Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2992576Ab2KOBaB (ORCPT ); Wed, 14 Nov 2012 20:30:01 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:63735 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S2992522Ab2KOBaA (ORCPT ); Wed, 14 Nov 2012 20:30:00 -0500 X-IronPort-AV: E=Sophos;i="4.83,254,1352044800"; d="scan'208";a="6199945" Message-ID: <50A4444A.7050305@cn.fujitsu.com> Date: Thu, 15 Nov 2012 09:24:26 +0800 From: Wen Congyang User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100413 Fedora/3.0.4-2.fc13 Thunderbird/3.0.4 MIME-Version: 1.0 To: "Rafael J. Wysocki" CC: Toshi Kani , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-acpi@vger.kernel.org, Len Brown , Andrew Morton , Yasuaki Ishimatsu , Lai Jiangshan , Jiang Liu , KOSAKI Motohiro , Minchan Kim , Mel Gorman , David Rientjes , Konrad Rzeszutek Wilk , Jiang Liu , Benjamin Herrenschmidt , Paul Mackerras , Christoph Lameter Subject: Re: [Patch v4 1/7] acpi,memory-hotplug: introduce a mutex lock to protect the list in acpi_memory_device References: <1352372693-32411-1-git-send-email-wency@cn.fujitsu.com> <1352754038.12509.16.camel@misato.fc.hp.com> <50A1AAC5.8000506@cn.fujitsu.com> <2008916.VzTIR8JBPq@vostro.rjw.lan> In-Reply-To: <2008916.VzTIR8JBPq@vostro.rjw.lan> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/11/15 09:18:06, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/11/15 09:29:49, Serialize complete at 2012/11/15 09:29:49 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1651 Lines: 46 At 11/15/2012 07:34 AM, Rafael J. Wysocki Wrote: > On Tuesday, November 13, 2012 10:04:53 AM Wen Congyang wrote: >> At 11/13/2012 05:00 AM, Toshi Kani Wrote: >>> On Thu, 2012-11-08 at 19:04 +0800, Wen Congyang wrote: >>>> The memory device can be removed by 2 ways: >>>> 1. send eject request by SCI >>>> 2. echo 1 >/sys/bus/pci/devices/PNP0C80:XX/eject >>>> >>>> This 2 events may happen at the same time, so we may touch >>>> acpi_memory_device.res_list at the same time. This patch >>>> introduce a lock to protect this list. >>> >>> Hi Wen, >>> >>> This race condition is not unique in memory hot-remove as the sysfs >>> eject interface is created for all objects with _EJ0. For CPU >>> hot-remove, I addressed this race condition by making the notify handler >>> to run the hot-remove operation on kacpi_hotplug_wq by calling >>> acpi_os_hotplug_execute(). This serializes the hot-remove operations >>> among the two events since the sysfs eject also runs on >>> kacpi_hotplug_wq. This way is much simpler and is easy to maintain, >>> although it does not allow both operations to run simultaneously (which >>> I do not think we need). Can it be used for memory hot-remove as well? >> >> Good idea. I will update it. > > Still waiting. :-) > > But if you want that in v3.8, please repost ASAP. I think I will send it today. It is in test now. Thanks Wen Congyang > > Thanks, > Rafael > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/