Re: [PATCH 6.18 129/398] net: bcmgenet: convert RX path to page_pool

[Karl Mehltretter <kmehltretter@gmail.com>]

I have a small objection to taking patch 129 into 6.18.y only as a
dependency for patch 130.

My LLM agent helped me running these tests.

On a 64 KiB arm64 kernel in a custom QEMU Pi 400 model with functional
GENET v5 DMA, patch 129 increased the socket receive-memory charge per
512-byte UDP datagram from 2,752 to 65,792 bytes.

With the same 512 KiB socket receive-buffer limit, this reduced the number
of queued datagrams from 190 to 7 and increased socket receive-buffer drops
from 810 to 993 per 1,000 datagrams. I obtained the same result in five
bursts.

The page-pool conversion otherwise worked in this test, and physical Pi 400
testing with 4 KiB pages found no correctness failure. However, patch 130
was also verified on the Pi 400 to work without patch 129 after a small
contextual adaptation.

I would appreciate the BCMGENET maintainers' view on whether this page-pool
conversion is appropriate for 6.18.y.

Please consider omitting patch 129 from 6.18.y and applying that adapted
version of patch 130 directly.

Full test details and logs are available if useful.

Thanks,
Karl