From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sagi Grimberg Subject: Re: [PATCH v1 01/24] IB/core: Introduce new fast registration API Date: Tue, 29 Sep 2015 09:42:36 +0300 Message-ID: <560A32DC.4040808@mellanox.com> References: <1442482947-27785-1-git-send-email-sagig@mellanox.com> <1442482947-27785-2-git-send-email-sagig@mellanox.com> <5601C65F.8060403@sandisk.com> <5603A841.70509@dev.mellanox.co.il> <5609A9D0.8030607@sandisk.com> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5609A9D0.8030607-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org> Sender: linux-nfs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Bart Van Assche , Sagi Grimberg , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, "Nicholas A. Bellinger" List-Id: linux-rdma@vger.kernel.org On 9/28/2015 11:57 PM, Bart Van Assche wrote: > On 09/24/2015 12:37 AM, Sagi Grimberg wrote: >> On 9/23/2015 12:21 AM, Bart Van Assche wrote: >>> On 09/17/2015 02:42 AM, Sagi Grimberg wrote: >>>> + } else if (last_page_off + dma_len < mr->page_size) { >>>> + /* chunk this fragment with the last */ >>>> + last_end_dma_addr += dma_len; >>>> + last_page_off += dma_len; >>>> + mr->length += dma_len; >>>> + continue; >>> >>> Shouldn't this code update last_page_addr ? >> >> Actually I think it doesn't since it is only relevant for the else >> statement where we are passing the page_size boundary. > > Hello Sagi, > > Suppose that the following sg-list is passed to this function as { > offset, length } pairs and that this list has not been coalesced by the > DMA mapping code: [ { 0, page_size / 4 }, { page_size / 4, page_size / 4 > }, { 2 * page_size / 4, page_size / 2 } ]. I think the algorithm in > patch 01/24 will map the above sample sg-list onto two pages. Shouldn't > that sg-list be mapped onto one page instead ? It seems to... In order to get that correct we'd need to change the condition to (last_page_off + dma_len <= mr->page_size) I'll change for v2. Thanks. Sagi. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html