diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/mm.h | 85 | ||||
| -rw-r--r-- | include/linux/mm_types.h | 21 | ||||
| -rw-r--r-- | include/linux/page-flags.h | 21 | ||||
| -rw-r--r-- | include/linux/rmap.h | 2 |
4 files changed, 82 insertions, 47 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 diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 44f1f8b6be02..44a1a699b5ad 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -142,6 +142,7 @@ struct page { unsigned char compound_dtor; unsigned char compound_order; atomic_t compound_mapcount; + atomic_t subpages_mapcount; atomic_t compound_pincount; #ifdef CONFIG_64BIT unsigned int compound_nr; /* 1 << compound_order */ @@ -270,7 +271,8 @@ struct page { * @_head_1: Points to the folio. Do not use. * @_folio_dtor: Which destructor to use for this folio. * @_folio_order: Do not use directly, call folio_order(). - * @_total_mapcount: Do not use directly, call folio_entire_mapcount(). + * @_compound_mapcount: Do not use directly, call folio_entire_mapcount(). + * @_subpages_mapcount: Do not use directly, call folio_mapcount(). * @_pincount: Do not use directly, call folio_maybe_dma_pinned(). * @_folio_nr_pages: Do not use directly, call folio_nr_pages(). * @_flags_2: For alignment. Do not use. @@ -323,7 +325,8 @@ struct folio { unsigned long _head_1; unsigned char _folio_dtor; unsigned char _folio_order; - atomic_t _total_mapcount; + atomic_t _compound_mapcount; + atomic_t _subpages_mapcount; atomic_t _pincount; #ifdef CONFIG_64BIT unsigned int _folio_nr_pages; @@ -365,7 +368,8 @@ FOLIO_MATCH(flags, _flags_1); FOLIO_MATCH(compound_head, _head_1); FOLIO_MATCH(compound_dtor, _folio_dtor); FOLIO_MATCH(compound_order, _folio_order); -FOLIO_MATCH(compound_mapcount, _total_mapcount); +FOLIO_MATCH(compound_mapcount, _compound_mapcount); +FOLIO_MATCH(subpages_mapcount, _subpages_mapcount); FOLIO_MATCH(compound_pincount, _pincount); #ifdef CONFIG_64BIT FOLIO_MATCH(compound_nr, _folio_nr_pages); @@ -388,11 +392,22 @@ static inline atomic_t *folio_mapcount_ptr(struct folio *folio) return &tail->compound_mapcount; } +static inline atomic_t *folio_subpages_mapcount_ptr(struct folio *folio) +{ + struct page *tail = &folio->page + 1; + return &tail->subpages_mapcount; +} + static inline atomic_t *compound_mapcount_ptr(struct page *page) { return &page[1].compound_mapcount; } +static inline atomic_t *subpages_mapcount_ptr(struct page *page) +{ + return &page[1].subpages_mapcount; +} + static inline atomic_t *compound_pincount_ptr(struct page *page) { return &page[1].compound_pincount; diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 0b0ae5084e60..e42c55a7e012 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -176,9 +176,6 @@ enum pageflags { /* SLOB */ PG_slob_free = PG_private, - /* Compound pages. Stored in first tail page's flags */ - PG_double_map = PG_workingset, - #ifdef CONFIG_MEMORY_FAILURE /* * Compound pages. Stored in first tail page's flags. @@ -874,29 +871,11 @@ static inline int PageTransTail(struct page *page) { return PageTail(page); } - -/* - * PageDoubleMap indicates that the compound page is mapped with PTEs as well - * as PMDs. - * - * This is required for optimization of rmap operations for THP: we can postpone - * per small page mapcount accounting (and its overhead from atomic operations) - * until the first PMD split. - * - * For the page PageDoubleMap means ->_mapcount in all sub-pages is offset up - * by one. This reference will go away with last compound_mapcount. - * - * See also __split_huge_pmd_locked() and page_remove_anon_compound_rmap(). - */ -PAGEFLAG(DoubleMap, double_map, PF_SECOND) - TESTSCFLAG(DoubleMap, double_map, PF_SECOND) #else TESTPAGEFLAG_FALSE(TransHuge, transhuge) TESTPAGEFLAG_FALSE(TransCompound, transcompound) TESTPAGEFLAG_FALSE(TransCompoundMap, transcompoundmap) TESTPAGEFLAG_FALSE(TransTail, transtail) -PAGEFLAG_FALSE(DoubleMap, double_map) - TESTSCFLAG_FALSE(DoubleMap, double_map) #endif #if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_TRANSPARENT_HUGEPAGE) diff --git a/include/linux/rmap.h b/include/linux/rmap.h index bd3504d11b15..1973649e8f93 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -206,6 +206,8 @@ void hugepage_add_new_anon_rmap(struct page *, struct vm_area_struct *, static inline void __page_dup_rmap(struct page *page, bool compound) { + if (!compound && PageCompound(page)) + atomic_inc(subpages_mapcount_ptr(compound_head(page))); atomic_inc(compound ? compound_mapcount_ptr(page) : &page->_mapcount); } |