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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>
Christoph Lameter9223b412008-04-28 02:12:48 -07009#ifndef __GENERATING_BOUNDS_H
Christoph Lameter6d777952007-05-06 14:49:40 -070010#include <linux/mm_types.h>
Sam Ravnborg01fc0ac2009-04-19 21:57:19 +020011#include <generated/bounds.h>
Christoph Lameter9223b412008-04-28 02:12:48 -070012#endif /* !__GENERATING_BOUNDS_H */
Andrew Mortonf886ed42006-06-23 02:03:06 -070013
Linus Torvalds1da177e2005-04-16 15:20:36 -070014/*
15 * Various page->flags bits:
16 *
17 * PG_reserved is set for special pages, which can never be swapped out. Some
18 * of them might not even exist (eg empty_bad_page)...
19 *
Nick Pigginda6052f2006-09-25 23:31:35 -070020 * The PG_private bitflag is set on pagecache pages if they contain filesystem
21 * specific data (which is normally at page->private). It can be used by
22 * private allocations for its own usage.
Linus Torvalds1da177e2005-04-16 15:20:36 -070023 *
Nick Pigginda6052f2006-09-25 23:31:35 -070024 * During initiation of disk I/O, PG_locked is set. This bit is set before I/O
25 * and cleared when writeback _starts_ or when read _completes_. PG_writeback
26 * is set before writeback starts and cleared when it finishes.
27 *
28 * PG_locked also pins a page in pagecache, and blocks truncation of the file
29 * while it is held.
30 *
31 * page_waitqueue(page) is a wait queue of all tasks waiting for the page
32 * to become unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -070033 *
34 * PG_uptodate tells whether the page's contents is valid. When a read
35 * completes, the page becomes uptodate, unless a disk I/O error happened.
36 *
Nick Pigginda6052f2006-09-25 23:31:35 -070037 * PG_referenced, PG_reclaim are used for page reclaim for anonymous and
38 * file-backed pagecache (see mm/vmscan.c).
Linus Torvalds1da177e2005-04-16 15:20:36 -070039 *
40 * PG_error is set to indicate that an I/O error occurred on this page.
41 *
42 * PG_arch_1 is an architecture specific page state bit. The generic code
43 * guarantees that this bit is cleared for a page when it first is entered into
44 * the page cache.
45 *
46 * PG_highmem pages are not permanently mapped into the kernel virtual address
47 * space, they need to be kmapped separately for doing IO on the pages. The
48 * struct page (these bits with information) are always mapped into kernel
49 * address space...
Nick Pigginda6052f2006-09-25 23:31:35 -070050 *
Andi Kleend466f2f2009-09-16 11:50:03 +020051 * PG_hwpoison indicates that a page got corrupted in hardware and contains
52 * data with incorrect ECC bits that triggered a machine check. Accessing is
53 * not safe since it may cause another machine check. Don't touch!
Linus Torvalds1da177e2005-04-16 15:20:36 -070054 */
55
56/*
57 * Don't use the *_dontuse flags. Use the macros. Otherwise you'll break
Andy Whitcroft91fc8ab2006-04-10 22:53:01 -070058 * locked- and dirty-page accounting.
59 *
60 * The page flags field is split into two parts, the main flags area
61 * which extends from the low bits upwards, and the fields area which
62 * extends from the high bits downwards.
63 *
64 * | FIELD | ... | FLAGS |
Christoph Lameter9223b412008-04-28 02:12:48 -070065 * N-1 ^ 0
66 * (NR_PAGEFLAGS)
Andy Whitcroft91fc8ab2006-04-10 22:53:01 -070067 *
Christoph Lameter9223b412008-04-28 02:12:48 -070068 * The fields area is reserved for fields mapping zone, node (for NUMA) and
69 * SPARSEMEM section (for variants of SPARSEMEM that require section ids like
70 * SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP).
