Re: [PATCH RFC v3 01/19] mm: thread user_addr through page allocator for cache-friendly zeroing

Michael S. Tsirkin
2026-04-24T18:37:01Z

On Fri, Apr 24, 2026 at 08:33:45PM +0200, David Hildenbrand (Arm) wrote:
> On 4/23/26 18:13, Michael S. Tsirkin wrote:
> > On Thu, Apr 23, 2026 at 05:54:26PM +0200, David Hildenbrand (Arm) wrote:
> >> On 4/23/26 16:46, Michael S. Tsirkin wrote:
> >>>
> >>> I just dislike it when things are non orthogonal.
> >>> People are used to: hugetlb = same perf as THP but more predictable at the cost
> >>> of being harder to use and using more resources.
> >>> Here, suddenly, we have an optimization but only for THP.
> >>
> >> Note that we also didn't care about user_alloc_needs_zeroing() with hugetlb so far.
> >
> >
> > You mean, that it stays because of the reserved pool?
>
> I meant, that if we are running with init_on_free or init_on_alloc, that we end
> up double-zeroing right now upstream. So nobody cared to optimize that part so far.

on the aliasing arches you mean? that double zeroing?

> --
> Cheers,
>
> David