On 2022/4/15 12:18, Naoya Horiguchi wrote:
> From: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
>
> We know that HPageFreed pages should have page refcount 0, so
> get_page_unless_zero() always fails and returns 0. So explicitly separate
> the branch based on page state for minor optimization and better readability.
>
> Suggested-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
> Suggested-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
> Signed-off-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
> ---
> mm/hugetlb.c | 4 +++-
> mm/memory-failure.c | 4 +++-
> 2 files changed, 6 insertions(+), 2 deletions(-)
>
Thanks!
Reviewed-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index e38cbfdf3e61..3638f166e554 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -6786,7 +6786,9 @@ int get_hwpoison_huge_page(struct page *page, bool *hugetlb)
> spin_lock_irq(&hugetlb_lock);
> if (PageHeadHuge(page)) {
> *hugetlb = true;
> - if (HPageFreed(page) || HPageMigratable(page))
> + if (HPageFreed(page))
> + ret = 0;
> + else if (HPageMigratable(page))
> ret = get_page_unless_zero(page);
> else
> ret = -EBUSY;
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index 5e3ad640f5bb..661079a37f29 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1517,7 +1517,9 @@ int __get_huge_page_for_hwpoison(unsigned long pfn, int flags)
> if (flags & MF_COUNT_INCREASED) {
> ret = 1;
> count_increased = true;
> - } else if (HPageFreed(head) || HPageMigratable(head)) {
> + } else if (HPageFreed(head)) {
> + ret = 0;
> + } else if (HPageMigratable(head)) {
> ret = get_page_unless_zero(head);
> if (ret)
> count_increased = true;
>
