Re: [PATCH v2] mm/hugetlb: get rid of page_hstate()

From: Mike Kravetz
Date: Wed Jul 19 2023 - 19:03:35 EST


On 07/19/23 11:41, Sidhartha Kumar wrote:
> Converts the last page_hstate() user to use folio_hstate() so
> page_hstate() can be safely removed.
>
> Signed-off-by: Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx>
> ---
> v1->v2:
> -change (page - &folio->page) to folio_page_idx(folio, page)
> per Matthew Wilcox
>
> include/linux/hugetlb.h | 10 ----------
> mm/hugetlb.c | 6 +++---
> mm/page_isolation.c | 8 ++++----
> 3 files changed, 7 insertions(+), 17 deletions(-)

Thanks Sid and Matthew!

Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
--
Mike Kravetz

>
> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> index 9f4bac3df59e4..0a393bc02f25b 100644
> --- a/include/linux/hugetlb.h
> +++ b/include/linux/hugetlb.h
> @@ -841,11 +841,6 @@ static inline struct hstate *folio_hstate(struct folio *folio)
> return size_to_hstate(folio_size(folio));
> }
>
> -static inline struct hstate *page_hstate(struct page *page)
> -{
> - return folio_hstate(page_folio(page));
> -}
> -
> static inline unsigned hstate_index_to_shift(unsigned index)
> {
> return hstates[index].order + PAGE_SHIFT;
> @@ -1062,11 +1057,6 @@ static inline struct hstate *folio_hstate(struct folio *folio)
> return NULL;
> }
>
> -static inline struct hstate *page_hstate(struct page *page)
> -{
> - return NULL;
> -}
> -
> static inline struct hstate *size_to_hstate(unsigned long size)
> {
> return NULL;
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index e0028cbb86c09..154cc5b315727 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -1812,10 +1812,10 @@ static void free_hpage_workfn(struct work_struct *work)
> node = node->next;
> page->mapping = NULL;
> /*
> - * The VM_BUG_ON_PAGE(!PageHuge(page), page) in page_hstate()
> - * is going to trigger because a previous call to
> + * The VM_BUG_ON_FOLIO(!folio_test_hugetlb(folio), folio) in
> + * folio_hstate() is going to trigger because a previous call to
> * remove_hugetlb_folio() will call folio_set_compound_dtor
> - * (folio, NULL_COMPOUND_DTOR), so do not use page_hstate()
> + * (folio, NULL_COMPOUND_DTOR), so do not use folio_hstate()
> * directly.

Looks like the code was updated in a commit prior to this comment change.
Thanks for updating the comment!

> */
> h = size_to_hstate(page_size(page));
> diff --git a/mm/page_isolation.c b/mm/page_isolation.c
> index 6599cc965e216..bcf99ba747a05 100644
> --- a/mm/page_isolation.c
> +++ b/mm/page_isolation.c
> @@ -79,17 +79,17 @@ static struct page *has_unmovable_pages(unsigned long start_pfn, unsigned long e
> * handle each tail page individually in migration.
> */
> if (PageHuge(page) || PageTransCompound(page)) {
> - struct page *head = compound_head(page);
> + struct folio *folio = page_folio(page);
> unsigned int skip_pages;
>
> if (PageHuge(page)) {
> - if (!hugepage_migration_supported(page_hstate(head)))
> + if (!hugepage_migration_supported(folio_hstate(folio)))
> return page;
> - } else if (!PageLRU(head) && !__PageMovable(head)) {
> + } else if (!folio_test_lru(folio) && !__folio_test_movable(folio)) {
> return page;
> }
>
> - skip_pages = compound_nr(head) - (page - head);
> + skip_pages = folio_nr_pages(folio) - folio_page_idx(folio, page);
> pfn += skip_pages - 1;
> continue;
> }
> --
> 2.41.0
>