From: Nick Piggin <piggin@cyberone.com.au>
To: Tim Hockin <thockin@hockin.org>
Cc: Rusty Russell <rusty@au1.ibm.com>,
vatsa@in.ibm.com, linux-kernel@vger.kernel.org,
torvalds@osdl.org, akpm@osdl.org, rml@tech9.net
Subject: Re: CPU Hotplug: Hotplug Script And SIGPWR
Date: Tue, 20 Jan 2004 18:11:49 +1100 [thread overview]
Message-ID: <400CD4B5.6020507@cyberone.com.au> (raw)
In-Reply-To: <20040120065207.GA10993@hockin.org>
Tim Hockin wrote:
>On Tue, Jan 20, 2004 at 05:43:59PM +1100, Nick Piggin wrote:
>
>>>I think the sanest thing for a CPU removal is to migrate everything off the
>>>processor in question, move unrunnable tasks into TASK_UNRUNNABLE state,
>>>then notify /sbin/hotplug. The hotplug script can then find and handle the
>>>unrunnable tasks. No SIGPWR grossness needed.
>>>
>>>Code against 2.4 at http://www.hockin.org/~thockin/procstate - it was
>>>heavily tested and I *think* it is all correct (for that kernel snapshot).
>>>
>>Seems less robust and more ad hoc than SIGPWR, however.
>>
>
>Disagree. SIGPWR will kill any process that doesn't catch it. That's
>policy. It seems more robust to let the hotplug script decide what to do.
>If it wants to kill each unrunnable task with SIGPWR, it can. But if it
>wants to let them live, it can.
>
I thought hotplug is allowed to fail? Thus you can have a hung system.
Or what if the hotplug script itself becomes TASK_UNRUNNABLE? What if the
process needs a guaranteed scheduling latency?
(I dropped lhcs-devel@lists.sourceforge.net because its moderated)
next prev parent reply other threads:[~2004-01-20 7:23 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20040116174446.A2820@in.ibm.com>
2004-01-20 5:44 ` CPU Hotplug: Hotplug Script And SIGPWR Rusty Russell
2004-01-20 6:33 ` Tim Hockin
2004-01-20 6:43 ` Nick Piggin
2004-01-20 6:52 ` Tim Hockin
2004-01-20 7:11 ` Nick Piggin [this message]
2004-01-20 7:30 ` Tim Hockin
2004-01-20 7:45 ` Nick Piggin
2004-01-20 7:54 ` Tim Hockin
2004-01-20 8:14 ` Nick Piggin
2004-01-20 8:29 ` Tim Hockin
2004-01-20 8:37 ` Nick Piggin
2004-01-20 8:43 ` Tim Hockin
2004-01-21 4:06 ` Srivatsa Vaddagiri
2004-01-21 4:14 ` Nick Piggin
2004-01-21 5:09 ` Srivatsa Vaddagiri
2004-01-21 7:08 ` Tim Hockin
2004-01-21 15:07 ` Matthias Urlichs
2004-01-22 5:29 ` Rusty Russell
2004-01-21 7:09 ` Tim Hockin
2004-01-21 7:31 ` Nick Piggin
2004-01-21 7:42 ` Tim Hockin
2004-01-21 8:11 ` Rusty Russell
2004-01-21 5:07 ` Rusty Russell
2004-01-20 8:41 ` Stefan Smietanowski
2004-01-20 8:49 ` Nick Piggin
2004-01-20 9:12 ` Tim Hockin
2004-01-21 0:00 ` Rusty Russell
2004-01-20 23:51 ` Rusty Russell
2004-01-20 7:45 ` Rusty Russell
2004-01-20 8:37 ` Tim Hockin
2004-01-20 9:29 ` Srivatsa Vaddagiri
2004-01-21 0:12 ` Rusty Russell
[not found] <fa.f37o48p.1io5q5@ifi.uio.no>
[not found] ` <fa.frjqvfo.170g8hq@ifi.uio.no>
2004-01-20 17:49 ` Andy Lutomirski
2004-01-21 4:33 ` Rusty Russell
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