From patchwork Tue Jan 14 00:29:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 11331117 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 261BB14E3 for ; Tue, 14 Jan 2020 00:29:33 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id DD35321556 for ; Tue, 14 Jan 2020 00:29:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="ynhqIfJc" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DD35321556 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 69EBD8E000E; Mon, 13 Jan 2020 19:29:31 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 53A4F8E0003; Mon, 13 Jan 2020 19:29:31 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 42A348E000E; Mon, 13 Jan 2020 19:29:31 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0004.hostedemail.com [216.40.44.4]) by kanga.kvack.org (Postfix) with ESMTP id 2C5728E0003 for ; Mon, 13 Jan 2020 19:29:31 -0500 (EST) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id C87492465 for ; Tue, 14 Jan 2020 00:29:30 +0000 (UTC) X-FDA: 76374356100.21.base01_7021cf13b352c X-Spam-Summary: 2,0,0,3ee02c455410cda3,d41d8cd98f00b204,akpm@linux-foundation.org,:tj@kernel.org:cai@lca.pw:axboe@kernel.dk:wenyang@linux.alibaba.com:akpm@linux-foundation.org::mm-commits@vger.kernel.org:torvalds@linux-foundation.org,RULES_HIT:41:355:379:800:960:967:973:988:989:1260:1263:1345:1359:1381:1431:1437:1534:1541:1711:1714:1730:1747:1777:1792:2393:2525:2559:2563:2682:2685:2859:2902:2933:2937:2939:2942:2945:2947:2951:2954:3022:3138:3139:3140:3141:3142:3351:3865:3866:3867:3871:3934:3936:3938:3941:3944:3947:3950:3953:3956:3959:4321:5007:6261:6653:7576:8599:9025:9545:10004:10913:11026:11658:11914:12043:12048:12297:12438:12517:12519:12555:12679:12783:12986:13069:13311:13357:14181:14384:14721:14849:21080:21444:21451:21611:21627:21939:30054,0,RBL:error,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:2,LUA_SUMMARY:none X-HE-Tag: base01_7021cf13b352c X-Filterd-Recvd-Size: 2368 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf04.hostedemail.com (Postfix) with ESMTP for ; Tue, 14 Jan 2020 00:29:30 +0000 (UTC) Received: from akpm3.svl.corp.google.com (unknown [104.133.8.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 95BCA21569; Tue, 14 Jan 2020 00:29:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1578961769; bh=f8yY6WegJZkctIbvx5wZEFjWMk4weBxOYh7Mfh8gzd0=; h=Date:From:To:Subject:In-Reply-To:From; b=ynhqIfJcx+2U/27nZFGuiYPmT7QpJYOvtCvHsJc/e4JkRZmYlufboVka9H+TK9wr1 pE1n1ORxDQZ+ehf4pSA+4AaCHpxkLN0iuZj3GP4lfoF+tmDyAFBZQvdl1eOFsVA+06 lJjfgc9I44+04FaCursk9nIrusA5X4liZdllh4ps= Date: Mon, 13 Jan 2020 16:29:29 -0800 From: Andrew Morton To: tj@kernel.org, cai@lca.pw, axboe@kernel.dk, wenyang@linux.alibaba.com, akpm@linux-foundation.org, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org Subject: [patch 09/11] mm/page-writeback.c: improve arithmetic divisions Message-ID: <20200114002929.P5URA%akpm@linux-foundation.org> In-Reply-To: <20200113162831.f7d69e11e9e673c40005c9b0@linux-foundation.org> User-Agent: s-nail v14.9.15 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: From: Wen Yang Subject: mm/page-writeback.c: improve arithmetic divisions Use div64_ul() instead of do_div() if the divisor is unsigned long, to avoid truncation to 32-bit on 64-bit platforms. Link: http://lkml.kernel.org/r/20200102081442.8273-4-wenyang@linux.alibaba.com Signed-off-by: Wen Yang Reviewed-by: Andrew Morton Cc: Qian Cai Cc: Tejun Heo Cc: Jens Axboe Signed-off-by: Andrew Morton --- mm/page-writeback.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/page-writeback.c~mm-page-writebackc-improve-arithmetic-divisions +++ a/mm/page-writeback.c @@ -1102,7 +1102,7 @@ static void wb_update_write_bandwidth(st 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; }