On Sat, Jan 23, 2021 at 3:55 AM Mike Kravetz <mike.kravetz@xxxxxxxxxx> wrote:
>
> X-Gm-Spam: 0
> X-Gm-Phishy: 0
>
> Use new hugetlb specific HPageTemporary flag to replace the
> PageHugeTemporary() interfaces. PageHugeTemporary does contain
> a PageHuge() check. However, this interface is only used within
> hugetlb code where we know we are dealing with a hugetlb page.
> Therefore, the check can be eliminated.
>
> Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
> Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>
Reviewed-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
> ---
> include/linux/hugetlb.h | 6 ++++++
> mm/hugetlb.c | 36 +++++++-----------------------------
> 2 files changed, 13 insertions(+), 29 deletions(-)
>
> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> index cd1960541f2a..3c86c3a0e144 100644
> --- a/include/linux/hugetlb.h
> +++ b/include/linux/hugetlb.h
> @@ -483,10 +483,15 @@ unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
> * HPG_migratable - Set after a newly allocated page is added to the page
> * cache and/or page tables. Indicates the page is a candidate for
> * migration.
> + * HPG_temporary - - Set on a page that is temporarily allocated from the buddy
> + * allocator. Typically used for migration target pages when no pages
> + * are available in the pool. The hugetlb free page path will
> + * immediately free pages with this flag set to the buddy allocator.
> */
> enum hugetlb_page_flags {
> HPG_restore_reserve = 0,
> HPG_migratable,
> + HPG_temporary,
> __NR_HPAGEFLAGS,
> };
>
> @@ -530,6 +535,7 @@ static inline void ClearHPage##uname(struct page *page) \
> */
> HPAGEFLAG(RestoreReserve, restore_reserve)
> HPAGEFLAG(Migratable, migratable)
> +HPAGEFLAG(Temporary, temporary)
>
> #ifdef CONFIG_HUGETLB_PAGE
>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 4da1a29ac5e2..70ffa1027988 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -1353,28 +1353,6 @@ struct hstate *size_to_hstate(unsigned long size)
> return NULL;
> }
>
> -/*
> - * Internal hugetlb specific page flag. Do not use outside of the hugetlb
> - * code
> - */
> -static inline bool PageHugeTemporary(struct page *page)
> -{
> - if (!PageHuge(page))
> - return false;
> -
> - return (unsigned long)page[2].mapping == -1U;
> -}
> -
> -static inline void SetPageHugeTemporary(struct page *page)
> -{
> - page[2].mapping = (void *)-1U;
> -}
> -
> -static inline void ClearPageHugeTemporary(struct page *page)
> -{
> - page[2].mapping = NULL;
> -}
> -
> static void __free_huge_page(struct page *page)
> {
> /*
> @@ -1422,9 +1400,9 @@ static void __free_huge_page(struct page *page)
> if (restore_reserve)
> h->resv_huge_pages++;
>
> - if (PageHugeTemporary(page)) {
> + if (HPageTemporary(page)) {
> list_del(&page->lru);
> - ClearPageHugeTemporary(page);
> + ClearHPageTemporary(page);
> update_and_free_page(h, page);
> } else if (h->surplus_huge_pages_node[nid]) {
> /* remove the page from active list */
> @@ -1860,7 +1838,7 @@ static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask,
> * codeflow
> */
> if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
> - SetPageHugeTemporary(page);
> + SetHPageTemporary(page);
> spin_unlock(&hugetlb_lock);
> put_page(page);
> return NULL;
> @@ -1891,7 +1869,7 @@ static struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask,
> * We do not account these pages as surplus because they are only
> * temporary and will be released properly on the last reference
> */
> - SetPageHugeTemporary(page);
> + SetHPageTemporary(page);
>
> return page;
> }
> @@ -5612,12 +5590,12 @@ void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason)
> * here as well otherwise the global surplus count will not match
> * the per-node's.
> */
> - if (PageHugeTemporary(newpage)) {
> + if (HPageTemporary(newpage)) {
> int old_nid = page_to_nid(oldpage);
> int new_nid = page_to_nid(newpage);
>
> - SetPageHugeTemporary(oldpage);
> - ClearPageHugeTemporary(newpage);
> + SetHPageTemporary(oldpage);
> + ClearHPageTemporary(newpage);
>
> spin_lock(&hugetlb_lock);
> if (h->surplus_huge_pages_node[old_nid]) {
> --
> 2.29.2
>
