From: Linus Torvalds <torvalds@linux-foundation.org>
To: Rik van Riel <riel@redhat.com>
Cc: akpm@linux-foundation.org, Mel Gorman <mel@csn.ul.ie>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Minchan Kim <minchan.kim@gmail.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Christoph Lameter <cl@linux.com>
Subject: Re: [PATCH 2/2] mm: fix race between shift_arg_pages and rmap_walk
Date: Mon, 3 May 2010 09:34:14 -0700 (PDT) [thread overview]
Message-ID: <alpine.LFD.2.00.1005030928350.5478@i5.linux-foundation.org> (raw)
In-Reply-To: <20100503121929.260ed5ee@annuminas.surriel.com>
On Mon, 3 May 2010, Rik van Riel wrote:
>
> migrate.c requires rmap to be able to find all ptes mapping a page at
> all times, otherwise the migration entry can be instantiated, but it
> can't be removed if the second rmap_walk fails to find the page.
Please correct me if I'm wrong, but this patch looks like pure and utter
garbage.
It looks like it makes execve() do a totally insane "create and then
immediately destroy temporary vma and anon_vma chain" for a case that is
unlikely to ever matter.
In fact, for a case that isn't even normally _enabled_, namely migration.
Why would we want to slow down execve() for that?
Linus
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next prev parent reply other threads:[~2010-05-03 16:36 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-03 16:17 [PATCH 0/2] Fix migration races in rmap_walk() V4 Rik van Riel
2010-05-03 16:18 ` [PATCH 1/2] mm: Take all anon_vma locks in anon_vma_lock Rik van Riel
2010-05-03 16:41 ` Linus Torvalds
2010-05-03 16:53 ` Rik van Riel
2010-05-03 17:17 ` Linus Torvalds
2010-05-03 17:58 ` Rik van Riel
2010-05-03 18:13 ` Andrea Arcangeli
2010-05-03 18:19 ` Linus Torvalds
2010-05-03 18:38 ` Rik van Riel
2010-05-04 13:12 ` Mel Gorman
2010-05-03 16:55 ` Peter Zijlstra
2010-05-03 17:02 ` Andrea Arcangeli
2010-05-03 17:11 ` Peter Zijlstra
2010-05-03 17:18 ` Andrea Arcangeli
2010-05-03 16:19 ` [PATCH 2/2] mm: fix race between shift_arg_pages and rmap_walk Rik van Riel
2010-05-03 16:34 ` Linus Torvalds [this message]
2010-05-03 16:37 ` Linus Torvalds
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