From: Shaohua Li <shli@fb.com>
To: Christoph Hellwig <hch@lst.de>
Cc: neilb@suse.de, linux-raid@vger.kernel.org, Kernel-team@fb.com,
dan.j.williams@intel.com
Subject: Re: raid5-cache I/O path improvements
Date: Mon, 7 Sep 2015 17:28:55 -0700 [thread overview]
Message-ID: <20150908002840.GA3196542@devbig257.prn2.facebook.com> (raw)
In-Reply-To: <1441603250-5119-1-git-send-email-hch@lst.de>
On Mon, Sep 07, 2015 at 07:20:40AM +0200, Christoph Hellwig wrote:
> Hi Shaohua, hi Neil,
>
> this series contains a few updates to the raid5-cache feature.
>
> The first patch just ports it to the post-4.2 block layer. As part of that
> I noticed that it currently doesn't handle I/O errors - fixes for that will
> follow.
>
> The second and third patch simplify the I/O unit state machine and reduce
> latency and memory usage for the I/O units. The remainder are just a couple
> of cleanups in this area that I stumbled upon.
Hi Christoph,
Thanks for these work. Yes, I/O error handling is in the plan. We could
simplify panic (people here like this option) or report error and bypass
log. Any way an option is good.
For the patches, FUA write does simplify things a lot. However, I tried
it before, the performance is quite bad in SSD. FUA is off in SATA by
default, the emulation is farily slow because FLUSH request isn't NCQ
command. I tried to enable FUA in SATA too, FUA write is still slow in
the SSD I tested. Other than this one, other patches look good:
Reviewed-by: Shaohua Li <shli@fb.com>
next prev parent reply other threads:[~2015-09-08 0:28 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-07 5:20 raid5-cache I/O path improvements Christoph Hellwig
2015-09-07 5:20 ` [PATCH 01/10] raid5-cache: port to 4.3-rc Christoph Hellwig
2015-09-07 5:20 ` [PATCH 02/10] raid5-cache: free I/O units earlier Christoph Hellwig
2015-09-07 5:20 ` [PATCH 03/10] raid5-cache: use FUA writes for the log Christoph Hellwig
2015-09-07 5:20 ` [PATCH 04/10] raid5-cache: clean up r5l_get_meta Christoph Hellwig
2015-09-07 5:20 ` [PATCH 05/10] raid5-cache: refactor bio allocation Christoph Hellwig
2015-09-07 5:20 ` [PATCH 06/10] raid5-cache: take rdev->data_offset into account early on Christoph Hellwig
2015-09-07 5:20 ` [PATCH 07/10] raid5-cache: inline r5l_alloc_io_unit into r5l_new_meta Christoph Hellwig
2015-09-07 5:20 ` [PATCH 08/10] raid5-cache: new helper: r5_reserve_log_entry Christoph Hellwig
2015-09-07 5:20 ` [PATCH 09/10] raid5-cache: small log->seq cleanup Christoph Hellwig
2015-09-07 5:20 ` [PATCH 10/10] raid5-cache: use bio chaining Christoph Hellwig
2015-09-08 0:28 ` Shaohua Li [this message]
2015-09-08 6:12 ` raid5-cache I/O path improvements Christoph Hellwig
2015-09-08 15:25 ` Tejun Heo
2015-09-08 15:26 ` Tejun Heo
2015-09-08 15:40 ` Christoph Hellwig
2015-09-08 16:56 ` Shaohua Li
2015-09-08 17:02 ` Tejun Heo
2015-09-08 17:07 ` Shaohua Li
2015-09-08 17:34 ` Tejun Heo
2015-09-09 15:59 ` Christoph Hellwig
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=20150908002840.GA3196542@devbig257.prn2.facebook.com \
--to=shli@fb.com \
--cc=Kernel-team@fb.com \
--cc=dan.j.williams@intel.com \
--cc=hch@lst.de \
--cc=linux-raid@vger.kernel.org \
--cc=neilb@suse.de \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.