linux-kernel - Re: [PATCH 2/2] mm,migration: Fix race between shift_arg_pages and rmap_walk by guaranteeing rmap_walk finds PTEs created within the temporary stack

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Message-ID: <alpine.LFD.2.00.1005091831140.3711@i5.linux-foundation.org>
Date:	Sun, 9 May 2010 18:32:32 -0700 (PDT)
From:	Linus Torvalds <torvalds@...ux-foundation.org>
To:	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
cc:	Mel Gorman <mel@....ul.ie>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Linux-MM <linux-mm@...ck.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Minchan Kim <minchan.kim@...il.com>,
	Christoph Lameter <cl@...ux.com>,
	Andrea Arcangeli <aarcange@...hat.com>,
	Rik van Riel <riel@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>
Subject: Re: [PATCH 2/2] mm,migration: Fix race between shift_arg_pages and
 rmap_walk by guaranteeing rmap_walk finds PTEs created within the temporary
 stack



On Sun, 9 May 2010, Linus Torvalds wrote:
> 
> So I never disliked that patch. I'm perfectly happy with a "don't migrate 
> these pages at all, because they are in a half-way state in the middle of 
> execve stack magic".

Btw, I also think that Mel's patch could be made a lot _less_ magic by 
just marking that initial stack vma with a VM_STACK_INCOMPLETE_SETUP bit, 
instead of doing that "maybe_stack" thing. We could easily make that 
initial vma setup very explicit indeed, and then just clear that bit when 
we've moved the stack to its final position.

		Linus
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