Linus Torvalds1da177e2005-04-16 15:20:36 -070071 */
Christoph Lametere2683182008-04-28 02:12:47 -070072enum pageflags {
73 PG_locked, /* Page is locked. Don't touch. */
74 PG_error,
75 PG_referenced,
76 PG_uptodate,
77 PG_dirty,
78 PG_lru,
79 PG_active,
80 PG_slab,
81 PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/
Christoph Lametere2683182008-04-28 02:12:47 -070082 PG_arch_1,
83 PG_reserved,
84 PG_private, /* If pagecache, has fs-private data */
David Howells266cf652009-04-03 16:42:36 +010085 PG_private_2, /* If pagecache, has fs aux data */
Christoph Lametere2683182008-04-28 02:12:47 -070086 PG_writeback, /* Page is under writeback */
Christoph Lametere20b8cc2008-04-28 02:12:55 -070087#ifdef CONFIG_PAGEFLAGS_EXTENDED
88 PG_head, /* A head page */
89 PG_tail, /* A tail page */
90#else
Christoph Lametere2683182008-04-28 02:12:47 -070091 PG_compound, /* A compound page */
Christoph Lametere20b8cc2008-04-28 02:12:55 -070092#endif
Christoph Lametere2683182008-04-28 02:12:47 -070093 PG_swapcache, /* Swap page: swp_entry_t in private */
94 PG_mappedtodisk, /* Has blocks allocated on-disk */
95 PG_reclaim, /* To be reclaimed asap */
Rik van Rielb2e18532008-10-18 20:26:30 -070096 PG_swapbacked, /* Page is backed by RAM/swap */
Lee Schermerhorn894bc312008-10-18 20:26:39 -070097 PG_unevictable, /* Page is "unevictable" */
Hugh Dickinsaf8e3352009-12-14 17:58:59 -080098#ifdef CONFIG_MMU
Nick Pigginb291f002008-10-18 20:26:44 -070099 PG_mlocked, /* Page is vma mlocked */
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700100#endif
Venkatesh Pallipadi46cf98c2009-07-10 09:57:37 -0700101#ifdef CONFIG_ARCH_USES_PG_UNCACHED
Christoph Lameter602c4d12008-04-28 02:12:52 -0700102 PG_uncached, /* Page has been mapped as uncached */
Andrew Mortonf886ed42006-06-23 02:03:06 -0700103#endif
Andi Kleend466f2f2009-09-16 11:50:03 +0200104#ifdef CONFIG_MEMORY_FAILURE
105 PG_hwpoison, /* hardware poisoned page. Don't touch */
106#endif
Andrea Arcangelie9da73d2011-01-13 15:46:32 -0800107#ifdef CONFIG_TRANSPARENT_HUGEPAGE
108 PG_compound_lock,
109#endif
Andy Whitcroft0cad47c2008-07-23 21:27:16 -0700110 __NR_PAGEFLAGS,
111
112 /* Filesystems */
113 PG_checked = PG_owner_priv_1,
114
David Howells266cf652009-04-03 16:42:36 +0100115 /* Two page bits are conscripted by FS-Cache to maintain local caching
116 * state. These bits are set on pages belonging to the netfs's inodes
117 * when those inodes are being locally cached.
118 */
119 PG_fscache = PG_private_2, /* page backed by cache */
120
Andy Whitcroft0cad47c2008-07-23 21:27:16 -0700121 /* XEN */
122 PG_pinned = PG_owner_priv_1,
123 PG_savepinned = PG_dirty,
Andy Whitcroft8a380822008-07-23 21:27:18 -0700124
Andy Whitcroft9023cb72008-07-23 21:27:19 -0700125 /* SLOB */
Andy Whitcroft9023cb72008-07-23 21:27:19 -0700126 PG_slob_free = PG_private,
Christoph Lametere2683182008-04-28 02:12:47 -0700127};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128
Christoph Lameter9223b412008-04-28 02:12:48 -0700129#ifndef __GENERATING_BOUNDS_H
130
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131/*
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700132 * Macros to create function definitions for page flags
133 */
134#define TESTPAGEFLAG(uname, lname) \
Ian Campbell67db3922011-07-25 17:11:52 -0700135static inline int Page##uname(const struct page *page) \
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700136 { return test_bit(PG_##lname, &page->flags); }
137
138#define SETPAGEFLAG(uname, lname) \
139static inline void SetPage##uname(struct page *page) \
140 { set_bit(PG_##lname, &page->flags); }
141
142#define CLEARPAGEFLAG(uname, lname) \
143static inline void ClearPage##uname(struct page *page) \
144 { clear_bit(PG_##lname, &page->flags); }
145
