From: Stanislav Fomichev <sdf.kernel@gmail.com>
To: "Björn Töpel" <bjorn@kernel.org>
Cc: Magnus Karlsson <magnus.karlsson@intel.com>,
Maciej Fijalkowski <maciej.fijalkowski@intel.com>,
Stanislav Fomichev <sdf@fomichev.me>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@kernel.org>,
Jakub Kicinski <kuba@kernel.org>,
Paolo Abeni <pabeni@redhat.com>, Simon Horman <horms@kernel.org>,
Jonathan Corbet <corbet@lwn.net>,
Shuah Khan <skhan@linuxfoundation.org>,
Randy Dunlap <rdunlap@infradead.org>,
Alexander Duyck <alexanderduyck@fb.com>,
kernel-team@meta.com, Andrew Lunn <andrew+netdev@lunn.ch>,
Jesper Dangaard Brouer <hawk@kernel.org>,
Ilias Apalodimas <ilias.apalodimas@linaro.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
John Fastabend <john.fastabend@gmail.com>,
Pavel Begunkov <asml.silence@gmail.com>,
Jens Axboe <axboe@kernel.dk>,
Andrii Nakryiko <andrii@kernel.org>,
Eduard Zingerman <eddyz87@gmail.com>,
Kumar Kartikeya Dwivedi <memxor@gmail.com>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
Jiri Olsa <jolsa@kernel.org>,
Emil Tsalapatis <emil@etsalapatis.com>,
Ihor Solodrai <ihor.solodrai@linux.dev>,
netdev@vger.kernel.org, bpf@vger.kernel.org,
io-uring@vger.kernel.org,
"Mike Marciniszyn (Meta)" <mike.marciniszyn@gmail.com>,
Weiming Shi <bestswngs@gmail.com>,
Nikolay Aleksandrov <razor@blackwall.org>,
David Wei <dw@davidwei.uk>,
Alexander Lobakin <aleksander.lobakin@intel.com>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
Mina Almasry <almasrymina@google.com>
Subject: Re: [RFC net-next 04/15] net: Let memory providers set RX buffer headroom
Date: Mon, 5 Oct 2026 09:52:05 -0700 [thread overview]
Message-ID: <asPVkD_QwZtqVLs4@devvm7509.cco0.facebook.com> (raw)
In-Reply-To: <20261002190018.696925-5-bjorn@kernel.org>
On 10/02, Björn Töpel wrote:
> AF_XDP lets userspace choose a headroom in front of the packet data
> in each UMEM chunk, and the kernel adds XDP_PACKET_HEADROOM to it. A
> driver whose buffers come from an AF_XDP memory provider must put
> packets after this headroom. The driver sees only the page pool, so
> it has no generic way to learn the value, and nothing checks that
> the driver supports it.
>
> Add rx_headroom to the provider parameters and to the queue
> configuration. It is the full headroom, including
> XDP_PACKET_HEADROOM; zero means the driver default. Add
> QCFG_RX_HEADROOM. A provider that sets a headroom can only be
> installed on a queue that supports it; otherwise the install fails
> with -EOPNOTSUPP. The driver checks the value with the rest of the
> queue configuration.
>
> Signed-off-by: Björn Töpel <bjorn@kernel.org>
This is also a bit confusing to read on its own. Do we not need to
convert existing users? The next patch does not seem to use this new rx_headroom?
next prev parent reply other threads:[~2026-10-05 16:52 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-02 19:00 [RFC net-next 00/15] xsk: Zero copy through page-pool memory providers Björn Töpel
2026-10-02 19:00 ` [RFC net-next 01/15] xdp: Size zero-copy skb heads by their contents Björn Töpel
2026-10-02 19:00 ` [RFC net-next 02/15] eth: fbnic: Report the logical XDP RX queue Björn Töpel
2026-10-02 19:00 ` [RFC net-next 03/15] net: Add memory provider capabilities Björn Töpel
2026-10-03 4:13 ` Mina Almasry
2026-10-05 16:26 ` Stanislav Fomichev
2026-10-02 19:00 ` [RFC net-next 04/15] net: Let memory providers set RX buffer headroom Björn Töpel
2026-10-05 16:52 ` Stanislav Fomichev [this message]
2026-10-02 19:00 ` [RFC net-next 05/15] page_pool: Extend memory provider operations Björn Töpel
2026-10-05 16:51 ` Stanislav Fomichev
2026-10-02 19:00 ` [RFC net-next 06/15] xdp: Track non-page netmem in receive buffers Björn Töpel
2026-10-05 17:01 ` Stanislav Fomichev
2026-10-02 19:00 ` [RFC net-next 07/15] xsk: Keep the DMA mapping in the buffer pool Björn Töpel
2026-10-02 19:00 ` [RFC net-next 08/15] xsk: Handle a detached FILL ring in RX wakeup Björn Töpel
2026-10-02 19:00 ` [RFC net-next 09/15] xsk: Add a page-pool memory provider for UMEM Björn Töpel
2026-10-05 17:38 ` Stanislav Fomichev
2026-10-02 19:00 ` [RFC net-next 10/15] xsk: Add RX helpers for page-pool drivers Björn Töpel
2026-10-02 19:00 ` [RFC net-next 11/15] xdp: Copy provider buffers on pass and redirect Björn Töpel
2026-10-02 19:00 ` [RFC net-next 12/15] xsk: Receive provider UMEM without copying Björn Töpel
2026-10-02 19:00 ` [RFC net-next 13/15] eth: fbnic: Support AF_XDP zero-copy receive Björn Töpel
2026-10-05 17:51 ` Stanislav Fomichev
2026-10-02 19:00 ` [RFC net-next 14/15] eth: fbnic: Support AF_XDP zero-copy transmit Björn Töpel
2026-10-02 19:00 ` [RFC net-next 15/15] Documentation: xsk: Document page-pool zero copy Björn Töpel
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