diff options
Diffstat (limited to 'include/linux/page-flags.h')
| -rw-r--r-- | include/linux/page-flags.h | 237 |
1 files changed, 154 insertions, 83 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index f34e040b34e9..91b7f9b2b774 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -134,49 +134,68 @@ enum pageflags { #ifndef __GENERATING_BOUNDS_H +/* Page flags policies wrt compound pages */ +#define PF_ANY(page, enforce) page +#define PF_HEAD(page, enforce) compound_head(page) +#define PF_NO_TAIL(page, enforce) ({ \ + if (enforce) \ + VM_BUG_ON_PAGE(PageTail(page), page); \ + else \ + page = compound_head(page); \ + page;}) +#define PF_NO_COMPOUND(page, enforce) ({ \ + if (enforce) \ + VM_BUG_ON_PAGE(PageCompound(page), page); \ + page;}) + /* * Macros to create function definitions for page flags */ -#define TESTPAGEFLAG(uname, lname) \ -static inline int Page##uname(const struct page *page) \ - { return test_bit(PG_##lname, &page->flags); } +#define TESTPAGEFLAG(uname, lname, policy) \ +static inline int Page##uname(struct page *page) \ + { return test_bit(PG_##lname, &policy(page, 0)->flags); } -#define SETPAGEFLAG(uname, lname) \ +#define SETPAGEFLAG(uname, lname, policy) \ static inline void SetPage##uname(struct page *page) \ - { set_bit(PG_##lname, &page->flags); } + { set_bit(PG_##lname, &policy(page, 1)->flags); } -#define CLEARPAGEFLAG(uname, lname) \ +#define CLEARPAGEFLAG(uname, lname, policy) \ static inline void ClearPage##uname(struct page *page) \ - { clear_bit(PG_##lname, &page->flags); } + { clear_bit(PG_##lname, &policy(page, 1)->flags); } -#define __SETPAGEFLAG(uname, lname) \ +#define __SETPAGEFLAG(uname, lname, policy) \ static inline void __SetPage##uname(struct page *page) \ - { __set_bit(PG_##lname, &page->flags); } + { __set_bit(PG_##lname, &policy(page, 1)->flags); } -#define __CLEARPAGEFLAG(uname, lname) \ +#define __CLEARPAGEFLAG(uname, lname, policy) \ static inline void __ClearPage##uname(struct page *page) \ - { __clear_bit(PG_##lname, &page->flags); } + { __clear_bit(PG_##lname, &policy(page, 1)->flags); } -#define TESTSETFLAG(uname, lname) \ +#define TESTSETFLAG(uname, lname, policy) \ static inline int TestSetPage##uname(struct page *page) \ - { return test_and_set_bit(PG_##lname, &page->flags); } + { return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); } -#define TESTCLEARFLAG(uname, lname) \ +#define TESTCLEARFLAG(uname, lname, policy) \ static inline int TestClearPage##uname(struct page *page) \ - { return test_and_clear_bit(PG_##lname, &page->flags); } + { return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); } -#define __TESTCLEARFLAG(uname, lname) \ +#define __TESTCLEARFLAG(uname, lname, policy) \ static inline int __TestClearPage##uname(struct page *page) \ - { return __test_and_clear_bit(PG_##lname, &page->flags); } + { return __test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); } -#define PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \ - SETPAGEFLAG(uname, lname) CLEARPAGEFLAG(uname, lname) +#define PAGEFLAG(uname, lname, policy) \ + TESTPAGEFLAG(uname, lname, policy) \ + SETPAGEFLAG(uname, lname, policy) \ + CLEARPAGEFLAG(uname, lname, policy) -#define __PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \ - __SETPAGEFLAG(uname, lname) __CLEARPAGEFLAG(uname, lname) +#define __PAGEFLAG(uname, lname, policy) \ + TESTPAGEFLAG(uname, lname, policy) \ + __SETPAGEFLAG(uname, lname, policy) \ + __CLEARPAGEFLAG(uname, lname, policy) -#define TESTSCFLAG(uname, lname) \ - TESTSETFLAG(uname, lname) TESTCLEARFLAG(uname, lname) +#define TESTSCFLAG(uname, lname, policy) \ + TESTSETFLAG(uname, lname, policy) \ + TESTCLEARFLAG(uname, lname, policy) #define TESTPAGEFLAG_FALSE(uname) \ static inline int Page##uname(const struct page *page) { return 0; } @@ -205,47 +224,100 @@ static inline int __TestClearPage##uname(struct page *page) { return 0; } #define TESTSCFLAG_FALSE(uname) \ TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname) -struct page; /* forward declaration */ - -TESTPAGEFLAG(Locked, locked) -PAGEFLAG(Error, error) TESTCLEARFLAG(Error, error) -PAGEFLAG(Referenced, referenced) TESTCLEARFLAG(Referenced, referenced) - __SETPAGEFLAG(Referenced, referenced) -PAGEFLAG(Dirty, dirty) TESTSCFLAG(Dirty, dirty) __CLEARPAGEFLAG(Dirty, dirty) -PAGEFLAG(LRU, lru) __CLEARPAGEFLAG(LRU, lru) -PAGEFLAG(Active, active) __CLEARPAGEFLAG(Active, active) - TESTCLEARFLAG(Active, active) -__PAGEFLAG(Slab, slab) -PAGEFLAG(Checked, checked) /* Used by some filesystems */ -PAGEFLAG(Pinned, pinned) TESTSCFLAG(Pinned, pinned) /* Xen */ -PAGEFLAG(SavePinned, savepinned); /* Xen */ -PAGEFLAG(Foreign, foreign); /* Xen */ -PAGEFLAG(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved) -PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked) - __SETPAGEFLAG(SwapBacked, swapbacked) - -__PAGEFLAG(SlobFree, slob_free) +/* Forward declarations */ +struct page; +static inline int PageCompound(struct page *page); +static inline int PageTail(struct page *page); + +static inline struct page *compound_head_by_tail(struct page *tail) +{ + struct page *head = tail->first_page; + + /* + * page->first_page may be a dangling pointer to an old + * compound page, so recheck that it is still a tail + * page before returning. + */ + smp_rmb(); + if (likely(PageTail(tail))) + return head; + return tail; +} + +/* + * Since either compound page could be dismantled asynchronously in THP + * or we access asynchronously arbitrary positioned struct page, there + * would be tail flag race. To handle this race, we should call + * smp_rmb() before checking tail flag. compound_head_by_tail() did it. + */ +static inline struct page *compound_head(struct page *page) +{ + if (unlikely(PageTail(page))) + return compound_head_by_tail(page); + return page; +} + +/* + * If we access compound page synchronously such as access to + * allocated page, there is no need to handle tail flag race, so we can + * check tail flag directly without any synchronization primitive. + */ +static inline struct page *compound_head_fast(struct page *page) +{ + if (unlikely(PageTail(page))) + return page->first_page; + return page; +} + +__PAGEFLAG(Locked, locked, PF_NO_TAIL) +PAGEFLAG(Error, error, PF_NO_COMPOUND) TESTCLEARFLAG(Error, error, PF_NO_COMPOUND) +PAGEFLAG(Referenced, referenced, PF_HEAD) + TESTCLEARFLAG(Referenced, referenced, PF_HEAD) + __SETPAGEFLAG(Referenced, referenced, PF_HEAD) +PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD) + __CLEARPAGEFLAG(Dirty, dirty, PF_HEAD) +PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD) +PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD) + TESTCLEARFLAG(Active, active, PF_HEAD) +__PAGEFLAG(Slab, slab, PF_NO_TAIL) +__PAGEFLAG(SlobFree, slob_free, PF_NO_TAIL) +PAGEFLAG(Checked, checked, PF_NO_COMPOUND) /* Used