diff options
Diffstat (limited to 'include/linux/page-flags.h')
| -rw-r--r-- | include/linux/page-flags.h | 741 |
1 files changed, 481 insertions, 260 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index f34767c5fc7..8304959ad33 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -5,9 +5,13 @@ #ifndef PAGE_FLAGS_H #define PAGE_FLAGS_H -#include <linux/percpu.h> -#include <linux/cache.h> -#include <asm/pgtable.h> +#include <linux/types.h> +#include <linux/bug.h> +#include <linux/mmdebug.h> +#ifndef __GENERATING_BOUNDS_H +#include <linux/mm_types.h> +#include <generated/bounds.h> +#endif /* !__GENERATING_BOUNDS_H */ /* * Various page->flags bits: @@ -15,24 +19,25 @@ * PG_reserved is set for special pages, which can never be swapped out. Some * of them might not even exist (eg empty_bad_page)... * - * The PG_private bitflag is set if page->private contains a valid value. + * 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 disk I/O, PG_locked is used. This bit is set before I/O and - * reset when I/O completes. page_waitqueue(page) is a wait queue of all tasks - * waiting for the I/O on this page to complete. + * 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. + * + * PG_locked also pins a page in pagecache, and blocks truncation of the file + * while it is held. + * + * page_waitqueue(page) is a wait queue of all tasks waiting for the page + * to become unlocked. * * PG_uptodate tells whether the page's contents is valid. When a read * completes, the page becomes uptodate, unless a disk I/O error happened. * - * For choosing which pages to swap out, inode pages carry a PG_referenced bit, - * which is set any time the system accesses that page through the (mapping, - * index) hash table. This referenced bit, together with the referenced bit - * in the page tables, is used to manipulate page->age and move the page across - * the active, inactive_dirty and inactive_clean lists. - * - * Note that the referenced bit, the page->lru list_head and the active, - * inactive_dirty and inactive_clean lists are protected by the - * zone->lru_lock, and *NOT* by the usual PG_locked bit! + * PG_referenced, PG_reclaim are used for page reclaim for anonymous and + * file-backed pagecache (see mm/vmscan.c). * * PG_error is set to indicate that an I/O error occurred on this page. * @@ -44,283 +49,499 @@ * space, they need to be kmapped separately for doing IO on the pages. The * struct page (these bits with information) are always mapped into kernel * address space... + * + * PG_hwpoison indicates that a page got corrupted in hardware and contains + * data with incorrect ECC bits that triggered a machine check. Accessing is + * not safe since it may cause another machine check. Don't touch! */ /* * Don't use the *_dontuse flags. Use the macros. Otherwise you'll break - * locked- and dirty-page accounting. The top eight bits of page->flags are - * used for page->zone, so putting flag bits there doesn't work. + * locked- and dirty-page accounting. + * + * The page flags field is split into two parts, the main flags area + * which extends from the low bits upwards, and the fields area which + * extends from the high bits downwards. + * + * | FIELD | ... | FLAGS | + * N-1 ^ 0 + * (NR_PAGEFLAGS) + * + * The fields area is reserved for fields mapping zone, node (for NUMA) and + * SPARSEMEM section (for variants of SPARSEMEM that require section ids like + * SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP). */ -#define PG_locked 0 /* Page is locked. Don't touch. */ -#define PG_error 1 -#define PG_referenced 2 -#define PG_uptodate 3 - -#define PG_dirty 4 -#define PG_lru 5 -#define PG_active 6 -#define PG_slab 7 /* slab debug (Suparna wants this) */ - -#define PG_checked 8 /* kill me in 2.5.