From: Andrea Arcangeli <aarcange@redhat.com>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Ying Han <yinghan@google.com>, Dave Jones <davej@redhat.com>,
Linux Kernel <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Oleg Nesterov <oleg@redhat.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>
Subject: Re: [PATCH] [BUGFIX] update mm->owner even if no next owner.
Date: Sat, 11 Jun 2011 20:44:16 +0200 [thread overview]
Message-ID: <20110611184416.GB3238@redhat.com> (raw)
In-Reply-To: <20110611175136.GA31154@cmpxchg.org>
On Sat, Jun 11, 2011 at 07:51:36PM +0200, Johannes Weiner wrote:
> This is a problem with the patch, but I think Kame's analysis and
> approach to fix it are still correct.
I agree with Kame's analysis too. This explains why removing the
mmap_sem read mode introduced the problem, it was quite some
unexpected subtleness not apparent to the naked eye, as memcg didn't
explicitly relay on mmap_sem but it did implicitly during exit because
of the __khugepaged_exit waiting if we were collapsing an hugepage...
So the fix is safe because the task struct is freed with
delayed_put_task_struct and that won't run until we rcu_read_unlock
after mem_cgroup_from_task.
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Thanks,
Andrea
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next prev parent reply other threads:[~2011-06-11 18:44 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20110609212956.GA2319@redhat.com>
2011-06-09 22:47 ` 3.0rc2 oops in mem_cgroup_from_task Ying Han
2011-06-09 23:42 ` Ying Han
2011-06-10 0:13 ` KAMEZAWA Hiroyuki
2011-06-10 1:30 ` Hugh Dickins
2011-06-10 2:33 ` KAMEZAWA Hiroyuki
2011-06-10 3:19 ` KAMEZAWA Hiroyuki
2011-06-10 3:55 ` KAMEZAWA Hiroyuki
2011-06-10 4:30 ` [PATCH] [BUGFIX] update mm->owner even if no next owner KAMEZAWA Hiroyuki
2011-06-10 5:06 ` Daisuke Nishimura
2011-06-10 5:21 ` Xiaotian Feng
2011-06-10 5:22 ` KAMEZAWA Hiroyuki
2011-06-10 21:49 ` Hugh Dickins
2011-06-10 23:54 ` Johannes Weiner
2011-06-11 17:51 ` Johannes Weiner
2011-06-11 18:44 ` Andrea Arcangeli [this message]
2011-06-11 23:04 ` Hiroyuki Kamezawa
2011-06-13 1:41 ` Hugh Dickins
2011-06-13 1:54 ` KAMEZAWA Hiroyuki
2011-06-13 14:03 ` Hugh Dickins
2011-06-11 0:46 ` Hiroyuki Kamezawa
2011-06-11 16:04 ` Hugh Dickins
2011-06-11 16:39 ` Andrea Arcangeli
2011-06-11 18:04 ` Johannes Weiner
2011-06-11 8:19 ` 3.0rc2 oops in mem_cgroup_from_task Michal Hocko
2011-06-11 15:46 ` Hugh Dickins
2011-06-12 9:09 ` Michal Hocko
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