From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from zimbra.linbit.com (zimbra.linbit.com [212.69.161.123]) by mail09.linbit.com (LINBIT Mail Daemon) with ESMTP id 0E2F01005425 for ; Wed, 30 May 2012 10:41:11 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by zimbra.linbit.com (Postfix) with ESMTP id CD2B61B435E for ; Wed, 30 May 2012 10:41:10 +0200 (CEST) Received: from zimbra.linbit.com ([127.0.0.1]) by localhost (zimbra.linbit.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 4WwxhITEuDrC for ; Wed, 30 May 2012 10:41:10 +0200 (CEST) Received: from soda.linbit (tuerlsteher.linbit.com [86.59.100.100]) by zimbra.linbit.com (Postfix) with ESMTP id 660671B435D for ; Wed, 30 May 2012 10:41:10 +0200 (CEST) Resent-Message-ID: <20120530084110.GS4141@soda.linbit> Received: from ipmail06.adl6.internode.on.net (ipmail06.adl6.internode.on.net [150.101.137.145]) by mail09.linbit.com (LINBIT Mail Daemon) with ESMTP id 456101019A78 for ; Tue, 29 May 2012 04:08:18 +0200 (CEST) Date: Tue, 29 May 2012 12:08:15 +1000 From: Dave Chinner To: Tejun Heo 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 Content-Disposition: inline In-Reply-To: <20120528230208.GA20954@dhcp-172-17-108-109.mtv.corp.google.com> Cc: axboe@kernel.dk, dm-devel@redhat.com, Mike Snitzer , Kent Overstreet , Dave Chinner , linux-kernel@vger.kernel.org, "Martin K. Petersen" , linux-bcache@vger.kernel.org, tytso@google.com, Mikulas Patocka , vgoyal@redhat.com, bharrosh@panasas.com, linux-fsdevel@vger.kernel.org, yehuda@hq.newdream.net, drbd-dev@lists.linbit.com, Alasdair G Kergon , sage@newdream.net Subject: Re: [Drbd-dev] [PATCH v3 14/16] Gut bio_add_page() List-Id: Coordination of development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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@fromorbit.com