diff options
Diffstat (limited to 'include/linux/page-flags.h')
| -rw-r--r-- | include/linux/page-flags.h | 64 |
1 files changed, 46 insertions, 18 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 7a863572adce..b0ddc652e76c 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -44,10 +44,6 @@ * Consequently, PG_reserved for a page mapped into user space can indicate * the zero page, the vDSO, MMIO pages or device memory. * - * The PG_private bitflag is set on pagecache pages if they contain filesystem - * specific data (which is normally at page->private). It can be used by - * private allocations for its own usage. - * * During initiation of disk I/O, PG_locked is set. This bit is set before I/O * and cleared when writeback _starts_ or when read _completes_. PG_writeback * is set before writeback starts and cleared when it finishes. @@ -105,7 +101,7 @@ enum pageflags { PG_owner_2, /* Owner use. If pagecache, fs may use */ PG_arch_1, PG_reserved, - PG_private, /* If pagecache, has fs-private data */ + PG_folio, /* Do not use: reserved for folio identification */ PG_private_2, /* If pagecache, has fs aux data */ PG_reclaim, /* To be reclaimed asap */ PG_swapbacked, /* Page is backed by RAM/swap */ @@ -208,14 +204,13 @@ enum pageflags { static __always_inline bool compound_info_has_mask(void) { /* - * Limit mask usage to HugeTLB vmemmap optimization (HVO) where it - * makes a difference. + * Limit mask usage to HVO where it makes a difference. * * The approach with mask would work in the wider set of conditions, * but it requires validating that struct pages are naturally aligned * for all orders up to the MAX_FOLIO_ORDER, which can be tricky. */ - if (!IS_ENABLED(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP)) + if (!IS_ENABLED(CONFIG_VMEMMAP_OPTIMIZATION)) return false; return is_power_of_2(sizeof(struct page)); @@ -576,9 +571,19 @@ FOLIO_FLAG(swapbacked, FOLIO_HEAD_PAGE) /* * Private page markings that may be used by the filesystem that owns the page * for its own purposes. - * - PG_private and PG_private_2 cause release_folio() and co to be invoked + * - folio->private and PG_private_2 cause release_folio() and co to be invoked */ -PAGEFLAG(Private, private, PF_ANY) + +static __always_inline bool folio_test_private(const struct folio *folio) +{ + /* + * data_race() is added for readers without holding the folio lock. + * Only the NULL/non-NULL answer is used and both are valid while + * private is being attached or detached, so the race is benign. + */ + return data_race(folio->private); +} + FOLIO_FLAG(private_2, FOLIO_HEAD_PAGE) /* owner_2 can be set on tail pages for anon memory */ @@ -588,13 +593,12 @@ FOLIO_FLAG(owner_2, FOLIO_HEAD_PAGE) * Only test-and-set exist for PG_writeback. The unconditional operators are * risky: they bypass page accounting. */ -TESTPAGEFLAG(Writeback, writeback, PF_NO_TAIL) - TESTSCFLAG(Writeback, writeback, PF_NO_TAIL) +FOLIO_TEST_FLAG(writeback, FOLIO_HEAD_PAGE) + FOLIO_TEST_SET_FLAG(writeback, FOLIO_HEAD_PAGE) FOLIO_FLAG(mappedtodisk, FOLIO_HEAD_PAGE) /* PG_readahead is only used for reads; PG_reclaim is only for writes */ -PAGEFLAG(Reclaim, reclaim, PF_NO_TAIL) - TESTCLEARFLAG(Reclaim, reclaim, PF_NO_TAIL) +FOLIO_FLAG(reclaim, FOLIO_HEAD_PAGE) FOLIO_FLAG(readahead, FOLIO_HEAD_PAGE) FOLIO_TEST_CLEAR_FLAG(readahead, FOLIO_HEAD_PAGE) @@ -656,6 +660,7 @@ TESTSCFLAG(HWPoison, hwpoison, PF_ANY) #define __PG_HWPOISON (1UL << PG_hwpoison) #else PAGEFLAG_FALSE(HWPoison, hwpoison) +TESTSCFLAG_FALSE(HWPoison, hwpoison) #define __PG_HWPOISON 0 #endif @@ -1170,7 +1175,7 @@ static __always_inline void __ClearPageAnonExclusive(struct page *page) */ #define PAGE_FLAGS_CHECK_AT_FREE \ (1UL << PG_lru | 1UL << PG_locked | \ - 1UL << PG_private | 1UL << PG_private_2 | \ + 1UL << PG_private_2 | \ 1UL << PG_writeback | 1UL << PG_reserved | \ 1UL << PG_active | \ 1UL << PG_unevictable | __PG_MLOCKED | LRU_GEN_MASK) @@ -1194,8 +1199,31 @@ static __always_inline void __ClearPageAnonExclusive(struct page *page) (0xffUL /* order */ | 1UL << PG_has_hwpoisoned | \ 1UL << PG_large_rmappable | 1UL << PG_partially_mapped) -#define PAGE_FLAGS_PRIVATE \ - (1UL << PG_private | 1UL << PG_private_2) +/** + * folio_has_attached_private - check if the folio has private data attached + * @folio: The folio to check. + * + * Use this in code that may encounter swapcache or hugetlb folios but only + * wants to detect attached private data. + * + * Return: true if the folio has private data attached. + */ +static inline bool folio_has_attached_private(const struct folio *folio) +{ + /* + * Swapcache stores swp_entry_t in folio->swap, a union with + * folio->private, and hugetlb stores its own flags in folio->private; + * both are excluded. + * + * NOTE: For swapcache, folio->swap.val PG_swapcache are not set as + * a whole, so folio_test_swapcache() is not reliable to exclude + * swapcache. Use folio_test_swapbacked() instead, since it remains set + * when a folio is added to/removed from swapcache. + */ + + return folio_test_private(folio) && !folio_test_swapbacked(folio) && + !folio_test_hugetlb(folio); +} /** * folio_has_private - Determine if folio has private stuff * @folio: The folio to be checked @@ -1205,7 +1233,7 @@ static __always_inline void __ClearPageAnonExclusive(struct page *page) */ static inline int folio_has_private(const struct folio *folio) { - return !!(folio->flags.f & PAGE_FLAGS_PRIVATE); + return folio_has_attached_private(folio) || folio_test_private_2(folio); } #undef PF_ANY |