Re: [LSF/MM/BPF TOPIC] 64k (or 16k) base page size on x86

[Kiryl Shutsemau]

On Thu, Feb 19, 2026 at 09:08:57AM -0800, Dave Hansen wrote:
> On 2/19/26 07:08, Kiryl Shutsemau wrote:
> >   - The order-0 page size cuts struct page overhead by a factor of 16. From
> >     ~1.6% of RAM to ~0.1%;
> ...
> But, it will mostly be getting better performance at the _cost_ of
> consuming more RAM, not saving RAM.

That's fair.

The problem with struct page memory consumption is that it is static and
cannot be reclaimed. You pay the struct page tax no matter what.

Page cache rounding overhead can be large, but a motivated userspace can
keep it under control by avoiding splitting a dataset into many small
files. And this memory is reclaimable.

-- 
  Kiryl Shutsemau / Kirill A. Shutemov