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From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Mon, 9 May 2011 15:31:42 -0700
Message-ID: <BANLkTim7ATRyJ2NvoCj4Sv=7CLizKMd_WA@mail.gmail.com>
Subject: Re: [PATCH] Don't mlock guardpage if the stack is growing up
To: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>,
        Tony Luck <tony.luck@intel.com>, Fenghua Yu <fenghua.yu@intel.com>,
        Hugh Dickins <hughd@google.com>, linux-kernel@vger.kernel.org,
        linux-parisc@vger.kernel.org, Michel Lespinasse <walken@google.com>,
        Oleg Nesterov <oleg@redhat.com>, linux-ia64@vger.kernel.org
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On Mon, May 9, 2011 at 3:19 PM, James Bottomley
<James.Bottomley@hansenpartnership.com> wrote:
>
> So I can test the patch, if you tell me how. =A0I don't use lvm2, so it
> would have to be a simple test case.

Something like the attached. Run it as root (it needs root just for
the mlockall), and see whether the stack it shows changes.

With current kernels, I think the stack expands by one page during the
mlockall (for STACK_GROWSUP), with the patch it shouldn't.

                   Linus

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