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[184.147.165.106]) by smtp.googlemail.com with ESMTPSA id w33sm9350850qth.34.2020.12.21.05.00.30 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 21 Dec 2020 05:00:30 -0800 (PST) Subject: Re: [PATCH v5 bpf-next 03/14] xdp: add xdp_shared_info data structure To: Jesper Dangaard Brouer Cc: Shay Agroskin , Lorenzo Bianconi , Saeed Mahameed , Lorenzo Bianconi , bpf@vger.kernel.org, netdev@vger.kernel.org, davem@davemloft.net, kuba@kernel.org, ast@kernel.org, daniel@iogearbox.net, sameehj@amazon.com, john.fastabend@gmail.com, dsahern@kernel.org, echaudro@redhat.com, jasowang@redhat.com References: <21d27f233e37b66c9ad4073dd09df5c2904112a4.1607349924.git.lorenzo@kernel.org> <5465830698257f18ae474877648f4a9fe2e1eefe.camel@kernel.org> <20201208110125.GC36228@lore-desk> <1b0a5b59-f7e6-78b3-93bd-2ea35274e783@mojatatu.com> <20201221100152.58fa6bd7@carbon> From: Jamal Hadi Salim Message-ID: Date: Mon, 21 Dec 2020 08:00:29 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.3 MIME-Version: 1.0 In-Reply-To: <20201221100152.58fa6bd7@carbon> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 2020-12-21 4:01 a.m., Jesper Dangaard Brouer wrote: > On Sat, 19 Dec 2020 10:30:57 -0500 >> Sorry to interject: >> Does it make sense to use it to store arbitrary metadata or a scratchpad >> in this space? Something equivalent to skb->cb which is lacking in >> XDP. > > Well, XDP have the data_meta area. But difficult to rely on because a > lot of driver don't implement it. And Saeed and I plan to use this > area and populate it with driver info from RX-descriptor. > What i was thinking is some scratch pad that i can write to within an XDP prog (not driver); example, in a prog array map the scratch pad is written by one program in the array and read by another later on. skb->cb allows for that. Unless you mean i can already write to some XDP data_meta area? cheers, jamal