Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751409AbbEYPTg (ORCPT ); Mon, 25 May 2015 11:19:36 -0400 Received: from mail-wi0-f169.google.com ([209.85.212.169]:32832 "EHLO mail-wi0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751087AbbEYPTe (ORCPT ); Mon, 25 May 2015 11:19:34 -0400 MIME-Version: 1.0 In-Reply-To: <20150525150827.GA27012@lst.de> References: <1432318723-18829-1-git-send-email-mlin@kernel.org> <1432318723-18829-9-git-send-email-mlin@kernel.org> <20150525140413.GA26065@lst.de> <20150525150827.GA27012@lst.de> Date: Mon, 25 May 2015 18:19:33 +0300 Message-ID: Subject: Re: [PATCH v4 08/11] block: kill merge_bvec_fn() completely From: Ilya Dryomov To: Christoph Hellwig Cc: Ming Lin , "linux-kernel@vger.kernel.org" , Kent Overstreet , Jens Axboe , Dongsu Park , Lars Ellenberg , drbd-user@lists.linbit.com, Jiri Kosina , Yehuda Sadeh , Sage Weil , Alex Elder , Ceph Development , Alasdair Kergon , Mike Snitzer , dm-devel@redhat.com, Neil Brown , linux-raid@vger.kernel.org, "Martin K. Petersen" , Alex Elder Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1853 Lines: 37 On Mon, May 25, 2015 at 6:08 PM, Christoph Hellwig wrote: > On Mon, May 25, 2015 at 06:02:30PM +0300, Ilya Dryomov wrote: >> I'm not Alex, but yeah, we have all the clone/split machinery and so we >> can handle a spanning case just fine. I think rbd_merge_bvec() exists >> to make sure we don't have to do that unless it's really necessary - >> like when a single page gets submitted at an inconvenient offset. >> >> I have a patch that adds a blk_queue_chunk_sectors(object_size) call to >> rbd_init_disk() but I haven't had a chance to play with it yet. In any >> case, we should be fine with getting rid of rbd_merge_bvec(). If this >> ends up a per-driver patchset, I can make rbd_merge_bvec() -> >> blk_queue_chunk_sectors() a single patch and push it through >> ceph-client.git. > > Hmm, looks like the new blk_queue_split_bio ignore the chunk_sectors > value, another thing that needs updating. I forgot how many weird > merging hacks we had to add for nvme.. > > While I'd like to see per-driver patches we'd still need to merge > them together through the block tree. Note that with this series > there won't be any benefit of using blk_queue_chunk_sectors over just > doing the split in rbd. Maybe we can even remove it again and do > that work in the drivers in the future. OK, I'll drop it, especially if it's potentially on its way out. With the fancy striping support, which I'll hopefully get to sometime, the striping pattern will become much more complicated anyway, so relying on rbd doing bio splitting is right in the long run as well. Thanks, Ilya -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/