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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Macros for manipulating and testing page->flags
3 */
4
5#ifndef PAGE_FLAGS_H
6#define PAGE_FLAGS_H
7
Andrew Mortonf886ed42006-06-23 02:03:06 -07008#include <linux/types.h>
Paul Gortmaker187f1882011-11-23 20:12:59 -05009#include <linux/bug.h>
Mel Gorman072bb0a2012-07-31 16:43:58 -070010#include <linux/mmdebug.h>
Christoph Lameter9223b4192008-04-28 02:12:48 -070011#ifndef __GENERATING_BOUNDS_H
Christoph Lameter6d777952007-05-06 14:49:40 -070012#include <linux/mm_types.h>
Sam Ravnborg01fc0ac2009-04-19 21:57:19 +020013#include <generated/bounds.h>
Christoph Lameter9223b4192008-04-28 02:12:48 -070014#endif /* !__GENERATING_BOUNDS_H */
Andrew Mortonf886ed42006-06-23 02:03:06 -070015
Linus Torvalds1da177e2005-04-16 15:20:36 -070016/*
17 * Various page->flags bits:
18 *
19 * PG_reserved is set for special pages, which can never be swapped out. Some
20 * of them might not even exist (eg empty_bad_page)...
21 *
Nick Pigginda6052f2006-09-25 23:31:35 -070022 * The PG_private bitflag is set on pagecache pages if they contain filesystem
23 * specific data (which is normally at page->private). It can be used by
24 * private allocations for its own usage.
Linus Torvalds1da177e2005-04-16 15:20:36 -070025 *
Nick Pigginda6052f2006-09-25 23:31:35 -070026 * During initiation of disk I/O, PG_locked is set. This bit is set before I/O
27 * and cleared when writeback _starts_ or when read _completes_. PG_writeback
28 * is set before writeback starts and cleared when it finishes.
29 *
30 * PG_locked also pins a page in pagecache, and blocks truncation of the file
31 * while it is held.
32 *
33 * page_waitqueue(page) is a wait queue of all tasks waiting for the page
34 * to become unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -070035 *
36 * PG_uptodate tells whether the page's contents is valid. When a read
37 * completes, the page becomes uptodate, unless a disk I/O error happened.
38 *
Nick Pigginda6052f2006-09-25 23:31:35 -070039 * PG_referenced, PG_reclaim are used for page reclaim for anonymous and
40 * file-backed pagecache (see mm/vmscan.c).
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 *
42 * PG_error is set to indicate that an I/O error occurred on this page.
43 *
44 * PG_arch_1 is an architecture specific page state bit. The generic code
45 * guarantees that this bit is cleared for a page when it first is entered into
46 * the page cache.
47 *
48 * PG_highmem pages are not permanently mapped into the kernel virtual address
49 * space, they need to be kmapped separately for doing IO on the pages. The
50 * struct page (these bits with information) are always mapped into kernel
51 * address space...
Nick Pigginda6052f2006-09-25 23:31:35 -070052 *
Andi Kleend466f2f2009-09-16 11:50:03 +020053 * PG_hwpoison indicates that a page got corrupted in hardware and contains
54 * data with incorrect ECC bits that triggered a machine check. Accessing is
55 * not safe since it may cause another machine check. Don't touch!
Linus Torvalds1da177e2005-04-16 15:20:36 -070056 */
57
58/*
59 * Don't use the *_dontuse flags. Use the macros. Otherwise you'll break
Andy Whitcroft91fc8ab2006-04-10 22:53:01 -070060 * locked- and dirty-page accounting.
61 *
62 * The page flags field is split into two parts, the main flags area
63 * which extends from the low bits upwards, and the fields area which
64 * extends from the high bits downwards.
65 *
66 * | FIELD | ... | FLAGS |
Christoph Lameter9223b4192008-04-28 02:12:48 -070067 * N-1 ^ 0
68 * (NR_PAGEFLAGS)
Andy Whitcroft91fc8ab2006-04-10 22:53:01 -070069 *
Christoph Lameter9223b4192008-04-28 02:12:48 -070070 * The fields area is reserved for fields mapping zone, node (for NUMA) and
71 * SPARSEMEM section (for variants of SPARSEMEM that require section ids like
72 * SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP).