<early>. */ -#define PG_arch_1 9 -#define PG_reserved 10 -#define PG_private 11 /* Has something at ->private */ - -#define PG_writeback 12 /* Page is under writeback */ -#define PG_nosave 13 /* Used for system suspend/resume */ -#define PG_compound 14 /* Part of a compound page */ -#define PG_swapcache 15 /* Swap page: swp_entry_t in private */ - -#define PG_mappedtodisk 16 /* Has blocks allocated on-disk */ -#define PG_reclaim 17 /* To be reclaimed asap */ -#define PG_nosave_free 18 /* Free, should not be written */ -#define PG_uncached 19 /* Page has been mapped as uncached */ +enum pageflags { + PG_locked, /* Page is locked. Don't touch. */ + PG_error, + PG_referenced, + PG_uptodate, + PG_dirty, + PG_lru, + PG_active, + PG_slab, + PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/ + PG_arch_1, + PG_reserved, + PG_private, /* If pagecache, has fs-private data */ + PG_private_2, /* If pagecache, has fs aux data */ + PG_writeback, /* Page is under writeback */ +#ifdef CONFIG_PAGEFLAGS_EXTENDED + PG_head, /* A head page */ + PG_tail, /* A tail page */ +#else + PG_compound, /* A compound page */ +#endif + PG_swapcache, /* Swap page: swp_entry_t in private */ + PG_mappedtodisk, /* Has blocks allocated on-disk */ + PG_reclaim, /* To be reclaimed asap */ + PG_swapbacked, /* Page is backed by RAM/swap */ + PG_unevictable, /* Page is "unevictable" */ +#ifdef CONFIG_MMU + PG_mlocked, /* Page is vma mlocked */ +#endif +#ifdef CONFIG_ARCH_USES_PG_UNCACHED + PG_uncached, /* Page has been mapped as uncached */ +#endif +#ifdef CONFIG_MEMORY_FAILURE + PG_hwpoison, /* hardware poisoned page. Don't touch */ +#endif +#ifdef CONFIG_TRANSPARENT_HUGEPAGE + PG_compound_lock, +#endif + __NR_PAGEFLAGS, -/* - * Global page accounting. One instance per CPU. Only unsigned longs are - * allowed. - */ -struct page_state { - unsigned long nr_dirty; /* Dirty writeable pages */ - unsigned long nr_writeback; /* Pages under writeback */ - unsigned long nr_unstable; /* NFS unstable pages */ - unsigned long nr_page_table_pages;/* Pages used for pagetables */ - unsigned long nr_mapped; /* mapped into pagetables */ - unsigned long nr_slab; /* In slab */ -#define GET_PAGE_STATE_LAST nr_slab + /* Filesystems */ + PG_checked = PG_owner_priv_1, - /* - * The below are zeroed by get_page_state(). Use get_full_page_state() - * to add up all these. + /* Two page bits are conscripted by FS-Cache to maintain local caching + * state. These bits are set on pages belonging to the netfs's inodes + * when those inodes are being locally cached. */ - unsigned long pgpgin; /* Disk reads */ - unsigned long pgpgout; /* Disk writes */ - unsigned long pswpin; /* swap reads */ - unsigned long pswpout; /* swap writes */ - unsigned long pgalloc_high; /* page allocations */ - - unsigned long pgalloc_normal; - unsigned long pgalloc_dma; - unsigned long pgfree; /* page freeings */ - unsigned long pgactivate; /* pages moved inactive->active */ - unsigned long pgdeactivate; /* pages moved active->inactive */ - - unsigned long pgfault; /* faults (major+minor) */ - unsigned long pgmajfault; /* faults (major only) */ - unsigned long pgrefill_high; /* inspected in refill_inactive_zone */ - unsigned long pgrefill_normal; - unsigned long pgrefill_dma; - - unsigned long pgsteal_high; /* total highmem pages reclaimed */ - unsigned long pgsteal_normal; - unsigned long pgsteal_dma; - unsigned long pgscan_kswapd_high;/* total highmem pages scanned */ - unsigned long