From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Chinner Subject: Re: [PATCH v3 14/16] Gut bio_add_page() Date: Tue, 29 May 2012 12:08:15 +1000 Message-ID: <20120529020815.GB5091@dastard> References: <1337977539-16977-1-git-send-email-koverstreet@google.com> <1337977539-16977-15-git-send-email-koverstreet@google.com> <20120525204651.GA24246@redhat.com> <20120525210944.GB14196@google.com> <20120525223937.GF5761@agk-dp.fab.redhat.com> <20120528202839.GA18537@dhcp-172-17-108-109.mtv.corp.google.com> <20120528213839.GB18537@dhcp-172-17-108-109.mtv.corp.google.com> <20120528230208.GA20954@dhcp-172-17-108-109.mtv.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Mikulas Patocka , Alasdair G Kergon , Kent Overstreet , Mike Snitzer , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org, yehuda-L5o5AL9CYN0tUFlbccrkMA@public.gmane.org, vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, bharrosh-C4P08NqkoRlBDgjK7y7TUQ@public.gmane.org, sage-BnTBU8nroG7k1uMJSBkQmQ@public.gmane.org, drbd-dev-cunTk1MwBs8qoQakbn7OcQ@public.gmane.org, Dave Chinner , tytso-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, "Martin K. Petersen" To: Tejun Heo Return-path: Content-Disposition: inline In-Reply-To: <20120528230208.GA20954-RcKxWJ4Cfj1J2suj2OqeGauc2jM2gXBXkQQo+JxHRPFibQn6LdNjmg@public.gmane.org> Sender: linux-bcache-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-fsdevel.vger.kernel.org On Tue, May 29, 2012 at 08:02:08AM +0900, Tejun Heo wrote: > (cc'ing Martin K. Petersen, hi!) > > On Tue, May 29, 2012 at 06:38:39AM +0900, Tejun Heo wrote: > > > With this patchset, you don't have to expose all the limits. You can > > > expose just a few most useful limits to avoid bio split in the cases > > > described above. > > > > Yeah, if that actually helps, sure. From what I read, dm is already > > (ab)using merge_bvec_fn() like that anyway. > > i thought a bit more about it and the only thing which makes sense to > me is exposing the stripe granularity for striped devices - > ie. something which says "if you go across this boundary, the > performance characteristics including latency might get affected", > which should fit nicely with the rest of topology information. > Martin, adding that shouldn't be difficult, right? We already have the optimal IO size/alignment field in the topology. Doesn't this fit what you want exactly? Cheers, Dave. -- Dave Chinner david-FqsqvQoI3Ljby3iVrkZq2A@public.gmane.org