From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kamezawa Hiroyuki Subject: Re: [PATCH v5 14/14] memory-hotplug: free node_data when a node is offlined Date: Fri, 28 Dec 2012 09:28:48 +0900 Message-ID: <50DCE7C0.8070407@jp.fujitsu.com> References: <1356350964-13437-1-git-send-email-tangchen@cn.fujitsu.com> <1356350964-13437-15-git-send-email-tangchen@cn.fujitsu.com> <50DA7533.6060407@jp.fujitsu.com> <50DC3C26.6060308@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <50DC3C26.6060308@cn.fujitsu.com> Sender: owner-linux-mm@kvack.org To: Wen Congyang Cc: Tang Chen , akpm@linux-foundation.org, rientjes@google.com, liuj97@gmail.com, len.brown@intel.com, benh@kernel.crashing.org, paulus@samba.org, cl@linux.com, minchan.kim@gmail.com, kosaki.motohiro@jp.fujitsu.com, isimatu.yasuaki@jp.fujitsu.com, wujianguo@huawei.com, hpa@zytor.com, linfeng@cn.fujitsu.com, laijs@cn.fujitsu.com, mgorman@suse.de, yinghai@kernel.org, x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-acpi@vger.kernel.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, linux-ia64@vger.kernel.org, cmetcalf@tilera.com, sparclinux@vger.kernel.org List-Id: linux-acpi@vger.kernel.org (2012/12/27 21:16), Wen Congyang wrote: > At 12/26/2012 11:55 AM, Kamezawa Hiroyuki Wrote: >> (2012/12/24 21:09), Tang Chen wrote: >>> From: Wen Congyang >>> >>> We call hotadd_new_pgdat() to allocate memory to store node_data. So we >>> should free it when removing a node. >>> >>> Signed-off-by: Wen Congyang >> >> I'm sorry but is it safe to remove pgdat ? All zone cache and zonelists are >> properly cleared/rebuilded in synchronous way ? and No threads are visinting >> zone in vmscan.c ? > > We have rebuilt zonelists when a zone has no memory after offlining some pages. > How do you guarantee that the address of pgdat/zone is not on stack of any kernel threads or other kernel objects without reference counting or other syncing method ? Thanks, -Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kamezawa Hiroyuki Date: Fri, 28 Dec 2012 00:28:48 +0000 Subject: Re: [PATCH v5 14/14] memory-hotplug: free node_data when a node is offlined Message-Id: <50DCE7C0.8070407@jp.fujitsu.com> List-Id: References: <1356350964-13437-1-git-send-email-tangchen@cn.fujitsu.com> <1356350964-13437-15-git-send-email-tangchen@cn.fujitsu.com> <50DA7533.6060407@jp.fujitsu.com> <50DC3C26.6060308@cn.fujitsu.com> In-Reply-To: <50DC3C26.6060308@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Wen Congyang Cc: Tang Chen , akpm@linux-foundation.org, rientjes@google.com, liuj97@gmail.com, len.brown@intel.com, benh@kernel.crashing.org, paulus@samba.org, cl@linux.com, minchan.kim@gmail.com, kosaki.motohiro@jp.fujitsu.com, isimatu.yasuaki@jp.fujitsu.com, wujianguo@huawei.com, hpa@zytor.com, linfeng@cn.fujitsu.com, laijs@cn.fujitsu.com, mgorman@suse.de, yinghai@kernel.org, x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-acpi@vger.kernel.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, linux-ia64@vger.kernel.org, cmetcalf@tilera.com, sparclinux@vger.kernel.org (2012/12/27 21:16), Wen Congyang wrote: > At 12/26/2012 11:55 AM, Kamezawa Hiroyuki Wrote: >> (2012/12/24 21:09), Tang Chen wrote: >>> From: Wen Congyang >>> >>> We call hotadd_new_pgdat() to allocate memory to store node_data. So we >>> should free it when removing a node. >>> >>> Signed-off-by: Wen Congyang >> >> I'm sorry but is it safe to remove pgdat ? All zone cache and zonelists are >> properly cleared/rebuilded in synchronous way ? and No threads are visinting >> zone in vmscan.c ? > > We have rebuilt zonelists when a zone has no memory after offlining some pages. > How do you guarantee that the address of pgdat/zone is not on stack of any kernel threads or other kernel objects without reference counting or other syncing method ? Thanks, -Kame From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from fgwmail5.fujitsu.co.jp (fgwmail5.fujitsu.co.jp [192.51.44.35]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 6F0522C00C2 for ; Fri, 28 Dec 2012 11:29:54 +1100 (EST) Received: from m4.gw.fujitsu.co.jp (unknown [10.0.50.74]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id 08F873EE0C1 for ; Fri, 28 Dec 2012 09:29:51 +0900 (JST) Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id E21F645DE55 for ; Fri, 28 Dec 2012 09:29:50 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (s4.gw.fujitsu.co.jp [10.0.50.94]) by m4.gw.fujitsu.co.jp (Postfix) with ESMTP id C82C045DE4F