From: Andrea Arcangeli <aarcange@redhat.com>
To: Christoph Lameter <cl@linux.com>
Cc: Mel Gorman <mel@csn.ul.ie>,
Andrew Morton <akpm@linux-foundation.org>,
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>,
Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH 2/2] mm,migration: Avoid race between shift_arg_pages() and rmap_walk() during migration by not migrating temporary stacks
Date: Mon, 10 May 2010 21:05:59 +0200 [thread overview]
Message-ID: <20100510190559.GD22632@random.random> (raw)
In-Reply-To: <alpine.DEB.2.00.1005101239400.13652@router.home>
On Mon, May 10, 2010 at 12:41:07PM -0500, Christoph Lameter wrote:
> A simple way to disallow migration of pages is to increment the refcount
> of a page.
Ok for migrate but it won't prevent to crash in split_huge_page rmap
walk, nor the PG_lock. Why for a rmap bug have a migrate specific fix?
The fix that makes execve the only special place to handle in every
rmap walk, is at least more maintainable than a fix that makes one of
the rmap walk users special and won't fix the others, as there will be
more than just 1 user that requires this. My fix didn't make execve
special and it didn't require execve knowledge into the every rmap
walk like migrate (split_huge_page etc...) but as long as the kernel
doesn't crash I'm fine ;).
WARNING: multiple messages have this Message-ID (diff)
From: Andrea Arcangeli <aarcange@redhat.com>
To: Christoph Lameter <cl@linux.com>
Cc: Mel Gorman <mel@csn.ul.ie>,
Andrew Morton <akpm@linux-foundation.org>,
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>,
Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH 2/2] mm,migration: Avoid race between shift_arg_pages() and rmap_walk() during migration by not migrating temporary stacks
Date: Mon, 10 May 2010 21:05:59 +0200 [thread overview]
Message-ID: <20100510190559.GD22632@random.random> (raw)
In-Reply-To: <alpine.DEB.2.00.1005101239400.13652@router.home>
On Mon, May 10, 2010 at 12:41:07PM -0500, Christoph Lameter wrote:
> A simple way to disallow migration of pages is to increment the refcount
> of a page.
Ok for migrate but it won't prevent to crash in split_huge_page rmap
walk, nor the PG_lock. Why for a rmap bug have a migrate specific fix?
The fix that makes execve the only special place to handle in every
rmap walk, is at least more maintainable than a fix that makes one of
the rmap walk users special and won't fix the others, as there will be
more than just 1 user that requires this. My fix didn't make execve
special and it didn't require execve knowledge into the every rmap
walk like migrate (split_huge_page etc...) but as long as the kernel
doesn't crash I'm fine ;).
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next prev parent reply other threads:[~2010-05-10 19:07 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-29 8:32 [PATCH 0/2] Fix migration races in rmap_walk() V3 Mel Gorman
2010-04-29 8:32 ` Mel Gorman
2010-04-29 8:32 ` [PATCH 1/2] mm: Take all anon_vma locks in anon_vma_lock Mel Gorman
2010-04-29 8:32 ` Mel Gorman
2010-05-02 17:28 ` Minchan Kim
2010-05-02 17:28 ` Minchan Kim
2010-04-29 8:32 ` [PATCH 2/2] mm,migration: Avoid race between shift_arg_pages() and rmap_walk() during migration by not migrating temporary stacks Mel Gorman
2010-04-29 8:32 ` Mel Gorman
2010-04-29 16:21 ` Andrea Arcangeli
2010-04-29 16:21 ` Andrea Arcangeli
2010-04-30 19:22 ` Andrea Arcangeli
2010-04-30 19:22 ` Andrea Arcangeli
2010-04-30 20:21 ` Rik van Riel
2010-04-30 20:21 ` Rik van Riel
2010-05-01 9:39 ` Andrea Arcangeli
2010-05-01 9:39 ` Andrea Arcangeli
2010-05-01 13:02 ` Rik van Riel
2010-05-01 13:02 ` Rik van Riel
2010-05-02 17:40 ` Minchan Kim
2010-05-02 17:40 ` Minchan Kim
2010-05-02 18:20 ` Andrea Arcangeli
2010-05-02 18:20 ` Andrea Arcangeli
2010-05-04 10:32 ` Mel Gorman
2010-05-04 10:32 ` Mel Gorman
2010-05-04 12:56 ` Andrea Arcangeli
2010-05-04 12:56 ` Andrea Arcangeli
2010-05-04 14:33 ` Mel Gorman
2010-05-04 14:33 ` Mel Gorman
2010-05-04 14:44 ` Andrea Arcangeli
2010-05-04 14:44 ` Andrea Arcangeli
2010-05-02 1:56 ` Christoph Lameter
2010-05-02 1:56 ` Christoph Lameter
2010-05-04 9:45 ` Mel Gorman
2010-05-04 9:45 ` Mel Gorman
2010-05-10 17:41 ` Christoph Lameter
2010-05-10 17:41 ` Christoph Lameter
2010-05-10 17:56 ` Mel Gorman
2010-05-10 17:56 ` Mel Gorman
2010-05-11 13:59 ` Christoph Lameter
2010-05-11 13:59 ` Christoph Lameter
2010-05-11 15:11 ` Mel Gorman
2010-05-11 15:11 ` Mel Gorman
2010-05-11 15:56 ` Christoph Lameter
2010-05-11 15:56 ` Christoph Lameter
2010-05-11 16:15 ` Mel Gorman
2010-05-11 16:15 ` Mel Gorman
2010-05-11 16:29 ` Andrea Arcangeli
2010-05-11 16:29 ` Andrea Arcangeli
2010-05-10 19:05 ` Andrea Arcangeli [this message]
2010-05-10 19:05 ` Andrea Arcangeli
2010-05-11 0:10 ` KAMEZAWA Hiroyuki
2010-05-11 0:10 ` KAMEZAWA Hiroyuki
2010-04-30 18:28 ` [PATCH 0/2] Fix migration races in rmap_walk() V3 Andrea Arcangeli
2010-04-30 18:28 ` Andrea Arcangeli
2010-05-01 13:51 ` Johannes Weiner
2010-05-01 13:51 ` Johannes Weiner
2010-05-03 15:33 ` Andrea Arcangeli
2010-05-03 15:33 ` Andrea Arcangeli
2010-05-03 23:41 ` Johannes Weiner
2010-05-03 23:41 ` Johannes Weiner
2010-05-04 17:35 ` Andrea Arcangeli
2010-05-04 17:35 ` Andrea Arcangeli
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