From: Peter Zijlstra <peterz@infradead.org>
To: Tejun Heo <tj@kernel.org>
Cc: tglx@linutronix.de, mingo@elte.hu, avi@redhat.com, efault@gmx.de,
rusty@rustcorp.com.au, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 7/7] sched: implement try_to_wake_up_local()
Date: Mon, 07 Dec 2009 09:56:39 +0100 [thread overview]
Message-ID: <1260176199.8223.1237.camel@laptop> (raw)
In-Reply-To: <1260175804.8223.1217.camel@laptop>
On Mon, 2009-12-07 at 09:50 +0100, Peter Zijlstra wrote:
> On Mon, 2009-12-07 at 12:26 +0900, Tejun Heo wrote:
> > Hmmm... it was intentional as, before this patch, there's no
> > try_to_wake_up_local() so it was strange to mention it in the comment.
> > I can move the comments but I don't think it's particularly better
> > that way.
>
> /me reads the comments and goes ah!
>
> OK, maybe you've got a point there ;-)
OK, so you fork and wakeup a new thread when an existing one goes to
sleep, but do you also limit the concurrency on wakeup?
Otherwise we can end up with say 100 workqueue tasks running, simply
because they all ran into a contended lock and then woke up again.
Where does that fork happen? Having to do memory allocations and all
that while holding the rq->lock doesn't seem like a very good idea.
What happens when you run out of memory and the workqueue progress is
needed to get free memory?
next prev parent reply other threads:[~2009-12-07 8:57 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-02 3:56 [PATCHSET tip/sched/core] sched: concurrency managed workqueue related sched patches Tejun Heo
2009-12-02 3:56 ` [PATCH 1/7] sched: revert 498657a478c60be092208422fefa9c7b248729c2 Tejun Heo
2009-12-02 10:42 ` [tip:sched/core] sched: Revert 498657a478c60be092208422fefa9c7b248729c2 tip-bot for Tejun Heo
2009-12-02 3:56 ` [PATCH 2/7] sched: rename preempt_notifiers to sched_notifiers and refactor implementation Tejun Heo
2009-12-02 3:56 ` [PATCH 3/7] sched: refactor try_to_wake_up() Tejun Heo
2009-12-02 9:05 ` Mike Galbraith
2009-12-02 9:51 ` Tejun Heo
2009-12-02 10:10 ` Mike Galbraith
2009-12-02 10:14 ` Tejun Heo
2009-12-02 11:01 ` Peter Zijlstra
2009-12-03 6:11 ` [PATCH UDPATED " Tejun Heo
2009-12-02 3:56 ` [PATCH 4/7] sched: implement force_cpus_allowed() Tejun Heo
2009-12-04 10:40 ` Peter Zijlstra
2009-12-04 10:43 ` Peter Zijlstra
2009-12-07 4:34 ` Tejun Heo
2009-12-07 8:35 ` Peter Zijlstra
2009-12-07 10:34 ` Tejun Heo
2009-12-07 10:54 ` Peter Zijlstra
2009-12-07 11:07 ` Tejun Heo
2009-12-08 8:41 ` Tejun Heo
2009-12-08 9:02 ` Peter Zijlstra
2009-12-08 9:12 ` Tejun Heo
2009-12-08 10:34 ` Peter Zijlstra
2009-12-08 10:38 ` Peter Zijlstra
2009-12-08 11:26 ` Tejun Heo
2009-12-08 11:24 ` Tejun Heo
2009-12-08 11:48 ` Peter Zijlstra
2009-12-08 11:56 ` Tejun Heo
2009-12-08 12:10 ` Peter Zijlstra
2009-12-08 12:23 ` Tejun Heo
2009-12-08 13:35 ` Peter Zijlstra
2009-12-09 5:25 ` Tejun Heo
2009-12-09 7:41 ` Peter Zijlstra
2009-12-09 8:03 ` Tejun Heo
2009-12-02 3:56 ` [PATCH 5/7] sched: make sched_notifiers unconditional Tejun Heo
2009-12-02 3:56 ` [PATCH 6/7] sched: add wakeup/sleep sched_notifiers and allow NULL notifier ops Tejun Heo
2009-12-02 3:56 ` [PATCH 7/7] sched: implement try_to_wake_up_local() Tejun Heo
2009-12-03 6:13 ` [PATCH UPDATED " Tejun Heo
2009-12-04 10:47 ` Peter Zijlstra
2009-12-07 3:31 ` Tejun Heo
2009-12-04 10:44 ` [PATCH " Peter Zijlstra
2009-12-07 3:26 ` Tejun Heo
2009-12-07 8:50 ` Peter Zijlstra
2009-12-07 8:56 ` Peter Zijlstra [this message]
2009-12-07 10:27 ` Tejun Heo
2009-12-08 8:53 ` Peter Zijlstra
2009-12-08 9:16 ` 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=1260176199.8223.1237.camel@laptop \
--to=peterz@infradead.org \
--cc=avi@redhat.com \
--cc=efault@gmx.de \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=rusty@rustcorp.com.au \
--cc=tglx@linutronix.de \
--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