woken up, so those smp_mb()'s are the most important. >> Everything else I added for correctness sake and to avoid getting bitten by >> this again somewhere else. Thanks, >> > > Hi Josef, > > I'll appreciate a lot if you can add some comments for each memory > barrier, because not everyone knows why it is used here and there. :) Everyone who wants to know should read the memory-barriers.txt file that's hiding in the oddly named "Documentation" folder of their kernel tree. :) -- 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
