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Subject: Re: [PATCH] Kick CPUS that might be sleeping in cpus_idle_wait
From: Steven Rostedt <rostedt@goodmis.org>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
       Andrew Morton <akpm@linux-foundation.org>, Ingo Molnar <mingo@elte.hu>,
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On Wed, 2008-01-09 at 15:42 -0500, Steven Rostedt wrote:
> This patch is different than the first patch I sent out.
> This one just sends an IPI to all CPUS that don't check in after 1 sec.
> 
> 
> Sometimes cpu_idle_wait gets stuck because it might miss CPUS that are
> already in idle, have no tasks waiting to run and have no interrupts
> going to them.  This is common on bootup when switching cpu idle
> governors.
> 
> This patch gives those CPUS that don't check in an IPI kick.

FYI, I just hit this hang on 2.6.24-rc6 without any extra patches. So,
unless 2.6.24-rc7 did anything to fix this issue, this is a high
priority bug (IMHO).

-- Steve