linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Vivek Goyal <vgoyal@redhat.com>
To: Kent Overstreet <koverstreet@google.com>
Cc: Tejun Heo <tj@kernel.org>,
	linux-bcache@vger.kernel.org, linux-kernel@vger.kernel.org,
	dm-devel@redhat.com, mpatocka@redhat.com, bharrosh@panasas.com,
	Jens Axboe <axboe@kernel.dk>
Subject: Re: [PATCH v7 9/9] block: Avoid deadlocks with bio allocation by stacking drivers
Date: Tue, 28 Aug 2012 21:31:50 -0400	[thread overview]
Message-ID: <20120829013150.GA9269@redhat.com> (raw)
In-Reply-To: <20120828230108.GI1048@moria.home.lan>

On Tue, Aug 28, 2012 at 04:01:08PM -0700, Kent Overstreet wrote:
> On Tue, Aug 28, 2012 at 03:28:00PM -0700, Kent Overstreet wrote:
> > On Tue, Aug 28, 2012 at 01:49:10PM -0700, Tejun Heo wrote:
> > > Overall, I *think* this is correct but need to think more about it to
> > > be sure.
> > 
> > Please do. As much time as I've spent staring at this kind of stuff,
> > I'm pretty sure I've got it correct but it still makes my head hurt to
> > work out all the various possible deadlocks.
> 
> Hilarious thought: We're punting bios to a rescuer thread that's
> specific to a certain bio_set, right? What if we happen to punt bios
> from a different bio_set? And then the rescuer goes to resubmit those
> bios, and in the process they happen to have dependencies on the
> original bio_set...

Are they not fully allocated bios and when you submit these to underlying
device, ideally we should not be sharing memory pool at different layers
of stack otherwise we will deadlock any way as stack depth increases. So
there should not be a dependency on original bio_set?

Or, am I missing something. May be an example will help.

Thanks
Vivek

  reply	other threads:[~2012-08-29  1:32 UTC|newest]

Thread overview: 75+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-28 17:37 [PATCH v7 0/9] Block cleanups, deadlock fix Kent Overstreet
2012-08-28 17:37 ` [PATCH v7 1/9] block: Generalized bio pool freeing Kent Overstreet
2012-08-28 17:37 ` [PATCH v7 2/9] dm: Use bioset's front_pad for dm_rq_clone_bio_info Kent Overstreet
2012-08-28 17:37 ` [PATCH v7 3/9] block: Add bio_reset() Kent Overstreet
2012-08-28 20:31   ` Tejun Heo
2012-08-28 22:17     ` Kent Overstreet
2012-08-28 22:53       ` Kent Overstreet
2012-09-01  2:23       ` Tejun Heo
2012-09-05 20:13         ` Kent Overstreet
2012-08-28 17:37 ` [PATCH v7 4/9] pktcdvd: Switch to bio_kmalloc() Kent Overstreet
2012-08-28 20:32   ` Tejun Heo
2012-08-28 22:24     ` Kent Overstreet
2012-09-04  9:05     ` Jiri Kosina
2012-09-05 19:44       ` Kent Overstreet
2012-08-28 17:37 ` [PATCH v7 5/9] block: Kill bi_destructor Kent Overstreet
2012-08-28 20:36   ` Tejun Heo
2012-08-28 22:07     ` Kent Overstreet
2012-08-28 17:37 ` [PATCH v7 6/9] block: Consolidate bio_alloc_bioset(), bio_kmalloc() Kent Overstreet
2012-08-28 20:41   ` Tejun Heo
2012-08-28 22:03     ` Kent Overstreet
2012-09-01  2:17       ` Tejun Heo
2012-08-28 17:37 ` [PATCH v7 7/9] block: Add bio_clone_bioset(), bio_clone_kmalloc() Kent Overstreet
2012-08-28 20:44   ` Tejun Heo
2012-08-28 22:05     ` Kent Overstreet
2012-09-01  2:19       ` Tejun Heo
2012-08-28 17:37 ` [PATCH v7 8/9] block: Reorder struct bio_set Kent Overstreet
2012-08-28 17:37 ` [PATCH v7 9/9] block: Avoid deadlocks with bio allocation by stacking drivers Kent Overstreet
2012-08-28 20:49   ` Tejun Heo
2012-08-28 22:28     ` Kent Overstreet
2012-08-28 23:01       ` Kent Overstreet
2012-08-29  1:31         ` Vivek Goyal [this message]
2012-08-29  3:25           ` Kent Overstreet
2012-08-29 12:57             ` Vivek Goyal
2012-08-29 14:39               ` [dm-devel] " Alasdair G Kergon
2012-08-29 16:26                 ` Kent Overstreet
2012-08-29 21:01                   ` John Stoffel
2012-08-29 21:08                     ` Kent Overstreet
2012-08-28 22:06   ` Vivek Goyal
2012-08-28 22:23     ` Kent Overstreet
2012-08-29 16:24   ` Mikulas Patocka
2012-08-29 16:50     ` Kent Overstreet
2012-08-29 16:57       ` [dm-devel] " Alasdair G Kergon
2012-08-29 17:07       ` Vivek Goyal
2012-08-29 17:13         ` Kent Overstreet
2012-08-29 17:23           ` [dm-devel] " Alasdair G Kergon
2012-08-29 17:32             ` Kent Overstreet
2012-08-30 22:07           ` Vivek Goyal
2012-08-31  1:43             ` Kent Overstreet
2012-08-31  1:55               ` Kent Overstreet
2012-08-31 15:01               ` Vivek Goyal
2012-09-03  1:26                 ` Kent Overstreet
2012-09-03 20:41               ` Mikulas Patocka
2012-09-04  3:41                 ` Kent Overstreet
2012-09-04 18:55                   ` Tejun Heo
2012-09-04 19:01                     ` Tejun Heo
2012-09-04 19:43                       ` Kent Overstreet
2012-09-04 19:42                     ` Kent Overstreet
2012-09-04 21:03                       ` Tejun Heo
2012-09-04 19:26                   ` Mikulas Patocka
2012-09-04 19:39                     ` Vivek Goyal
2012-09-04 19:51                     ` [PATCH] dm: Use bioset's front_pad for dm_target_io Kent Overstreet
2012-09-04 21:20                       ` Tejun Heo
2012-09-11 19:28                       ` [PATCH 2] " Mikulas Patocka
2012-09-11 19:50                         ` Kent Overstreet
2012-09-12 22:31                           ` Mikulas Patocka
2012-09-14 23:09                             ` [dm-devel] " Alasdair G Kergon
2012-09-01  2:13             ` [PATCH v7 9/9] block: Avoid deadlocks with bio allocation by stacking drivers Tejun Heo
2012-09-03  1:34               ` [PATCH v2] " Kent Overstreet
2012-09-04 15:00               ` [PATCH v7 9/9] " Vivek Goyal
2012-09-03  0:49             ` Dave Chinner
2012-09-03  1:17               ` Kent Overstreet
2012-09-04 13:54               ` Vivek Goyal
2012-09-04 18:26                 ` Tejun Heo
2012-09-05  3:57                   ` Dave Chinner
2012-09-05  4:37                     ` Tejun Heo

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20120829013150.GA9269@redhat.com \
    --to=vgoyal@redhat.com \
    --cc=axboe@kernel.dk \
    --cc=bharrosh@panasas.com \
    --cc=dm-devel@redhat.com \
    --cc=koverstreet@google.com \
    --cc=linux-bcache@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mpatocka@redhat.com \
    --cc=tj@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).