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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 EE5D5C2BA2B for ; Sun, 12 Apr 2020 10:18:27 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 87AC12072D for ; Sun, 12 Apr 2020 10:18:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="YaUeSOCX" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 87AC12072D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 02E718E00CE; Sun, 12 Apr 2020 06:18:27 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id F23638E0007; Sun, 12 Apr 2020 06:18:26 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E0F1D8E00CE; Sun, 12 Apr 2020 06:18:26 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0057.hostedemail.com [216.40.44.57]) by kanga.kvack.org (Postfix) with ESMTP id C6A0F8E0007 for ; Sun, 12 Apr 2020 06:18:26 -0400 (EDT) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 8B2C445A3 for ; Sun, 12 Apr 2020 10:18:26 +0000 (UTC) X-FDA: 76698803412.23.beds63_66c95d6d99c59 X-HE-Tag: beds63_66c95d6d99c59 X-Filterd-Recvd-Size: 2685 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf36.hostedemail.com (Postfix) with ESMTP for ; Sun, 12 Apr 2020 10:18:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=pWtIcYQcyh9/XzWH8jhEXH0VHKQdeo/n3FuwkbHfYzU=; b=YaUeSOCX/4NCs53tW+ngw8gdbD zMdn5eGV1Cz8tumemrHNvWfssmJXOMhwrStGFzj7w1h9+b9KsX2/e3dr2+xRxf14tWHhJ9o14mmS0 m99nKuyl44J7V4d00/pYl/VmcMqQ16UtpqWOdfjKOQTCVccH5PzzsZetXx5CJv+fOJB+TssJ5hcYQ dutZTanj7PfALwmvuGcQvQQYlpOW21/W27JlaZOo+yxG7FxFXaHSuTkAk586jlbMllB6OHfBaRLJ/ 60u5ygtm5oZemsqBBXFqAWh6a2ItoXkeaSB3gBhM3E1jxcVYlD1zFrS2A1Gaufg+B0OUmJOs0VAGy F5Fbzt2g==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jNZgt-0005dP-EX; Sun, 12 Apr 2020 10:18:15 +0000 Date: Sun, 12 Apr 2020 03:18:15 -0700 From: Matthew Wilcox To: chenqiwu Cc: akpm@linux-foundation.org, david@redhat.com, richard.weiyang@gmail.com, mhocko@suse.com, pankaj.gupta.linux@gmail.com, yang.shi@linux.alibaba.com, cai@lca.pw, bhe@redhat.com, linux-mm@kvack.org, chenqiwu Subject: Re: [RESEND PATCH 3/3] mm/vmscan: make several optimizations for isolate_lru_pages() Message-ID: <20200412101815.GL21484@bombadil.infradead.org> References: <1586599916-15456-1-git-send-email-qiwuchen55@gmail.com> <1586599916-15456-3-git-send-email-qiwuchen55@gmail.com> <20200411161021.GD21484@bombadil.infradead.org> <20200412073516.GA31142@cqw-OptiPlex-7050> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200412073516.GA31142@cqw-OptiPlex-7050> 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 Sun, Apr 12, 2020 at 03:35:16PM +0800, chenqiwu wrote: > On Sat, Apr 11, 2020 at 09:10:21AM -0700, Matthew Wilcox wrote: > > On Sat, Apr 11, 2020 at 06:11:56PM +0800, qiwuchen55@gmail.com wrote: > > > 1) Simplify the code of initializing some variables. > > > - unsigned long scan, total_scan, nr_pages; > > > + unsigned long scan = 0, total_scan = 0, nr_pages; > > > > > > - total_scan = 0; > > > - scan = 0; > > > > I do not find this to be a simplification. > > > Hi willy, > This slightly simplify the code by definition and initialization > meanwhile instead of separating them into the two steps. > This can save two lines of code. And it buries the initialisation on a more complicated line. Number of lines is not the only metric.