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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CD001C4332F for ; Thu, 10 Nov 2022 02:48:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232563AbiKJCsd (ORCPT ); Wed, 9 Nov 2022 21:48:33 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51770 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232549AbiKJCs2 (ORCPT ); Wed, 9 Nov 2022 21:48:28 -0500 Received: from mail-pg1-x544.google.com (mail-pg1-x544.google.com [IPv6:2607:f8b0:4864:20::544]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7E192BE3D for ; Wed, 9 Nov 2022 18:48:27 -0800 (PST) Received: by mail-pg1-x544.google.com with SMTP id h193so442500pgc.10 for ; Wed, 09 Nov 2022 18:48:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to:subject :user-agent:mime-version:date:message-id:from:to:cc:subject:date :message-id:reply-to; bh=e7eUyiQ6IzU2+8YpPxlxYGEz6hnrs4cMH/uVBORMyPA=; b=hJj2r8CBurme6Ps/PCRGDQ3Ut2BotHl6PwfMBtsW7ln7DRdh0pA3cM5hiaEWBSqlVP SY66mlbXOKxsctjgeY4XX4nHLI2vM3O2SKr6OqdnrVRYFEdos4rJ9QHklqnYLqaHG5aN /WJeRVBHALT+4aBNRJ8FpvYsP2q+OydgmEW3BojR3++p3aWiGlb8agop3By+kFGHXJo2 oEsKLhzBRhbwc0fFfqJWkjRMUS1jm4kP+P/WCLgCaEpSyMurjI1dK61vyWeybyzTsmP7 80cfVi/G89288QVex5RaQ/VzondOZ4PCka2oSB8tOAWBYGu71bOhMV85fxIUh4Od3Oyo YnnA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to:subject :user-agent:mime-version:date:message-id:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=e7eUyiQ6IzU2+8YpPxlxYGEz6hnrs4cMH/uVBORMyPA=; b=kGrymT7c9Nu4ODvd/Mk8EDIW/eP9GCBrHG1JuULqBEPbRSnifbyTBHcszwTuuGQ5Al rT6DmdBr5JKtaUNdZPKPIJ/mC3WO0R6TqJHgg5uNYNvOV7Q1PPOPDdiIKXgZjrcl1RML RB+vhnDtqHaCYwpLQL25RCxgdO1QyWBnDjbAztpl5+rSW/4r3D/PJT14araZiOQrwRUI T/1F5zLjSwktEibVn1JksML++xjLwLPwR0O7cweVFn+oXhBS9XMg+aD6cb7JODsc6wiB e+Qv9GQybMiLmVHHmxISsAqm4ypcw2enRRKtcVg1hAldXrR9FJ9ajPCjWpQk1npcOgNZ XGYA== X-Gm-Message-State: ACrzQf1HQ3yZvmvkej6Swe5JPyWFB1l4aU0unl+LMVlg9uaUuBnDiqhY aH4RcsLwR6vwCEQtY44o0kI= X-Google-Smtp-Source: AMsMyM52mojWHoQ9X8h45pTN2+QLha+lM23Z556YFa768OQUBcX3vm/KoCOk34Z0LACmhNVGf8hYJQ== X-Received: by 2002:a65:4b88:0:b0:44e:74d0:e843 with SMTP id t8-20020a654b88000000b0044e74d0e843mr1616131pgq.95.1668048506995; Wed, 09 Nov 2022 18:48:26 -0800 (PST) Received: from [10.114.96.16] ([129.227.152.6]) by smtp.gmail.com with ESMTPSA id ij26-20020a170902ab5a00b0017f6c9622b9sm9744756plb.183.2022.11.09.18.48.24 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 09 Nov 2022 18:48:26 -0800 (PST) Message-ID: <7113d66a-9792-b026-cece-5c1b21dd989d@gmail.com> Date: Thu, 10 Nov 2022 10:48:24 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.4.2 Subject: Re: [PATCH] mm/vmscan: simplify the nr assignment logic for pages to scan To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Chao Xu References: <20221109070416.620887-1-Chao.Xu9@zeekrlife.com> <20221109171952.826d991327e07319c5eb8cd3@linux-foundation.org> From: Chao Xu In-Reply-To: <20221109171952.826d991327e07319c5eb8cd3@linux-foundation.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2022/11/10 9:19, Andrew Morton 写道: > On Wed, 9 Nov 2022 15:04:16 +0800 Chao Xu wrote: > >> By default the assignment logic of anonymouns or file inactive >> pages and active pages to scan using the same duplicated code >> snippet. To simplify the logic, merge the same part. >> >> --- a/mm/vmscan.c >> +++ b/mm/vmscan.c >> @@ -5932,14 +5932,11 @@ static void shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc) >> * scan target and the percentage scanning already complete >> */ >> lru = (lru == LRU_FILE) ? LRU_BASE : LRU_FILE; >> - nr_scanned = targets[lru] - nr[lru]; >> - nr[lru] = targets[lru] * (100 - percentage) / 100; >> - nr[lru] -= min(nr[lru], nr_scanned); >> - >> - lru += LRU_ACTIVE; >> - nr_scanned = targets[lru] - nr[lru]; >> - nr[lru] = targets[lru] * (100 - percentage) / 100; >> - nr[lru] -= min(nr[lru], nr_scanned); >> + for ( ; lru <= lru + LRU_ACTIVE; lru++) { > The "lru++" implicitly assumes that LRU_ACTIVE=1. That happens to be > the case, but a more accurate translation of the existing code would > use "lru += LRU_ACTIVE" here, yes? By default the value of LRU_ACTIVE is 1，but if someone change it one day, I use "lru++" maybe facing some exceptions, which is not robust. So I agree with that "lru += LRU_ACTIVE" is appropriate instead of "lru++". I will send a new patch. >> + nr_scanned = targets[lru] - nr[lru]; >> + nr[lru] = targets[lru] * (100 - percentage) / 100; >> + nr[lru] -= min(nr[lru], nr_scanned); >> + } >> >> scan_adjusted = true; >> }