From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: Date: Fri, 14 Apr 2017 10:13:05 -0700 From: Omar Sandoval To: Bart Van Assche Cc: "hare@suse.com" , "linux-block@vger.kernel.org" , "osandov@fb.com" , "axboe@kernel.dk" Subject: Re: [PATCH 1/6] blk-mq: Do not invoke queue operations on a dead queue Message-ID: <20170414171305.GA28522@vader.dhcp.thefacebook.com> References: <20170411205842.28137-1-bart.vanassche@sandisk.com> <20170411205842.28137-2-bart.vanassche@sandisk.com> <20170413230102.GA1550@vader.DHCP.thefacebook.com> <1492124731.2723.1.camel@sandisk.com> <20170414074023.GA24673@vader> <1492186320.2644.7.camel@sandisk.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1492186320.2644.7.camel@sandisk.com> List-ID: On Fri, Apr 14, 2017 at 04:12:01PM +0000, Bart Van Assche wrote: > On Fri, 2017-04-14 at 00:40 -0700, Omar Sandoval wrote: > > On Thu, Apr 13, 2017 at 11:05:32PM +0000, Bart Van Assche wrote: > > > On Thu, 2017-04-13 at 16:01 -0700, Omar Sandoval wrote: > > > > Looking at this, I think we have similar issues with most of the other > > > > debugfs files. Should we move the debugfs cleanup earlier? > > > > > > That's a good question. However, while I was debugging it was very convenient > > > to be able to access the queue state after it had reached the "dead" state. > > > Performing the cleanup earlier would be an alternative solution but would > > > make debugging a bit harder ... > > > > What useful information were you getting out of debugfs once the queue > > was already dead? Wasn't the interesting stuff freed at that point? > > Hello Omar, > > I'm currently chasing a stall of dm-rq + dm-mpath that occurs after the > queues below it have reached the "dead" state. I will look for another > way to obtain the information I need such that we can remove the block > layer queue debugfs information before these queues reach the "dead" > state. > > Bart. Thanks, Bart. In this case, the absence of the "mq" directory should tell you that the queue is dead. Will you move the cleanup in v2 or should I submit a separate patch?