From mboxrd@z Thu Jan  1 00:00:00 1970
From: Yong Zhang <yong.zhang@windriver.com>
Subject: Re: [RFC] sched: implement the exclusive wait queue as a LIFO queue
Date: Wed, 28 Apr 2010 16:15:45 +0800
Message-ID: <20100428081545.GA19027@windriver.com>
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Cc: 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>,
	David Howells <dhowells@redhat.com>,
	Takashi Iwai <tiwai@suse.de>, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org
To: Changli Gao <xiaosuo@gmail.com>
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On Wed, Apr 28, 2010 at 03:52:01PM +0800, Changli Gao wrote:
> On Wed, Apr 28, 2010 at 3:47 PM, Xiaotian Feng <xtfeng@gmail.com> wro=
te:
> > On Wed, Apr 28, 2010 at 1:03 PM, Changli Gao <xiaosuo@gmail.com> wr=
ote:
> >> implement the exclusive wait queue as a LIFO queue
> >>
> >> If the exclusive wait queue is also a LIFO queue as the normal wai=
t queue, the
> >> process who goes to sleep recently, will be woke up first. As its =
memory is
> >> more likely in cache, we will get better performance. And when the=
re are many
> >> processes waiting on a exclusive wait queue, some of them may not =
be woke up,
> >> if the others can handle the workload, and it will reduce the load=
 of
> >> the scheduler.
> >>
> >
> > Starve some processes for performance?
> >
>=20
> Starve? Oh, No. If we don't need these processes, and we can do bette=
r

What do you mean "we don't need these processes"?

> without them, why we wake them up?

So some processs(at the tail of exclusive list)will be treated abnormal=
ly
and it will sleep for a long time, is this reasonable?

>=20
>=20
> --=20
> Regards=EF=BC=8C
> Changli Gao(xiaosuo@gmail.com)
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