Subject: Re: [RFC net-next] net: page_pool: cap alloc cache size and refill by pool ring size

From: Jakub Kicinski <[email-masked]>
Date: Thu, 26 Feb 2026 08:56:43 -0800

On Thu, 26 Feb 2026 17:28:55 +0200 Nimrod Oren wrote:
> On 25/02/2026 1:39, Jakub Kicinski wrote:
> > I'd simply change the defines based on PAGE_SIZE. The allocation batch
> > size has nothing to do with the ring size, it's just amortizing
> > allocations within a single NAPI cycle.  
> 
> Thanks, that sounds good to me.
> Do you think a formula like this would work?
> 
> #define PP_ALLOC_CACHE_REFILL ((64 * SZ_4K) / PAGE_SIZE)
> #define PP_ALLOC_CACHE_SIZE   (PP_ALLOC_CACHE_REFILL * 2)
> 
> It keeps both values constant in bytes across page sizes, ensuring a
> consistent memory footprint for pool alloc-caches regardless of a
> system's page size.

I like the clarity / obviousness of the if/elif/else list. 
No need to think what the result would be for a given page size. 
But up to you.