From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Snitzer Subject: Re: [PATCH 0/6] Support DAX for device-mapper dm-linear devices Date: Tue, 14 Jun 2016 11:41:31 -0400 Message-ID: <20160614154131.GB25876@redhat.com> References: <1465856497-19698-1-git-send-email-toshi.kani@hpe.com> <1465861755.3504.185.camel@hpe.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Jeff Moyer Cc: "Kani, Toshimitsu" , "axboe@kernel.dk" , "linux-nvdimm@lists.01.org" , "linux-kernel@vger.kernel.org" , "linux-raid@vger.kernel.org" , "dm-devel@redhat.com" , "viro@zeniv.linux.org.uk" , "dan.j.williams@intel.com" , "ross.zwisler@linux.intel.com" , "agk@redhat.com" List-Id: linux-raid.ids On Tue, Jun 14 2016 at 9:50am -0400, Jeff Moyer wrote: > "Kani, Toshimitsu" writes: >=20 > >> I had dm-linear and md-raid0 support on my list of things to look = at, > >> did you have raid0 in your plans? > > > > Yes, I hope to extend further and raid0 is a good candidate. =A0=A0 >=20 > dm-flakey would allow more xfstests test cases to run. I'd say that'= s > more important than linear or raid0. ;-) Regardless of which target(s) grow DAX support the most pressing initia= l concern is getting the DM device stacking correct. And verifying that IO that cross pmem device boundaries are being properly split by DM core (via drivers/md/dm.c:__split_and_process_non_flush()'s call to max_io_len). My hope is to nail down the DM core and its dependencies in block etc. Doing so in terms of dm-linear doesn't seem like wasted effort considering you told me it'd be useful to have for pmem devices. =20 > Also, the next step in this work is to then decide how to determine o= n > what numa node an LBA resides. We had discussed this at a prior > plumbers conference, and I think the consensus was to use xattrs. > Toshi, do you also plan to do that work? How does the associated NUMA node relate to this? Does the DM requests_queue need to be setup to only allocate from the NUMA node the pmem device is attached to? I recently added support for this to DM. But there will likely be some code need to propagate the NUMA node id accordingly. Mike -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html