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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,URIBL_BLOCKED,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 2F95DC2BA1B for ; Mon, 6 Apr 2020 18:16:09 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 051992064A for ; Mon, 6 Apr 2020 18:16:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 051992064A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 976618E000E; Mon, 6 Apr 2020 14:16:08 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 924FD8E000D; Mon, 6 Apr 2020 14:16:08 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 83B268E000E; Mon, 6 Apr 2020 14:16:08 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0184.hostedemail.com [216.40.44.184]) by kanga.kvack.org (Postfix) with ESMTP id 655C08E000D for ; Mon, 6 Apr 2020 14:16:08 -0400 (EDT) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 1EF6452D9 for ; Mon, 6 Apr 2020 18:16:08 +0000 (UTC) X-FDA: 76678234416.07.rate01_8cc3fd97fd456 X-HE-Tag: rate01_8cc3fd97fd456 X-Filterd-Recvd-Size: 2472 Received: from out30-56.freemail.mail.aliyun.com (out30-56.freemail.mail.aliyun.com [115.124.30.56]) by imf31.hostedemail.com (Postfix) with ESMTP for ; Mon, 6 Apr 2020 18:16:06 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R361e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e01358;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0Tuq9-ti_1586196959; Received: from US-143344MP.local(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0Tuq9-ti_1586196959) by smtp.aliyun-inc.com(127.0.0.1); Tue, 07 Apr 2020 02:16:01 +0800 Subject: Re: [PATCHv2 3/8] khugepaged: Drain all LRU caches before scanning pages To: "Kirill A. Shutemov" , akpm@linux-foundation.org, Andrea Arcangeli Cc: Zi Yan , linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" References: <20200403112928.19742-1-kirill.shutemov@linux.intel.com> <20200403112928.19742-4-kirill.shutemov@linux.intel.com> From: Yang Shi Message-ID: <3f0514c3-7f1e-0ba0-b458-683600bd5905@linux.alibaba.com> Date: Mon, 6 Apr 2020 11:15:58 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20200403112928.19742-4-kirill.shutemov@linux.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 4/3/20 4:29 AM, Kirill A. Shutemov wrote: > Having a page in LRU add cache offsets page refcount and gives > false-negative on PageLRU(). It reduces collapse success rate. > > Drain all LRU add caches before scanning. It happens relatively > rare and should not disturb the system too much. > > Signed-off-by: Kirill A. Shutemov Acked-by: Yang Shi > --- > mm/khugepaged.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index 14d7afc90786..fdc10ffde1ca 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -2065,6 +2065,8 @@ static void khugepaged_do_scan(void) > > barrier(); /* write khugepaged_pages_to_scan to local stack */ > > + lru_add_drain_all(); > + > while (progress < pages) { > if (!khugepaged_prealloc_page(&hpage, &wait)) > break;