Linus Torvalds1da177e2005-04-16 15:20:36 -070073 */
Christoph Lametere2683182008-04-28 02:12:47 -070074enum pageflags {
75 PG_locked, /* Page is locked. Don't touch. */
76 PG_error,
77 PG_referenced,
78 PG_uptodate,
79 PG_dirty,
80 PG_lru,
81 PG_active,
82 PG_slab,
83 PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/
Christoph Lametere2683182008-04-28 02:12:47 -070084 PG_arch_1,
85 PG_reserved,
86 PG_private, /* If pagecache, has fs-private data */
David Howells266cf652009-04-03 16:42:36 +010087 PG_private_2, /* If pagecache, has fs aux data */
Christoph Lametere2683182008-04-28 02:12:47 -070088 PG_writeback, /* Page is under writeback */
Christoph Lametere20b8cc2008-04-28 02:12:55 -070089 PG_head, /* A head page */
Christoph Lametere2683182008-04-28 02:12:47 -070090 PG_swapcache, /* Swap page: swp_entry_t in private */
91 PG_mappedtodisk, /* Has blocks allocated on-disk */
92 PG_reclaim, /* To be reclaimed asap */
Rik van Rielb2e18532008-10-18 20:26:30 -070093 PG_swapbacked, /* Page is backed by RAM/swap */
Lee Schermerhorn894bc312008-10-18 20:26:39 -070094 PG_unevictable, /* Page is "unevictable" */
Hugh Dickinsaf8e3352009-12-14 17:58:59 -080095#ifdef CONFIG_MMU
Nick Pigginb291f002008-10-18 20:26:44 -070096 PG_mlocked, /* Page is vma mlocked */
Lee Schermerhorn894bc312008-10-18 20:26:39 -070097#endif
Venkatesh Pallipadi46cf98c2009-07-10 09:57:37 -070098#ifdef CONFIG_ARCH_USES_PG_UNCACHED
Christoph Lameter602c4d12008-04-28 02:12:52 -070099 PG_uncached, /* Page has been mapped as uncached */
Andrew Mortonf886ed42006-06-23 02:03:06 -0700100#endif
Andi Kleend466f2f2009-09-16 11:50:03 +0200101#ifdef CONFIG_MEMORY_FAILURE
102 PG_hwpoison, /* hardware poisoned page. Don't touch */
103#endif
Vladimir Davydov33c3fc72015-09-09 15:35:45 -0700104#if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT)
105 PG_young,
106 PG_idle,
107#endif
Andy Whitcroft0cad47c2008-07-23 21:27:16 -0700108 __NR_PAGEFLAGS,
109
110 /* Filesystems */
111 PG_checked = PG_owner_priv_1,
112
David Howells266cf652009-04-03 16:42:36 +0100113 /* Two page bits are conscripted by FS-Cache to maintain local caching
114 * state. These bits are set on pages belonging to the netfs's inodes
115 * when those inodes are being locally cached.
116 */
117 PG_fscache = PG_private_2, /* page backed by cache */
118
Andy Whitcroft0cad47c2008-07-23 21:27:16 -0700119 /* XEN */
Jennifer Herbertd8ac3dd2015-01-05 13:24:09 +0000120 /* Pinned in Xen as a read-only pagetable page. */
Andy Whitcroft0cad47c2008-07-23 21:27:16 -0700121 PG_pinned = PG_owner_priv_1,
Jennifer Herbertd8ac3dd2015-01-05 13:24:09 +0000122 /* Pinned as part of domain save (see xen_mm_pin_all()). */
Andy Whitcroft0cad47c2008-07-23 21:27:16 -0700123 PG_savepinned = PG_dirty,
Jennifer Herbertd8ac3dd2015-01-05 13:24:09 +0000124 /* Has a grant mapping of another (foreign) domain's page. */
125 PG_foreign = PG_owner_priv_1,
Andy Whitcroft8a380822008-07-23 21:27:18 -0700126
Andy Whitcroft9023cb72008-07-23 21:27:19 -0700127 /* SLOB */
Andy Whitcroft9023cb72008-07-23 21:27:19 -0700128 PG_slob_free = PG_private,
Christoph Lametere2683182008-04-28 02:12:47 -0700129};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130
Christoph Lameter9223b4192008-04-28 02:12:48 -0700131#ifndef __GENERATING_BOUNDS_H
132
Kirill A. Shutemov0e6d31a2016-01-15 16:51:17 -0800133struct page; /* forward declaration */
134
135static inline struct page *compound_head(struct page *page)
136{
137 unsigned long head = READ_ONCE(page->compound_head);
138
139 if (unlikely(head & 1))
140 return (struct page *) (head - 1);
141 return page;
142}
143
144static inline int PageTail(struct page *page)
145{
146 return READ_ONCE(page->compound_head) & 1;
147}
148
149static inline int PageCompound(struct page *page)
150{
151 return test_bit(PG_head, &page->flags) || PageTail(page);
152}
153
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154/*
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800155 * Page flags policies wrt compound pages
156 *
157 * PF_ANY:
158 * the page flag is relevant for small, head and tail pages.
