Date: Mon, 19 Sep 2005 10:58:30 +0530
From: Srivatsa Vaddagiri <vatsa@in.ibm.com>
To: Nigel Cunningham <ncunningham@cyclades.com>
Cc: Li Shaohua <shaohua.li@intel.com>, Andrew Morton <akpm@osdl.org>,
       Linus Torvalds <torvalds@osdl.org>,
       Zwane Mwaikambo <zwane@arm.linux.org.uk>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Rusty Russell <rusty@rustcorp.com.au>
Subject: Re: PATCH: Fix race in cpu_down (hotplug cpu)
Message-ID: <20050919052830.GB8653@in.ibm.com>
Reply-To: vatsa@in.ibm.com
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On Mon, Sep 19, 2005 at 03:23:01PM +1000, Nigel Cunningham wrote:
> Maybe I'm just an ignoramus, but I was thinking (without being a
> scheduler expert at all) that if the idle thread was already running,
> trying to set it up to run next might possibly have zero effect. I've

sched_idle_next actually adds the idle task to its runqueue (normally
it is not present in a runqueue while running) and as well changes its 
priority/policy. So it does have *some* effect!

> added a bit of debugging code to try and see in better detail what's
> happening.

Could you elaborate (with some stack traces maybe) on the deadlock you are 
seeing during resume? Maybe that can throw some light.

-- 


Thanks and Regards,
Srivatsa Vaddagiri,
Linux Technology Center,
IBM Software Labs,
Bangalore, INDIA - 560017
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