pgscan_kswapd_normal; - - unsigned long pgscan_kswapd_dma; - unsigned long pgscan_direct_high;/* total highmem pages scanned */ - unsigned long pgscan_direct_normal; - unsigned long pgscan_direct_dma; - unsigned long pginodesteal; /* pages reclaimed via inode freeing */ - - unsigned long slabs_scanned; /* slab objects scanned */ - unsigned long kswapd_steal; /* pages reclaimed by kswapd */ - unsigned long kswapd_inodesteal;/* reclaimed via kswapd inode freeing */ - unsigned long pageoutrun; /* kswapd's calls to page reclaim */ - unsigned long allocstall; /* direct reclaim calls */ - - unsigned long pgrotated; /* pages rotated to tail of the LRU */ - unsigned long nr_bounce; /* pages for bounce buffers */ + PG_fscache = PG_private_2, /* page backed by cache */ + + /* XEN */ + PG_pinned = PG_owner_priv_1, + PG_savepinned = PG_dirty, + + /* SLOB */ + PG_slob_free = PG_private, }; -extern void get_page_state(struct page_state *ret); -extern void get_page_state_node(struct page_state *ret, int node); -extern void get_full_page_state(struct page_state *ret); -extern unsigned long __read_page_state(unsigned long offset); -extern void __mod_page_state(unsigned long offset, unsigned long delta); - -#define read_page_state(member) \ - __read_page_state(offsetof(struct page_state, member)) - -#define mod_page_state(member, delta) \ - __mod_page_state(offsetof(struct page_state, member), (delta)) - -#define inc_page_state(member) mod_page_state(member, 1UL) -#define dec_page_state(member) mod_page_state(member, 0UL - 1) -#define add_page_state(member,delta) mod_page_state(member, (delta)) -#define sub_page_state(member,delta) mod_page_state(member, 0UL - (delta)) - -#define mod_page_state_zone(zone, member, delta) \ - do { \ - unsigned offset; \ - if (is_highmem(zone)) \ - offset = offsetof(struct page_state, member##_high); \ - else if (is_normal(zone)) \ - offset = offsetof(struct page_state, member##_normal); \ - else \ - offset = offsetof(struct page_state, member##_dma); \ - __mod_page_state(offset, (delta)); \ - } while (0) +#ifndef __GENERATING_BOUNDS_H /* - * Manipulation of page state flags + * Macros to create function definitions for page flags */ -#define PageLocked(page) \ - test_bit(PG_locked, &(page)->flags) -#define SetPageLocked(page) \ - set_bit(PG_locked, &(page)->flags) -#define TestSetPageLocked(page) \ - test_and_set_bit(PG_locked, &(page)->flags) -#define ClearPageLocked(page) \ - clear_bit(PG_locked, &(page)->flags) -#define TestClearPageLocked(page) \ - test_and_clear_bit(PG_locked, &(page)->flags) - -#define PageError(page) test_bit(PG_error, &(page)->flags) -#define SetPageError(page) set_bit(PG_error, &(page)->flags) -#define ClearPageError(page) clear_bit(PG_error, &(page)->flags) - -#define PageReferenced(page) test_bit(PG_referenced, &(page)->flags) -#define SetPageReferenced(page) set_bit(PG_referenced, &(page)->flags) -#define ClearPageReferenced(page) clear_bit(PG_referenced, &(page)->flags) -#define TestClearPageReferenced(page) test_and_clear_bit(PG_referenced, &(page)->flags) - -#define PageUptodate(page) test_bit(PG_uptodate, &(page)->flags) -#ifndef SetPageUptodate -#define SetPageUptodate(page) set_bit(PG_uptodate, &(page)->flags) -#endif -#define ClearPageUptodate(page) clear_bit(PG_uptodate, &(page)->flags) - -#define PageDirty(page) test_bit(PG_dirty, &(page)->flags) -#define SetPageDirty(page) set_bit(PG_dirty, &(page)->flags) -#define TestSetPageDirty(page) test_and_set_bit(PG_dirty, &(page)->flags) -#define ClearPageDirty(page) clear_bit(PG_dirty, &(page)->flags) -#define __ClearPageDirty(page) __clear_bit(PG_dirty, &(page)->flags) -#define