From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>, Mel Gorman <mel@csn.ul.ie>,
Rik van Riel <riel@redhat.com>,
Minchan Kim <minchan.kim@gmail.com>,
Balbir Singh <balbir@linux.vnet.ibm.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Christoph Lameter <cl@linux-foundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [RFC][BUGFIX][PATCH] memcg: fix underflow of mapped_file stat
Date: Wed, 14 Apr 2010 10:56:08 +0900 [thread overview]
Message-ID: <20100414105608.d40c70ab.kamezawa.hiroyu@jp.fujitsu.com> (raw)
In-Reply-To: <20100414104010.7a359d04.kamezawa.hiroyu@jp.fujitsu.com>
On Wed, 14 Apr 2010 10:40:10 +0900
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:
> On Wed, 14 Apr 2010 10:03:08 +0900
> KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:
>
> > > > @@ -2563,6 +2565,15 @@ void mem_cgroup_end_migration(struct mem
> > > > */
> > > > if (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
> > > > mem_cgroup_uncharge_page(target);
> > > > + else {
> > > > + /*
> > > > + * When a migrated file cache is remapped, it's not charged.
> > > > + * Verify it. Because we're under lock_page(), there are
> > > > + * no race with uncharge.
> > > > + */
> > > > + if (page_mapped(target))
> > > > + mem_cgroup_update_file_mapped(mem, target, 1);
> > > > + }
> > > We cannot rely on page lock, because when we succeeded in page migration,
> > > "target" = "newpage" has already unlocked in move_to_new_page(). So the "target"
> > > can be removed from the radix-tree theoretically(it's not related to this
> > > underflow problem, though).
> > > Shouldn't we call lock_page(target) and check "if (!target->mapping)" to handle
> > > this case(maybe in another patch) ?
> > >
> > Sounds reasonable. I think about that.
> >
>
Thinking again....new page is unlocked here. It means the new page may be
removed from radix-tree before commit_charge().
Haha, it seems totally wrong. please wait..
Thanks,
-Kame
next prev parent reply other threads:[~2010-04-14 2:00 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-13 4:42 [RFC][BUGFIX][PATCH] memcg: fix underflow of mapped_file stat Daisuke Nishimura
2010-04-13 6:14 ` KAMEZAWA Hiroyuki
2010-04-14 0:54 ` Daisuke Nishimura
2010-04-14 1:03 ` KAMEZAWA Hiroyuki
2010-04-14 1:40 ` KAMEZAWA Hiroyuki
2010-04-14 1:56 ` KAMEZAWA Hiroyuki [this message]
2010-04-14 3:06 ` KAMEZAWA Hiroyuki
2010-04-14 5:31 ` Daisuke Nishimura
2010-04-14 5:40 ` KAMEZAWA Hiroyuki
2010-04-15 2:22 ` Daisuke Nishimura
2010-04-13 6:45 ` Balbir Singh
2010-04-15 3:05 ` [RFC][BUGFIX][PATCH 1/2] memcg: fix charge bypass route of migration KAMEZAWA Hiroyuki
2010-04-15 3:06 ` [RFC][BUGFIX][PATCH 2/2] memcg: fix file mapped underflow at migration (v2) KAMEZAWA Hiroyuki
2010-04-16 10:31 ` [RFC][BUGFIX][PATCH 2/2] memcg: fix file mapped underflow at migration (v3) KAMEZAWA Hiroyuki
2010-04-19 3:42 ` Daisuke Nishimura
2010-04-19 4:18 ` KAMEZAWA Hiroyuki
2010-04-19 8:07 ` Daisuke Nishimura
2010-04-19 8:26 ` KAMEZAWA Hiroyuki
2010-04-20 4:20 ` Daisuke Nishimura
2010-04-20 4:26 ` KAMEZAWA Hiroyuki
2010-04-20 9:19 ` KAMEZAWA Hiroyuki
2010-04-23 8:08 ` Daisuke Nishimura
2010-04-23 8:23 ` KAMEZAWA Hiroyuki
2010-04-15 6:43 ` [RFC][BUGFIX][PATCH 1/2] memcg: fix charge bypass route of migration Daisuke Nishimura
2010-04-15 6:56 ` KAMEZAWA Hiroyuki
2010-04-15 8:17 ` Andrea Arcangeli
2010-04-16 16:13 ` Interleave policy on 2M pages (was Re: [RFC][BUGFIX][PATCH 1/2] memcg: fix charge bypass route of migration) Christoph Lameter
2010-04-16 17:51 ` Andrea Arcangeli
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