159 *
160 * PF_HEAD:
161 * for compound page all operations related to the page flag applied to
162 * head page.
163 *
164 * PF_NO_TAIL:
165 * modifications of the page flag must be done on small or head pages,
166 * checks can be done on tail pages too.
167 *
168 * PF_NO_COMPOUND:
169 * the page flag is not relevant for compound pages.
170 */
171#define PF_ANY(page, enforce) page
172#define PF_HEAD(page, enforce) compound_head(page)
173#define PF_NO_TAIL(page, enforce) ({ \
174 VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page); \
175 compound_head(page);})
Kirill A. Shutemov822cdd112016-01-15 16:52:03 -0800176#define PF_NO_COMPOUND(page, enforce) ({ \
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800177 VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page); \
178 page;})
179
180/*
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700181 * Macros to create function definitions for page flags
182 */
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800183#define TESTPAGEFLAG(uname, lname, policy) \
184static inline int Page##uname(struct page *page) \
185 { return test_bit(PG_##lname, &policy(page, 0)->flags); }
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700186
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800187#define SETPAGEFLAG(uname, lname, policy) \
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700188static inline void SetPage##uname(struct page *page) \
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800189 { set_bit(PG_##lname, &policy(page, 1)->flags); }
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700190
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800191#define CLEARPAGEFLAG(uname, lname, policy) \
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700192static inline void ClearPage##uname(struct page *page) \
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800193 { clear_bit(PG_##lname, &policy(page, 1)->flags); }
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700194
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800195#define __SETPAGEFLAG(uname, lname, policy) \
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700196static inline void __SetPage##uname(struct page *page) \
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800197 { __set_bit(PG_##lname, &policy(page, 1)->flags); }
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700198
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800199#define __CLEARPAGEFLAG(uname, lname, policy) \
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700200static inline void __ClearPage##uname(struct page *page) \
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800201 { __clear_bit(PG_##lname, &policy(page, 1)->flags); }
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700202
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800203#define TESTSETFLAG(uname, lname, policy) \
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700204static inline int TestSetPage##uname(struct page *page) \
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800205 { return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); }
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700206
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800207#define TESTCLEARFLAG(uname, lname, policy) \
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700208static inline int TestClearPage##uname(struct page *page) \
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800209 { return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); }
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700210
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800211#define PAGEFLAG(uname, lname, policy) \
212 TESTPAGEFLAG(uname, lname, policy) \
213 SETPAGEFLAG(uname, lname, policy) \
214 CLEARPAGEFLAG(uname, lname, policy)
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700215
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800216#define __PAGEFLAG(uname, lname, policy) \
217 TESTPAGEFLAG(uname, lname, policy) \
218 __SETPAGEFLAG(uname, lname, policy) \
219 __CLEARPAGEFLAG(uname, lname, policy)
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700220
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800221#define TESTSCFLAG(uname, lname, policy) \
222 TESTSETFLAG(uname, lname, policy) \
223 TESTCLEARFLAG(uname, lname, policy)
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700224
Johannes Weiner2f3e4422014-08-06 16:05:40 -0700225#define TESTPAGEFLAG_FALSE(uname) \
226static inline int Page##uname(const struct page *page) { return 0; }
