Received-SPF: pass (google.com: domain of linux-kernel+bounces-114737-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1;
Date: Sun, 24 Mar 2024 16:35:13 -0700
From: Christoph Hellwig <hch@infradead.org>
To: Mina Almasry <almasrymina@google.com>
Cc: Christoph Hellwig <hch@infradead.org>, David Wei <dw@davidwei.uk>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-doc@vger.kernel.org, linux-alpha@vger.kernel.org,
	linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org,
	sparclinux@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
	linux-arch@vger.kernel.org, bpf@vger.kernel.org,
	linux-kselftest@vger.kernel.org, linux-media@vger.kernel.org,
	dri-devel@lists.freedesktop.org,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Richard Henderson <richard.henderson@linaro.org>,
	Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
	Matt Turner <mattst88@gmail.com>,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	"James E.J. Bottomley" <James.Bottomley@hansenpartnership.com>,
	Helge Deller <deller@gmx.de>, Andreas Larsson <andreas@gaisler.com>,
	Jesper Dangaard Brouer <hawk@kernel.org>,
	Ilias Apalodimas <ilias.apalodimas@linaro.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Arnd Bergmann <arnd@arndb.de>, Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Martin KaFai Lau <martin.lau@linux.dev>,
	Eduard Zingerman <eddyz87@gmail.com>, Song Liu <song@kernel.org>,
	Yonghong Song <yonghong.song@linux.dev>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@kernel.org>, Stanislav Fomichev <sdf@google.com>,
	Hao Luo <haoluo@google.com>, Jiri Olsa <jolsa@kernel.org>,
	David Ahern <dsahern@kernel.org>,
	Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
	Shuah Khan <shuah@kernel.org>,
	Sumit Semwal <sumit.semwal@linaro.org>,
	Christian =?iso-8859-1?Q?K=F6nig?= <christian.koenig@amd.com>,
	Pavel Begunkov <asml.silence@gmail.com>,
	Jason Gunthorpe <jgg@ziepe.ca>,
	Yunsheng Lin <linyunsheng@huawei.com>,
	Shailend Chand <shailend@google.com>,
	Harshitha Ramamurthy <hramamurthy@google.com>,
	Jeroen de Borst <jeroendb@google.com>,
	Praveen Kaligineedi <pkaligineedi@google.com>
Subject: Re: [RFC PATCH net-next v6 02/15] net: page_pool: create hooks for
 custom page providers
Message-ID: <ZgC4sWfHFGTY9HzY@infradead.org>
References: <20240305020153.2787423-1-almasrymina@google.com>
 <20240305020153.2787423-3-almasrymina@google.com>
 <ZfegzB341oNc_Ocz@infradead.org>
 <b938514c-61cc-41e6-b592-1003b8deccae@davidwei.uk>
 <ZfjMopBl27-7asBc@infradead.org>
 <CAHS8izMT1Smz6UWu2uwAQRqgZPU7jTfS3GKiA_sDw9KLqoP-JA@mail.gmail.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <CAHS8izMT1Smz6UWu2uwAQRqgZPU7jTfS3GKiA_sDw9KLqoP-JA@mail.gmail.com>

On Fri, Mar 22, 2024 at 10:40:26AM -0700, Mina Almasry wrote:
> Hi Christoph,
> 
> Sorry for the late reply, I've been out for a few days.
> 
> On Mon, Mar 18, 2024 at 4:22 PM Christoph Hellwig <hch@infradead.org> wrote:
> >
> > On Sun, Mar 17, 2024 at 07:49:43PM -0700, David Wei wrote:
> > > I'm working on a similar proposal for zero copy Rx but to host memory
> > > and depend on this memory provider API.
> >
> > How do you need a different provider for that vs just udmabuf?
> >
> 
> This was discussed on the io_uring ZC RFC in one of the earliest RFCs.
> Here is a link to Pavel's response:
> 
> https://patchwork.kernel.org/project/netdevbpf/patch/20231106024413.2801438-6-almasrymina@google.com/#25589471

Undesirable is not a good argument.  We need one proper API that
different subsystems share for this use case (this is the same Feedback
I gave Keith for the similar block proposal btw, not picking on the net
folks here).

If dmabuf/udmabuf doesn't work for that we need to enhance or replace
it, but not come up with little subsystem specific side channels.