On Wed, 13 Apr 2011 00:34:52 +1000 Dave Chinner <david@xxxxxxxxxxxxx> wrote: > On Tue, Apr 12, 2011 at 03:45:52PM +0200, Jens Axboe wrote: > Not until you > > schedule() or call blk_finish_plug(), both of which are events that you > > can control. > > Well, not really - now taking any sleeping lock or waiting on > anything can trigger a plug flush where previously you had to > explicitly issue them. I'm not saying what we had is better, just > that there are implicit flushes with your changes that are > inherently uncontrollable... It's not just sleeping locks - if preempt is enabled a schedule can happen at any time - at any depth. I've seen a spin_unlock do it. NeilBrown -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
