From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx138.postini.com [74.125.245.138]) by kanga.kvack.org (Postfix) with SMTP id 03DAF6B0044 for ; Thu, 18 Oct 2012 21:49:53 -0400 (EDT) Message-ID: <5080B310.50608@cn.fujitsu.com> Date: Fri, 19 Oct 2012 09:55:28 +0800 From: Wen Congyang MIME-Version: 1.0 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> <5080A394.2000409@jp.fujitsu.com> In-Reply-To: <5080A394.2000409@jp.fujitsu.com> Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Yasuaki Ishimatsu Cc: KOSAKI Motohiro , 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, rientjes@google.com, liuj97@gmail.com, len.brown@intel.com, cl@linux.com, minchan.kim@gmail.com, akpm@linux-foundation.org At 10/19/2012 08:49 AM, Yasuaki Ishimatsu Wrote: > 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. OK Thanks Wen Congyang > > 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/ > -- 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