by some filesystems */ + +/* Xen */ +PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND) TESTSCFLAG(Pinned, pinned, PF_NO_COMPOUND) +PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND) +PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND) + +PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) + __CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) +PAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) + __CLEARPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) + __SETPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) /* * 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 releasepage() and co to be invoked */ -PAGEFLAG(Private, private) __SETPAGEFLAG(Private, private) - __CLEARPAGEFLAG(Private, private) -PAGEFLAG(Private2, private_2) TESTSCFLAG(Private2, private_2) -PAGEFLAG(OwnerPriv1, owner_priv_1) TESTCLEARFLAG(OwnerPriv1, owner_priv_1) +PAGEFLAG(Private, private, PF_ANY) __SETPAGEFLAG(Private, private, PF_ANY) + __CLEARPAGEFLAG(Private, private, PF_ANY) +PAGEFLAG(Private2, private_2, PF_ANY) TESTSCFLAG(Private2, private_2, PF_ANY) +PAGEFLAG(OwnerPriv1, owner_priv_1, PF_ANY) + TESTCLEARFLAG(OwnerPriv1, owner_priv_1, PF_ANY) /* * Only test-and-set exist for PG_writeback. The unconditional operators are * risky: they bypass page accounting. */ -TESTPAGEFLAG(Writeback, writeback) TESTSCFLAG(Writeback, writeback) -PAGEFLAG(MappedToDisk, mappedtodisk) +TESTPAGEFLAG(Writeback, writeback, PF_NO_COMPOUND) + TESTSCFLAG(Writeback, writeback, PF_NO_COMPOUND) +PAGEFLAG(MappedToDisk, mappedtodisk, PF_NO_COMPOUND) /* PG_readahead is only used for reads; PG_reclaim is only for writes */ -PAGEFLAG(Reclaim, reclaim) TESTCLEARFLAG(Reclaim, reclaim) -PAGEFLAG(Readahead, reclaim) TESTCLEARFLAG(Readahead, reclaim) +PAGEFLAG(Reclaim, reclaim, PF_NO_COMPOUND) + TESTCLEARFLAG(Reclaim, reclaim, PF_NO_COMPOUND) +PAGEFLAG(Readahead, reclaim, PF_NO_COMPOUND) + TESTCLEARFLAG(Readahead, reclaim, PF_NO_COMPOUND) #ifdef CONFIG_HIGHMEM /* @@ -258,31 +330,33 @@ PAGEFLAG_FALSE(HighMem) #endif #ifdef CONFIG_SWAP -PAGEFLAG(SwapCache, swapcache) +PAGEFLAG(SwapCache, swapcache, PF_NO_COMPOUND) #else PAGEFLAG_FALSE(SwapCache) #endif -PAGEFLAG(Unevictable, unevictable) __CLEARPAGEFLAG(Unevictable, unevictable) - TESTCLEARFLAG(Unevictable, unevictable) +PAGEFLAG(Unevictable, unevictable, PF_HEAD) + __CLEARPAGEFLAG(Unevictable, unevictable, PF_HEAD) + TESTCLEARFLAG(Unevictable, unevictable, PF_HEAD) #ifdef CONFIG_MMU -PAGEFLAG(Mlocked, mlocked) __CLEARPAGEFLAG(Mlocked, mlocked) - TESTSCFLAG(Mlocked, mlocked) __TESTCLEARFLAG(Mlocked, mlocked) +PAGEFLAG(Mlocked, mlocked, PF_NO_TAIL) __CLEARPAGEFLAG(Mlocked, mlocked, PF_NO_TAIL) + TESTSCFLAG(Mlocked, mlocked, PF_NO_TAIL) + __TESTCLEARFLAG(Mlocked, mlocked, PF_NO_TAIL) #else PAGEFLAG_FALSE(Mlocked) __CLEARPAGEFLAG_NOOP(Mlocked) TESTSCFLAG_FALSE(Mlocked) __TESTCLEARFLAG_FALSE(Mlocked) #endif #ifdef CONFIG_ARCH_USES_PG_UNCACHED -PAGEFLAG(Uncached, uncached) +PAGEFLAG(Uncached, uncached, PF_NO_COMPOUND) #else PAGEFLAG_FALSE(Uncached) #endif #ifdef CONFIG_MEMORY_FAILURE -PAGEFLAG(HWPoison, hwpoison) -TESTSCFLAG(HWPoison, hwpoison) +PAGEFLAG(HWPoison, hwpoison, PF_ANY) +TESTSCFLAG(HWPoison, hwpoison, PF_ANY) #define __PG_HWPOISON (1UL << PG_hwpoison) #else PAGEFLAG_FALSE(HWPoison) @@ -311,6 +385,7 @@ PAGEFLAG_FALSE(HWPoison) static inline int PageAnon(struct page *page) { + page = compound_head(page); return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0; } @@ -323,6 +398,7 @@ static inline int PageAnon(struct page *page) */ static inline int PageKsm(struct page *page) { + page = compound_head(page); return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) == (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM); } @@ -334,8 +410,9 @@ u64 stable_page_flags(struct page *page); static inline int PageUptodate(struct page *page) { - int ret = test_bit(PG_uptodate, &(page)->flags); - + int ret; + page = compound_head(page); + ret = test_bit(PG_uptodate, &(page)->flags); /* * Must ensure that the data we read out of the page is loaded * _after_ we've loaded page->flags to check for PageUptodate. @@ -352,22 +429,24 @@ static inline int PageUptodate(struct page *page) static inline void __SetPageUptodate(struct page *page) { + VM_BUG_ON_PAGE(PageTail(page), page); smp_wmb(); - __set_bit(PG_uptodate, &(page)->flags); + __set_bit(PG_uptodate, &page->flags); } static inline void SetPageUptodate(struct page *page) { + VM_BUG_ON_PAGE(PageTail(page), page); /* * Memory barrier must be issued before setting the PG_uptodate bit, * so that all previous stores issued in order to bring the page * uptodate are actually visible before PageUptodate becomes true. */ smp_wmb(); - set_bit(PG_uptodate, &(page)->flags); + set_bit(PG_uptodate, &page->flags); } -CLEARPAGEFLAG(Uptodate, uptodate) +CLEARPAGEFLAG(Uptodate, uptodate, PF_NO_TAIL) int test_clear_page_writeback(struct page *page); int __test_set_page_writeback(struct page *page, bool keep_write); @@ -396,8 +475,8 @@ static inline void set_page_writeback_keepwrite(struct page *page) * and arch/powerpc/kvm/book3s_64_vio_hv.c which use it to detect huge pages * and avoid handling those in real mode. */ -__PAGEFLAG(Head, head) CLEARPAGEFLAG(Head, head) -__PAGEFLAG(Tail, tail) +__PAGEFLAG(Head, head, PF_ANY) CLEARPAGEFLAG(Head, head, PF_ANY) +__PAGEFLAG(Tail, tail, PF_ANY) static inline int PageCompound(struct page *page) { @@ -421,8 +500,8 @@ static inline void ClearPageCompound(struct page *page) * because PageCompound is always set for compound pages and not for * pages on the LRU and/or pagecache. */ -TESTPAGEFLAG(Compound, compound) -__SETPAGEFLAG(Head, compound) __CLEARPAGEFLAG(Head, compound) +TESTPAGEFLAG(Compound, compound, PF_ANY) +__SETPAGEFLAG(Head, compound, PF_ANY) __CLEARPAGEFLAG(Head, compound, PF_ANY) /* * PG_reclaim is used in combination with PG_compound to mark the @@ -518,21 +597,9 @@ static inline int PageTransTail(struct page *page) } #else - -static inline int PageTransHuge(struct page *page) -{ - return 0; -} - -static inline int PageTransCompound(struct page *page) -{ - return 0; -} - -static inline int PageTransTail(struct page *page) -{ - return 0; -} +TESTPAGEFLAG_FALSE(TransHuge) +TESTPAGEFLAG_FALSE(TransCompound) +TESTPAGEFLAG_FALSE(TransTail) #endif /* @@ -655,6 +722,10 @@ static inline int page_has_private(struct page *page) return !!(page->flags & PAGE_FLAGS_PRIVATE); } +#undef PF_ANY +#undef PF_HEAD +#undef PF_NO_TAIL +#undef PF_NO_COMPOUND #endif /* !__GENERATING_BOUNDS_H */ #endif /* PAGE_FLAGS_H */ |