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Date: Thu, 6 May 2010 19:12:59 -0700 (PDT)
From: Linus Torvalds <torvalds@linux-foundation.org>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
cc: Mel Gorman <mel@csn.ul.ie>, Andrew Morton <akpm@linux-foundation.org>,
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       Andrea Arcangeli <aarcange@redhat.com>, Rik van Riel <riel@redhat.com>,
       Peter Zijlstra <peterz@infradead.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
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On Fri, 7 May 2010, KAMEZAWA Hiroyuki wrote:
> 
> IIUC, move_page_tables() may call "page table allocation" and it cannot be
> done under spinlock.

Bah. It only does a "alloc_new_pmd()", and we could easily move that out 
of the loop and pre-allocate the pmd's.

If that's the only reason, then it's a really weak one, methinks.

			Linus