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 6F291C433E1 for ; Sun, 19 Jul 2020 03:59:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4C3AF207DA for ; Sun, 19 Jul 2020 03:59:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726485AbgGSD7n (ORCPT ); Sat, 18 Jul 2020 23:59:43 -0400 Received: from out30-131.freemail.mail.aliyun.com ([115.124.30.131]:56930 "EHLO out30-131.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726284AbgGSD7m (ORCPT ); Sat, 18 Jul 2020 23:59:42 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R141e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07484;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=18;SR=0;TI=SMTPD_---0U36eCsi_1595131176; Received: from IT-FVFX43SYHV2H.local(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0U36eCsi_1595131176) by smtp.aliyun-inc.com(127.0.0.1); Sun, 19 Jul 2020 11:59:37 +0800 Subject: Re: [PATCH v16 15/22] 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" References: <1594429136-20002-1-git-send-email-alex.shi@linux.alibaba.com> <1594429136-20002-16-git-send-email-alex.shi@linux.alibaba.com> From: Alex Shi Message-ID: Date: Sun, 19 Jul 2020 11:59:36 +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 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2020/7/18 上午12:09, Alexander Duyck 写道: >>> I wonder if it wouldn't make sense to combine these two atomic ops >>> with tests and the put_page into a single inline function? Then it >>> could be possible to just do one check and if succeeds you do the >>> block of code below, otherwise you just fall-through into the -EBUSY >>> case. >>> >> Uh, since get_page changes page->_refcount, TestClearPageLRU changes page->flags, >> So I don't know how to combine them, could you make it more clear with code? > Actually it is pretty straight forward. Something like this: > static inline bool get_page_unless_zero_or_nonlru(struct page *page) > { > if (get_page_unless_zero(page)) { > if (TestClearPageLRU(page)) > return true; > put_page(page); > } > return false; > } > > You can then add comments as necessary. The general idea is you are > having to do this in two different spots anyway so why not combine the > logic? Although it does assume you can change the ordering of the > other test above. It doesn't look different with original code, does it? Thanks Alex From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Shi Subject: Re: [PATCH v16 15/22] mm/compaction: do page isolation first in compaction Date: Sun, 19 Jul 2020 11:59:36 +0800 Message-ID: References: <1594429136-20002-1-git-send-email-alex.shi@linux.alibaba.com> <1594429136-20002-16-git-send-email-alex.shi@linux.alibaba.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="utf-8" 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-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Shakeel Butt , Joonsoo Kim , Wei Yang , "Kirill A. Shutemov" 在 2020/7/18 上午12:09, Alexander Duyck 写道: >>> I wonder if it wouldn't make sense to combine these two atomic ops >>> with tests and the put_page into a single inline function? Then it >>> could be possible to just do one check and if succeeds you do the >>> block of code below, otherwise you just fall-through into the -EBUSY >>> case. >>> >> Uh, since get_page changes page->_refcount, TestClearPageLRU changes page->flags, >> So I don't know how to combine them, could you make it more clear with code? > Actually it is pretty straight forward. Something like this: > static inline bool get_page_unless_zero_or_nonlru(struct page *page) > { > if (get_page_unless_zero(page)) { > if (TestClearPageLRU(page)) > return true; > put_page(page); > } > return false; > } > > You can then add comments as necessary. The general idea is you are > having to do this in two different spots anyway so why not combine the > logic? Although it does assume you can change the ordering of the > other test above. It doesn't look different with original code, does it? Thanks Alex