From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: "Martin K. Petersen"
<martin.petersen-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
Cc: Kent Overstreet
<koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
mpatocka-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
bharrosh-C4P08NqkoRlBDgjK7y7TUQ@public.gmane.org,
Jens Axboe <axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>,
NeilBrown <neilb-l3A5Bk7waGM@public.gmane.org>,
Lars Ellenberg
<lars.ellenberg-63ez5xqkn6DQT0dZR+AlfA@public.gmane.org>,
Peter Osterlund <petero2-zq6IREYz3ykAvxtiuMwx3w@public.gmane.org>,
Sage Weil <sage-4GqslpFJ+cxBDgjK7y7TUQ@public.gmane.org>
Subject: Re: [PATCH v6 11/13] block: Rework bio_pair_split()
Date: Fri, 24 Aug 2012 13:58:12 -0700 [thread overview]
Message-ID: <20120824205812.GJ21325@google.com> (raw)
In-Reply-To: <yq1y5l5hvpw.fsf-+q57XtR/GgMb6DWv4sQWN6xOck334EZe@public.gmane.org>
Hello, Martin.
On Thu, Aug 23, 2012 at 10:25:47PM -0400, Martin K. Petersen wrote:
> However, I'm not sure I like the overall approach of the new splitting.
> Instead of all this cloning, slicing and dicing of bio_vecs I'd rather
> we bit the bullet and had an offset + length for the vector inside each
> bio. That way we could keep the bio_vec immutable and make clones more
> lightweight since their vecs would always point to the parent. This also
> makes it trivial to split I/Os in the stacking drivers and removes evils
> in the partial completion code path. It would also allow to sever the
> ties between "size of block range operated on" vs. bi_size which we need
> for copy offload, discard, etc.
Yeah, I'm fairly sure we all want that but that's gonna have to be a
separate not-so-small project. Also, how we split underlying bvec
doesn't affect the split interface update being done here. This
patchset is updating split so that it can handle arbirarily sized
bios, which is useful whether its implementation is using immutable
bvec or COWing it.
Thanks.
--
tejun
next prev parent reply other threads:[~2012-08-24 20:58 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-22 17:03 [PATCH v6 00/13] Block cleanups Kent Overstreet
2012-08-22 17:03 ` [PATCH v6 01/13] block: Generalized bio pool freeing Kent Overstreet
[not found] ` <1345655050-28199-2-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-08-22 21:27 ` Nicholas A. Bellinger
2012-08-22 17:03 ` [PATCH v6 02/13] dm: Use bioset's front_pad for dm_rq_clone_bio_info Kent Overstreet
[not found] ` <1345655050-28199-3-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-08-22 18:32 ` Tejun Heo
2012-08-22 21:30 ` Vivek Goyal
[not found] ` <20120822213010.GA8020-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-08-24 7:14 ` Kent Overstreet
[not found] ` <20120824071448.GF11977-jC9Py7bek1znysI04z7BkA@public.gmane.org>
2012-08-24 18:40 ` Vivek Goyal
2012-08-22 17:04 ` [PATCH v6 03/13] block: Add bio_reset() Kent Overstreet
[not found] ` <1345655050-28199-4-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-08-22 18:34 ` Tejun Heo
2012-08-22 19:51 ` Tejun Heo
2012-08-22 17:04 ` [PATCH v6 04/13] pktcdvd: Switch to bio_kmalloc() Kent Overstreet
[not found] ` <1345655050-28199-5-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-08-22 19:55 ` Tejun Heo
[not found] ` <20120822195546.GG19212-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-08-28 23:19 ` Jiri Kosina
2012-08-29 4:35 ` Peter Osterlund
2012-09-03 16:15 ` Jiri Kosina
2012-08-22 17:04 ` [PATCH v6 05/13] block: Kill bi_destructor Kent Overstreet