TestClearPageDirty(page) test_and_clear_bit(PG_dirty, &(page)->flags) - -#define SetPageLRU(page) set_bit(PG_lru, &(page)->flags) -#define PageLRU(page) test_bit(PG_lru, &(page)->flags) -#define TestSetPageLRU(page) test_and_set_bit(PG_lru, &(page)->flags) -#define TestClearPageLRU(page) test_and_clear_bit(PG_lru, &(page)->flags) - -#define PageActive(page) test_bit(PG_active, &(page)->flags) -#define SetPageActive(page) set_bit(PG_active, &(page)->flags) -#define ClearPageActive(page) clear_bit(PG_active, &(page)->flags) -#define TestClearPageActive(page) test_and_clear_bit(PG_active, &(page)->flags) -#define TestSetPageActive(page) test_and_set_bit(PG_active, &(page)->flags) - -#define PageSlab(page) test_bit(PG_slab, &(page)->flags) -#define SetPageSlab(page) set_bit(PG_slab, &(page)->flags) -#define ClearPageSlab(page) clear_bit(PG_slab, &(page)->flags) -#define TestClearPageSlab(page) test_and_clear_bit(PG_slab, &(page)->flags) -#define TestSetPageSlab(page) test_and_set_bit(PG_slab, &(page)->flags) +#define TESTPAGEFLAG(uname, lname) \ +static inline int Page##uname(const struct page *page) \ + { return test_bit(PG_##lname, &page->flags); } + +#define SETPAGEFLAG(uname, lname) \ +static inline void SetPage##uname(struct page *page) \ + { set_bit(PG_##lname, &page->flags); } + +#define CLEARPAGEFLAG(uname, lname) \ +static inline void ClearPage##uname(struct page *page) \ + { clear_bit(PG_##lname, &page->flags); } + +#define __SETPAGEFLAG(uname, lname) \ +static inline void __SetPage##uname(struct page *page) \ + { __set_bit(PG_##lname, &page->flags); } + +#define __CLEARPAGEFLAG(uname, lname) \ +static inline void __ClearPage##uname(struct page *page) \ + { __clear_bit(PG_##lname, &page->flags); } + +#define TESTSETFLAG(uname, lname) \ +static inline int TestSetPage##uname(struct page *page) \ + { return test_and_set_bit(PG_##lname, &page->flags); } + +#define TESTCLEARFLAG(uname, lname) \ +static inline int TestClearPage##uname(struct page *page) \ + { return test_and_clear_bit(PG_##lname, &page->flags); } + +#define __TESTCLEARFLAG(uname, lname) \ +static inline int __TestClearPage##uname(struct page *page) \ + { return __test_and_clear_bit(PG_##lname, &page->flags); } + +#define PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \ + SETPAGEFLAG(uname, lname) CLEARPAGEFLAG(uname, lname) + +#define __PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \ + __SETPAGEFLAG(uname, lname) __CLEARPAGEFLAG(uname, lname) + +#define PAGEFLAG_FALSE(uname) \ +static inline int Page##uname(const struct page *page) \ + { return 0; } + +#define TESTSCFLAG(uname, lname) \ + TESTSETFLAG(uname, lname) TESTCLEARFLAG(uname, lname) + +#define SETPAGEFLAG_NOOP(uname) \ +static inline void SetPage##uname(struct page *page) { } + +#define CLEARPAGEFLAG_NOOP(uname) \ +static inline void ClearPage##uname(struct page *page) { } + +#define __CLEARPAGEFLAG_NOOP(uname) \ +static inline void __ClearPage##uname(struct page *page) { } + +#define TESTCLEARFLAG_FALSE(uname) \ +static inline int TestClearPage##uname(struct page *page) { return 0; } + +#define __TESTCLEARFLAG_FALSE(uname) \ +static inline int __TestClearPage##uname(struct page *page) { return 0; } + +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(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved) +PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked) + __SETPAGEFLAG(SwapBacked, swapbacked) + +__PAGEFLAG(SlobFree, slob_free) + +/* + * 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) + +/* + * 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) + +/* 