From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: Kent Overstreet <koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org,
neilb-l3A5Bk7waGM@public.gmane.org,
Vivek Goyal <vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Subject: Re: [PATCH v2 03/26] block: Refactor blk_update_request()
Date: Thu, 20 Sep 2012 16:41:33 -0700 [thread overview]
Message-ID: <20120920234133.GM7264@google.com> (raw)
In-Reply-To: <20120920233632.GC5519-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Hey,
On Thu, Sep 20, 2012 at 04:36:32PM -0700, Kent Overstreet wrote:
> > Other than that, I definitely like this. It would be nice to note
> > that the custom partial bio advancing in blk_update_request() is
> > replaced with multiple calls to req_bio_endio(). I don't think it has
> > any meaningful performance implications. It's just nice to future
> > readers of the commit.
>
> The number of calls to req_bio_endio() isn't changing...
> blk_update_request() called it for partial completions before. It's just
> where the bio itself is updated that's getting shuffled around.
>
> Or did you mean that bio_advance() is getting called on every bio
> instead of the custom advancing in blk_update_request() before? That is
> different, yeah - it's now always looping over the iovec, not just for
> partial completions.
>
> Yeah, I will note that in the commit message, in case Jens sees a
> performance regression from it :)
I don't think there's any performance implication. It's just nice to
explain how the complexity went away. If for nothing else, to point
out how silly the original code was. :)
> > Also, it would be really nice if you can verify this actually works
> > with partial blk_update_request(). sector update bug in the previous
> > patch scares me a bit. Implementing some debug hacks in the
> > completion path might be the easiest way to verify. A subtle bug here
> > could be pretty painful.
>
> Any suggestions on how to trigger partial updates?
ide along with many legacy drivers do it. Any SCSI driver including
libata only does full completion. I don't know. Even just trying to
call the function and comparing before & after with the original code
would be good. I'd like to see at least some form of verification
because the manifested bugs could be extremely nasty and difficult to
track down.
Thanks.
--
tejun
next prev parent reply other threads:[~2012-09-20 23:41 UTC|newest]
Thread overview: 81+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-11 0:22 [PATCH v2 00/26] Prep work for immutable bio vecs Kent Overstreet
2012-09-11 0:22 ` [PATCH v2 01/26] block: Convert integrity to bvec_alloc_bs(), and a bugfix Kent Overstreet
[not found] ` <1347322957-25260-2-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-11 20:36 ` [dm-devel] " Vivek Goyal
2012-09-11 20:48 ` Kent Overstreet
2012-09-11 22:07 ` Kent Overstreet
[not found] ` <20120911220750.GM19739-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-12 19:39 ` Martin K. Petersen
[not found] ` <yq1wqzzrpy1.fsf-+q57XtR/GgMb6DWv4sQWN6xOck334EZe@public.gmane.org>
2012-09-17 21:08 ` Kent Overstreet
2012-09-20 21:53 ` Tejun Heo
2012-09-11 0:22 ` [PATCH v2 02/26] block: Add bio_advance() Kent Overstreet
[not found] ` <1347322957-25260-3-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-20 21:58 ` Tejun Heo
2012-09-20 23:13 ` Kent Overstreet
[not found] ` <20120920231308.GB5519-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-20 23:25 ` Tejun Heo
[not found] ` <20120920232506.GI7264-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-20 23:38 ` Kent Overstreet
2012-09-11 0:22 ` [PATCH v2 03/26] block: Refactor blk_update_request() Kent Overstreet
[not found] ` <1347322957-25260-4-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-20 23:20 ` Tejun Heo
2012-09-20 23:36 ` Kent Overstreet
[not found] ` <20120920233632.GC5519-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-20 23:41 ` Tejun Heo [this message]
[not found] ` <20120920234133.GM7264-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-20 23:50 ` Kent Overstreet
2012-09-11 0:22 ` [PATCH v2 04/26] md: Convert md_trim_bio() to use bio_advance() Kent Overstreet
[not found] ` <1347322957-25260-5-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-20 23:27 ` Tejun Heo
2012-09-11 0:22 ` [PATCH v2 05/26] block: Add bio_end() Kent Overstreet
[not found] ` <1347322957-25260-6-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-17 9:17 ` Steven Whitehouse
2012-09-20 23:32 ` Tejun Heo
[not found] ` <20120920233225.GK7264-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-20 23:44 ` Kent Overstreet
2012-09-11 0:22 ` [PATCH v2 06/26] block: Use bio_sectors() more consistently Kent Overstreet
[not found] ` <1347322957-25260-7-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-20 23:36 ` Tejun Heo
[not found] ` <20120920233618.GL7264-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-20 23:47 ` Kent Overstreet
2012-09-11 0:22 ` [PATCH v2 07/26] block: Don't use bi_idx in bio_split() or require it to be 0 Kent Overstreet
