net: page_pool: scale alloc cache with PAGE_SIZE

net: page_pool: scale alloc cache with PAGE_SIZE

The current page_pool alloc-cache size and refill values were chosen to
match the NAPI budget and to leave headroom for XDP_DROP recycling.
These fixed values do not scale well with large pages,
as they significantly increase a given page_pool's memory footprint.

Scale these values to better balance memory footprint across page sizes,
while keeping behavior on 4KB-page systems unchanged.

Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Nimrod Oren <noren@nvidia.com>
Link: https://patch.msgid.link/20260309081301.103152-1-noren@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>