diff options
Diffstat (limited to 'include/linux/mm.h')
-rw-r--r-- | include/linux/mm.h | 85 |
1 files changed, 62 insertions, 23 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 3950ef45b9a9..a904c2d60f12 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -818,8 +818,8 @@ static inline int is_vmalloc_or_module_addr(const void *x) /* * How many times the entire folio is mapped as a single unit (eg by a * PMD or PUD entry). This is probably not what you want, except for - * debugging purposes; look at folio_mapcount() or page_mapcount() - * instead. + * debugging purposes - it does not include PTE-mapped sub-pages; look + * at folio_mapcount() or page_mapcount() or total_mapcount() instead. */ static inline int folio_entire_mapcount(struct folio *folio) { @@ -829,12 +829,20 @@ static inline int folio_entire_mapcount(struct folio *folio) /* * Mapcount of compound page as a whole, does not include mapped sub-pages. - * - * Must be called only for compound pages. + * Must be called only on head of compound page. */ -static inline int compound_mapcount(struct page *page) +static inline int head_compound_mapcount(struct page *head) { - return folio_entire_mapcount(page_folio(page)); + return atomic_read(compound_mapcount_ptr(head)) + 1; +} + +/* + * Sum of mapcounts of sub-pages, 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)); } /* @@ -847,11 +855,9 @@ static inline void page_mapcount_reset(struct page *page) atomic_set(&(page)->_mapcount, -1); } -int __page_mapcount(struct page *page); - /* * Mapcount of 0-order page; when compound sub-page, includes - * compound_mapcount(). + * compound_mapcount of compound_head of page. * * Result is undefined for pages which cannot be mapped into userspace. * For example SLAB or special types of pages. See function page_has_type(). @@ -859,25 +865,61 @@ int __page_mapcount(struct page *page); */ static inline int page_mapcount(struct page *page) { - if (unlikely(PageCompound(page))) - return __page_mapcount(page); - return atomic_read(&page->_mapcount) + 1; -} + int mapcount = atomic_read(&page->_mapcount) + 1; -int folio_mapcount(struct folio *folio); + if (likely(!PageCompound(page))) + return mapcount; + page = compound_head(page); + return head_compound_mapcount(page) + mapcount; +} -#ifdef CONFIG_TRANSPARENT_HUGEPAGE static inline int total_mapcount(struct page *page) { - return folio_mapcount(page_folio(page)); + if (likely(!PageCompound(page))) + return atomic_read(&page->_mapcount) + 1; + page = compound_head(page); + return head_compound_mapcount(page) + head_subpages_mapcount(page); } -#else -static inline int total_mapcount(struct page *page) +/* + * Return true if this page is mapped into pagetables. + * For compound page it returns true if any subpage of compound page is mapped, + * even if this particular subpage is not itself mapped by any PTE or PMD. + */ +static inline bool page_mapped(struct page *page) { - return page_mapcount(page); + return total_mapcount(page) > 0; +} + +/** + * folio_mapcount() - Calculate the number of mappings of this folio. + * @folio: The folio. + * + * A large folio tracks both how many times the entire folio is mapped, + * and how many times each individual page in the folio is mapped. + * This function calculates the total number of times the folio is + * mapped. + * + * Return: The number of times this folio is mapped. + */ +static inline int folio_mapcount(struct folio *folio) +{ + if (likely(!folio_test_large(folio))) + return atomic_read(&folio->_mapcount) + 1; + return atomic_read(folio_mapcount_ptr(folio)) + 1 + + atomic_read(folio_subpages_mapcount_ptr(folio)); +} + +/** + * folio_mapped - Is this folio mapped into userspace? + * @folio: The folio. + * + * Return: True if any page in this folio is referenced by user page tables. + */ +static inline bool folio_mapped(struct folio *folio) +{ + return folio_mapcount(folio) > 0; } -#endif static inline struct page *virt_to_head_page(const void *x) { @@ -1800,9 +1842,6 @@ static inline pgoff_t page_index(struct page *page) return page->index; } -bool page_mapped(struct page *page); -bool folio_mapped(struct folio *folio); - /* * Return true only if the page has been allocated with * ALLOC_NO_WATERMARKS and the low watermark was not |