From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Vincent Li <vincent.mc.li@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>, Don Zickus <dzickus@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Mandeep Singh Baines <msb@chromium.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Softlockup (out of cpu) killer
Date: Mon, 12 Dec 2011 10:38:22 +0100 [thread overview]
Message-ID: <1323682702.16764.59.camel@twins> (raw)
In-Reply-To: <1323643735-1999-1-git-send-email-vincent.mc.li@gmail.com>
On Sun, 2011-12-11 at 14:48 -0800, Vincent Li wrote:
> In kernel, there is out of memory (OOM) killer, why not make an out of cpu (OOC) killer?
> I tested following patch by running an user-space cpu hogging process and the softlockukp
> detector killed the process successfully.
>
> Softlockup could be caused by user-space process hogging cpu, add softlockup_kill kernel
> config to allow kernel to kill the user space cpu hogging process. this feature is
> useful for high availability systems that have uptime gurantees and where a softlockup
> must be resolved ASAP
>
> echo 1 > /proc/sys/kernel/softlockukp_kill to enable cpu hog process killer
> echo 0 > /proc/sys/kernel/softlockup_kill to disable cpu hog process killer
>
> Signed-off-by: Vincent Li <vincent.mc.li@gmail.com>
Your whole premise is broken. Being a cpu hog and the softlockup
mechanism aren't related at all.
Furthermore, since the normal scheduling policy is a proportional one, a
cpu hog can't in fact starve anybody (although a fork bomb could). And
FIFO/RR are privileged ops.
Furthermore the distinction between memory and cpu-time is that memory
isn't a renewable resource, whereas time is. There's always more time,
but there's not always more memory.
So no, I don't think either you patch nor your concept make any sense.
Consider it nacked.
next prev parent reply other threads:[~2011-12-12 9:39 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-11 22:48 [PATCH] Softlockup (out of cpu) killer Vincent Li
2011-12-12 0:28 ` Frederic Weisbecker
2011-12-12 9:38 ` Peter Zijlstra [this message]
2011-12-12 18:00 ` Vincent Li
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