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 8AC34C2D0DD for ; Thu, 2 Jan 2020 08:15:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6586821734 for ; Thu, 2 Jan 2020 08:15:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727866AbgABIPc (ORCPT ); Thu, 2 Jan 2020 03:15:32 -0500 Received: from out30-54.freemail.mail.aliyun.com ([115.124.30.54]:35298 "EHLO out30-54.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727714AbgABIPb (ORCPT ); Thu, 2 Jan 2020 03:15:31 -0500 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: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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_writeback *wb, bw = written - min(written, wb->written_stamp); bw *= HZ; if (unlikely(elapsed > period)) { - do_div(bw, elapsed); + bw = div64_ul(bw, elapsed); avg = bw; goto out; } -- 1.8.3.1