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) #ifdef CONFIG_HIGHMEM -#define PageHighMem(page) is_highmem(page_zone(page)) +/* + * Must use a macro here due to header dependency issues. page_zone() is not + * available at this point. + */ +#define PageHighMem(__p) is_highmem(page_zone(__p)) #else -#define PageHighMem(page) 0 /* needed to optimize away at compile time */ +PAGEFLAG_FALSE(HighMem) #endif -#define PageChecked(page) test_bit(PG_checked, &(page)->flags) -#define SetPageChecked(page) set_bit(PG_checked, &(page)->flags) -#define ClearPageChecked(page) clear_bit(PG_checked, &(page)->flags) - -#define PageReserved(page) test_bit(PG_reserved, &(page)->flags) -#define SetPageReserved(page) set_bit(PG_reserved, &(page)->flags) -#define ClearPageReserved(page) clear_bit(PG_reserved, &(page)->flags) -#define __ClearPageReserved(page) __clear_bit(PG_reserved, &(page)->flags) - -#define SetPagePrivate(page) set_bit(PG_private, &(page)->flags) -#define ClearPagePrivate(page) clear_bit(PG_private, &(page)->flags) -#define PagePrivate(page) test_bit(PG_private, &(page)->flags) -#define __SetPagePrivate(page) __set_bit(PG_private, &(page)->flags) -#define __ClearPagePrivate(page) __clear_bit(PG_private, &(page)->flags) - -#define PageWriteback(page) test_bit(PG_writeback, &(page)->flags) -#define SetPageWriteback(page) \ - do { \ - if (!test_and_set_bit(PG_writeback, \ - &(page)->flags)) \ - inc_page_state(nr_writeback); \ - } while (0) -#define TestSetPageWriteback(page) \ - ({ \ - int ret; \ - ret = test_and_set_bit(PG_writeback, \ - &(page)->flags); \ - if (!ret) \ - inc_page_state(nr_writeback); \ - ret; \ - }) -#define ClearPageWriteback(page) \ - do { \ - if (test_and_clear_bit(PG_writeback, \ - &(page)->flags)) \ - dec_page_state(nr_writeback); \ - } while (0) -#define TestClearPageWriteback(page) \ - ({ \ - int ret; \ - ret = test_and_clear_bit(PG_writeback, \ - &(page)->flags); \ - if (ret) \ - dec_page_state(nr_writeback); \ - ret; \ - }) - -#define PageNosave(page) test_bit(PG_nosave, &(page)->flags) -#define SetPageNosave(page) set_bit(PG_nosave, &(page)->flags) -#define TestSetPageNosave(page) test_and_set_bit(PG_nosave, &(page)->flags) -#define ClearPageNosave(page) clear_bit(PG_nosave, &(page)->flags) -#define TestClearPageNosave(page) test_and_clear_bit(PG_nosave, &(page)->flags) - -#define PageNosaveFree(page) test_bit(PG_nosave_free, &(page)->flags) -#define SetPageNosaveFree(page) set_bit(PG_nosave_free, &(page)->flags) -#define ClearPageNosaveFree(page) clear_bit(PG_nosave_free, &(page)->flags) - -#define PageMappedToDisk(page) test_bit(PG_mappedtodisk, &(page)->flags) -#define SetPageMappedToDisk(page) set_bit(PG_mappedtodisk, &(page)->flags) -#define ClearPageMappedToDisk(page) clear_bit(PG_mappedtodisk, &(page)->flags) - -#define PageReclaim(page) test_bit(PG_reclaim, &(page)->flags) -#define SetPageReclaim(page) set_bit(PG_reclaim, &(page)->flags) -#define ClearPageReclaim(page) clear_bit(PG_reclaim, &(page)->flags) -#define TestClearPageReclaim(page) test_and_clear_bit(PG_reclaim, &(page)->flags) - -#ifdef CONFIG_HUGETLB_PAGE -#define PageCompound(page) test_bit(PG_compound, &(page)->flags) +#ifdef CONFIG_SWAP +PAGEFLAG(SwapCache, swapcache) #else -#define PageCompound(page) 0 +PAGEFLAG_FALSE(SwapCache) + SETPAGEFLAG_NOOP(SwapCache) CLEARPAGEFLAG_NOOP(SwapCache) #endif -#define SetPageCompound(page) set_bit(PG_compound, &(page)->flags) -#define ClearPageCompound(page) clear_bit(PG_compound, &(page)->flags) -#ifdef CONFIG_SWAP -#define PageSwapCache(page) test_bit(PG_swapcache, &(page)->flags) -#define SetPageSwapCache(page) set_bit(PG_swapcache, &(page)->flags) -#define