From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [PATCH block/for-4.0-fixes] writeback: add missing INITIAL_JIFFIES init in global_update_bandwidth() Date: Wed, 04 Mar 2015 08:31:51 -0700 Message-ID: <54F72567.3060406@kernel.dk> References: <20150304152243.GG3122@htj.duckdns.org> <20150304153050.GA1249@quack.suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: Wu Fengguang , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org To: Jan Kara , Tejun Heo Return-path: In-Reply-To: <20150304153050.GA1249@quack.suse.cz> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.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 -- 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