227
Lee Schermerhorn8a7a8542008-10-18 20:26:37 -0700228#define SETPAGEFLAG_NOOP(uname) \
229static inline void SetPage##uname(struct page *page) { }
230
231#define CLEARPAGEFLAG_NOOP(uname) \
232static inline void ClearPage##uname(struct page *page) { }
233
234#define __CLEARPAGEFLAG_NOOP(uname) \
235static inline void __ClearPage##uname(struct page *page) { }
236
Johannes Weiner2f3e4422014-08-06 16:05:40 -0700237#define TESTSETFLAG_FALSE(uname) \
238static inline int TestSetPage##uname(struct page *page) { return 0; }
239
Lee Schermerhorn8a7a8542008-10-18 20:26:37 -0700240#define TESTCLEARFLAG_FALSE(uname) \
241static inline int TestClearPage##uname(struct page *page) { return 0; }
242
Johannes Weiner2f3e4422014-08-06 16:05:40 -0700243#define PAGEFLAG_FALSE(uname) TESTPAGEFLAG_FALSE(uname) \
244 SETPAGEFLAG_NOOP(uname) CLEARPAGEFLAG_NOOP(uname)
245
246#define TESTSCFLAG_FALSE(uname) \
247 TESTSETFLAG_FALSE(uname) TESTCLEARFLAG_FALSE(uname)
248
Kirill A. Shutemov48c935a2016-01-15 16:51:24 -0800249__PAGEFLAG(Locked, locked, PF_NO_TAIL)
Kirill A. Shutemovdf8c94d2016-01-15 16:51:28 -0800250PAGEFLAG(Error, error, PF_NO_COMPOUND) TESTCLEARFLAG(Error, error, PF_NO_COMPOUND)
Kirill A. Shutemov8cb38fa2016-01-15 16:51:32 -0800251PAGEFLAG(Referenced, referenced, PF_HEAD)
252 TESTCLEARFLAG(Referenced, referenced, PF_HEAD)
253 __SETPAGEFLAG(Referenced, referenced, PF_HEAD)
Kirill A. Shutemovdf8c94d2016-01-15 16:51:28 -0800254PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD)
255 __CLEARPAGEFLAG(Dirty, dirty, PF_HEAD)
Kirill A. Shutemov8cb38fa2016-01-15 16:51:32 -0800256PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD)
257PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD)
258 TESTCLEARFLAG(Active, active, PF_HEAD)
Kirill A. Shutemovdcb351cd2016-01-15 16:51:35 -0800259__PAGEFLAG(Slab, slab, PF_NO_TAIL)
260__PAGEFLAG(SlobFree, slob_free, PF_NO_TAIL)
Kirill A. Shutemovdf8c94d2016-01-15 16:51:28 -0800261PAGEFLAG(Checked, checked, PF_NO_COMPOUND) /* Used by some filesystems */
Kirill A. Shutemovc13985fa2016-01-15 16:51:39 -0800262
263/* Xen */
264PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND)
265 TESTSCFLAG(Pinned, pinned, PF_NO_COMPOUND)
266PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND);
267PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND);
268
Kirill A. Shutemovde09d312016-01-15 16:51:42 -0800269PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
270 __CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
Kirill A. Shutemovda5efc42016-01-15 16:51:46 -0800271PAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
272 __CLEARPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
273 __SETPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700274
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700275/*
David Howells266cf652009-04-03 16:42:36 +0100276 * Private page markings that may be used by the filesystem that owns the page
277 * for its own purposes.
278 * - PG_private and PG_private_2 cause releasepage() and co to be invoked
279 */
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800280PAGEFLAG(Private, private, PF_ANY) __SETPAGEFLAG(Private, private, PF_ANY)
281 __CLEARPAGEFLAG(Private, private, PF_ANY)
282PAGEFLAG(Private2, private_2, PF_ANY) TESTSCFLAG(Private2, private_2, PF_ANY)
283PAGEFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
284 TESTCLEARFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
David Howells266cf652009-04-03 16:42:36 +0100285
286/*
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700287 * Only test-and-set exist for PG_writeback. The unconditional operators are
288 * risky: they bypass page accounting.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 */
Kirill A. Shutemovdf8c94d2016-01-15 16:51:28 -0800290TESTPAGEFLAG(Writeback, writeback, PF_NO_COMPOUND)
291 TESTSCFLAG(Writeback, writeback, PF_NO_COMPOUND)
292PAGEFLAG(MappedToDisk, mappedtodisk, PF_NO_COMPOUND)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293
Shaohua Li579f8292014-02-06 12:04:21 -0800294/* PG_readahead is only used for reads; PG_reclaim is only for writes */
Kirill A. Shutemovdf8c94d2016-01-15 16:51:28 -0800295PAGEFLAG(Reclaim, reclaim, PF_NO_COMPOUND)
296 TESTCLEARFLAG(Reclaim, reclaim, PF_NO_COMPOUND)
297PAGEFLAG(Readahead, reclaim, PF_NO_COMPOUND)
298 TESTCLEARFLAG(Readahead, reclaim, PF_NO_COMPOUND)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700300#ifdef CONFIG_HIGHMEM
301/*
302 * Must use a macro here due to header dependency issues. page_zone() is not
303 * available at this point.
