From: Manfred Spraul <manfred@colorfullife.com>
To: Andrew Morton <akpm@digeo.com>
Cc: Matthew Wilcox <willy@debian.org>, linux-kernel@vger.kernel.org
Subject: Re: flock(fd, LOCK_UN) taking 500ms+ ?
Date: Wed, 02 Oct 2002 23:36:46 +0200 [thread overview]
Message-ID: <3D9B66EE.90001@colorfullife.com> (raw)
akpm wrote:
> It's not really clear why that yield is in there at all? Unless that
> code is really, really slow (milliseconds) then probably it should just
> be deleted.
>
It looks like a very simple starvation control:
thread 1:
for(;;) {
F_LOCK
<do a few seconds work>
F_UNLCK
}
thread 2:
F_LOCK.
If there is no yield after unlock, thread 2 might never receive the lock.
Is it possible to figure out if someone is waiting on the lock? F_UNLCK
should schedule, if there is a waiter with higher priority.
--
Manfred
next reply other threads:[~2002-10-02 21:31 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-10-02 21:36 Manfred Spraul [this message]
-- strict thread matches above, loose matches on Subject: below --
2002-10-02 2:39 flock(fd, LOCK_UN) taking 500ms+ ? John Levon
2002-10-02 3:23 ` John Levon
2002-10-02 13:14 ` Matthew Wilcox
2002-10-02 17:04 ` Andrew Morton
2002-10-02 18:30 ` Matthew Wilcox
2002-10-02 18:58 ` John Levon
2002-10-02 19:10 ` Robert Love
2002-10-02 19:21 ` Robert Love
2002-10-02 19:23 ` Andrew Morton
2002-10-02 20:05 ` Matthew Wilcox
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