Message-ID: <20240607145247.GG791043@ziepe.ca>
Date: Fri, 7 Jun 2024 11:52:47 -0300
From: Jason Gunthorpe <jgg@...pe.ca>
To: David Ahern <dsahern@...nel.org>
Cc: Pavel Begunkov <asml.silence@...il.com>,
	Mina Almasry <almasrymina@...gle.com>,
	Christoph Hellwig <hch@...radead.org>, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org,
	linux-alpha@...r.kernel.org, linux-mips@...r.kernel.org,
	linux-parisc@...r.kernel.org, sparclinux@...r.kernel.org,
	linux-trace-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
	bpf@...r.kernel.org, linux-kselftest@...r.kernel.org,
	linux-media@...r.kernel.org, dri-devel@...ts.freedesktop.org,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Donald Hunter <donald.hunter@...il.com>,
	Jonathan Corbet <corbet@....net>,
	Richard Henderson <richard.henderson@...aro.org>,
	Ivan Kokshaysky <ink@...assic.park.msu.ru>,
	Matt Turner <mattst88@...il.com>,
	Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
	"James E.J. Bottomley" <James.Bottomley@...senpartnership.com>,
	Helge Deller <deller@....de>, Andreas Larsson <andreas@...sler.com>,
	Jesper Dangaard Brouer <hawk@...nel.org>,
	Ilias Apalodimas <ilias.apalodimas@...aro.org>,
	Steven Rostedt <rostedt@...dmis.org>,
	Masami Hiramatsu <mhiramat@...nel.org>,
	Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
	Arnd Bergmann <arnd@...db.de>, Alexei Starovoitov <ast@...nel.org>,
	Daniel Borkmann <daniel@...earbox.net>,
	Andrii Nakryiko <andrii@...nel.org>,
	Martin KaFai Lau <martin.lau@...ux.dev>,
	Eduard Zingerman <eddyz87@...il.com>, Song Liu <song@...nel.org>,
	Yonghong Song <yonghong.song@...ux.dev>,
	John Fastabend <john.fastabend@...il.com>,
	KP Singh <kpsingh@...nel.org>, Stanislav Fomichev <sdf@...gle.com>,
	Hao Luo <haoluo@...gle.com>, Jiri Olsa <jolsa@...nel.org>,
	Steffen Klassert <steffen.klassert@...unet.com>,
	Herbert Xu <herbert@...dor.apana.org.au>,
	Willem de Bruijn <willemdebruijn.kernel@...il.com>,
	Shuah Khan <shuah@...nel.org>,
	Sumit Semwal <sumit.semwal@...aro.org>,
	Christian König <christian.koenig@....com>,
	David Wei <dw@...idwei.uk>, Yunsheng Lin <linyunsheng@...wei.com>,
	Shailend Chand <shailend@...gle.com>,
	Harshitha Ramamurthy <hramamurthy@...gle.com>,
	Shakeel Butt <shakeel.butt@...ux.dev>,
	Jeroen de Borst <jeroendb@...gle.com>,
	Praveen Kaligineedi <pkaligineedi@...gle.com>
Subject: Re: [PATCH net-next v10 02/14] net: page_pool: create hooks for
 custom page providers

On Fri, Jun 07, 2024 at 08:27:29AM -0600, David Ahern wrote:
> On 6/7/24 7:42 AM, Pavel Begunkov wrote:
> > I haven't seen any arguments against from the (net) maintainers so
> > far. Nor I see any objection against callbacks from them (considering
> > that either option adds an if).
> 
> I have said before I do not understand why the dmabuf paradigm is not
> sufficient for both device memory and host memory. A less than ideal
> control path to put hostmem in a dmabuf wrapper vs extra checks and
> changes in the datapath. The former should always be preferred.

I think Pavel explained this - his project is principally to replace
the lifetime policy of pages in the data plane. He wants to change
when a page is considered available for re-allocation because
userspace may continue to use the page after the netstack thinks it is
done with it. It sounds like having a different source of the pages is
the less important part.

IMHO it seems to compose poorly if you can only use the io_uring
lifecycle model with io_uring registered memory, and not with DMABUF
memory registered through Mina's mechanism.

Jason

Powered by blists - more mailing lists