From: Minchan Kim <minchan.kim@gmail.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Christoph Lameter <cl@linux.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [BUGFIX][mm][PATCH] fix migration race in rmap_walk
Date: Mon, 26 Apr 2010 18:48:42 +0900 [thread overview]
Message-ID: <r2o28c262361004260248s62729484g14a720d37d5916f7@mail.gmail.com> (raw)
In-Reply-To: <20100426182838.2cab9844.kamezawa.hiroyu@jp.fujitsu.com>
On Mon, Apr 26, 2010 at 6:28 PM, KAMEZAWA Hiroyuki
<kamezawa.hiroyu@jp.fujitsu.com> wrote:
> On Mon, 26 Apr 2010 08:49:01 +0900
> KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:
>
>> On Sat, 24 Apr 2010 11:43:24 +0100
>> Mel Gorman <mel@csn.ul.ie> wrote:
>
>> > It looks nice but it still broke after 28 hours of running. The
>> > seq-counter is still insufficient to catch all changes that are made to
>> > the list. I'm beginning to wonder if a) this really can be fully safely
>> > locked with the anon_vma changes and b) if it has to be a spinlock to
>> > catch the majority of cases but still a lazy cleanup if there happens to
>> > be a race. It's unsatisfactory and I'm expecting I'll either have some
>> > insight to the new anon_vma changes that allow it to be locked or Rik
>> > knows how to restore the original behaviour which as Andrea pointed out
>> > was safe.
>> >
>> Ouch.
>
> Ok, reproduced. Here is status in my test + printk().
>
> * A race doesn't seem to happen if swap=off.
> I need to swapon to cause the bug
FYI,
Do you have a swapon/off bomb test?
When I saw your mail, I feel it might be culprit.
http://lkml.org/lkml/2010/4/22/762.
It is just guessing. I don't have a time to look into, now.
--
Kind regards,
Minchan Kim
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next prev parent reply other threads:[~2010-04-26 9:48 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-23 3:01 [BUGFIX][mm][PATCH] fix migration race in rmap_walk KAMEZAWA Hiroyuki
2010-04-23 5:11 ` Minchan Kim
2010-04-23 5:27 ` KAMEZAWA Hiroyuki
2010-04-23 7:00 ` Minchan Kim
2010-04-23 7:17 ` KAMEZAWA Hiroyuki
2010-04-23 7:53 ` Minchan Kim
2010-04-23 7:55 ` KAMEZAWA Hiroyuki
2010-04-23 9:59 ` Mel Gorman
2010-04-23 15:58 ` Mel Gorman
2010-04-24 2:02 ` KAMEZAWA Hiroyuki
2010-04-24 10:43 ` Mel Gorman
2010-04-25 23:49 ` KAMEZAWA Hiroyuki
2010-04-26 2:53 ` KAMEZAWA Hiroyuki
2010-04-26 4:31 ` Minchan Kim
2010-04-26 4:06 ` Minchan Kim
2010-04-26 9:28 ` KAMEZAWA Hiroyuki
2010-04-26 9:48 ` Minchan Kim [this message]
2010-04-26 9:49 ` KAMEZAWA Hiroyuki
2010-04-26 10:07 ` Minchan Kim
2010-04-26 11:36 ` Mel Gorman
2010-04-26 4:00 ` Minchan Kim
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