From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f52.google.com (mail-pa0-f52.google.com [209.85.220.52]) by kanga.kvack.org (Postfix) with ESMTP id 8C6326B0035 for ; Wed, 30 Apr 2014 17:01:01 -0400 (EDT) Received: by mail-pa0-f52.google.com with SMTP id kx10so2664588pab.39 for ; Wed, 30 Apr 2014 14:01:01 -0700 (PDT) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTP id fd9si18242170pad.60.2014.04.30.14.00.59 for ; Wed, 30 Apr 2014 14:01:00 -0700 (PDT) Date: Wed, 30 Apr 2014 14:00:57 -0700 From: Andrew Morton Subject: Re: [PATCH v5] mm,writeback: fix divide by zero in pos_ratio_polynom Message-Id: <20140430140057.7d2a6e984b2ec987182d2a4e@linux-foundation.org> In-Reply-To: <20140430164255.7a753a8e@cuia.bos.redhat.com> References: <20140429151910.53f740ef@annuminas.surriel.com> <5360C9E7.6010701@jp.fujitsu.com> <20140430093035.7e7226f2@annuminas.surriel.com> <20140430134826.GH4357@dhcp22.suse.cz> <20140430104114.4bdc588e@cuia.bos.redhat.com> <20140430120001.b4b95061ac7252a976b8a179@linux-foundation.org> <53614F3C.8020009@redhat.com> <20140430123526.bc6a229c1ea4addad1fb483d@linux-foundation.org> <20140430160218.442863e0@cuia.bos.redhat.com> <20140430131353.fa9f49604ea39425bc93c24a@linux-foundation.org> <20140430164255.7a753a8e@cuia.bos.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Rik van Riel Cc: Michal Hocko , Masayoshi Mizuma , linux-kernel@vger.kernel.org, linux-mm@kvack.org, sandeen@redhat.com, jweiner@redhat.com, kosaki.motohiro@jp.fujitsu.com, fengguang.wu@intel.com, mpatlasov@parallels.com, Motohiro.Kosaki@us.fujitsu.com On Wed, 30 Apr 2014 16:42:55 -0400 Rik van Riel wrote: > On Wed, 30 Apr 2014 13:13:53 -0700 > Andrew Morton wrote: > > > This was a consequence of 64->32 truncation and it can't happen any > > more, can it? > > Andrew, this is cleaner indeed :) I'm starting to get worried about 32-bit wraparound in the patch version number ;) > Masayoshi-san, does the bug still happen with this version, or does > this fix the problem? > We could put something like if (WARN_ON_ONCE(setpoint == limit)) setpoint--; in there if we're not sure. But it's better to be sure! -- 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/ . Don't email: email@kvack.org