From: Jens Axboe <jaxboe@fusionio.com>
To: Tejun Heo <tj@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCHSET] backing-dev: replace private thread pool with workqueue
Date: Tue, 07 Sep 2010 14:29:46 +0200 [thread overview]
Message-ID: <4C86303A.90601@fusionio.com> (raw)
In-Reply-To: <4C862DDC.6010702@kernel.org>
On 2010-09-07 14:19, Tejun Heo wrote:
> Hello,
>
> On 09/07/2010 02:16 PM, Christoph Hellwig wrote:
>> What does this conversion buy us?
>>
>> Having explicit per-bdi threads makes the model very simple and safe,
>> while I don't quite trust the now extremly complex work queues yet.
>
> Well, the whole idea behind the new workqueue is unifying all those
> dedicated pools of threads. If the conversion is too early given the
> new workqueue implementation, we can postpone bdi conversion by one
> more release cycle, but in the long run there is no point in keeping
> these private thread pools.
I agree (with both of you). It's definitely too early to convert it
over, but if we can in the longer run, it never hurts to get rid of
code. The writeback threads aren't a typical threadpool, in that the
threads stick around and only go away when idle for too long. If they
stick around, you get the same process hammering IO at your device. So
converting that over to the generic cwq may or may not be at a
performance cost, it'll definitely have to be tested.
--
Jens Axboe
next prev parent reply other threads:[~2010-09-07 12:29 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-06 12:46 [PATCHSET] backing-dev: replace private thread pool with workqueue Tejun Heo
2010-09-06 12:46 ` [PATCH 1/5] workqueue: implement workqueue_on_rescuer() Tejun Heo
2010-09-06 12:46 ` [PATCH 2/5] backing-dev: kill unused bdi_writeback->nr Tejun Heo
2010-09-08 8:57 ` Artem Bityutskiy
2010-09-06 12:46 ` [PATCH 3/5] backing-dev: replace private thread pool with workqueue Tejun Heo
2010-09-06 12:46 ` [PATCH 4/5] backing-dev: update trace points Tejun Heo
2010-09-06 12:46 ` [PATCH 5/5] backing-dev: replace sync_supers_tsk/timer with a delayed_work Tejun Heo
2010-09-08 9:00 ` Artem Bityutskiy
2010-09-07 12:16 ` [PATCHSET] backing-dev: replace private thread pool with workqueue Christoph Hellwig
2010-09-07 12:19 ` Tejun Heo
2010-09-07 12:29 ` Jens Axboe [this message]
2010-09-07 12:36 ` Tejun Heo
2010-11-27 16:02 ` Tejun Heo
2010-11-27 18:50 ` Jens Axboe
2010-11-27 20:30 ` Tejun Heo
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=4C86303A.90601@fusionio.com \
--to=jaxboe@fusionio.com \
--cc=hch@lst.de \
--cc=linux-kernel@vger.kernel.org \
--cc=tj@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