[PATCH v3 21/27] mm/hugetlb: Introduce huge version of special swap pte helpers
From: Peter Xu <peterx@redhat.com>
Date: 2021-05-27 20:23:46
Also in:
lkml
Subsystem:
hugetlb subsystem, memory management, the rest · Maintainers:
Muchun Song, Oscar Salvador, Andrew Morton, Linus Torvalds
This is to let hugetlbfs be prepared to also recognize swap special ptes just like uffd-wp special swap ptes. Reviewed-by: Mike Kravetz <redacted> Signed-off-by: Peter Xu <peterx@redhat.com> --- mm/hugetlb.c | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index b101c3af3ab5..c64dfd0a9883 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c@@ -133,6 +133,26 @@ static inline bool subpool_is_free(struct hugepage_subpool *spool) return true; } +/* + * These are sister versions of is_swap_pte() and pte_has_swap_entry(). We + * need standalone ones because huge_pte_none() is handled differently from + * pte_none(). For more information, please refer to comments above + * is_swap_pte() and pte_has_swap_entry(). + * + * Here we directly reuse the pte level of swap special ptes, for example, the + * pte_swp_uffd_wp_special(). It just stands for a huge page rather than a + * small page for hugetlbfs pages. + */ +static inline bool is_huge_swap_pte(pte_t pte) +{ + return !huge_pte_none(pte) && !pte_present(pte); +} + +static inline bool huge_pte_has_swap_entry(pte_t pte) +{ + return is_huge_swap_pte(pte) && !is_swap_special_pte(pte); +} + static inline void unlock_or_release_subpool(struct hugepage_subpool *spool, unsigned long irq_flags) {
@@ -4061,7 +4081,7 @@ bool is_hugetlb_entry_migration(pte_t pte) { swp_entry_t swp; - if (huge_pte_none(pte) || pte_present(pte)) + if (!huge_pte_has_swap_entry(pte)) return false; swp = pte_to_swp_entry(pte); if (is_migration_entry(swp))
@@ -4074,7 +4094,7 @@ static bool is_hugetlb_entry_hwpoisoned(pte_t pte) { swp_entry_t swp; - if (huge_pte_none(pte) || pte_present(pte)) + if (!huge_pte_has_swap_entry(pte)) return false; swp = pte_to_swp_entry(pte); if (is_hwpoison_entry(swp))
--
2.31.1