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Date: Fri, 31 Jul 2015 13:12:46 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>, Rik van Riel <riel@redhat.com>,
        Tejun Heo <tj@kernel.org>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 6/6] stop_machine: kill stop_cpus_lock and
 lg_double_lock/unlock()
Message-ID: <20150731111246.GS18673@twins.programming.kicks-ass.net>
References: <20150721192219.GA31150@redhat.com>
 <20150721192247.GA31191@redhat.com>
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On Thu, Jul 30, 2015 at 11:55:27PM +0200, Peter Zijlstra wrote:
> 
> Exclusion between stop_{one,two}_cpu{,s}() and stop_cpus() makes this
> trivially go away.
> 
> Paul's RCU branch already kills try_stop_cpus() dead, so that wart is
> also gone. But we're still stuck with stop_machine_from_inactive_cpu()
> which does a spin-wait for exclusive state. So I suppose we'll have to
> keep stop_cpus_mutex :/

*groan* we really need to kill that from_inactive_cpu() shite too. Lemme
go have a look at how this MTRR crap works.