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Subject: Re: [patch 08/15] sched: migrate throttled tasks on HOTPLUG
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Paul Turner <pjt@google.com>
Cc: linux-kernel@vger.kernel.org, Bharata B Rao <bharata@linux.vnet.ibm.com>,
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Date: Tue, 05 Apr 2011 15:28:12 +0200
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On Tue, 2011-03-22 at 20:03 -0700, Paul Turner wrote:
> Throttled tasks are invisisble to cpu-offline since they are not eligible for
> selection by pick_next_task().  The regular 'escape' path for a thread that is
> blocked at offline is via ttwu->select_task_rq, however this will not handle a
> throttled group since there are no individual thread wakeups on an unthrottle.
> 
> Resolve this by unthrottling offline cpus so that threads can be migrated.

Fair enough, the flip side is that they all can again increase their
debt by a whole tick, right?