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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,USER_AGENT_GIT autolearn=ham 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 8F389C2D0DD for ; Thu, 2 Jan 2020 08:15:35 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 52CF621835 for ; Thu, 2 Jan 2020 08:15:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 52CF621835 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 02B258E0008; Thu, 2 Jan 2020 03:15:35 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id F1D948E0003; Thu, 2 Jan 2020 03:15:34 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E5A198E0008; Thu, 2 Jan 2020 03:15:34 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0036.hostedemail.com [216.40.44.36]) by kanga.kvack.org (Postfix) with ESMTP id CFF478E0003 for ; Thu, 2 Jan 2020 03:15:34 -0500 (EST) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id 796D0181AC9C6 for ; Thu, 2 Jan 2020 08:15:34 +0000 (UTC) X-FDA: 76331984988.09.sheet64_87d97034e2103 X-HE-Tag: sheet64_87d97034e2103 X-Filterd-Recvd-Size: 2183 Received: from out30-44.freemail.mail.aliyun.com (out30-44.freemail.mail.aliyun.com [115.124.30.44]) by imf25.hostedemail.com (Postfix) with ESMTP for ; Thu, 2 Jan 2020 08:15:33 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R121e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01f04446;MF=wenyang@linux.alibaba.com;NM=1;PH=DS;RN=8;SR=0;TI=SMTPD_---0TmaHn71_1577952921; Received: from localhost(mailfrom:wenyang@linux.alibaba.com fp:SMTPD_---0TmaHn71_1577952921) by smtp.aliyun-inc.com(127.0.0.1); Thu, 02 Jan 2020 16:15:28 +0800 From: Wen Yang To: Andrew Morton , Qian Cai Cc: xlpang@linux.alibaba.com, Wen Yang , Tejun Heo , Jens Axboe , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH 3/3] mm/page-writeback.c: improve arithmetic divisions Date: Thu, 2 Jan 2020 16:14:42 +0800 Message-Id: <20200102081442.8273-4-wenyang@linux.alibaba.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20200102081442.8273-1-wenyang@linux.alibaba.com> References: <20200102081442.8273-1-wenyang@linux.alibaba.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000004, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Use div64_ul() instead of do_div() if the divisor is unsigned long, to avoid truncation to 32-bit on 64-bit platforms. Signed-off-by: Wen Yang Cc: Andrew Morton Cc: Qian Cai Cc: Tejun Heo Cc: Jens Axboe Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org --- mm/page-writeback.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/page-writeback.c b/mm/page-writeback.c index c74c6bd..2caf780 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -1102,7 +1102,7 @@ static void wb_update_write_bandwidth(struct bdi_wr= iteback *wb, bw =3D written - min(written, wb->written_stamp); bw *=3D HZ; if (unlikely(elapsed > period)) { - do_div(bw, elapsed); + bw =3D div64_ul(bw, elapsed); avg =3D bw; goto out; } --=20 1.8.3.1