Re: [PATCH] hugetlb: Convert alloc_buddy_hugetlb_folio to use a folio

[Matthew Wilcox <willy@infradead.org>]

On Wed, Apr 03, 2024 at 09:25:41AM +0200, Oscar Salvador wrote:
> On Wed, Apr 03, 2024 at 02:19:19PM +0800, Muchun Song wrote:
> > I think you mean this patch [1], right? With alloc_frozen_pages()
> > introduced, we could get rid of the trick from HugeTLB code.
> 
> Ah yes, that one, thanks.
> It would be nice, but having read the discussion I am kind of skeptical.
> 
> But maybe some to revisit.

I haven't given up on it.  It's just currently parked, awaiting more
cleanups, some of which I have scheduled for the next merge window.
Part of the memdesc project will involve not having refcounts for some
memdescs.  Slab, percpu and pagetable don't need them, for example.

I think hugetlb is being unnecessarily paranoid here, tbh.  Or maybe
this part is just badly structured; if we're allocating a hugetlb folio,
it should be fine for its refcount to be temporarily elevated by someone
else.  Not sure I can figure out what's going on in
alloc_and_dissolve_hugetlb_folio() though.