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From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Thu, 25 Oct 2012 16:09:48 -0700
Message-ID: <CA+55aFzoxMYLXdBvdMYTy_LhrVuU233qh1eDyAda5otUTHojPA@mail.gmail.com>
Subject: Re: [patch for-3.7] mm, mempolicy: fix printing stack contents in numa_maps
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Sender: owner-linux-mm@kvack.org
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To: Peter Zijlstra <peterz@infradead.org>
Cc: David Rientjes <rientjes@google.com>, Sasha Levin <levinsasha928@gmail.com>, Mel Gorman <mgorman@suse.de>, Rik van Riel <riel@redhat.com>, Dave Jones <davej@redhat.com>, Andrew Morton <akpm@linux-foundation.org>, KOSAKI Motohiro <kosaki.motohiro@gmail.com>, bhutchings@solarflare.com, Konstantin Khlebnikov <khlebnikov@openvz.org>, Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>, Hugh Dickins <hughd@google.com>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>, linux-kernel@vger.kernel.org, linux-mm@kvack.org

On Thu, Oct 25, 2012 at 7:39 AM, Peter Zijlstra <peterz@infradead.org> wrote:
>
> So I think the below should work, we hold the spinlock over both rb-tree
> modification as sp free, this makes mpol_shared_policy_lookup() which
> returns the policy with an incremented refcount work with just the
> spinlock.
>
> Comments?

Looks reasonable, if annoyingly complex for something that shouldn't
be important enough for this. Oh well.

However, please check me on this: the need for this is only for
linux-next right now, correct? All the current users in my tree are ok
with just the mutex, no?

            Linus

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