From mboxrd@z Thu Jan 1 00:00:00 1970 From: Or Gerlitz Subject: Re: [PATCH, RFC 0/5] IB: Optimize DMA mapping Date: Thu, 8 Dec 2016 08:48:16 +0200 Message-ID: References: <07c07529-4636-fafb-2598-7358d8a1460d@sandisk.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: In-Reply-To: <07c07529-4636-fafb-2598-7358d8a1460d-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Bart Van Assche Cc: Doug Ledford , Christoph Hellwig , Sagi Grimberg , "linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-rdma@vger.kernel.org On Thu, Dec 8, 2016 at 3:10 AM, Bart Van Assche wrote: > The DMA mapping operations are in the hot path so it is important that the > overhead of these operations is as low as possible. There has been a reason > in the past to have DMA mapping operations that are specific to the IB > subsystem but that reason no longer exists today. can you elaborate on that a little further... I recall it was something with the ipath and Co drivers and memory extensions on 32 bit systems? > An additional benefit is that the size of HW and SW > drivers that do not use DMA is reduced by switching to dma_noop_ops. few words on that? -- 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