From: Tejun Heo <tj@kernel.org>
To: Kent Overstreet <koverstreet@google.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>,
Vivek Goyal <vgoyal@redhat.com>,
linux-bcache@vger.kernel.org, linux-kernel@vger.kernel.org,
dm-devel@redhat.com, bharrosh@panasas.com,
Jens Axboe <axboe@kernel.dk>
Subject: Re: [PATCH] dm: Use bioset's front_pad for dm_target_io
Date: Tue, 4 Sep 2012 14:20:22 -0700 [thread overview]
Message-ID: <20120904212022.GB8724@dhcp-172-17-108-109.mtv.corp.google.com> (raw)
In-Reply-To: <20120904195156.GE25236@google.com>
Hello, Kent.
On Tue, Sep 04, 2012 at 12:51:56PM -0700, Kent Overstreet wrote:
> I wrote a patch for dm_target_io last night. I think I know an easy way
> to go about converting the rest but it'll probably have to wait until
> I'm further along with my immutable bvec stuff.
>
> Completely untested patch below:
Yeap, this looks great to me. In the end, I think it's better to
require stacking drivers to not use separate mempools other than
bioset. Timer or not, using multiple alloc pools is brittle. Any
path which ends up allocating in different orders for whatever reason
can lead to subtle deadlock scenarios which can be very difficult to
track down and, at least currently, there's no way to automatically
detect them. Besides, w/ front-pad, it really shouldn't be necessary.
Thanks.
--
tejun
next prev parent reply other threads:[~2012-09-04 21:20 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
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 [this message]
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
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