ClearPageSwapCache(page) clear_bit(PG_swapcache, &(page)->flags) +PAGEFLAG(Unevictable, unevictable) __CLEARPAGEFLAG(Unevictable, unevictable) + TESTCLEARFLAG(Unevictable, unevictable) + +#ifdef CONFIG_MMU +PAGEFLAG(Mlocked, mlocked) __CLEARPAGEFLAG(Mlocked, mlocked) + TESTSCFLAG(Mlocked, mlocked) __TESTCLEARFLAG(Mlocked, mlocked) #else -#define PageSwapCache(page) 0 +PAGEFLAG_FALSE(Mlocked) SETPAGEFLAG_NOOP(Mlocked) + TESTCLEARFLAG_FALSE(Mlocked) __TESTCLEARFLAG_FALSE(Mlocked) #endif -#define PageUncached(page) test_bit(PG_uncached, &(page)->flags) -#define SetPageUncached(page) set_bit(PG_uncached, &(page)->flags) -#define ClearPageUncached(page) clear_bit(PG_uncached, &(page)->flags) +#ifdef CONFIG_ARCH_USES_PG_UNCACHED +PAGEFLAG(Uncached, uncached) +#else +PAGEFLAG_FALSE(Uncached) +#endif -struct page; /* forward declaration */ +#ifdef CONFIG_MEMORY_FAILURE +PAGEFLAG(HWPoison, hwpoison) +TESTSCFLAG(HWPoison, hwpoison) +#define __PG_HWPOISON (1UL << PG_hwpoison) +#else +PAGEFLAG_FALSE(HWPoison) +#define __PG_HWPOISON 0 +#endif -int test_clear_page_dirty(struct page *page); -int test_clear_page_writeback(struct page *page); -int test_set_page_writeback(struct page *page); +u64 stable_page_flags(struct page *page); -static inline void clear_page_dirty(struct page *page) +static inline int PageUptodate(struct page *page) { - test_clear_page_dirty(page); + int 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. + * We can skip the barrier if the page is not uptodate, because + * we wouldn't be reading anything from it. + * + * See SetPageUptodate() for the other side of the story. + */ + if (ret) + smp_rmb(); + + return ret; } +static inline void __SetPageUptodate(struct page *page) +{ + smp_wmb(); + __set_bit(PG_uptodate, &(page)->flags); +} + +static inline void SetPageUptodate(struct 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); +} + +CLEARPAGEFLAG(Uptodate, uptodate) + +extern void cancel_dirty_page(struct page *page, unsigned int account_size); + +int test_clear_page_writeback(struct page *page); +int __test_set_page_writeback(struct page *page, bool keep_write); + +#define test_set_page_writeback(page) \ + __test_set_page_writeback(page, false) +#define test_set_page_writeback_keepwrite(page) \ + __test_set_page_writeback(page, true) + static inline void set_page_writeback(struct page *page) { test_set_page_writeback(page); } +static inline void set_page_writeback_keepwrite(struct page *page) +{ + test_set_page_writeback_keepwrite(page); +} + +#ifdef CONFIG_PAGEFLAGS_EXTENDED +/* + * System with lots of page flags available. This allows separate + * flags for PageHead() and PageTail() checks of compound pages so that bit + * tests can be used in performance sensitive paths. PageCompound is + * generally not used in hot code paths except arch/powerpc/mm/init_64.c + * 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) + +static inline int PageCompound(struct page *page) +{ + return page->flags & ((1L << PG_head) | (1L << PG_tail)); + +} +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +static inline void ClearPageCompound(struct page *page) +{ + BUG_ON(!PageHead(page)); + ClearPageHead(page); +} +#endif + +#define PG_head_mask ((1L << PG_head)) + +#else +/* + * Reduce page flag use as much as possible by overlapping + * compound page flags with the flags used for page cache pages. Possible + * 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) + +/* + * PG_reclaim is used in combination with PG_compound to mark the + * head and tail of a compound page. This saves one page flag + * but