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Date: Thu, 10 Oct 2013 18:50:46 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>, Oleg Nesterov <oleg@redhat.com>,
        Paul McKenney <paulmck@linux.vnet.ibm.com>,
        Mel Gorman <mgorman@suse.de>, Rik van Riel <riel@redhat.com>,
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        Steven Rostedt <rostedt@goodmis.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/6] Optimize the cpu hotplug locking -v2
Message-ID: <20131010165045.GB12998@gmail.com>
References: <20131008102505.404025673@infradead.org>
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 <20131010121908.GB28601@twins.programming.kicks-ass.net>
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* Peter Zijlstra <peterz@infradead.org> wrote:

> On Thu, Oct 10, 2013 at 04:57:38PM +0200, Ingo Molnar wrote:
>
> > So ... why not make it _really_ cheap, i.e. the read lock costing 
> > nothing, and tie CPU hotplug to freezing all tasks in the system?
> 
> Such that we freeze regular tasks in userspace and kernel tasks in their 
> special freezer callback so as to guarantee minimal state?

Yes, absolutely.

Thanks,

	Ingo