From: Stanislav Fomichev <stfomichev@gmail•com>
To: Mina Almasry <almasrymina@google•com>
Cc: netdev@vger•kernel.org, linux-kernel@vger•kernel.org,
linux-doc@vger•kernel.org, virtualization@lists•linux.dev,
kvm@vger•kernel.org, linux-kselftest@vger•kernel.org,
"David S. Miller" <davem@davemloft•net>,
"Eric Dumazet" <edumazet@google•com>,
"Jakub Kicinski" <kuba@kernel•org>,
"Paolo Abeni" <pabeni@redhat•com>,
"Simon Horman" <horms@kernel•org>,
"Donald Hunter" <donald.hunter@gmail•com>,
"Jonathan Corbet" <corbet@lwn•net>,
"Andrew Lunn" <andrew+netdev@lunn•ch>,
"Jeroen de Borst" <jeroendb@google•com>,
"Praveen Kaligineedi" <pkaligineedi@google•com>,
"Shailend Chand" <shailend@google•com>,
"Kuniyuki Iwashima" <kuniyu@amazon•com>,
"Willem de Bruijn" <willemb@google•com>,
"David Ahern" <dsahern@kernel•org>,
"Neal Cardwell" <ncardwell@google•com>,
"Michael S. Tsirkin" <mst@redhat•com>,
"Jason Wang" <jasowang@redhat•com>,
"Xuan Zhuo" <xuanzhuo@linux•alibaba.com>,
"Eugenio Pérez" <eperezma@redhat•com>,
"Stefan Hajnoczi" <stefanha@redhat•com>,
"Stefano Garzarella" <sgarzare@redhat•com>,
"Shuah Khan" <shuah@kernel•org>,
sdf@fomichev•me, asml.silence@gmail•com, dw@davidwei•uk,
"Jamal Hadi Salim" <jhs@mojatatu•com>,
"Victor Nogueira" <victor@mojatatu•com>,
"Pedro Tammela" <pctammela@mojatatu•com>,
"Samiullah Khawaja" <skhawaja@google•com>
Subject: Re: [PATCH net-next v4 1/9] net: add get_netmem/put_netmem support
Date: Thu, 20 Feb 2025 11:34:02 -0800 [thread overview]
Message-ID: <Z7eDqnkwmpTW5963@mini-arch> (raw)
In-Reply-To: <20250220020914.895431-2-almasrymina@google.com>
On 02/20, Mina Almasry wrote:
> Currently net_iovs support only pp ref counts, and do not support a
> page ref equivalent.
>
> This is fine for the RX path as net_iovs are used exclusively with the
> pp and only pp refcounting is needed there. The TX path however does not
> use pp ref counts, thus, support for get_page/put_page equivalent is
> needed for netmem.
>
> Support get_netmem/put_netmem. Check the type of the netmem before
> passing it to page or net_iov specific code to obtain a page ref
> equivalent.
>
> For dmabuf net_iovs, we obtain a ref on the underlying binding. This
> ensures the entire binding doesn't disappear until all the net_iovs have
> been put_netmem'ed. We do not need to track the refcount of individual
> dmabuf net_iovs as we don't allocate/free them from a pool similar to
> what the buddy allocator does for pages.
>
> This code is written to be extensible by other net_iov implementers.
> get_netmem/put_netmem will check the type of the netmem and route it to
> the correct helper:
>
> pages -> [get|put]_page()
> dmabuf net_iovs -> net_devmem_[get|put]_net_iov()
> new net_iovs -> new helpers
>
> Signed-off-by: Mina Almasry <almasrymina@google•com>
Acked-by: Stanislav Fomichev <sdf@fomichev•me>
I remember you wanted to have more fine grained refcnt, but starting
with this is good enough for me.
next prev parent reply other threads:[~2025-02-20 19:34 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-20 2:09 [PATCH net-next v4 0/9] Device memory TCP TX Mina Almasry
2025-02-20 2:09 ` [PATCH net-next v4 1/9] net: add get_netmem/put_netmem support Mina Almasry
2025-02-20 19:34 ` Stanislav Fomichev [this message]
2025-02-20 2:09 ` [PATCH net-next v4 2/9] net: devmem: TCP tx netlink api Mina Almasry
2025-02-20 2:09 ` [PATCH net-next v4 3/9] net: devmem: Implement TX path Mina Almasry
2025-02-20 21:00 ` Stanislav Fomichev
2025-02-20 2:09 ` [PATCH net-next v4 4/9] net: devmem: make dmabuf unbinding scheduled work Mina Almasry
2025-02-20 21:00 ` Stanislav Fomichev
2025-02-20 2:09 ` [PATCH net-next v4 5/9] net: add devmem TCP TX documentation Mina Almasry
2025-02-20 8:13 ` Bagas Sanjaya
2025-02-20 21:04 ` Stanislav Fomichev
2025-02-20 2:09 ` [PATCH net-next v4 6/9] net: enable driver support for netmem TX Mina Almasry
2025-02-20 19:13 ` Stanislav Fomichev
2025-02-22 0:11 ` Mina Almasry
2025-02-22 0:35 ` Stanislav Fomichev
2025-02-20 2:09 ` [PATCH net-next v4 7/9] gve: add netmem TX support to GVE DQO-RDA mode Mina Almasry
2025-02-20 2:09 ` [PATCH net-next v4 8/9] net: check for driver support in netmem TX Mina Almasry
2025-02-20 21:05 ` Stanislav Fomichev
2025-02-20 2:09 ` [PATCH net-next v4 9/9] selftests: ncdevmem: Implement devmem TCP TX Mina Almasry
2025-02-20 19:09 ` Stanislav Fomichev
2025-02-20 20:01 ` Stanislav Fomichev
2025-02-22 0:08 ` Mina Almasry
2025-02-22 0:20 ` Stanislav Fomichev
2025-02-22 0:24 ` Mina Almasry
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