From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [RFC] writeback and cgroup Date: Thu, 5 Apr 2012 09:38:54 -0700 Message-ID: <20120405163854.GE12854__49209.9488074475$1333643953$gmane$org@google.com> References: <20120403183655.GA23106@dhcp-172-17-108-109.mtv.corp.google.com> <20120404145134.GC12676@redhat.com> <20120404184909.GB29686@dhcp-172-17-108-109.mtv.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20120404184909.GB29686-RcKxWJ4Cfj1J2suj2OqeGauc2jM2gXBXkQQo+JxHRPFibQn6LdNjmg@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Vivek Goyal Cc: Jens Axboe , ctalbott-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, Jan Kara , rni-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, andrea-oIIqvOZpAevzfdHfmsDf5w@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, sjayaraman-IBi9RG/b67k@public.gmane.org, lsf-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, jmoyer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Fengguang Wu List-Id: containers.vger.kernel.org Hey, Vivek. On Wed, Apr 04, 2012 at 11:49:09AM -0700, Tejun Heo wrote: > > I am not sure what are you trying to say here. But primarily blk-throttle > > will throttle read and direct IO. Buffered writes will go to root cgroup > > which is typically unthrottled. > > Ooh, my bad then. Anyways, then the same applies to blk-throttle. > Our current implementation essentially collapses at the face of > write-heavy workload. I went through the code and couldn't find where blk-throttle is discriminating async IOs. Were you saying that blk-throttle currently doesn't throttle because those IOs aren't associated with the dirtying task? If so, note that it's different from cfq which explicitly assigns all async IOs when choosing cfqq even if we fix tagging. Thanks. -- tejun