From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesper Dangaard Brouer Subject: Re: [PATCH v7 net-next 5/5] net: ethernet: ti: cpsw: add XDP support Date: Fri, 5 Jul 2019 10:36:42 +0200 Message-ID: <20190705103642.5489bc87@carbon> References: <20190704231406.27083-1-ivan.khoronzhuk@linaro.org> <20190704231406.27083-6-ivan.khoronzhuk@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190704231406.27083-6-ivan.khoronzhuk@linaro.org> Sender: linux-kernel-owner@vger.kernel.org To: Ivan Khoronzhuk Cc: grygorii.strashko@ti.com, davem@davemloft.net, ast@kernel.org, linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org, ilias.apalodimas@linaro.org, netdev@vger.kernel.org, daniel@iogearbox.net, jakub.kicinski@netronome.com, john.fastabend@gmail.com, brouer@redhat.com List-Id: linux-omap@vger.kernel.org On Fri, 5 Jul 2019 02:14:06 +0300 Ivan Khoronzhuk wrote: > Add XDP support based on rx page_pool allocator, one frame per page. > Page pool allocator is used with assumption that only one rx_handler > is running simultaneously. DMA map/unmap is reused from page pool > despite there is no need to map whole page. > > Due to specific of cpsw, the same TX/RX handler can be used by 2 > network devices, so special fields in buffer are added to identify > an interface the frame is destined to. Thus XDP works for both > interfaces, that allows to test xdp redirect between two interfaces > easily. Aslo, each rx queue have own page pools, but common for both ^^^^ Also > netdevs. > > XDP prog is common for all channels till appropriate changes are added > in XDP infrastructure. Also, once page_pool recycling becomes part of > skb netstack some simplifications can be added, like removing > page_pool_release_page() before skb receive. > > In order to keep rx_dev while redirect, that can be somehow used in > future, do flush in rx_handler, that allows to keep rx dev the same > while reidrect. It allows to conform with tracing rx_dev pointed ^^^^^^^^ redirect > by Jesper. > > Also, there is probability, that XDP generic code can be extended to > support multi ndev drivers like this one, using same rx queue for > several ndevs, based on switchdev for instance or else. In this case, > driver can be modified like exposed here: > https://lkml.org/lkml/2019/7/3/243 > > Signed-off-by: Ivan Khoronzhuk Acked-by: Jesper Dangaard Brouer I didn't spot any issues, but I don't have access to this hardware, so I've not tested it. -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer