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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_SANE_1 autolearn=no 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 1C2CEC433E0 for ; Mon, 10 Aug 2020 13:10:55 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B5540206C3 for ; Mon, 10 Aug 2020 13:10:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B5540206C3 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 1EE936B0002; Mon, 10 Aug 2020 09:10:54 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 19D486B0006; Mon, 10 Aug 2020 09:10:54 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 08B656B0007; Mon, 10 Aug 2020 09:10:54 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0085.hostedemail.com [216.40.44.85]) by kanga.kvack.org (Postfix) with ESMTP id E24916B0002 for ; Mon, 10 Aug 2020 09:10:53 -0400 (EDT) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 9B5C93620 for ; Mon, 10 Aug 2020 13:10:53 +0000 (UTC) X-FDA: 77134693986.16.size01_050d14426fda Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin16.hostedemail.com (Postfix) with ESMTP id 5B5B1100E690C for ; Mon, 10 Aug 2020 13:10:53 +0000 (UTC) X-HE-Tag: size01_050d14426fda X-Filterd-Recvd-Size: 3109 Received: from out30-42.freemail.mail.aliyun.com (out30-42.freemail.mail.aliyun.com [115.124.30.42]) by imf09.hostedemail.com (Postfix) with ESMTP for ; Mon, 10 Aug 2020 13:10:51 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R871e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e01358;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=19;SR=0;TI=SMTPD_---0U5Mm29u_1597065044; Received: from IT-FVFX43SYHV2H.local(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0U5Mm29u_1597065044) by smtp.aliyun-inc.com(127.0.0.1); Mon, 10 Aug 2020 21:10:46 +0800 Subject: Re: [PATCH v17 14/21] mm/compaction: do page isolation first in compaction To: Alexander Duyck Cc: Andrew Morton , Mel Gorman , Tejun Heo , Hugh Dickins , Konstantin Khlebnikov , Daniel Jordan , Yang Shi , Matthew Wilcox , Johannes Weiner , kbuild test robot , linux-mm , LKML , cgroups@vger.kernel.org, Shakeel Butt , Joonsoo Kim , Wei Yang , "Kirill A. Shutemov" , Rong Chen References: <1595681998-19193-1-git-send-email-alex.shi@linux.alibaba.com> <1595681998-19193-15-git-send-email-alex.shi@linux.alibaba.com> <241ca157-104f-4f0d-7d5b-de394443788d@linux.alibaba.com> From: Alex Shi Message-ID: <8dbd004e-8eba-f1ec-a5eb-5dc551978936@linux.alibaba.com> Date: Mon, 10 Aug 2020 21:10:17 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 X-Rspamd-Queue-Id: 5B5B1100E690C X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 Content-Transfer-Encoding: quoted-printable 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: =E5=9C=A8 2020/8/7 =E4=B8=8B=E5=8D=8810:51, Alexander Duyck =E5=86=99=E9=81= =93: > I wonder if this entire section shouldn't be restructured. This is the > only spot I can see where we are resetting the LRU flag instead of > pulling the page from the LRU list with the lock held. Looking over > the code it seems like something like that should be possible. I am > not sure the LRU lock is really protecting us in either the > PageCompound check nor the skip bits. It seems like holding a > reference on the page should prevent it from switching between > compound or not, and the skip bits are per pageblock with the LRU bits > being per node/memcg which I would think implies that we could have > multiple LRU locks that could apply to a single skip bit. Hi Alexander, I don't find problem yet on compound or skip bit usage. Would you clarify= the issue do you concerned?=20 Thanks!