makes it impossible to use compound pages for the page cache. + * The PG_reclaim bit would have to be used for reclaim or readahead + * if compound pages enter the page cache. + * + * PG_compound & PG_reclaim => Tail page + * PG_compound & ~PG_reclaim => Head page + */ +#define PG_head_mask ((1L << PG_compound)) +#define PG_head_tail_mask ((1L << PG_compound) | (1L << PG_reclaim)) + +static inline int PageHead(struct page *page) +{ + return ((page->flags & PG_head_tail_mask) == PG_head_mask); +} + +static inline int PageTail(struct page *page) +{ + return ((page->flags & PG_head_tail_mask) == PG_head_tail_mask); +} + +static inline void __SetPageTail(struct page *page) +{ + page->flags |= PG_head_tail_mask; +} + +static inline void __ClearPageTail(struct page *page) +{ + page->flags &= ~PG_head_tail_mask; +} + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +static inline void ClearPageCompound(struct page *page) +{ + BUG_ON((page->flags & PG_head_tail_mask) != (1 << PG_compound)); + clear_bit(PG_compound, &page->flags); +} +#endif + +#endif /* !PAGEFLAGS_EXTENDED */ + +#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(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. + */ +static inline int PageTransCompound(struct page *page) +{ + return PageCompound(page); +} + +/* + * PageTransTail 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. + */ +static inline int PageTransTail(struct page *page) +{ + return PageTail(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; +} +#endif + +/* + * If network-based swap is enabled, sl*b must keep track of whether pages + * were allocated from pfmemalloc reserves. + */ +static inline int PageSlabPfmemalloc(struct page *page) +{ + VM_BUG_ON_PAGE(!PageSlab(page), page); + return PageActive(page); +} + +static inline void SetPageSlabPfmemalloc(struct page *page) +{ + VM_BUG_ON_PAGE(!PageSlab(page), page); + SetPageActive(page); +} + +static inline void __ClearPageSlabPfmemalloc(struct page *page) +{ + VM_BUG_ON_PAGE(!PageSlab(page), page); + __ClearPageActive(page); +} + +static inline void ClearPageSlabPfmemalloc(struct page *page) +{ + VM_BUG_ON_PAGE(!PageSlab(page), page); + ClearPageActive(page); +} + +#ifdef CONFIG_MMU +#define __PG_MLOCKED (1 << PG_mlocked) +#else +#define __PG_MLOCKED 0 +#endif + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +#define __PG_COMPOUND_LOCK (1 << PG_compound_lock) +#else +#define __PG_COMPOUND_LOCK 0 +#endif + +/* + * Flags checked when a page is freed. Pages being freed should not have + * these flags set. It they are, there is a problem. + */ +#define PAGE_FLAGS_CHECK_AT_FREE \ + (1 << PG_lru | 1 << PG_locked | \ + 1 << PG_private | 1 << PG_private_2 | \ + 1 << PG_writeback | 1 << PG_reserved | \ + 1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \ + 1 << PG_unevictable | __PG_MLOCKED | __PG_HWPOISON | \ + __PG_COMPOUND_LOCK) + +/* + * Flags checked when a page is prepped for return by the page allocator. + * Pages being prepped should not have any flags set. It they are set, + * there has been a kernel bug or struct page corruption. + */ +#define PAGE_FLAGS_CHECK_AT_PREP ((1 << NR_PAGEFLAGS) - 1) + +#define PAGE_FLAGS_PRIVATE \ + (1 << PG_private | 1 << PG_private_2) +/** + * page_has_private - Determine if page has private stuff + * @page: The page to be checked + * + * Determine if a page has private stuff, indicating that release routines + * should be invoked upon it. + */ +static inline int page_has_private(struct page *page) +{ + return !!(page->flags & PAGE_FLAGS_PRIVATE); +} + +#endif /* !__GENERATING_BOUNDS_H */ + #endif /* PAGE_FLAGS_H */ |