From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [PATCH] writeback: prevent bandwidth calculation overflow Date: Thu, 18 Nov 2010 17:29:00 +0100 Message-ID: <1290097740.2109.1527.camel@laptop> References: <20101118065725.GB8458@localhost> <4CE537BE.6090103@redhat.com> <20101118154408.GA18582@localhost> <1290096121.2109.1525.camel@laptop> <20101118160652.GA19459@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable 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 To: Wu Fengguang Return-path: In-Reply-To: <20101118160652.GA19459@localhost> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org 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