From: Kent Overstreet <kmo@daterainc.com>
To: Mikulas Patocka <mpatocka@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-kernel@vger.kernel.org, dm-devel@redhat.com,
"Alasdair G. Kergon" <agk@redhat.com>,
Mike Snitzer <msnitzer@redhat.com>
Subject: Re: [PATCH] block: flush queued bios when the process blocks
Date: Tue, 27 May 2014 13:06:00 -0700 [thread overview]
Message-ID: <20140527200600.GG2276@kmo> (raw)
In-Reply-To: <alpine.LRH.2.02.1405271526570.3223@file01.intranet.prod.int.rdu2.redhat.com>
On Tue, May 27, 2014 at 03:56:00PM -0400, Mikulas Patocka wrote:
>
>
> On Tue, 27 May 2014, Jens Axboe wrote:
>
> > On 2014-05-27 10:26, Mikulas Patocka 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.
> >
> > Except such a thing already exists, there are unplug callback chains. All I'm
> > asking is that you look into how feasible it would be to use something like
> > that, instead of reinventing the wheel.
> >
> > --
> > Jens Axboe
>
> Do you mean moving current->bio_list to struct blk_plug and calling
> blk_start_plug/blk_finish_plug around generic_make_request?
>
> It would be possible on a condition that we can redirect all bios to a
> workqueue (i.e. eliminate bio_kmalloc and always use bio_alloc_bioset).
>
> What are performance implications of this - does it make sense to have
> blk_start_plug/blk_finish_plug around every call to generic_make_request?
> - that means that all i/o requests will be added to a plug and then
> unplugged.
We've already got blk_start_plug() calls around IO submission at higher points
in the stack. (I actually have seen it show up in profiles though, it probably
would be worth inlining and slimming down a bit).
next prev parent reply other threads:[~2014-05-27 20:06 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-27 15:03 [PATCH] block: flush queued bios when the process blocks Mikulas Patocka
2014-05-27 15:08 ` Jens Axboe
2014-05-27 15:23 ` Mikulas Patocka
2014-05-27 15:42 ` Jens Axboe
2014-05-27 16:26 ` Mikulas Patocka
2014-05-27 17:33 ` Mike Snitzer
2014-05-27 19:56 ` Kent Overstreet
2015-10-05 19:50 ` Mike Snitzer
2014-05-27 17:42 ` [PATCH] " Jens Axboe
2014-05-27 18:14 ` [dm-devel] " Christoph Hellwig
2014-05-27 19:59 ` Kent Overstreet
2014-05-27 19:56 ` Mikulas Patocka
2014-05-27 20:06 ` Kent Overstreet [this message]
2014-05-29 23:52 ` Mikulas Patocka
2015-10-05 20:59 ` Mike Snitzer
2015-10-06 13:28 ` Mikulas Patocka
2015-10-06 13:47 ` Mike Snitzer
2015-10-06 14:10 ` Mikulas Patocka
2015-10-06 14:26 ` Mikulas Patocka
2015-10-06 18:17 ` [dm-devel] " Mikulas Patocka
2015-10-06 18:50 ` Mike Snitzer
2015-10-06 20:16 ` [PATCH v2] " Mike Snitzer
2015-10-06 20:26 ` Mike Snitzer
2015-10-08 15:04 ` Mikulas Patocka
2015-10-08 15:08 ` Mike Snitzer
2015-10-09 19:52 ` Mike Snitzer
2015-10-09 19:59 ` Mike Snitzer
2015-10-14 20:47 ` [PATCH v3 for-4.4] block: flush queued bios when process blocks to avoid deadlock Mike Snitzer
2015-10-14 21:44 ` Jeff Moyer
2015-10-17 16:04 ` Ming Lei
2015-10-20 19:57 ` Mike Snitzer
2015-10-20 20:03 ` Mikulas Patocka
2015-10-21 16:38 ` Ming Lei
2015-10-21 21:49 ` Mikulas Patocka
2015-10-22 1:53 ` Ming Lei
2015-10-15 3:27 ` [PATCH v2] block: flush queued bios when the process blocks Ming Lei
2015-10-15 8:06 ` Mike Snitzer
2015-10-16 3:08 ` Ming Lei
2015-10-16 15:29 ` Mike Snitzer
2015-10-17 15:54 ` Ming Lei
2015-10-09 11:58 ` kbuild test robot
2014-05-27 17:59 ` [PATCH] " Kent Overstreet
2014-06-26 23:46 Mikulas Patocka
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