Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932924AbcCKRHr (ORCPT ); Fri, 11 Mar 2016 12:07:47 -0500 Received: from mx2.suse.de ([195.135.220.15]:41927 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932596AbcCKRHp (ORCPT ); Fri, 11 Mar 2016 12:07:45 -0500 Subject: Re: Suspicious error for CMA stress test To: Joonsoo Kim , "Leizhen (ThunderTown)" References: <56D6F008.1050600@huawei.com> <56D79284.3030009@redhat.com> <56D832BD.5080305@huawei.com> <20160304020232.GA12036@js1304-P5Q-DELUXE> <20160304043232.GC12036@js1304-P5Q-DELUXE> <56D92595.60709@huawei.com> <20160304063807.GA13317@js1304-P5Q-DELUXE> <56D93ABE.9070406@huawei.com> <20160307043442.GB24602@js1304-P5Q-DELUXE> <56DD38E7.3050107@huawei.com> <56DDCB86.4030709@redhat.com> <56DE30CB.7020207@huawei.com> <56DF7B28.9060108@huawei.com> Cc: Laura Abbott , Joonsoo Kim , Hanjun Guo , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Andrew Morton , Sasha Levin , Laura Abbott , qiuxishi , Catalin Marinas , Will Deacon , Arnd Bergmann , dingtinahong , chenjie6@huawei.com, "linux-mm@kvack.org" From: Vlastimil Babka Message-ID: <56E2FB5C.1040602@suse.cz> Date: Fri, 11 Mar 2016 18:07:40 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2770 Lines: 84 On 03/11/2016 04:00 PM, Joonsoo Kim wrote: > 2016-03-09 10:23 GMT+09:00 Leizhen (ThunderTown) : >> >> Hi, Joonsoo: >> This new patch worked well. Do you plan to upstream it in the near furture? > > Of course! > But, I should think more because it touches allocator's fastpatch and > I'd like to detour. > If I fail to think a better solution, I will send it as is, soon. How about something like this? Just and idea, probably buggy (off-by-one etc.). Should keep away cost from pageblock_order iterations. diff --git a/mm/page_alloc.c b/mm/page_alloc.c index ff1e3cbc8956..b8005a07b2a1 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -685,21 +685,13 @@ static inline void __free_one_page(struct page *page, unsigned long combined_idx; unsigned long uninitialized_var(buddy_idx); struct page *buddy; - unsigned int max_order = MAX_ORDER; + unsigned int max_order = pageblock_order + 1; VM_BUG_ON(!zone_is_initialized(zone)); VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP, page); VM_BUG_ON(migratetype == -1); - if (is_migrate_isolate(migratetype)) { - /* - * We restrict max order of merging to prevent merge - * between freepages on isolate pageblock and normal - * pageblock. Without this, pageblock isolation - * could cause incorrect freepage accounting. - */ - max_order = min_t(unsigned int, MAX_ORDER, pageblock_order + 1); - } else { + if (likely(!is_migrate_isolate(migratetype))) { __mod_zone_freepage_state(zone, 1 << order, migratetype); } @@ -708,11 +700,12 @@ static inline void __free_one_page(struct page *page, VM_BUG_ON_PAGE(page_idx & ((1 << order) - 1), page); VM_BUG_ON_PAGE(bad_range(zone, page), page); +continue_merging: while (order < max_order - 1) { buddy_idx = __find_buddy_index(page_idx, order); buddy = page + (buddy_idx - page_idx); if (!page_is_buddy(page, buddy, order)) - break; + goto done_merging; /* * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page, * merge with it and move up one order. @@ -729,6 +722,26 @@ static inline void __free_one_page(struct page *page, page_idx = combined_idx; order++; } + if (max_order < MAX_ORDER) { + if (IS_ENABLED(CONFIG_CMA) && + unlikely(has_isolate_pageblock(zone))) { + + int buddy_mt; + + buddy_idx = __find_buddy_index(page_idx, order); + buddy = page + (buddy_idx - page_idx); + buddy_mt = get_pageblock_migratetype(buddy); + + if (migratetype != buddy_mt && + (is_migrate_isolate(migratetype) || + is_migrate_isolate(buddy_mt))) + goto done_merging; + } + max_order++; + goto continue_merging; + } + +done_merging: set_page_order(page, order); /*