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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 9960FC47257 for ; Wed, 6 May 2020 01:33:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 74C712073B for ; Wed, 6 May 2020 01:33:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729722AbgEFBd6 (ORCPT ); Tue, 5 May 2020 21:33:58 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:3849 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727989AbgEFBd6 (ORCPT ); Tue, 5 May 2020 21:33:58 -0400 Received: from DGGEMS413-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 44882CD09A619D1254D8; Wed, 6 May 2020 09:33:53 +0800 (CST) Received: from [127.0.0.1] (10.166.215.55) by DGGEMS413-HUB.china.huawei.com (10.3.19.213) with Microsoft SMTP Server id 14.3.487.0; Wed, 6 May 2020 09:33:52 +0800 Subject: Re: [PATCH 2/4] mm/swap: use SECTORS_PER_PAGE_SHIFT to clean up code To: Matthew Wilcox CC: Minchan Kim , Nitin Gupta , "Sergey Senozhatsky" , Jens Axboe , linux-block , Andrew Morton , linux-mm , Alasdair Kergon , Mike Snitzer , dm-devel , Song Liu , linux-raid , linux-kernel References: <20200505115543.1660-1-thunder.leizhen@huawei.com> <20200505115543.1660-3-thunder.leizhen@huawei.com> <20200505172520.GI16070@bombadil.infradead.org> From: "Leizhen (ThunderTown)" Message-ID: <32ba9907-60ad-27c0-c565-e7b5c80ab03c@huawei.com> Date: Wed, 6 May 2020 09:33:50 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <20200505172520.GI16070@bombadil.infradead.org> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 8bit X-Originating-IP: [10.166.215.55] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020/5/6 1:25, Matthew Wilcox wrote: > On Tue, May 05, 2020 at 07:55:41PM +0800, Zhen Lei wrote: >> +++ b/mm/swapfile.c >> @@ -177,8 +177,8 @@ static int discard_swap(struct swap_info_struct *si) >> >> /* Do not discard the swap header page! */ >> se = first_se(si); >> - start_block = (se->start_block + 1) << (PAGE_SHIFT - 9); >> - nr_blocks = ((sector_t)se->nr_pages - 1) << (PAGE_SHIFT - 9); >> + start_block = (se->start_block + 1) << SECTORS_PER_PAGE_SHIFT; >> + nr_blocks = ((sector_t)se->nr_pages - 1) << SECTORS_PER_PAGE_SHIFT; > > Thinking about this some more, wouldn't this look better? > > start_block = page_sectors(se->start_block + 1); > nr_block = page_sectors(se->nr_pages - 1); > OKļ¼ŒThat's fine, it's clearer. And in this way, there won't be more than 80 columns. > > . >