for ; Fri, 28 Dec 2012 09:29:50 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id B99E7E08005 for ; Fri, 28 Dec 2012 09:29:50 +0900 (JST) Received: from m1000.s.css.fujitsu.com (m1000.s.css.fujitsu.com [10.240.81.136]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 6EE8B1DB8040 for ; Fri, 28 Dec 2012 09:29:50 +0900 (JST) Message-ID: <50DCE7C0.8070407@jp.fujitsu.com> Date: Fri, 28 Dec 2012 09:28:48 +0900 From: Kamezawa Hiroyuki MIME-Version: 1.0 To: Wen Congyang Subject: Re: [PATCH v5 14/14] memory-hotplug: free node_data when a node is offlined References: <1356350964-13437-1-git-send-email-tangchen@cn.fujitsu.com> <1356350964-13437-15-git-send-email-tangchen@cn.fujitsu.com> <50DA7533.6060407@jp.fujitsu.com> <50DC3C26.6060308@cn.fujitsu.com> In-Reply-To: <50DC3C26.6060308@cn.fujitsu.com> Content-Type: text/plain; charset=ISO-2022-JP Cc: linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, Tang Chen , linux-mm@kvack.org, paulus@samba.org, hpa@zytor.com, sparclinux@vger.kernel.org, cl@linux.com, linux-s390@vger.kernel.org, x86@kernel.org, linux-acpi@vger.kernel.org, isimatu.yasuaki@jp.fujitsu.com, linfeng@cn.fujitsu.com, mgorman@suse.de, kosaki.motohiro@jp.fujitsu.com, rientjes@google.com, liuj97@gmail.com, len.brown@intel.com, cmetcalf@tilera.com, wujianguo@huawei.com, yinghai@kernel.org, laijs@cn.fujitsu.com, linux-kernel@vger.kernel.org, minchan.kim@gmail.com, akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , (2012/12/27 21:16), Wen Congyang wrote: > At 12/26/2012 11:55 AM, Kamezawa Hiroyuki Wrote: >> (2012/12/24 21:09), Tang Chen wrote: >>> From: Wen Congyang >>> >>> We call hotadd_new_pgdat() to allocate memory to store node_data. So we >>> should free it when removing a node. >>> >>> Signed-off-by: Wen Congyang >> >> I'm sorry but is it safe to remove pgdat ? All zone cache and zonelists are >> properly cleared/rebuilded in synchronous way ? and No threads are visinting >> zone in vmscan.c ? > > We have rebuilt zonelists when a zone has no memory after offlining some pages. > How do you guarantee that the address of pgdat/zone is not on stack of any kernel threads or other kernel objects without reference counting or other syncing method ? Thanks, -Kame From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752496Ab2L1A3z (ORCPT ); Thu, 27 Dec 2012 19:29:55 -0500 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:47615 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751236Ab2L1A3w (ORCPT ); Thu, 27 Dec 2012 19:29:52 -0500 X-SecurityPolicyCheck: OK by SHieldMailChecker v1.8.4 Message-ID: <50DCE7C0.8070407@jp.fujitsu.com> Date: Fri, 28 Dec 2012 09:28:48 +0900 From: Kamezawa Hiroyuki User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Wen Congyang CC: Tang Chen , akpm@linux-foundation.org, rientjes@google.com, liuj97@gmail.com, len.brown@intel.com, benh@kernel.crashing.org, paulus@samba.org, cl@linux.com, minchan.kim@gmail.com, kosaki.motohiro@jp.fujitsu.com, isimatu.yasuaki@jp.fujitsu.com, wujianguo@huawei.com, hpa@zytor.com, linfeng@cn.fujitsu.com, laijs@cn.fujitsu.com, mgorman@suse.de, yinghai@kernel.org, x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-acpi@vger.kernel.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, linux-ia64@vger.kernel.org, cmetcalf@tilera.com, sparclinux@vger.kernel.org Subject: Re: [PATCH v5 14/14] memory-hotplug: free node_data when a node is offlined References: <1356350964-13437-1-git-send-email-tangchen@cn.fujitsu.com> <1356350964-13437-15-git-send-email-tangchen@cn.fujitsu.com> <50DA7533.6060407@jp.fujitsu.com> <50DC3C26.6060308@cn.fujitsu.com> In-Reply-To: <50DC3C26.6060308@cn.fujitsu.com> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (2012/12/27 21:16), Wen Congyang wrote: > At 12/26/2012 11:55 AM, Kamezawa Hiroyuki Wrote: >> (2012/12/24 21:09), Tang Chen wrote: >>> From: Wen Congyang >>> >>> We call hotadd_new_pgdat() to allocate memory to store node_data. So we >>> should free it when removing a node. >>> >>> Signed-off-by: Wen Congyang >> >> I'm sorry but is it safe to remove pgdat ? All zone cache and zonelists are >> properly cleared/rebuilded in synchronous way ? and No threads are visinting >> zone in vmscan.c ? > > We have rebuilt zonelists when a zone has no memory after offlining some pages. > How do you guarantee that the address of pgdat/zone is not on stack of any kernel threads or other kernel objects without reference counting or other syncing method ? Thanks, -Kame