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

From: "Michael S. Tsirkin" <[email-masked]>
Date: Thu, 23 Apr 2026 12:13:03 -0400

On Thu, Apr 23, 2026 at 05:54:26PM +0200, David Hildenbrand (Arm) wrote:
> On 4/23/26 16:46, Michael S. Tsirkin wrote:
> > On Thu, Apr 23, 2026 at 04:13:50PM +0200, David Hildenbrand (Arm) wrote:
> >> But really, that hugetlb code is rather messy. I'd vote for leaving hugetlb
> >> alone on a v1, and focusing on non-hugetlb first.
> > 
> > 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?

> It's not that it cannot be done with hugetlb, it's just a question about how it
> can be done more cleanly; and that requires more work to clean the hugetlb part up.
> 
> Best done separately.
> 
> -- 
> Cheers,
> 
> David