146#define __SETPAGEFLAG(uname, lname) \
147static inline void __SetPage##uname(struct page *page) \
148 { __set_bit(PG_##lname, &page->flags); }
149
150#define __CLEARPAGEFLAG(uname, lname) \
151static inline void __ClearPage##uname(struct page *page) \
152 { __clear_bit(PG_##lname, &page->flags); }
153
154#define TESTSETFLAG(uname, lname) \
155static inline int TestSetPage##uname(struct page *page) \
156 { return test_and_set_bit(PG_##lname, &page->flags); }
157
158#define TESTCLEARFLAG(uname, lname) \
159static inline int TestClearPage##uname(struct page *page) \
160 { return test_and_clear_bit(PG_##lname, &page->flags); }
161
Johannes Weiner451ea252009-09-21 17:01:48 -0700162#define __TESTCLEARFLAG(uname, lname) \
163static inline int __TestClearPage##uname(struct page *page) \
164 { return __test_and_clear_bit(PG_##lname, &page->flags); }
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700165
166#define PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \
167 SETPAGEFLAG(uname, lname) CLEARPAGEFLAG(uname, lname)
168
169#define __PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \
170 __SETPAGEFLAG(uname, lname) __CLEARPAGEFLAG(uname, lname)
171
Christoph Lameterec7cade2008-04-28 02:12:53 -0700172#define PAGEFLAG_FALSE(uname) \
Ian Campbell67db3922011-07-25 17:11:52 -0700173static inline int Page##uname(const struct page *page) \
Christoph Lameterec7cade2008-04-28 02:12:53 -0700174 { return 0; }
175
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700176#define TESTSCFLAG(uname, lname) \
177 TESTSETFLAG(uname, lname) TESTCLEARFLAG(uname, lname)
178
Lee Schermerhorn8a7a8542008-10-18 20:26:37 -0700179#define SETPAGEFLAG_NOOP(uname) \
180static inline void SetPage##uname(struct page *page) { }
181
182#define CLEARPAGEFLAG_NOOP(uname) \
183static inline void ClearPage##uname(struct page *page) { }
184
185#define __CLEARPAGEFLAG_NOOP(uname) \
186static inline void __ClearPage##uname(struct page *page) { }
187
188#define TESTCLEARFLAG_FALSE(uname) \
189static inline int TestClearPage##uname(struct page *page) { return 0; }
190
Johannes Weiner451ea252009-09-21 17:01:48 -0700191#define __TESTCLEARFLAG_FALSE(uname) \
192static inline int __TestClearPage##uname(struct page *page) { return 0; }
193
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700194struct page; /* forward declaration */
195
Michel Lespinassecb240452011-03-22 16:32:49 -0700196TESTPAGEFLAG(Locked, locked)
Rik van Riel212260a2011-01-13 15:46:06 -0800197PAGEFLAG(Error, error) TESTCLEARFLAG(Error, error)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700198PAGEFLAG(Referenced, referenced) TESTCLEARFLAG(Referenced, referenced)
199PAGEFLAG(Dirty, dirty) TESTSCFLAG(Dirty, dirty) __CLEARPAGEFLAG(Dirty, dirty)
200PAGEFLAG(LRU, lru) __CLEARPAGEFLAG(LRU, lru)
201PAGEFLAG(Active, active) __CLEARPAGEFLAG(Active, active)
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700202 TESTCLEARFLAG(Active, active)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700203__PAGEFLAG(Slab, slab)
Andy Whitcroft0cad47c2008-07-23 21:27:16 -0700204PAGEFLAG(Checked, checked) /* Used by some filesystems */
205PAGEFLAG(Pinned, pinned) TESTSCFLAG(Pinned, pinned) /* Xen */
206PAGEFLAG(SavePinned, savepinned); /* Xen */
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700207PAGEFLAG(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved)
Rik van Rielb2e18532008-10-18 20:26:30 -0700208PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700209
Andy Whitcroft9023cb72008-07-23 21:27:19 -0700210__PAGEFLAG(SlobFree, slob_free)
211
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700212/*
David Howells266cf652009-04-03 16:42:36 +0100213 * Private page markings that may be used by the filesystem that owns the page
214 * for its own purposes.