[not found] ` <1347322957-25260-8-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-20 23:45 ` Tejun Heo
[not found] ` <20120920234544.GN7264-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-21 0:00 ` Kent Overstreet
2012-09-11 0:22 ` [PATCH v2 09/26] block: Remove some unnecessary bi_vcnt usage Kent Overstreet
[not found] ` <1347322957-25260-10-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-20 23:51 ` Tejun Heo
2012-09-11 0:22 ` [PATCH v2 10/26] block: Add submit_bio_wait(), remove from md Kent Overstreet
[not found] ` <1347322957-25260-11-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-20 23:56 ` Tejun Heo
[not found] ` <20120920235643.GQ7264-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-21 0:06 ` Kent Overstreet
2012-09-11 0:22 ` [PATCH v2 11/26] raid10: Use bio_reset() Kent Overstreet
2012-09-20 23:59 ` Tejun Heo
2012-09-11 0:22 ` [PATCH v2 13/26] raid5: use bio_reset() Kent Overstreet
[not found] ` <1347322957-25260-14-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-11 5:03 ` NeilBrown
[not found] ` <20120911150326.79f066c0-wvvUuzkyo1EYVZTmpyfIwg@public.gmane.org>
2012-09-11 19:26 ` Kent Overstreet
2012-09-11 0:22 ` [PATCH v2 14/26] raid1: Refactor narrow_write_error() to not use bi_idx Kent Overstreet
2012-09-11 0:22 ` [PATCH v2 15/26] block: Add bio_copy_data() Kent Overstreet
[not found] ` <1347322957-25260-16-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-21 0:06 ` Tejun Heo
2012-09-21 0:09 ` Kent Overstreet
[not found] ` <20120921000945.GK5519-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-21 0:15 ` Tejun Heo
2012-09-21 0:09 ` Tejun Heo
[not found] ` <20120921000947.GT7264-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-21 0:13 ` Kent Overstreet
2012-09-11 0:22 ` [PATCH v2 16/26] pktcdvd: use bio_copy_data() Kent Overstreet
2012-09-11 0:22 ` [PATCH v2 17/26] pktcdvd: Use bio_reset() in disabled code to kill bi_idx usage Kent Overstreet
2012-09-11 0:22 ` [PATCH v2 18/26] raid1: use bio_copy_data() Kent Overstreet
2012-09-11 0:22 ` [PATCH v2 20/26] block: Add bio_for_each_segment_all() Kent Overstreet
[not found] ` <1347322957-25260-21-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-21 0:35 ` Tejun Heo
2012-09-11 0:22 ` [PATCH v2 22/26] block: Add bio_alloc_pages() Kent Overstreet
[not found] ` <1347322957-25260-23-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-21 0:47 ` Tejun Heo
[not found] ` <20120921004711.GZ7264-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-21 4:50 ` Kent Overstreet
[not found] ` <1347322957-25260-1-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-11 0:22 ` [PATCH v2 08/26] block: Remove bi_idx references Kent Overstreet
[not found] ` <1347322957-25260-9-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-20 23:49 ` Tejun Heo
2012-09-21 0:04 ` Kent Overstreet
2012-09-11 0:22 ` [PATCH v2 12/26] raid1: use bio_reset() Kent Overstreet
[not found] ` <1347322957-25260-13-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-11 4:59 ` NeilBrown
2012-09-11 18:28 ` Kent Overstreet
[not found] ` <20120911182825.GG19739-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-11 21:17 ` NeilBrown
2012-09-11 0:22 ` [PATCH v2 19/26] bounce: Refactor __blk_queue_bounce to not use bi_io_vec Kent Overstreet
[not found] ` <1347322957-25260-20-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-21 0:25 ` Tejun Heo
2012-09-21 0:29 ` Kent Overstreet
2012-09-21 0:27 ` Tejun Heo
2012-09-21 0:34 ` Kent Overstreet
2012-09-11 0:22 ` [PATCH v2 21/26] block: Convert some code to bio_for_each_segment_all() Kent Overstreet
[not found] ` <1347322957-25260-22-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-21 0:38 ` Tejun Heo
[not found] ` <20120921003832.GY7264-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-21 0:50 ` Kent Overstreet
2012-09-11 0:22 ` [PATCH v2 23/26] raid1: use bio_alloc_pages() Kent Overstreet
[not found] ` <1347322957-25260-24-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-21 0:48 ` Tejun Heo
[not found] ` <20120921004827.GA7264-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-21 4:51 ` Kent Overstreet
2012-09-11 0:22 ` [PATCH v2 25/26] bio-integrity: Add explicit field for owner of bip_buf Kent Overstreet
[not found] ` <1347322957-25260-26-git-send-email-koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2012-09-12 19:41 ` Martin K. Petersen
[not found] ` <yq1sjanrpu7.fsf-+q57XtR/GgMb6DWv4sQWN6xOck334EZe@public.gmane.org>
2012-09-17 21:09 ` Kent Overstreet
2012-09-11 0:22 ` [PATCH v2 26/26] block: Add BIO_SUBMITTED flag, kill BIO_CLONED Kent Overstreet
2012-09-11 5:22 ` [PATCH v2 00/26] Prep work for immutable bio vecs NeilBrown
2012-09-11 0:22 ` [PATCH v2 24/26] block: Add an explicit bio flag for bios that own their bvec Kent Overstreet
2012-09-20 23:22 ` [PATCH v2 00/26] Prep work for immutable bio vecs Tejun Heo
-- strict thread matches above, loose matches on Subject: below --
2012-10-15 20:08 [PATCH v4 00/24] " Kent Overstreet
2012-10-15 20:09 ` [PATCH v2 03/26] block: Refactor blk_update_request() Kent Overstreet
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