Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757022Ab2JSAud (ORCPT ); Thu, 18 Oct 2012 20:50:33 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:60824 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752882Ab2JSAub (ORCPT ); Thu, 18 Oct 2012 20:50:31 -0400 X-SecurityPolicyCheck: OK by SHieldMailChecker v1.7.4 Message-ID: <5080A394.2000409@jp.fujitsu.com> Date: Fri, 19 Oct 2012 09:49:24 +0900 From: Yasuaki Ishimatsu User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:16.0) Gecko/20121010 Thunderbird/16.0.1 MIME-Version: 1.0 To: KOSAKI Motohiro , CC: , , , , , , , , , , , , , , , Subject: Re: [PATCH 5/10] memory-hotplug : memory-hotplug: check page type in get_page_bootmem References: <506E43E0.70507@jp.fujitsu.com> <506E46B6.3060502@jp.fujitsu.com> In-Reply-To: Content-Type: text/plain; charset="ISO-8859-1"; 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: 3255 Lines: 88 Hi Kosaki, Sorry for late reply. 2012/10/13 4:28, KOSAKI Motohiro wrote: > On Thu, Oct 4, 2012 at 10:32 PM, Yasuaki Ishimatsu > wrote: >> The function get_page_bootmem() may be called more than one time to the same >> page. There is no need to set page's type, private if the function is not >> the first time called to the page. >> >> Note: the patch is just optimization and does not fix any problem. >> >> CC: David Rientjes >> CC: Jiang Liu >> CC: Len Brown >> CC: Christoph Lameter >> Cc: Minchan Kim >> CC: Andrew Morton >> CC: KOSAKI Motohiro >> CC: Wen Congyang >> Signed-off-by: Yasuaki Ishimatsu >> --- >> mm/memory_hotplug.c | 15 +++++++++++---- >> 1 file changed, 11 insertions(+), 4 deletions(-) >> >> Index: linux-3.6/mm/memory_hotplug.c >> =================================================================== >> --- linux-3.6.orig/mm/memory_hotplug.c 2012-10-04 18:29:58.284676075 +0900 >> +++ linux-3.6/mm/memory_hotplug.c 2012-10-04 18:30:03.454680542 +0900 >> @@ -95,10 +95,17 @@ static void release_memory_resource(stru >> static void get_page_bootmem(unsigned long info, struct page *page, >> unsigned long type) >> { >> - page->lru.next = (struct list_head *) type; >> - SetPagePrivate(page); >> - set_page_private(page, info); >> - atomic_inc(&page->_count); >> + unsigned long page_type; >> + >> + page_type = (unsigned long)page->lru.next; > > If I understand correctly, page->lru.next might be uninitialized yet. Ah yes. I was misunderstanding... Hi Wen, When you update the physical hot remove patch-set, please drop the patch. Thanks, Yasuaki Ishimatsu > Moreover, I have no seen any good effect in this patch. I don't understand > why we need to increase code complexity. > > > >> + if (page_type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE || >> + page_type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE){ >> + page->lru.next = (struct list_head *)type; >> + SetPagePrivate(page); >> + set_page_private(page, info); >> + atomic_inc(&page->_count); >> + } else >> + atomic_inc(&page->_count); >> } >> >> /* reference to __meminit __free_pages_bootmem is valid >> >> -- >> 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 > -- > 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/ > -- 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/