Re: [PATCH mm-unstable 3/8] mm/hugetlb: convert dequeue_hugetlb_page_node functions to folios

Mike Kravetz
2023-01-06T23:58:20Z

On 01/03/23 21:00, Matthew Wilcox wrote:
> On Tue, Jan 03, 2023 at 01:13:35PM -0600, Sidhartha Kumar wrote:
> > +static struct folio *dequeue_hugetlb_folio_node_exact(struct hstate *h,
> > + int nid)
> > {
> > struct page *page;
> > + struct folio *folio;
> > bool pin = !!(current->flags & PF_MEMALLOC_PIN);
> >
> > lockdep_assert_held(&hugetlb_lock);
> > list_for_each_entry(page, &h->hugepage_freelists[nid], lru) {
> > - if (pin && !is_longterm_pinnable_page(page))
> > + folio = page_folio(page);
>
> I'd argue that you can pull folios directly off the hugepage_freelists.
> Since they're attached through the 'lru', you know they're not tail
> pages, because lru.prev aliases with compound_head.

Yes, then we can get rid of the local variable *page.

A quick grep shows only the routine __mem_cgroup_uncharge_list() does
this today.
--
Mike Kravetz