[not found] ` <1345655050-28199-6-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-08-22 20:00 ` Tejun Heo
[not found] ` <20120822200032.GH19212-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-08-24 5:09 ` Kent Overstreet
2012-08-22 17:04 ` [PATCH v6 06/13] block: Consolidate bio_alloc_bioset(), bio_kmalloc() Kent Overstreet
[not found] ` <1345655050-28199-7-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-08-22 20:17 ` Tejun Heo
[not found] ` <20120822201730.GI19212-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-08-24 5:04 ` Kent Overstreet
[not found] ` <20120824050400.GA11977-jC9Py7bek1znysI04z7BkA@public.gmane.org>
2012-08-24 20:08 ` Tejun Heo
2012-08-22 17:04 ` [PATCH v6 07/13] block: Avoid deadlocks with bio allocation by stacking drivers Kent Overstreet
2012-08-22 20:30 ` Tejun Heo
2012-08-24 5:55 ` Kent Overstreet
[not found] ` <20120824055554.GC11977-jC9Py7bek1znysI04z7BkA@public.gmane.org>
2012-08-24 20:28 ` Tejun Heo
2012-08-22 17:04 ` [PATCH v6 11/13] block: Rework bio_pair_split() Kent Overstreet
[not found] ` <1345655050-28199-12-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-08-22 21:04 ` Tejun Heo
[not found] ` <20120822210410.GL19212-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-08-24 2:25 ` Martin K. Petersen
[not found] ` <yq1y5l5hvpw.fsf-+q57XtR/GgMb6DWv4sQWN6xOck334EZe@public.gmane.org>
2012-08-24 10:37 ` Kent Overstreet
2012-08-24 20:58 ` Tejun Heo [this message]
2012-08-24 10:30 ` Kent Overstreet
2012-08-24 20:53 ` Tejun Heo
2012-08-22 17:04 ` [PATCH v6 13/13] block: Only clone bio vecs that are in use Kent Overstreet
[not found] ` <1345655050-28199-14-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-08-22 21:10 ` Tejun Heo
[not found] ` <20120822211045.GN19212-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-08-24 7:05 ` Kent Overstreet
[not found] ` <20120824070508.GE11977-jC9Py7bek1znysI04z7BkA@public.gmane.org>
2012-08-24 20:42 ` Tejun Heo
[not found] ` <1345655050-28199-1-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-08-22 17:04 ` [PATCH v6 08/13] block: Add an explicit bio flag for bios that own their bvec Kent Overstreet
[not found] ` <1345655050-28199-9-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-08-22 17:43 ` Adrian Bunk
[not found] ` <20120822174351.GA27453-c9qLp6CXzmZPEsXTsnYjsA@public.gmane.org>
2012-08-22 19:22 ` Kent Overstreet
2012-08-22 20:00 ` Adrian Bunk
[not found] ` <20120822200038.GB27453-c9qLp6CXzmZPEsXTsnYjsA@public.gmane.org>
2012-08-28 17:23 ` Kent Overstreet
2012-08-22 17:04 ` [PATCH v6 09/13] block: Rename bio_split() -> bio_pair_split() Kent Overstreet
2012-08-22 17:04 ` [PATCH v6 10/13] block: Introduce new bio_split() Kent Overstreet
[not found] ` <1345655050-28199-11-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-08-22 20:46 ` Tejun Heo
2012-08-22 17:04 ` [PATCH v6 12/13] block: Add bio_clone_bioset(), bio_clone_kmalloc() Kent Overstreet
[not found] ` <1345655050-28199-13-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-08-22 17:13 ` Jeff Garzik
2012-08-22 21:07 ` Tejun Heo
[not found] ` <20120822210740.GM19212-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-08-24 6:24 ` Kent Overstreet
[not found] ` <20120824062418.GD11977-jC9Py7bek1znysI04z7BkA@public.gmane.org>
2012-08-24 20:36 ` Tejun Heo
2012-08-23 18:00 ` [PATCH v6 00/13] Block cleanups Vivek Goyal
[not found] ` <20120823180041.GK12232-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2012-08-24 12:46 ` Kent Overstreet
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