304 */
Vineet Gupta3ca65c12015-11-05 18:48:29 -0800305#define PageHighMem(__p) is_highmem_idx(page_zonenum(__p))
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700306#else
Christoph Lameterec7cade2008-04-28 02:12:53 -0700307PAGEFLAG_FALSE(HighMem)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700308#endif
309
310#ifdef CONFIG_SWAP
Kirill A. Shutemov50ea78d2016-01-15 16:51:49 -0800311PAGEFLAG(SwapCache, swapcache, PF_NO_COMPOUND)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700312#else
Christoph Lameterec7cade2008-04-28 02:12:53 -0700313PAGEFLAG_FALSE(SwapCache)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700314#endif
315
Kirill A. Shutemov8cb38fa2016-01-15 16:51:32 -0800316PAGEFLAG(Unevictable, unevictable, PF_HEAD)
317 __CLEARPAGEFLAG(Unevictable, unevictable, PF_HEAD)
318 TESTCLEARFLAG(Unevictable, unevictable, PF_HEAD)
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700319
Hugh Dickinsaf8e3352009-12-14 17:58:59 -0800320#ifdef CONFIG_MMU
Kirill A. Shutemove4f87d52016-01-15 16:51:53 -0800321PAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
322 __CLEARPAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
323 TESTSCFLAG(Mlocked, mlocked, PF_NO_TAIL)
David Howells33925b22009-03-31 15:23:26 -0700324#else
Johannes Weiner2f3e4422014-08-06 16:05:40 -0700325PAGEFLAG_FALSE(Mlocked) __CLEARPAGEFLAG_NOOP(Mlocked)
Kirill A. Shutemov685eaad2016-01-15 16:52:10 -0800326 TESTSCFLAG_FALSE(Mlocked)
David Howells33925b22009-03-31 15:23:26 -0700327#endif
328
Venkatesh Pallipadi46cf98c2009-07-10 09:57:37 -0700329#ifdef CONFIG_ARCH_USES_PG_UNCACHED
Kirill A. Shutemovb9d41812016-01-15 16:51:56 -0800330PAGEFLAG(Uncached, uncached, PF_NO_COMPOUND)
Christoph Lameter602c4d12008-04-28 02:12:52 -0700331#else
Christoph Lameterec7cade2008-04-28 02:12:53 -0700332PAGEFLAG_FALSE(Uncached)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700333#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334
Andi Kleend466f2f2009-09-16 11:50:03 +0200335#ifdef CONFIG_MEMORY_FAILURE
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800336PAGEFLAG(HWPoison, hwpoison, PF_ANY)
337TESTSCFLAG(HWPoison, hwpoison, PF_ANY)
Andi Kleend466f2f2009-09-16 11:50:03 +0200338#define __PG_HWPOISON (1UL << PG_hwpoison)
339#else
340PAGEFLAG_FALSE(HWPoison)
341#define __PG_HWPOISON 0
342#endif
343
Vladimir Davydov33c3fc72015-09-09 15:35:45 -0700344#if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT)
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800345TESTPAGEFLAG(Young, young, PF_ANY)
346SETPAGEFLAG(Young, young, PF_ANY)
347TESTCLEARFLAG(Young, young, PF_ANY)
348PAGEFLAG(Idle, idle, PF_ANY)
Vladimir Davydov33c3fc72015-09-09 15:35:45 -0700349#endif
350
Kirill A. Shutemove8c61582015-04-15 16:13:08 -0700351/*
352 * On an anonymous page mapped into a user virtual memory area,
353 * page->mapping points to its anon_vma, not to a struct address_space;
354 * with the PAGE_MAPPING_ANON bit set to distinguish it. See rmap.h.
355 *
356 * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled,
357 * the PAGE_MAPPING_KSM bit may be set along with the PAGE_MAPPING_ANON bit;
358 * and then page->mapping points, not to an anon_vma, but to a private
359 * structure which KSM associates with that merged page. See ksm.h.
360 *
361 * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is currently never used.
362 *
363 * Please note that, confusingly, "page_mapping" refers to the inode
364 * address_space which maps the page from disk; whereas "page_mapped"
365 * refers to user virtual address space into which the page is mapped.
366 */
367#define PAGE_MAPPING_ANON 1
368#define PAGE_MAPPING_KSM 2
369#define PAGE_MAPPING_FLAGS (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM)
370
371static inline int PageAnon(struct page *page)
372{
Kirill A. Shutemov822cdd112016-01-15 16:52:03 -0800373 page = compound_head(page);
Kirill A. Shutemove8c61582015-04-15 16:13:08 -0700374 return ((unsigned long)page->mapping & PAGE_MAPPING_ANON) != 0;
375}
376
377#ifdef CONFIG_KSM
378/*
379 * A KSM page is one of those write-protected "shared pages" or "merged pages"
380 * which KSM maps into multiple mms, wherever identical anonymous page content
381 * is found in VM_MERGEABLE vmas. It's a PageAnon page, pointing not to any
382 * anon_vma, but to that page's node of the stable tree.
