From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with ESMTP id 069D16B0089 for ; Thu, 18 Nov 2010 11:29:02 -0500 (EST) Subject: Re: [PATCH] writeback: prevent bandwidth calculation overflow From: Peter Zijlstra In-Reply-To: <20101118160652.GA19459@localhost> References: <20101118065725.GB8458@localhost> <4CE537BE.6090103@redhat.com> <20101118154408.GA18582@localhost> <1290096121.2109.1525.camel@laptop> <20101118160652.GA19459@localhost> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Date: Thu, 18 Nov 2010 17:29:00 +0100 Message-ID: <1290097740.2109.1527.camel@laptop> Mime-Version: 1.0 Sender: owner-linux-mm@kvack.org To: Wu Fengguang Cc: Rik van Riel , Andrew Morton , Jan Kara , "Li, Shaohua" , Christoph Hellwig , Dave Chinner , Theodore Ts'o , Chris Mason , Mel Gorman , KOSAKI Motohiro , linux-mm , "linux-fsdevel@vger.kernel.org" , LKML List-ID: On Fri, 2010-11-19 at 00:06 +0800, Wu Fengguang wrote: > On Fri, Nov 19, 2010 at 12:02:01AM +0800, Peter Zijlstra wrote: > > On Thu, 2010-11-18 at 23:44 +0800, Wu Fengguang wrote: > > > + pause =3D HZ * pages_dirtied / (bw + 1); > >=20 > > Shouldn't that be using something like div64_u64 ? >=20 > OK, but a dumb question: gcc cannot handle this implicitly? it could, but we chose not to implement the symbol it emits for these things so as to cause pain.. that was still assuming the world of 32bit computing was relevant and 64bit divides were expensive ;-) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org