From: David Howells <dhowells@redhat.com>
To: Changli Gao <xiaosuo@gmail.com>
Cc: dhowells@redhat.com, Yong Zhang <yong.zhang@windriver.com>,
Xiaotian Feng <xtfeng@gmail.com>, Ingo Molnar <mingo@elte.hu>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Davide Libenzi <davidel@xmailserver.org>,
Roland Dreier <rolandd@cisco.com>,
Stefan Richter <stefanr@s5r6.in-berlin.de>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <dada1@cosmosbay.com>,
Christoph Lameter <cl@linux.com>,
Andreas Herrmann <andreas.herrmann3@amd.com>,
Thomas Gleixner <tglx@linutronix.de>,
Takashi Iwai <tiwai@suse.de>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC] sched: implement the exclusive wait queue as a LIFO queue
Date: Wed, 28 Apr 2010 10:29:47 +0100 [thread overview]
Message-ID: <8482.1272446987@redhat.com> (raw)
In-Reply-To: <u2t412e6f7f1004280123k642a1511gbce3ed784431dc1d@mail.gmail.com>
Changli Gao <xiaosuo@gmail.com> wrote:
> If there isn't enough work to be done, we'd better not disrupt them
> and leave them sleeping forever to keep the scheduler happier. Do we
> have reason to keep fair to all the workers? Does it have benefit?
You've made one important assumption: the processes on the wait queue are
sleeping waiting to service things... but what if the wait queue governs
access to a resource, and all the processes on that wait queue need access to
that resource to do things? Some of the processes waiting for it may never
get a go, and so necessary work may be left undone.
So NACK.
David
next prev parent reply other threads:[~2010-04-28 9:31 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-28 5:03 [RFC] sched: implement the exclusive wait queue as a LIFO queue Changli Gao
2010-04-28 6:22 ` Changli Gao
2010-04-28 8:05 ` Changli Gao
2010-04-28 7:47 ` Xiaotian Feng
2010-04-28 7:52 ` Changli Gao
2010-04-28 8:15 ` Yong Zhang
2010-04-28 8:23 ` Changli Gao
2010-04-28 9:25 ` Johannes Weiner
2010-04-28 9:29 ` David Howells [this message]
2010-04-28 11:17 ` Changli Gao
2010-04-28 13:21 ` Jamie Lokier
2010-04-28 13:42 ` Changli Gao
2010-04-28 15:25 ` Jamie Lokier
2010-04-28 15:49 ` Changli Gao
2010-04-28 18:57 ` Davide Libenzi
2010-04-28 13:21 ` David Howells
2010-04-28 9:32 ` David Howells
2010-04-28 13:56 ` Changli Gao
2010-04-28 14:06 ` David Howells
2010-04-28 14:53 ` Changli Gao
2010-04-28 15:00 ` David Howells
2010-04-28 15:33 ` Changli Gao
2010-04-28 9:34 ` David Howells
2010-04-28 13:47 ` Changli Gao
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=8482.1272446987@redhat.com \
--to=dhowells@redhat.com \
--cc=a.p.zijlstra@chello.nl \
--cc=akpm@linux-foundation.org \
--cc=andreas.herrmann3@amd.com \
--cc=cl@linux.com \
--cc=dada1@cosmosbay.com \
--cc=davem@davemloft.net \
--cc=davidel@xmailserver.org \
--cc=ebiederm@xmission.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=rolandd@cisco.com \
--cc=stefanr@s5r6.in-berlin.de \
--cc=tglx@linutronix.de \
--cc=tiwai@suse.de \
--cc=viro@zeniv.linux.org.uk \
--cc=xiaosuo@gmail.com \
--cc=xtfeng@gmail.com \
--cc=yong.zhang@windriver.com \
/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;
as well as URLs for NNTP newsgroup(s).