From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1754663Ab1AKGhh (ORCPT <rfc822;w@1wt.eu>);
	Tue, 11 Jan 2011 01:37:37 -0500
Received: from freeflow.nu ([178.79.134.28]:53409 "EHLO freeflow.nu"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1752790Ab1AKGhb (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Tue, 11 Jan 2011 01:37:31 -0500
Message-ID: <4D2BFAA9.2050200@kernel.org>
Date: Tue, 11 Jan 2011 08:37:29 +0200
From: Pekka Enberg <penberg@kernel.org>
User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.2.13) Gecko/20101207 Thunderbird/3.1.7
MIME-Version: 1.0
To: David Rientjes <rientjes@google.com>
CC: Christoph Lameter <cl@linux.com>, Bart Van Assche <bvanassche@acm.org>,
        KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
        linux-kernel@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] slub: Fix sysfs circular locking dependency
References: <1294172717-6044-1-git-send-email-penberg@kernel.org>  <alpine.DEB.2.00.1101041939030.27551@chino.kir.corp.google.com>  <alpine.DEB.2.00.1101050943120.13032@router.home>  <alpine.DEB.2.00.1101051108520.14761@router.home> <AANLkTinft80dXqE-U=YDB23d9=BgXLCxJzgiA_gF4cVL@mail.gmail.com>  <AANLkTinCZzJWYGnxXq_Nwv7QSkEV4Tg-te-1y0PCeRRY@mail.gmail.com>  <AANLkTinQMahgVrWLxR0J6Zbh-_SPjxVJ-wuZt8B5TNjc@mail.gmail.com>  <alpine.DEB.2.00.1101060019140.25879@chino.kir.corp.google.com> <alpine.DEB.2.00.1101061107500.8655@router.home>  <20110107091106.aaa07abe.kamezawa.hiroyu@jp.fujitsu.com>  <alpine.DEB.2.00.1101070922100.3014@router.home>  <alpine.DEB.2.00.1101071227160.31653@chino.kir.corp.google.com>  <AANLkTin6N2s1RN6PBX=f0v69Ny-NkEKk_iAgqscuYgMM@mail.gmail.com> <1294475323.5248.74.camel@jaguar> <alpine.DEB.2.00.1101101014470.12243@router.home> <alpine.DEB.2.00.1101101230190.11969@chino.kir.corp.google.com>
In-Reply-To: <alpine.DEB.2.00.1101101230190.11969@chino.kir.corp.google.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 1/10/11 10:30 PM, David Rientjes wrote:
> On Mon, 10 Jan 2011, Christoph Lameter wrote:
>
>> New patch that just covers the slub changes.
>>
>> Subject: slub: Avoid use of slub_lock in show_slab_objects()
>>
>> The purpose of the locking is to prevent removal and additions
>> of nodes when statistics are gathered for a slab cache. So we
>> need to avoid racing with memory hotplug functionality.
>>
>> It is enough to take the memory hotplug locks there instead
>> of the slub_lock.
>>
>> online_pages() currently does not acquire the memory_hotplug
>> lock. Another patch will be submitted by the memory hotplug
>> authors to take the memory hotplug lock and describe the
>> uses of the memory hotplug lock to protect against
>> adding and removal of nodes from non hotplug data structures.
>>
>> Signed-off-by: Christoph Lameter<cl@linux.com>
> Acked-by: David Rientjes<rientjes@google.com>

Is this safe to be applied without the other hotplug parts?