[dm-devel] block: flush queued bios when the process blocks

[Mike Snitzer]

On Tue, May 27 2014 at 12:26pm -0400,
Mikulas Patocka <mpatocka at redhat.com> wrote:

> On Tue, 27 May 2014, Jens Axboe wrote:
> 
> > On 2014-05-27 09:23, Mikulas Patocka wrote:
> > 
> > > The patch adds bio list flushing to the scheduler just besides plug
> > > flushsing.
> > 
> > ... which is exactly why I'm commenting. It'd be great to avoid yet one more
> > scheduler hook for this sort of thing.
> > 
> > -- 
> > Jens Axboe
> 
> One could create something like schedule notifier chain, but I'm not sure 
> if it is worth the complexity because of just two users. If more users 
> come in the future, it could be generalized.

It could be that Jens is suggesting updating blk_needs_flush_plug() and
blk_schedule_flush_plug() to be bio_list aware too (rather than train
sched_submit_work() from this new bio_list)?

Somewhat awkward, but _could_ be made to work.