On Mon, Apr 13, 2026 at 11:05:40AM +0200, David Hildenbrand (Arm) wrote: ...
> (2) Use a dedicated allocation interface for user pages in the buddy. > > I hate the whole user_alloc_needs_zeroing()+folio_zero_user() handling. > > It shouldn't exist. We should just be passing GFP_ZERO and let the buddy > handle > all that. > > > For example, vma_alloc_folio() already gets passed the address in. > > Pass the address from vma_alloc_folio_noprof()->folio_alloc_noprof(), and let > folio_alloc_noprof() use a buddy interface that can handle it. > > Imagine if we had a alloc_user_pages_noprof() that consumes an address. It > could just > do what folio_zero_user() does, and only if really required. > > The whole user_alloc_needs_zeroing() could go away and you could just handle > the > pre-zeroed optimization internally. I looked at this a bit, and I think the issue is that the buddy allocator doesn't do the arch-specific cache handling. So allocating it is a fundamentally different thing from GFP_ZERO which is "zero a kernel address range". So I don't get how you want to do it. > > -- > Cheers, > > David
