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

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Thu, Sep 24, 2026 at 08:58:39AM +0200, Karl Mehltretter wrote:
> 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.

But when you update to a newer release, that memory increase will
happen, right?  So why not fix the root problem upstream first?

Also, there is no context here in the email, please always include that
when replying.

thanks,

greg k-h