diff options
Diffstat (limited to 'include/linux/page-flags.h')
| -rw-r--r-- | include/linux/page-flags.h | 171 |
1 files changed, 110 insertions, 61 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 5bd9492a66ee..8e4d6eda8a8d 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -167,8 +167,12 @@ enum pageflags { /* Remapped by swiotlb-xen. */ PG_xen_remapped = PG_owner_priv_1, - /* non-lru isolated movable page */ - PG_isolated = PG_reclaim, +#ifdef CONFIG_MIGRATION + /* movable_ops page that is isolated for migration */ + PG_movable_ops_isolated = PG_reclaim, + /* this is a movable_ops page (for selected typed pages only) */ + PG_movable_ops = PG_uptodate, +#endif /* Only valid for buddy pages. Used to track pages that are reported */ PG_reported = PG_uptodate, @@ -226,11 +230,48 @@ static __always_inline const struct page *page_fixed_fake_head(const struct page } return page; } + +static __always_inline bool page_count_writable(const struct page *page, int u) +{ + if (!static_branch_unlikely(&hugetlb_optimize_vmemmap_key)) + return true; + + /* + * The refcount check is ordered before the fake-head check to prevent + * the following race: + * CPU 1 (HVO) CPU 2 (speculative PFN walker) + * + * page_ref_freeze() + * synchronize_rcu() + * rcu_read_lock() + * page_is_fake_head() is false + * vmemmap_remap_pte() + * XXX: struct page[] becomes r/o + * + * page_ref_unfreeze() + * page_ref_count() is not zero + * + * atomic_add_unless(&page->_refcount) + * XXX: try to modify r/o struct page[] + * + * The refcount check also prevents modification attempts to other (r/o) + * tail pages that are not fake heads. + */ + if (atomic_read_acquire(&page->_refcount) == u) + return false; + + return page_fixed_fake_head(page) == page; +} #else static inline const struct page *page_fixed_fake_head(const struct page *page) { return page; } + +static inline bool page_count_writable(const struct page *page, int u) +{ + return true; +} #endif static __always_inline int page_is_fake_head(const struct page *page) @@ -578,6 +619,13 @@ FOLIO_FLAG(dropbehind, FOLIO_HEAD_PAGE) PAGEFLAG_FALSE(HighMem, highmem) #endif +/* Does kmap_local_folio() only allow access to one page of the folio? */ +#ifdef CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP +#define folio_test_partial_kmap(f) true +#else +#define folio_test_partial_kmap(f) folio_test_highmem(f) +#endif + #ifdef CONFIG_SWAP static __always_inline bool folio_test_swapcache(const struct folio *folio) { @@ -647,15 +695,12 @@ PAGEFLAG_FALSE(VmemmapSelfHosted, vmemmap_self_hosted) /* * On an anonymous folio mapped into a user virtual memory area, * folio->mapping points to its anon_vma, not to a struct address_space; - * with the PAGE_MAPPING_ANON bit set to distinguish it. See rmap.h. + * with the FOLIO_MAPPING_ANON bit set to distinguish it. See rmap.h. * - * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled, - * the PAGE_MAPPING_MOVABLE bit may be set along with the PAGE_MAPPING_ANON + * On an anonymous folio in a VM_MERGEABLE area, if CONFIG_KSM is enabled, + * the FOLIO_MAPPING_ANON_KSM bit may be set along with the FOLIO_MAPPING_ANON * bit; and then folio->mapping points, not to an anon_vma, but to a private - * structure which KSM associates with that merged page. See ksm.h. - * - * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is used for non-lru movable - * page and then folio->mapping points to a struct movable_operations. + * structure which KSM associates with that merged folio. See ksm.h. * * Please note that, confusingly, "folio_mapping" refers to the inode * address_space which maps the folio from disk; whereas "folio_mapped" @@ -668,50 +713,27 @@ PAGEFLAG_FALSE(VmemmapSelfHosted, vmemmap_self_hosted) * false before calling the following functions (e.g., folio_test_anon). * See mm/slab.h. */ -#define PAGE_MAPPING_ANON 0x1 -#define PAGE_MAPPING_MOVABLE 0x2 -#define PAGE_MAPPING_KSM (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE) -#define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE) - -static __always_inline bool folio_mapping_flags(const struct folio *folio) -{ - return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) != 0; -} - -static __always_inline bool PageMappingFlags(const struct page *page) -{ - return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != 0; -} +#define FOLIO_MAPPING_ANON 0x1 +#define FOLIO_MAPPING_ANON_KSM 0x2 +#define FOLIO_MAPPING_KSM (FOLIO_MAPPING_ANON | FOLIO_MAPPING_ANON_KSM) +#define FOLIO_MAPPING_FLAGS (FOLIO_MAPPING_ANON | FOLIO_MAPPING_ANON_KSM) static __always_inline bool folio_test_anon(const struct folio *folio) { - return ((unsigned long)folio->mapping & PAGE_MAPPING_ANON) != 0; + return ((unsigned long)folio->mapping & FOLIO_MAPPING_ANON) != 0; } static __always_inline bool PageAnonNotKsm(const struct page *page) { unsigned long flags = (unsigned long)page_folio(page)->mapping; - return (flags & PAGE_MAPPING_FLAGS) == PAGE_MAPPING_ANON; + return (flags & FOLIO_MAPPING_FLAGS) == FOLIO_MAPPING_ANON; } static __always_inline bool PageAnon(const struct page *page) { return folio_test_anon(page_folio(page)); } - -static __always_inline bool __folio_test_movable(const struct folio *folio) -{ - return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) == - PAGE_MAPPING_MOVABLE; -} - -static __always_inline bool __PageMovable(const struct page *page) -{ - return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) == - PAGE_MAPPING_MOVABLE; -} - #ifdef CONFIG_KSM /* * A KSM page is one of those write-protected "shared pages" or "merged pages" @@ -721,8 +743,8 @@ static __always_inline bool __PageMovable(const struct page *page) */ static __always_inline bool folio_test_ksm(const struct folio *folio) { - return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) == - PAGE_MAPPING_KSM; + return ((unsigned long)folio->mapping & FOLIO_MAPPING_FLAGS) == + FOLIO_MAPPING_KSM; } #else FOLIO_TEST_FLAG_FALSE(ksm) @@ -871,20 +893,6 @@ FOLIO_FLAG_FALSE(partially_mapped) #ifdef CONFIG_TRANSPARENT_HUGEPAGE /* - * PageHuge() only returns true for hugetlbfs pages, but not for - * normal or transparent huge pages. - * - * PageTransHuge() returns true for both transparent huge and - * hugetlbfs pages, but not normal pages. PageTransHuge() can only be - * called only in the core VM paths where hugetlbfs pages can't exist. - */ -static inline int PageTransHuge(const struct page *page) -{ - VM_BUG_ON_PAGE(PageTail(page), page); - return PageHead(page); -} - -/* * PageTransCompound returns true for both transparent huge pages * and hugetlbfs pages, so it should only be called when it's known * that hugetlbfs pages aren't involved. @@ -894,7 +902,6 @@ static inline int PageTransCompound(const struct page *page) return PageCompound(page); } #else -TESTPAGEFLAG_FALSE(TransHuge, transhuge) TESTPAGEFLAG_FALSE(TransCompound, transcompound) #endif @@ -945,7 +952,7 @@ static inline bool page_mapcount_is_type(unsigned int mapcount) static inline bool page_has_type(const struct page *page) { - return page_mapcount_is_type(data_race(page->page_type)); + return page_type_has_type(data_race(page->page_type)); } #define FOLIO_TYPE_OPS(lname, fname) \ @@ -1108,7 +1115,53 @@ static inline bool folio_contain_hwpoisoned_page(struct folio *folio) bool is_free_buddy_page(const struct page *page); -PAGEFLAG(Isolated, isolated, PF_ANY); +#ifdef CONFIG_MIGRATION +/* + * This page is migratable through movable_ops (for selected typed pages + * only). + * + * Page migration of such pages might fail, for example, if the page is + * already isolated by somebody else, or if the page is about to get freed. + * + * While a subsystem might set selected typed pages that support page migration + * as being movable through movable_ops, it must never clear this flag. + * + * This flag is only cleared when the page is freed back to the buddy. + * + * Only selected page types support this flag (see page_movable_ops()) and + * the flag might be used in other context for other pages. Always use + * page_has_movable_ops() instead. + */ +TESTPAGEFLAG(MovableOps, movable_ops, PF_NO_TAIL); +SETPAGEFLAG(MovableOps, movable_ops, PF_NO_TAIL); +/* + * A movable_ops page has this flag set while it is isolated for migration. + * This flag primarily protects against concurrent migration attempts. + * + * Once migration ended (success or failure), the flag is cleared. The + * flag is managed by the migration core. + */ +PAGEFLAG(MovableOpsIsolated, movable_ops_isolated, PF_NO_TAIL); +#else /* !CONFIG_MIGRATION */ +TESTPAGEFLAG_FALSE(MovableOps, movable_ops); +SETPAGEFLAG_NOOP(MovableOps, movable_ops); +PAGEFLAG_FALSE(MovableOpsIsolated, movable_ops_isolated); +#endif /* CONFIG_MIGRATION */ + +/** + * page_has_movable_ops - test for a movable_ops page + * @page: The page to test. + * + * Test whether this is a movable_ops page. Such pages will stay that + * way until freed. + * + * Returns true if this is a movable_ops page, otherwise false. + */ +static inline bool page_has_movable_ops(const struct page *page) +{ + return PageMovableOps(page) && + (PageOffline(page) || PageZsmalloc(page)); +} static __always_inline int PageAnonExclusive(const struct page *page) { @@ -1193,10 +1246,6 @@ static inline int folio_has_private(const struct folio *folio) return !!(folio->flags & PAGE_FLAGS_PRIVATE); } -static inline bool folio_test_large_maybe_mapped_shared(const struct folio *folio) -{ - return test_bit(FOLIO_MM_IDS_SHARED_BITNUM, &folio->_mm_ids); -} #undef PF_ANY #undef PF_HEAD #undef PF_NO_TAIL |