From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f197.google.com (mail-pf0-f197.google.com [209.85.192.197]) by kanga.kvack.org (Postfix) with ESMTP id BBFE26B0038 for ; Fri, 2 Dec 2016 04:30:18 -0500 (EST) Received: by mail-pf0-f197.google.com with SMTP id 17so389895670pfy.2 for ; Fri, 02 Dec 2016 01:30:18 -0800 (PST) Received: from out0-147.mail.aliyun.com (out0-147.mail.aliyun.com. [140.205.0.147]) by mx.google.com with ESMTP id y64si4385964pgd.113.2016.12.02.01.30.17 for ; Fri, 02 Dec 2016 01:30:17 -0800 (PST) Reply-To: "Hillf Danton" From: "Hillf Danton" References: <20161202002244.18453-1-mgorman@techsingularity.net> <20161202002244.18453-2-mgorman@techsingularity.net> <01d601d24c4e$dca6e190$95f4a4b0$@alibaba-inc.com> <55e1d640-72cf-d7b5-695b-87863ca7a843@suse.cz> In-Reply-To: <55e1d640-72cf-d7b5-695b-87863ca7a843@suse.cz> Subject: Re: [PATCH 1/2] mm, page_alloc: Keep pcp count and list contents in sync if struct page is corrupted Date: Fri, 02 Dec 2016 17:30:07 +0800 Message-ID: <01f201d24c7e$ac04ed40$040ec7c0$@alibaba-inc.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Language: zh-cn Sender: owner-linux-mm@kvack.org List-ID: To: 'Vlastimil Babka' , 'Mel Gorman' , 'Andrew Morton' Cc: 'Christoph Lameter' , 'Michal Hocko' , 'Johannes Weiner' , 'Jesper Dangaard Brouer' , 'Linux-MM' , 'Linux-Kernel' On Friday, December 02, 2016 2:19 PM Vlastimil Babka wrote: > On 12/02/2016 04:47 AM, Hillf Danton wrote: > > On Friday, December 02, 2016 8:23 AM Mel Gorman wrote: > >> Vlastimil Babka pointed out that commit 479f854a207c ("mm, page_alloc: > >> defer debugging checks of pages allocated from the PCP") will allow the > >> per-cpu list counter to be out of sync with the per-cpu list contents > >> if a struct page is corrupted. This patch keeps the accounting in sync. > >> > >> Fixes: 479f854a207c ("mm, page_alloc: defer debugging checks of pages allocated from the PCP") > >> Signed-off-by: Mel Gorman > >> cc: stable@vger.kernel.org [4.7+] > > Acked-by: Vlastimil Babka > > >> --- > >> mm/page_alloc.c | 5 +++-- > >> 1 file changed, 3 insertions(+), 2 deletions(-) > >> > >> diff --git a/mm/page_alloc.c b/mm/page_alloc.c > >> index 6de9440e3ae2..777ed59570df 100644 > >> --- a/mm/page_alloc.c > >> +++ b/mm/page_alloc.c > >> @@ -2192,7 +2192,7 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order, > >> unsigned long count, struct list_head *list, > >> int migratetype, bool cold) > >> { > >> - int i; > >> + int i, alloced = 0; > >> > >> spin_lock(&zone->lock); > >> for (i = 0; i < count; ++i) { > >> @@ -2217,13 +2217,14 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order, > >> else > >> list_add_tail(&page->lru, list); > >> list = &page->lru; > >> + alloced++; > >> if (is_migrate_cma(get_pcppage_migratetype(page))) > >> __mod_zone_page_state(zone, NR_FREE_CMA_PAGES, > >> -(1 << order)); > >> } > >> __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order)); > > > > Now i is a pure index, yes? > > No, even if a page fails the check_pcp_refill() check and is not > "allocated", it is also no longer a free page, so it's correct to > subtract it from NR_FREE_PAGES. > Yes, we can allocate free page next time. thanks Hillf -- 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