All of lore.kernel.org
 help / color / mirror / Atom feed
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

  parent reply	other threads:[~2010-04-28  9:31 UTC|newest]

Thread overview: 32+ 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  7:47   ` Xiaotian Feng
2010-04-28  7:52   ` Changli Gao
2010-04-28  7:52     ` Changli Gao
2010-04-28  8:15     ` Yong Zhang
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 11:17             ` Changli Gao
2010-04-28 13:21             ` David Howells
2010-04-28 13:21             ` Jamie Lokier
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  9:32 ` David Howells
2010-04-28 13:56   ` Changli Gao
2010-04-28 13:56     ` Changli Gao
2010-04-28 14:06     ` David Howells
2010-04-28 14:53       ` Changli Gao
2010-04-28 14:53         ` Changli Gao
2010-04-28 15:00         ` David Howells
2010-04-28 15:33           ` Changli Gao
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 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.