Re: [PATCH net-next] net: mana: Force full-page RX buffers for 4K page size on specific systems.

Simon Horman
2026-03-02T14:02:19Z

On Fri, Feb 27, 2026 at 02:15:12AM -0800, Dipayaan Roy wrote:
> On certain systems configured with 4K PAGE_SIZE, utilizing page_pool
> fragments for RX buffers results in a significant throughput regression.
> Profiling reveals that this regression correlates with high overhead in the
> fragment allocation and reference counting paths on these specific
> platforms, rendering the multi-buffer-per-page strategy counterproductive.
>
> To mitigate this, bypass the page_pool fragment path and force a single RX
> packet per page allocation when all the following conditions are met:
> 1. The system is configured with a 4K PAGE_SIZE.
> 2. A processor-specific quirk is detected via SMBIOS Type 4 data.
>
> This approach restores expected line-rate performance by ensuring
> predictable RX refill behavior on affected hardware.
>
> There is no behavioral change for systems using larger page sizes
> (16K/64K), or platforms where this processor-specific quirk do not
> apply.
>
> Signed-off-by: Dipayaan Roy <dipayanroy@linux.microsoft.com>

Reviewed-by: Simon Horman <horms@kernel.org>