From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bart Van Assche Subject: Re: [PATCH 2/2] IB/iser: set max_segment_size Date: Tue, 12 Apr 2016 11:13:52 -0700 Message-ID: <570D3AE0.4040104@sandisk.com> References: <1460470405-11673-1-git-send-email-hch@lst.de> <1460470405-11673-3-git-send-email-hch@lst.de> <570D156B.7010206@sandisk.com> <20160412165130.GB9568@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160412165130.GB9568-jcswGhMUV9g@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Christoph Hellwig Cc: "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-rdma@vger.kernel.org On 04/12/2016 09:51 AM, Christoph Hellwig wrote: > On Tue, Apr 12, 2016 at 08:34:03AM -0700, Bart Van Assche wrote: >> ib_sg_to_pages() can handle segments that are larger than mr->page_size. > > The interface handles it fine, but we'll still end up using a segment > per (MR) page. > >> Have you considered to set queue_limits.max_hw_sectors instead of >> max_segment_size? > > That's what NVMe does, but I don't think it's a good idea. Because > of the unaligned start into the page this means you have to set the limit > to one lower than the actual hardware limit. I think this means that there is a mismatch between the current block layer limits and what NVMe / RDMA drivers need ... Bart. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html