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 08:38:21 -0700 Message-ID: <54F726ED.4010801@kernel.dk> References: <20150304152243.GG3122@htj.duckdns.org> <20150304153050.GA1249@quack.suse.cz> <54F72567.3060406@kernel.dk> <20150304153743.GH3122@htj.duckdns.org> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: Jan Kara , Wu Fengguang , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org To: Tejun Heo Return-path: In-Reply-To: <20150304153743.GH3122@htj.duckdns.org> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org On 03/04/2015 08:37 AM, Tejun Heo wrote: > Subject: writeback: add missing INITIAL_JIFFIES init in global_update_bandwidth() > > 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. > > Fixes: c42843f2f0bb ("writeback: introduce smoothed global dirty limit") > Signed-off-by: Tejun Heo > Acked-by: Jan Kara > Cc: Wu Fengguang > Cc: Jens Axboe > Cc: stable@vger.kernel.org > --- > Added the "fixes" tag. Jens, can you please route this one? Yup will do, thanks Tejun. -- 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