From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with SMTP id 9F95E6B0047 for ; Tue, 31 Aug 2010 21:24:41 -0400 (EDT) Received: from m1.gw.fujitsu.co.jp ([10.0.50.71]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id o811Od4P016154 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Wed, 1 Sep 2010 10:24:39 +0900 Received: from smail (m1 [127.0.0.1]) by outgoing.m1.gw.fujitsu.co.jp (Postfix) with ESMTP id 3054A45DE50 for ; Wed, 1 Sep 2010 10:24:39 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (s1.gw.fujitsu.co.jp [10.0.50.91]) by m1.gw.fujitsu.co.jp (Postfix) with ESMTP id 0C95045DE4D for ; Wed, 1 Sep 2010 10:24:39 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id E3325E38003 for ; Wed, 1 Sep 2010 10:24:38 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.249.87.104]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 912AEE38001 for ; Wed, 1 Sep 2010 10:24:38 +0900 (JST) Date: Wed, 1 Sep 2010 10:19:35 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH] Make is_mem_section_removable more conformable with offlining code Message-Id: <20100901101935.c2fedfe4.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20100831143649.GA31730@localhost> References: <20100820141400.GD4636@tiehlicka.suse.cz> <20100822004232.GA11007@localhost> <20100823092246.GA25772@tiehlicka.suse.cz> <20100831141942.GA30353@localhost> <20100831143649.GA31730@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Wu Fengguang Cc: Michal Hocko , "linux-mm@kvack.org" , Andrew Morton , "Kleen, Andi" , Haicheng Li , Christoph Lameter , "linux-kernel@vger.kernel.org" , Mel Gorman List-ID: On Tue, 31 Aug 2010 22:36:49 +0800 Wu Fengguang wrote: > On Tue, Aug 31, 2010 at 10:19:42PM +0800, Wu Fengguang wrote: > > On Mon, Aug 23, 2010 at 05:22:46PM +0800, Michal Hocko wrote: > > > On Sun 22-08-10 08:42:32, Wu Fengguang wrote: > > > > Hi Michal, > > > > > > Hi, > > > > > > > > > > > It helps to explain in changelog/code > > > > > > > > - in what situation a ZONE_MOVABLE will contain !MIGRATE_MOVABLE > > > > pages? > > > > > > page can be MIGRATE_RESERVE IIUC. > > > > Yup, it may also be set to MIGRATE_ISOLATE by soft_offline_page(). > > Ah a non-movable page allocation could fall back into the movable > zone. See __rmqueue_fallback() and the fallbacks[][] array. So the > > if (type != MIGRATE_MOVABLE && !pageblock_free(page)) > > check in is_mem_section_removable() is correct. It is > set_migratetype_isolate() that should be fixed to use the same check. > Here is a patch for set_migratetype_isolate(). This is not a _fix_ but an improvement. == From: KAMEZAWA Hiroyuki At memory hotplug, we set pageblock's movable-type as ISOLATE. At failure, we make it back to be MOVABLE. So, - pageblock's type shoule be movable before isolation. - pageblock's contents should be really movable before isolation. Add document about it and add pageblock_free() call for fast-path. Signed-off-by: KAMEZAWA Hiroyuki --- include/linux/mmzone.h | 4 ++++ mm/memory_hotplug.c | 2 +- mm/page_alloc.c | 17 +++++++++++++---- 3 files changed, 18 insertions(+), 5 deletions(-) Index: mmotm-0827/mm/page_alloc.c =================================================================== --- mmotm-0827.orig/mm/page_alloc.c +++ mmotm-0827/mm/page_alloc.c @@ -5282,19 +5282,28 @@ int set_migratetype_isolate(struct page unsigned long immobile = 0; struct memory_isolate_notify arg; int notifier_ret; - int ret = -EBUSY; + int ret = 0; int zone_idx; zone = page_zone(page); zone_idx = zone_idx(zone); spin_lock_irqsave(&zone->lock, flags); + /* + * At failure of hotplug, we turns this block to be MOVABLE if + * isolation has been successfully done. So, if page-block is movable + * or freed, we can try this without check contents.. + */ if (get_pageblock_migratetype(page) == MIGRATE_MOVABLE || - zone_idx == ZONE_MOVABLE) { - ret = 0; + pageblock_free(page) || + zone_idx == ZONE_MOVABLE) goto out; - } + ret = -EBUSY; + /* + * check contents, because we move this pageblocks type to be MOVABLE + * at failure, the contents should be movable. + */ pfn = page_to_pfn(page); arg.start_pfn = pfn; arg.nr_pages = pageblock_nr_pages; Index: mmotm-0827/include/linux/mmzone.h =================================================================== --- mmotm-0827.orig/include/linux/mmzone.h +++ mmotm-0827/include/linux/mmzone.h @@ -54,6 +54,10 @@ static inline int get_pageblock_migratet return get_pageblock_flags_group(page, PB_migrate, PB_migrate_end); } +#ifdef CONFIG_MEMORY_HOTREMOVE +extern int pageblock_free(struct page *page); +#endif + struct free_area { struct list_head free_list[MIGRATE_TYPES]; unsigned long nr_free; Index: mmotm-0827/mm/memory_hotplug.c =================================================================== --- mmotm-0827.orig/mm/memory_hotplug.c +++ mmotm-0827/mm/memory_hotplug.c @@ -576,7 +576,7 @@ EXPORT_SYMBOL_GPL(add_memory); * Due to buddy contraints, a free page at least the size of a pageblock will * be located at the start of the pageblock */ -static inline int pageblock_free(struct page *page) +int pageblock_free(struct page *page) { return PageBuddy(page) && page_order(page) >= pageblock_order; } -- 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