From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lars Ellenberg Subject: Re: [PATCH 0/3] offload bios to a thread Date: Mon, 4 Jul 2016 10:09:36 +0200 Message-ID: <20160704080935.GM3239@soda.linbit> References: <20160630194023.GA21338@redhat.com> <20160630231518.GA22518@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20160630231518.GA22518@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Mike Snitzer Cc: axboe@kernel.dk, linux-block@vger.kernel.org, dm-devel@redhat.com, Mikulas Patocka , Zdenek Kabelac , "Alasdair G. Kergon" , Roland Kammerer List-Id: dm-devel.ids On Thu, Jun 30, 2016 at 07:15:18PM -0400, Mike Snitzer wrote: > > Lars, please feel free to see if this set addresses the similar deadlock > > you saw/fixed with drbd. I'm pretty sure it will help, but will confirm. > > We need to converge on an acceptable fix for > > this problem -- preferably sooner rather than later! > > > > Conversely, Mikulas: if you can easily reproduce the dm-snapshot > > deadlock please try Lars' fix to see if it is workable for our DM needs. > > I hadn't reviewed Lars' patch yet but Mikulas pointed out to me that > Lars' patch is focused on the blk_queue_split() path -- and given that > DM doesn't use this function (nor do DM devices even have a 'bio_split' > bioset, see commit dbba42d8a9e) it won't fix the DM (snapshot) deadlock. Don't you get it implicitly when using dm-mq -> blk-mq? Lars From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Mon, 4 Jul 2016 10:09:36 +0200 From: Lars Ellenberg To: Mike Snitzer Cc: Mikulas Patocka , axboe@kernel.dk, linux-block@vger.kernel.org, dm-devel@redhat.com, Roland Kammerer , "Alasdair G. Kergon" , Zdenek Kabelac Subject: Re: [PATCH 0/3] offload bios to a thread Message-ID: <20160704080935.GM3239@soda.linbit> References: <20160630194023.GA21338@redhat.com> <20160630231518.GA22518@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20160630231518.GA22518@redhat.com> List-ID: On Thu, Jun 30, 2016 at 07:15:18PM -0400, Mike Snitzer wrote: > > Lars, please feel free to see if this set addresses the similar deadlock > > you saw/fixed with drbd. I'm pretty sure it will help, but will confirm. > > We need to converge on an acceptable fix for > > this problem -- preferably sooner rather than later! > > > > Conversely, Mikulas: if you can easily reproduce the dm-snapshot > > deadlock please try Lars' fix to see if it is workable for our DM needs. > > I hadn't reviewed Lars' patch yet but Mikulas pointed out to me that > Lars' patch is focused on the blk_queue_split() path -- and given that > DM doesn't use this function (nor do DM devices even have a 'bio_split' > bioset, see commit dbba42d8a9e) it won't fix the DM (snapshot) deadlock. Don't you get it implicitly when using dm-mq -> blk-mq? Lars