From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759063AbbCDPb4 (ORCPT ); Wed, 4 Mar 2015 10:31:56 -0500 Received: from mail-ig0-f178.google.com ([209.85.213.178]:46391 "EHLO mail-ig0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758999AbbCDPbx (ORCPT ); Wed, 4 Mar 2015 10:31:53 -0500 Message-ID: <54F72567.3060406@kernel.dk> Date: Wed, 04 Mar 2015 08:31:51 -0700 From: Jens Axboe User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Jan Kara , Tejun Heo CC: Wu Fengguang , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH block/for-4.0-fixes] writeback: add missing INITIAL_JIFFIES init in global_update_bandwidth() References: <20150304152243.GG3122@htj.duckdns.org> <20150304153050.GA1249@quack.suse.cz> In-Reply-To: <20150304153050.GA1249@quack.suse.cz> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/04/2015 08:30 AM, Jan Kara wrote: > On Wed 04-03-15 10:22:43, Tejun Heo wrote: >> global_update_bandwidth() uses static variable update_time as the >> timestamp for the last update but forgets to initialize it to >> INITIALIZE_JIFFIES. >> >> This means that global_dirty_limit will be 5 mins into the future on >> 32bit and some large amount jiffies into the past on 64bit. This >> isn't critical as the only effect is that global_dirty_limit won't be >> updated for the first 5 mins after booting on 32bit machines, >> especially given the auxiliary nature of global_dirty_limit's role - >> protecting against global dirty threshold's sudden dips; however, it >> does lead to unintended suboptimal behavior. Fix it. > Looks good. You can add: > Reviewed-by: Jan Kara We should add that it fixes c42843f2f0bbc (from 2011!) as well. -- Jens Axboe