From b283d983a7a6ffe3939ff26f06d151331a7c1071 Mon Sep 17 00:00:00 2001 From: Naoya Horiguchi Date: Thu, 28 Apr 2022 23:16:02 -0700 Subject: [PATCH] mm, hugetlb, hwpoison: separate branch for free and in-use hugepage 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. Link: https://lkml.kernel.org/r/20220415041848.GA3034499@ik1-406-35019.vs.sakura.ne.jp Signed-off-by: Naoya Horiguchi Suggested-by: Mike Kravetz Suggested-by: Miaohe Lin Reviewed-by: Mike Kravetz Reviewed-by: Miaohe Lin Signed-off-by: Andrew Morton --- mm/hugetlb.c | 4 +++- mm/memory-failure.c | 4 +++- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 3fc7217..f8e048b 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -6776,7 +6776,9 @@ 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 e01a2da..9711c0e 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; -- 2.7.4