From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 550C8C43460 for ; Fri, 30 Apr 2021 09:43:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 334376145B for ; Fri, 30 Apr 2021 09:43:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231559AbhD3JoY (ORCPT ); Fri, 30 Apr 2021 05:44:24 -0400 Received: from mail-m121142.qiye.163.com ([115.236.121.142]:18330 "EHLO mail-m121142.qiye.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229699AbhD3JoW (ORCPT ); Fri, 30 Apr 2021 05:44:22 -0400 Received: from [0.0.0.0] (unknown [14.154.30.39]) by mail-m121142.qiye.163.com (Hmail) with ESMTPA id 9D1E3800C9; Fri, 30 Apr 2021 17:43:30 +0800 (CST) Subject: Re: [RFC PATCH] mm/page_alloc: fix counting of free pages after take off from buddy To: David Hildenbrand , akpm@linux-foundation.org, naoya.horiguchi@nec.com, osalvador@suse.de Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20210421020426.5914-1-dinghui@sangfor.com.cn> From: Ding Hui Message-ID: <8cd355d2-1adc-4189-7b65-cfea13129db5@sangfor.com.cn> Date: Fri, 30 Apr 2021 17:43:40 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-HM-Spam-Status: e1kfGhgUHx5ZQUtXWQgYFAkeWUFZS1VLWVdZKFlBSE83V1ktWUFJV1kPCR oVCBIfWUFZGU1LHlZDSEgeS0xDS0gfQxpVEwETFhoSFyQUDg9ZV1kWGg8SFR0UWUFZT0tIVUpKS0 9ISVVLWQY+ X-HM-Sender-Digest: e1kMHhlZQR0aFwgeV1kSHx4VD1lBWUc6KyI6ERw5IT8WOE9CMAgxDyg* MzcKChdVSlVKTUpCTExOQ0pKSk1KVTMWGhIXVR8SFRwTDhI7CBoVHB0UCVUYFBZVGBVFWVdZEgtZ QVlKT1VKTk9VSEtVSEJZV1kIAVlBSUNPSDcG X-HM-Tid: 0a7922296d45b037kuuu9d1e3800c9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/4/28 22:54, David Hildenbrand wrote: > On 21.04.21 04:04, Ding Hui wrote: >> Recently we found there is a lot MemFree left in /proc/meminfo after >> do a lot of pages soft offline. >> >> I think it's incorrect since NR_FREE_PAGES should not contain HWPoison >> pages. >> After take_page_off_buddy, the page is no longer belong to buddy >> allocator, and will not be used any more, but we maybe missed accounting >> NR_FREE_PAGES in this situation. >> >> Signed-off-by: Ding Hui >> --- >>   mm/page_alloc.c | 1 + >>   1 file changed, 1 insertion(+) >> >> diff --git a/mm/page_alloc.c b/mm/page_alloc.c >> index cfc72873961d..8d65b62784d8 100644 >> --- a/mm/page_alloc.c >> +++ b/mm/page_alloc.c >> @@ -8947,6 +8947,7 @@ bool take_page_off_buddy(struct page *page) >>               del_page_from_free_list(page_head, zone, page_order); >>               break_down_buddy_pages(zone, page_head, page, 0, >>                           page_order, migratetype); >> +            __mod_zone_page_state(zone, NR_FREE_PAGES, -1); >>               ret = true; >>               break; >>           } >> > > Should this use __mod_zone_freepage_state() instead? > Yes, you're right. I'll use it in v2. -- Thanks, - Ding Hui