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Mon, 12 May 2025 05:58:10 -0700 (PDT) Message-ID: Date: Mon, 12 May 2025 13:59:21 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC 00/19] Split netmem from struct page To: Byungchul Park , Mina Almasry Cc: willy@infradead.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel_team@skhynix.com, kuba@kernel.org, ilias.apalodimas@linaro.org, harry.yoo@oracle.com, hawk@kernel.org, akpm@linux-foundation.org, ast@kernel.org, daniel@iogearbox.net, davem@davemloft.net, john.fastabend@gmail.com, andrew+netdev@lunn.ch, edumazet@google.com, pabeni@redhat.com, vishal.moola@gmail.com References: <20250509115126.63190-1-byungchul@sk.com> <20250512123626.GB45370@system.software.com> Content-Language: en-US From: Pavel Begunkov In-Reply-To: <20250512123626.GB45370@system.software.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 5/12/25 13:36, Byungchul Park wrote: > On Fri, May 09, 2025 at 07:09:16AM -0700, Mina Almasry wrote: >> On Fri, May 9, 2025 at 4:51 AM Byungchul Park wrote: >>> >>> The MM subsystem is trying to reduce struct page to a single pointer. >>> The first step towards that is splitting struct page by its individual >>> users, as has already been done with folio and slab. This patchset does >>> that for netmem which is used for page pools. >>> >>> Matthew Wilcox tried and stopped the same work, you can see in: >>> >>> https://lore.kernel.org/linux-mm/20230111042214.907030-1-willy@infradead.org/ >>> >>> Mina Almasry already has done a lot fo prerequisite works by luck, he >>> said :). I stacked my patches on the top of his work e.i. netmem. >>> >>> I focused on removing the page pool members in struct page this time, >>> not moving the allocation code of page pool from net to mm. It can be >>> done later if needed. >>> >>> There are still a lot of works to do, to remove the dependency on struct >>> page in the network subsystem. I will continue to work on this after >>> this base patchset is merged. >>> >>> This patchset is based on mm tree's mm-unstable branch. >>> >> >> This series largely looks good to me, but a couple of things: >> >> - For deep changes like this to the page_pool, I think we need a >> before/after run to Jesper's currently out-of-tree benchmark to see >> any regressions: >> https://lore.kernel.org/netdev/20250309084118.3080950-1-almasrymina@google.com/ > > Sure. I will check it. > >> - Also please CC Pavel on iterations related to netmem/net_iov, they >> are reusing that in io_uring code for iouring rx rc as well. > > I will. Thank you. Mina, thanks for CC'ing. And since it's touching io_uring, future versions need to CC it as well. -- Pavel Begunkov