[PATCH net-next v8 0/9] Add support for providers with large rx buffer

Pavel Begunkov
2026-01-09T13:05:56Z

Note: it's net/ only bits and doesn't include changes, which shoulf be
merged separately and are posted separately. The full branch for
convenience is at [1], and the patch is here:

https://lore.kernel.org/io-uring/7486ab32e99be1f614b3ef8d0e9bc77015b173f7.1764265323.git.asml.silence@gmail.com

Many modern NICs support configurable receive buffer lengths, and zcrx and
memory providers can use buffers larger than 4K to improve performance. When
paired with hw-gro larger rx buffer sizes can drastically reduce the number
of buffers traversing the stack and save a lot of processing time. It also
allows to give to users larger contiguous chunks of data. The idea was first
floated around by Saeed during netdev conf 2024 and was asked about by a few
folks.

Single stream benchmarks showed up to ~30% CPU util improvement.
E.g. comparison for 4K vs 32K buffers using a 200Gbit NIC:

packets=23987040 (MB=2745098), rps=199559 (MB/s=22837)
CPU %usr %nice %sys %iowait %irq %soft %idle
0 1.53 0.00 27.78 2.72 1.31 66.45 0.22
packets=24078368 (MB=2755550), rps=200319 (MB/s=22924)
CPU %usr %nice %sys %iowait %irq %soft %idle
0 0.69 0.00 8.26 31.65 1.83 57.00 0.57

This series adds net infrastructure for memory providers configuring
the size and implements it for bnxt. It's an opt-in feature for drivers,
they should advertise support for the parameter in the qops and must check
if the hardware supports the given size. It's limited to memory providers
as it drastically simplifies implementation. It doesn't affect the fast
path zcrx uAPI, and the user exposed parameter is defined in zcrx terms,
which allows it to be flexible and adjusted in the future.

A liburing example can be found at [2]

full branch:
[1] https://github.com/isilence/linux.git zcrx/large-buffers-v8
Liburing example:
[2] https://github.com/isilence/liburing.git zcrx/rx-buf-len

---

The following changes since commit 9ace4753a5202b02191d54e9fdf7f9e3d02b85eb:

Linux 6.19-rc4 (2026-01-04 14:41:55 -0800)

are available in the Git repository at:

https://github.com/isilence/linux.git tags/net-queue-rx-buf-len-v8

for you to fetch changes up to 37f5abe6929963fc6086777056b59ecb034d0e19:

io_uring/zcrx: document area chunking parameter (2026-01-08 11:35:20 +0000)

v8: - Add stripped down qcfg
- Retain the page size across resets for bnxt

v7: - Add xa_destroy
- Rebase

v6: - Update docs and add a selftest

v5: https://lore.kernel.org/netdev/cover.1760440268.git.asml.silence@gmail.com/
- Remove all unnecessary bits like configuration via netlink, and
multi-stage queue configuration.

v4: https://lore.kernel.org/all/cover.1760364551.git.asml.silence@gmail.com/
- Update fbnic qops
- Propagate max buf len for hns3
- Use configured buf size in __bnxt_alloc_rx_netmem
- Minor stylistic changes
v3: https://lore.kernel.org/all/cover.1755499375.git.asml.silence@gmail.com/
- Rebased, excluded zcrx specific patches
- Set agg_size_fac to 1 on warning
v2: https://lore.kernel.org/all/cover.1754657711.git.asml.silence@gmail.com/
- Add MAX_PAGE_ORDER check on pp init
- Applied comments rewording
- Adjust pp.max_len based on order
- Patch up mlx5 queue callbacks after rebase
- Minor ->queue_mgmt_ops refactoring
- Rebased to account for both fill level and agg_size_fac
- Pass providers buf length in struct pp_memory_provider_params and
apply it in __netdev_queue_confi().
- Use ->supported_ring_params to validate drivers support of set
qcfg parameters.

Jakub Kicinski (2):
net: reduce indent of struct netdev_queue_mgmt_ops members
eth: bnxt: adjust the fill level of agg queues with larger buffers

Pavel Begunkov (7):
net: memzero mp params when closing a queue
net: add bare bone queue configs
net: pass queue rx page size from memory provider
eth: bnxt: store rx buffer size per queue
eth: bnxt: support qcfg provided rx page size
selftests: iou-zcrx: test large chunk sizes
io_uring/zcrx: document area chunking parameter

Documentation/networking/iou-zcrx.rst | 20 +++
drivers/net/ethernet/broadcom/bnxt/bnxt.c | 126 ++++++++++++++----
drivers/net/ethernet/broadcom/bnxt/bnxt.h | 2 +
drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c | 6 +-
drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.h | 2 +-
drivers/net/ethernet/google/gve/gve_main.c | 9 +-
.../net/ethernet/mellanox/mlx5/core/en_main.c | 10 +-
drivers/net/ethernet/meta/fbnic/fbnic_txrx.c | 8 +-
drivers/net/netdevsim/netdev.c | 7 +-
include/net/netdev_queues.h | 47 +++++--
include/net/netdev_rx_queue.h | 2 +
include/net/page_pool/types.h | 1 +
net/core/dev.c | 17 +++
net/core/netdev_rx_queue.c | 31 +++--
.../selftests/drivers/net/hw/iou-zcrx.c | 72 ++++++++--
.../selftests/drivers/net/hw/iou-zcrx.py | 37 +++++
16 files changed, 318 insertions(+), 79 deletions(-)

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2.52.0