383 */
384static inline int PageKsm(struct page *page)
385{
Kirill A. Shutemov822cdd112016-01-15 16:52:03 -0800386 page = compound_head(page);
Kirill A. Shutemove8c61582015-04-15 16:13:08 -0700387 return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) ==
388 (PAGE_MAPPING_ANON | PAGE_MAPPING_KSM);
389}
390#else
391TESTPAGEFLAG_FALSE(Ksm)
392#endif
393
Wu Fengguang1a9b5b72009-12-16 12:19:59 +0100394u64 stable_page_flags(struct page *page);
395
Nick Piggin0ed361d2008-02-04 22:29:34 -0800396static inline int PageUptodate(struct page *page)
397{
Kirill A. Shutemovd2998c42016-01-15 16:52:00 -0800398 int ret;
399 page = compound_head(page);
400 ret = test_bit(PG_uptodate, &(page)->flags);
Nick Piggin0ed361d2008-02-04 22:29:34 -0800401 /*
402 * Must ensure that the data we read out of the page is loaded
403 * _after_ we've loaded page->flags to check for PageUptodate.
404 * We can skip the barrier if the page is not uptodate, because
405 * we wouldn't be reading anything from it.
406 *
407 * See SetPageUptodate() for the other side of the story.
408 */
409 if (ret)
410 smp_rmb();
411
412 return ret;
413}
414
415static inline void __SetPageUptodate(struct page *page)
416{
Kirill A. Shutemovd2998c42016-01-15 16:52:00 -0800417 VM_BUG_ON_PAGE(PageTail(page), page);
Nick Piggin0ed361d2008-02-04 22:29:34 -0800418 smp_wmb();
Kirill A. Shutemovdf8c94d2016-01-15 16:51:28 -0800419 __set_bit(PG_uptodate, &page->flags);
Nick Piggin0ed361d2008-02-04 22:29:34 -0800420}
421
Heiko Carstens2dcea572006-09-29 01:58:41 -0700422static inline void SetPageUptodate(struct page *page)
423{
Kirill A. Shutemovd2998c42016-01-15 16:52:00 -0800424 VM_BUG_ON_PAGE(PageTail(page), page);
Nick Piggin0ed361d2008-02-04 22:29:34 -0800425 /*
426 * Memory barrier must be issued before setting the PG_uptodate bit,
427 * so that all previous stores issued in order to bring the page
428 * uptodate are actually visible before PageUptodate becomes true.
Nick Piggin0ed361d2008-02-04 22:29:34 -0800429 */
430 smp_wmb();
Kirill A. Shutemovdf8c94d2016-01-15 16:51:28 -0800431 set_bit(PG_uptodate, &page->flags);
Nick Piggin0ed361d2008-02-04 22:29:34 -0800432}
433
Kirill A. Shutemovd2998c42016-01-15 16:52:00 -0800434CLEARPAGEFLAG(Uptodate, uptodate, PF_NO_TAIL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436int test_clear_page_writeback(struct page *page);
Namjae Jeon1c8349a2014-05-12 08:12:25 -0400437int __test_set_page_writeback(struct page *page, bool keep_write);
438
439#define test_set_page_writeback(page) \
440 __test_set_page_writeback(page, false)
441#define test_set_page_writeback_keepwrite(page) \
442 __test_set_page_writeback(page, true)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444static inline void set_page_writeback(struct page *page)
445{
446 test_set_page_writeback(page);
447}
448
Namjae Jeon1c8349a2014-05-12 08:12:25 -0400449static inline void set_page_writeback_keepwrite(struct page *page)
450{
451 test_set_page_writeback_keepwrite(page);
452}
453
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800454__PAGEFLAG(Head, head, PF_ANY) CLEARPAGEFLAG(Head, head, PF_ANY)
Kirill A. Shutemov1d798ca2015-11-06 16:29:54 -0800455
Kirill A. Shutemov1d798ca2015-11-06 16:29:54 -0800456static inline void set_compound_head(struct page *page, struct page *head)
457{
458 WRITE_ONCE(page->compound_head, (unsigned long)head + 1);
459}
460
461static inline void clear_compound_head(struct page *page)
462{
463 WRITE_ONCE(page->compound_head, 0);
464}
465
Andrea Arcangeli4e6af672011-01-13 15:46:44 -0800466#ifdef CONFIG_TRANSPARENT_HUGEPAGE
467static inline void ClearPageCompound(struct page *page)
468{
469 BUG_ON(!PageHead(page));
470 ClearPageHead(page);
471}
472#endif
Petr Tesarikb3acc562014-06-23 13:22:03 -0700473
474#define PG_head_mask ((1L << PG_head))
475
Kirill A. Shutemove8c61582015-04-15 16:13:08 -0700476#ifdef CONFIG_HUGETLB_PAGE
477int PageHuge(struct page *page);
478int PageHeadHuge(struct page *page);
Naoya Horiguchi7e1f0492015-04-15 16:14:41 -0700479bool page_huge_active(struct page *page);
Kirill A. Shutemove8c61582015-04-15 16:13:08 -0700480#else
481TESTPAGEFLAG_FALSE(Huge)
482TESTPAGEFLAG_FALSE(HeadHuge)
Naoya Horiguchi7e1f0492015-04-15 16:14:41 -0700483
484static inline bool page_huge_active(struct page *page)
485{
486 return 0;
487}
Kirill A. Shutemove8c61582015-04-15 16:13:08 -0700488#endif
489
Naoya Horiguchi7e1f0492015-04-15 16:14:41 -0700490
Andrea Arcangeli936a5fe2011-01-13 15:46:48 -0800491#ifdef CONFIG_TRANSPARENT_HUGEPAGE
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800492/*
493 * PageHuge() only returns true for hugetlbfs pages, but not for
494 * normal or transparent huge pages.
