Subject: Re: [RFC] [PATCH 0/5 V2] Huge page backed user-space stacks
From: Dave Hansen <dave@linux.vnet.ibm.com>
To: Mel Gorman <mel@csn.ul.ie>
Cc: Andrew Morton <akpm@linux-foundation.org>, ebmunson@us.ibm.com,
       linux-mm@kvack.org, linux-kernel@vger.kernel.org,
       linuxppc-dev@ozlabs.org, libhugetlbfs-devel@lists.sourceforge.net,
       abh@cray.com
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Date: Tue, 05 Aug 2008 09:12:28 -0700
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On Tue, 2008-08-05 at 12:11 +0100, Mel Gorman wrote:
> See, that's great until you start dealing with MAP_SHARED|MAP_ANONYMOUS.
> To get that right between children, you end up something very fs-like
> when the child needs to fault in a page that is already populated by the
> parent. I strongly suspect we end up back at hugetlbfs backing it :/

Yeah, but the case I'm worried about is plain anonymous.  We already
have the fs to back SHARED|ANONYMOUS, and they're not really
anonymous. :)

This patch *really* needs anonymous pages, and it kinda shoehorns them
in with the filesystem.  Stacks aren't shared at all, so this is a
perfect example of where we can forget the fs, right?

-- Dave

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