From: Rusty Russell <rusty@rustcorp.com.au>
To: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>,
rusty@au1.ibm.com, Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@osdl.org>,
lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
LHCS list <lhcs-devel@lists.sourceforge.net>
Subject: Re: [lhcs-devel] Re: CPU Hotplug broken -mm5 onwards
Date: Tue, 20 Apr 2004 09:07:57 +1000 [thread overview]
Message-ID: <1082416075.5564.4.camel@bach> (raw)
In-Reply-To: <408458D5.5030208@yahoo.com.au>
On Tue, 2004-04-20 at 08:55, Nick Piggin wrote:
> > So, as Rusty said, I think we really need to consider removing
> > lock_cpu_hotplug from sched_migrate_task. AFAICS that lock
> > was needed to prevent adding tasks to dead cpus. The same
> > can be accomplished by removing lock_cpu_hotplug from sched_migrate_task
> > and adding a cpu_is_offline check in __migrate_task.
> > This will eliminate all the deadlocks I have been hitting.
> >
>
> Yes this would be a better idea. Care to send Andrew a patch
> against -mm?
What surprises me is that this is a regression. The original hotplug
code on top of Nicksched(TM) removed that lock as part of the "don't
change cpus_allowed to migrate on exec" fix. When we pushed the patch
straight into Linus' tree, we had to do lock_cpu_hotplug because we
didn't have that code.
Obviously, it escaped somewhere...
Cheers,
Rusty.
--
Anyone who quotes me in their signature is an idiot -- Rusty Russell
next prev parent reply other threads:[~2004-04-19 23:08 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-04-18 17:06 CPU Hotplug broken -mm5 onwards Srivatsa Vaddagiri
2004-04-19 3:34 ` Nick Piggin
2004-04-19 12:58 ` [lhcs-devel] " Srivatsa Vaddagiri
2004-04-19 22:55 ` Nick Piggin
2004-04-19 23:07 ` Rusty Russell [this message]
[not found] ` <20040421023650.24b9f85a.akpm@osdl.org>
[not found] ` <20040421095939.GB10767@in.ibm.com>
2004-04-21 16:44 ` Srivatsa Vaddagiri
2004-04-22 7:03 ` Andrew Morton
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