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Miller" , Eric Dumazet , Paolo Abeni , Willem de Bruijn , David Ahern , Matthew Wilcox , Jens Axboe , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next v5 03/14] splice, net: Use sendmsg(MSG_SPLICE_PAGES) rather than ->sendpage() Message-ID: <20230607095541.586a3300@kernel.org> In-Reply-To: <20230607140559.2263470-4-dhowells@redhat.com> References: <20230607140559.2263470-1-dhowells@redhat.com> <20230607140559.2263470-4-dhowells@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 98931180017 X-Stat-Signature: 9j7p4gyz1gbqnazxfgqq1kerg5kgc5ks X-Rspam-User: X-HE-Tag: 1686156944-52340 X-HE-Meta: U2FsdGVkX19AK8U33K0d+fNCB6y7ME4ix9GCEhWk4LHCSMSG6fJ75Smc1SmKfe/1hEQdR012XyxnmOK+KGdmndfpGri/RpWDYkxZzDPP+mUIiNN3W3SFZZR1/UFgByxxoW79XYdQFmAKP/1TvHV484VeYk3NbQbTmmElTOQ81TlRkzEJbYfvz6r0bRvNMHCeTMMXUAapupe1s2uPZ4jUt5dEdSFO4IYI3Cu/ebPeOeu9gmK+IH284dZvoCUUd7sNhoWLk4i8eFdw2mWcT30VvJvw9k83LlVquCA/+3kve3ZjVbXJG1p7z5kzUZcxkowsUamc+F2Ak9Ay7QZeZSiVb1WMUpBpEB5iw2V12RMWJ84tGzcaM8117rg7UQZuegPF3ntZq84FZKTrgmbTHMtGeKSvRwZWQeWiZlTsV3QMm8dTkEHPpaawCGuoVmA9tOnuCGF+MwAhHcpKx+OgTn58emZ+zP7ay8SxmHnrXyg0/IAUmjcJUeGBINgzD5fNPSuLzrtZ1s+Q8uhHHX/moLP7ehgpjHYLMWW438bVIUzd7ApYY8W3avfV2PWiN99BRVulM2dNhQifCyj+3wopXjsse3YB1Wd5eUD3TLLZK6wTYOYTMLR/BTxG+sEETTN+zQwhYyHP3U2yfkGPVVHEMYs+TtqiyIdzKrgrlOMjuo/RSC91IhBRx+h3eLFfxhwH93LFt+YM6G6jr4LyPmoAOraSU+uhRWj7/2UiuKFFTxLHKZb3x7/4aNju4NaISDW/iichKW220thMWOn58Kjp/vfiDldReqAyLqCrlbmzWEWiMDsPUZw4LUt6LH1hxWRT3pl0/9FMJ0Q/2JzUvhYB76QPKQ1wR39ib9kzm2ugkD34aWFHEZNKzqZ6sSrFPJoJOltlBIJKHEwJGqEJhvqZn+tClElNXjdwNIp4pqxtrCTjW9YzJ5yDP8869a9hjBaZRds0lPjukMJjK0n4wV3/ydb /HE9jRjZ QoQMJJTlSBK3yBN5G3Bc8dUTjjCo50+qFEgjUeSHmE26f4god+TaePP6ZKi4S2J5l0ueHQhNLO4CzqwaVG/5xxkMdhQMrKPxP5lRh4kvS1kM1/w2B0DtbYKRay+A2syrhAJgclxMdt/to0hKZJIKAQnkVH4BeWL9hLa7qHJkw5zBDUQonhRKmRotVlfl1+IfrIjyFbFaufl0kII1zlHNNqCDbgHyVXq7lW6d9crsOf7T0S1hv0lzvGcnI6/C9Xqxv+JyKEJaFnpkbDE5K5J4n+r7UaG0Gnck15S5COfmVtw3uRSpSPQVttGkeT3YNLaWPm3TfDU5N2DQm6qlNWtncJU8BQeBt3uJWBD5CCYPv7vKrxIKkPLnYjG/HrlGF8NMtfbQlWbQqvZnQTZr+2ECSYEKf1IZf0AtHtaYp66LkUrvEeprTuhv7KputnUXse4k791xln8ZMSHy2PezYlJZYaAC97A== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, 7 Jun 2023 15:05:48 +0100 David Howells wrote: > Replace generic_splice_sendpage() + splice_from_pipe + pipe_to_sendpage() > with a net-specific handler, splice_to_socket(), that calls sendmsg() with > MSG_SPLICE_PAGES set instead of calling ->sendpage(). > > MSG_MORE is used to indicate if the sendmsg() is expected to be followed > with more data. > > This allows multiple pipe-buffer pages to be passed in a single call in a > BVEC iterator, allowing the processing to be pushed down to a loop in the > protocol driver. This helps pave the way for passing multipage folios down > too. > > Protocols that haven't been converted to handle MSG_SPLICE_PAGES yet should > just ignore it and do a normal sendmsg() for now - although that may be a > bit slower as it may copy everything. Reviewed-by: Jakub Kicinski