diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/mm.h | 19 | ||||
| -rw-r--r-- | include/linux/rmap.h | 13 |
2 files changed, 22 insertions, 10 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 84fb91f6f56e..d33639be3db3 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -837,12 +837,21 @@ static inline int head_compound_mapcount(struct page *head) } /* + * If a 16GB hugetlb page were mapped by PTEs of all of its 4kB sub-pages, + * its subpages_mapcount would be 0x400000: choose the COMPOUND_MAPPED bit + * above that range, instead of 2*(PMD_SIZE/PAGE_SIZE). Hugetlb currently + * leaves subpages_mapcount at 0, but avoid surprise if it participates later. + */ +#define COMPOUND_MAPPED 0x800000 +#define SUBPAGES_MAPPED (COMPOUND_MAPPED - 1) + +/* * Number of sub-pages mapped by PTE, does not include compound mapcount. * Must be called only on head of compound page. */ static inline int head_subpages_mapcount(struct page *head) { - return atomic_read(subpages_mapcount_ptr(head)); + return atomic_read(subpages_mapcount_ptr(head)) & SUBPAGES_MAPPED; } /* @@ -902,8 +911,12 @@ static inline int total_mapcount(struct page *page) static inline bool folio_large_is_mapped(struct folio *folio) { - return atomic_read(folio_mapcount_ptr(folio)) + - atomic_read(folio_subpages_mapcount_ptr(folio)) >= 0; + /* + * Reading folio_mapcount_ptr() below could be omitted if hugetlb + * participated in incrementing subpages_mapcount when compound mapped. + */ + return atomic_read(folio_subpages_mapcount_ptr(folio)) > 0 || + atomic_read(folio_mapcount_ptr(folio)) >= 0; } /** diff --git a/include/linux/rmap.h b/include/linux/rmap.h index 5dadb9a3e010..bd3504d11b15 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -204,15 +204,14 @@ void hugepage_add_anon_rmap(struct page *, struct vm_area_struct *, void hugepage_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long address); -void page_dup_compound_rmap(struct page *page); +static inline void __page_dup_rmap(struct page *page, bool compound) +{ + atomic_inc(compound ? compound_mapcount_ptr(page) : &page->_mapcount); +} static inline void page_dup_file_rmap(struct page *page, bool compound) { - /* Is page being mapped by PTE? */ - if (likely(!compound)) - atomic_inc(&page->_mapcount); - else - page_dup_compound_rmap(page); + __page_dup_rmap(page, compound); } /** @@ -261,7 +260,7 @@ static inline int page_try_dup_anon_rmap(struct page *page, bool compound, * the page R/O into both processes. */ dup: - page_dup_file_rmap(page, compound); + __page_dup_rmap(page, compound); return 0; } |