495 *
496 * PageTransHuge() returns true for both transparent huge and
497 * hugetlbfs pages, but not normal pages. PageTransHuge() can only be
498 * called only in the core VM paths where hugetlbfs pages can't exist.
499 */
500static inline int PageTransHuge(struct page *page)
501{
Sasha Levin309381fea2014-01-23 15:52:54 -0800502 VM_BUG_ON_PAGE(PageTail(page), page);
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800503 return PageHead(page);
504}
505
Dean Nelson385de352012-03-21 16:34:05 -0700506/*
507 * PageTransCompound returns true for both transparent huge pages
508 * and hugetlbfs pages, so it should only be called when it's known
509 * that hugetlbfs pages aren't involved.
510 */
Andrea Arcangeli936a5fe2011-01-13 15:46:48 -0800511static inline int PageTransCompound(struct page *page)
512{
513 return PageCompound(page);
514}
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800515
Dean Nelson385de352012-03-21 16:34:05 -0700516/*
517 * PageTransTail returns true for both transparent huge pages
518 * and hugetlbfs pages, so it should only be called when it's known
519 * that hugetlbfs pages aren't involved.
520 */
521static inline int PageTransTail(struct page *page)
522{
523 return PageTail(page);
524}
525
Andrea Arcangeli936a5fe2011-01-13 15:46:48 -0800526#else
Kirill A. Shutemovd8c1bde2016-01-15 16:51:13 -0800527TESTPAGEFLAG_FALSE(TransHuge)
528TESTPAGEFLAG_FALSE(TransCompound)
529TESTPAGEFLAG_FALSE(TransTail)
Andrea Arcangeli936a5fe2011-01-13 15:46:48 -0800530#endif
531
Mel Gorman072bb0a2012-07-31 16:43:58 -0700532/*
Kirill A. Shutemove8c61582015-04-15 16:13:08 -0700533 * PageBuddy() indicate that the page is free and in the buddy system
534 * (see mm/page_alloc.c).
535 *
536 * PAGE_BUDDY_MAPCOUNT_VALUE must be <= -2 but better not too close to
537 * -2 so that an underflow of the page_mapcount() won't be mistaken
538 * for a genuine PAGE_BUDDY_MAPCOUNT_VALUE. -128 can be created very
539 * efficiently by most CPU architectures.
540 */
541#define PAGE_BUDDY_MAPCOUNT_VALUE (-128)
542
543static inline int PageBuddy(struct page *page)
544{
545 return atomic_read(&page->_mapcount) == PAGE_BUDDY_MAPCOUNT_VALUE;
546}
547
548static inline void __SetPageBuddy(struct page *page)
549{
550 VM_BUG_ON_PAGE(atomic_read(&page->_mapcount) != -1, page);
551 atomic_set(&page->_mapcount, PAGE_BUDDY_MAPCOUNT_VALUE);
552}
553
554static inline void __ClearPageBuddy(struct page *page)
555{
556 VM_BUG_ON_PAGE(!PageBuddy(page), page);
557 atomic_set(&page->_mapcount, -1);
558}
559
560#define PAGE_BALLOON_MAPCOUNT_VALUE (-256)
561
562static inline int PageBalloon(struct page *page)
563{
564 return atomic_read(&page->_mapcount) == PAGE_BALLOON_MAPCOUNT_VALUE;
565}
566
567static inline void __SetPageBalloon(struct page *page)
568{
569 VM_BUG_ON_PAGE(atomic_read(&page->_mapcount) != -1, page);
570 atomic_set(&page->_mapcount, PAGE_BALLOON_MAPCOUNT_VALUE);
571}
572
573static inline void __ClearPageBalloon(struct page *page)
574{
575 VM_BUG_ON_PAGE(!PageBalloon(page), page);
576 atomic_set(&page->_mapcount, -1);
577}
578
579/*
Mel Gorman072bb0a2012-07-31 16:43:58 -0700580 * If network-based swap is enabled, sl*b must keep track of whether pages
581 * were allocated from pfmemalloc reserves.
