From: Robert Love <rml@tech9.net>
To: linux-kernel@vger.kernel.org
Subject: [PATCH] preempt-kernel on 2.4.19-pre2-ac2 bugfix
Date: 04 Mar 2002 19:23:10 -0500 [thread overview]
Message-ID: <1015287791.882.25.camel@phantasy> (raw)
The same schedule_tail bug affecting 2.5 affects 2.4 with O(1). I.e.,
2.4.19-pre2-ac2.
In recent O(1) scheduler releases, an optimization was made that removed
schedule_tail from UP kernels. This causes the initial preempt_count of
a new task, which starts at 1, to never decrement to zero and thus never
become preemptible. CONFIG_PREEMPT requires schedule_tail, too.
Users of 2.4+O(1)+preempt (i.e. -ac) should use this patch:
http://www.kernel.org/pub/linux/kernel/people/rml/preempt-kernel/v2.4/preempt-kernel-rml-2.4.19-pre2-ac2-2.patch
instead. Thanks to everyone who pointed out the lousy performance. Enjoy,
Robert Love
next reply other threads:[~2002-03-05 0:23 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-03-05 0:23 Robert Love [this message]
2002-03-05 0:41 ` [PATCH] preempt-kernel on 2.4.19-pre2-ac2 bugfix Mike Fedyk
2002-03-05 0:52 ` Robert Love
2002-03-07 23:21 ` Mike Fedyk
2002-03-07 23:46 ` Alan Cox
2002-03-08 0:05 ` Mike Fedyk
2002-03-08 0:38 ` Alan Cox
2002-03-08 2:27 ` Mike Fedyk
2002-03-08 13:21 ` Alan Cox
2002-03-08 19:26 ` Mike Fedyk
2002-03-09 23:35 ` Mike Fedyk
2002-03-10 0:53 ` Alan Cox
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