From: "Holger Hoffstätte" <holger@applied-asynchrony.com>
To: linux-block@vger.kernel.org
Subject: Re: WBT for SQ devices interface
Date: Tue, 11 Apr 2017 15:16:16 +0000 (UTC) [thread overview]
Message-ID: <pan$69397$61f9566$49954c7$3612ea5f@applied-asynchrony.com> (raw)
In-Reply-To: 20170411093827.GC2471@quack2.suse.cz
On Tue, 11 Apr 2017 11:38:27 +0200, Jan Kara wrote:
> when testing my fix for 0-day reports with writeback throttling I came
> across somewhat unexpected behavior with user interface of writeback
> throttling. So currently if CFQ is used as an IO scheduler, we disable
> writeback throttling because they don't go well together. However when user
> has CONFIG_BLK_WBT_SQ=y and switches IO scheduler to NOOP or DEADLINE
> writeback throttling still stays disabled. This is somewhat unexpected
> especially because the switching of IO scheduler from CFQ to something else
> can have happened behind user's back by some udev rule or so. So basically
> CONFIG_DEFAULT_CFQ=y and CONFIG_BLK_WBT_SQ=y don't make sense together.
:(
> So do people thing we should enable WBT if CONFIG_BLK_WBT_SQ=y and IO
> scheduler is switched from CFQ to something else?
Yes please. If a scheduler doesn't like WBT then that is its own problem.
Deadline with WBT has worked fine for me.
-h
next prev parent reply other threads:[~2017-04-11 15:40 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-11 9:38 WBT for SQ devices interface Jan Kara
2017-04-11 15:16 ` Holger Hoffstätte [this message]
2017-04-11 16:22 ` Jens Axboe
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='pan$69397$61f9566$49954c7$3612ea5f@applied-asynchrony.com' \
--to=holger@applied-asynchrony.com \
--cc=linux-block@vger.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