582 */
583static inline int PageSlabPfmemalloc(struct page *page)
584{
Sasha Levin309381fea2014-01-23 15:52:54 -0800585 VM_BUG_ON_PAGE(!PageSlab(page), page);
Mel Gorman072bb0a2012-07-31 16:43:58 -0700586 return PageActive(page);
587}
588
589static inline void SetPageSlabPfmemalloc(struct page *page)
590{
Sasha Levin309381fea2014-01-23 15:52:54 -0800591 VM_BUG_ON_PAGE(!PageSlab(page), page);
Mel Gorman072bb0a2012-07-31 16:43:58 -0700592 SetPageActive(page);
593}
594
595static inline void __ClearPageSlabPfmemalloc(struct page *page)
596{
Sasha Levin309381fea2014-01-23 15:52:54 -0800597 VM_BUG_ON_PAGE(!PageSlab(page), page);
Mel Gorman072bb0a2012-07-31 16:43:58 -0700598 __ClearPageActive(page);
599}
600
601static inline void ClearPageSlabPfmemalloc(struct page *page)
602{
Sasha Levin309381fea2014-01-23 15:52:54 -0800603 VM_BUG_ON_PAGE(!PageSlab(page), page);
Mel Gorman072bb0a2012-07-31 16:43:58 -0700604 ClearPageActive(page);
605}
606
Hugh Dickinsaf8e3352009-12-14 17:58:59 -0800607#ifdef CONFIG_MMU
David Howells33925b22009-03-31 15:23:26 -0700608#define __PG_MLOCKED (1 << PG_mlocked)
609#else
Nick Pigginb291f002008-10-18 20:26:44 -0700610#define __PG_MLOCKED 0
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700611#endif
612
Russ Andersondfa7e202008-06-09 11:18:45 -0500613/*
614 * Flags checked when a page is freed. Pages being freed should not have
615 * these flags set. It they are, there is a problem.
616 */
Hugh Dickins79f4b7b2009-01-06 14:40:05 -0800617#define PAGE_FLAGS_CHECK_AT_FREE \
David Howells266cf652009-04-03 16:42:36 +0100618 (1 << PG_lru | 1 << PG_locked | \
619 1 << PG_private | 1 << PG_private_2 | \
Andrea Arcangeli5f24ce52011-01-13 15:47:00 -0800620 1 << PG_writeback | 1 << PG_reserved | \
David Howells266cf652009-04-03 16:42:36 +0100621 1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \
Kirill A. Shutemov3ac808f2016-01-15 16:53:07 -0800622 1 << PG_unevictable | __PG_MLOCKED)
Russ Andersondfa7e202008-06-09 11:18:45 -0500623
624/*
625 * Flags checked when a page is prepped for return by the page allocator.
Naoya Horiguchif4c18e62015-08-06 15:47:08 -0700626 * Pages being prepped should not have these flags set. It they are set,
Hugh Dickins79f4b7b2009-01-06 14:40:05 -0800627 * there has been a kernel bug or struct page corruption.
Naoya Horiguchif4c18e62015-08-06 15:47:08 -0700628 *
629 * __PG_HWPOISON is exceptional because it needs to be kept beyond page's
630 * alloc-free cycle to prevent from reusing the page.
Russ Andersondfa7e202008-06-09 11:18:45 -0500631 */
Naoya Horiguchif4c18e62015-08-06 15:47:08 -0700632#define PAGE_FLAGS_CHECK_AT_PREP \
633 (((1 << NR_PAGEFLAGS) - 1) & ~__PG_HWPOISON)
Russ Andersondfa7e202008-06-09 11:18:45 -0500634
Johannes Weineredcf4742009-09-21 17:02:59 -0700635#define PAGE_FLAGS_PRIVATE \
636 (1 << PG_private | 1 << PG_private_2)
David Howells266cf652009-04-03 16:42:36 +0100637/**
638 * page_has_private - Determine if page has private stuff
639 * @page: The page to be checked
640 *
641 * Determine if a page has private stuff, indicating that release routines
642 * should be invoked upon it.
643 */
Johannes Weineredcf4742009-09-21 17:02:59 -0700644static inline int page_has_private(struct page *page)
645{
646 return !!(page->flags & PAGE_FLAGS_PRIVATE);
647}
648
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800649#undef PF_ANY
650#undef PF_HEAD
651#undef PF_NO_TAIL
652#undef PF_NO_COMPOUND
Johannes Weineredcf4742009-09-21 17:02:59 -0700653#endif /* !__GENERATING_BOUNDS_H */
David Howells266cf652009-04-03 16:42:36 +0100654
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655#endif /* PAGE_FLAGS_H */