Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757367Ab3HQARw (ORCPT ); Fri, 16 Aug 2013 20:17:52 -0400 Received: from mail-gh0-f177.google.com ([209.85.160.177]:49781 "EHLO mail-gh0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757096Ab3HQARt (ORCPT ); Fri, 16 Aug 2013 20:17:49 -0400 X-Greylist: delayed 7620 seconds by postgrey-1.27 at vger.kernel.org; Fri, 16 Aug 2013 20:17:49 EDT Message-ID: <520E8C13.5020406@gmail.com> Date: Fri, 16 Aug 2013 16:31:15 -0400 From: KOSAKI Motohiro User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:17.0) Gecko/20130620 Thunderbird/17.0.7 MIME-Version: 1.0 To: Toshi Kani CC: KOSAKI Motohiro , akpm@linux-foundation.org, linux-mm@kvack.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, rjw@sisk.pl, kosaki.motohiro@jp.fujitsu.com, kamezawa.hiroyu@jp.fujitsu.com, tangchen@cn.fujitsu.com, isimatu.yasuaki@jp.fujitsu.com, liwanp@linux.vnet.ibm.com Subject: Re: [PATCH] mm/hotplug: Remove stop_machine() from try_offline_node() References: <1376336071-9128-1-git-send-email-toshi.kani@hp.com> <520C2D04.8060408@gmail.com> <1376584540.10300.416.camel@misato.fc.hp.com> In-Reply-To: <1376584540.10300.416.camel@misato.fc.hp.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1165 Lines: 35 >>> This patch removes the use of stop_machine() in try_offline_node() and >>> adds comments to try_offline_node() and remove_memory() that >>> lock_device_hotplug() is required. >> >> This patch need more verbose explanation. check_cpu_on_node() traverse cpus >> and cpu hotplug seems to use cpu_hotplug_driver_lock() instead of lock_device_hotplug(). > > As described: > > | lock_device_hotplug() serializes hotplug & online/offline operations. > | The lock is held in common sysfs online/offline interfaces and ACPI > | hotplug code paths. > > And here are their code paths. > > - CPU & Mem online/offline via sysfs online > store_online()->lock_device_hotplug() > > - Mem online via sysfs state: > store_mem_state()->lock_device_hotplug() > > - ACPI CPU & Mem hot-add: > acpi_scan_bus_device_check()->lock_device_hotplug() > > - ACPI CPU & Mem hot-delete: > acpi_scan_hot_remove()->lock_device_hotplug() O.K. -- 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/