215 * - PG_private and PG_private_2 cause releasepage() and co to be invoked
216 */
217PAGEFLAG(Private, private) __SETPAGEFLAG(Private, private)
218 __CLEARPAGEFLAG(Private, private)
219PAGEFLAG(Private2, private_2) TESTSCFLAG(Private2, private_2)
220PAGEFLAG(OwnerPriv1, owner_priv_1) TESTCLEARFLAG(OwnerPriv1, owner_priv_1)
221
222/*
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700223 * Only test-and-set exist for PG_writeback. The unconditional operators are
224 * risky: they bypass page accounting.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 */
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700226TESTPAGEFLAG(Writeback, writeback) TESTSCFLAG(Writeback, writeback)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700227PAGEFLAG(MappedToDisk, mappedtodisk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700229/* PG_readahead is only used for file reads; PG_reclaim is only for writes */
230PAGEFLAG(Reclaim, reclaim) TESTCLEARFLAG(Reclaim, reclaim)
Christoph Lameter0a128b22008-04-28 02:12:52 -0700231PAGEFLAG(Readahead, reclaim) /* Reminder to do async read-ahead */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700233#ifdef CONFIG_HIGHMEM
234/*
235 * Must use a macro here due to header dependency issues. page_zone() is not
236 * available at this point.
237 */
Christoph Lameter0a128b22008-04-28 02:12:52 -0700238#define PageHighMem(__p) is_highmem(page_zone(__p))
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700239#else
Christoph Lameterec7cade2008-04-28 02:12:53 -0700240PAGEFLAG_FALSE(HighMem)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700241#endif
242
243#ifdef CONFIG_SWAP
244PAGEFLAG(SwapCache, swapcache)
245#else
Christoph Lameterec7cade2008-04-28 02:12:53 -0700246PAGEFLAG_FALSE(SwapCache)
Hugh Dickins6d91add2009-01-06 14:39:24 -0800247 SETPAGEFLAG_NOOP(SwapCache) CLEARPAGEFLAG_NOOP(SwapCache)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700248#endif
249
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700250PAGEFLAG(Unevictable, unevictable) __CLEARPAGEFLAG(Unevictable, unevictable)
251 TESTCLEARFLAG(Unevictable, unevictable)
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700252
Hugh Dickinsaf8e3352009-12-14 17:58:59 -0800253#ifdef CONFIG_MMU
David Howells33925b22009-03-31 15:23:26 -0700254PAGEFLAG(Mlocked, mlocked) __CLEARPAGEFLAG(Mlocked, mlocked)
Johannes Weiner451ea252009-09-21 17:01:48 -0700255 TESTSCFLAG(Mlocked, mlocked) __TESTCLEARFLAG(Mlocked, mlocked)
David Howells33925b22009-03-31 15:23:26 -0700256#else
Johannes Weiner451ea252009-09-21 17:01:48 -0700257PAGEFLAG_FALSE(Mlocked) SETPAGEFLAG_NOOP(Mlocked)
258 TESTCLEARFLAG_FALSE(Mlocked) __TESTCLEARFLAG_FALSE(Mlocked)
David Howells33925b22009-03-31 15:23:26 -0700259#endif
260
Venkatesh Pallipadi46cf98c2009-07-10 09:57:37 -0700261#ifdef CONFIG_ARCH_USES_PG_UNCACHED
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700262PAGEFLAG(Uncached, uncached)
Christoph Lameter602c4d12008-04-28 02:12:52 -0700263#else
Christoph Lameterec7cade2008-04-28 02:12:53 -0700264PAGEFLAG_FALSE(Uncached)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700265#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266
Andi Kleend466f2f2009-09-16 11:50:03 +0200267#ifdef CONFIG_MEMORY_FAILURE
268PAGEFLAG(HWPoison, hwpoison)
Wu Fengguang847ce402009-12-16 12:19:58 +0100269TESTSCFLAG(HWPoison, hwpoison)
Andi Kleend466f2f2009-09-16 11:50:03 +0200270#define __PG_HWPOISON (1UL << PG_hwpoison)
271#else
272PAGEFLAG_FALSE(HWPoison)
273#define __PG_HWPOISON 0
274#endif
275
Wu Fengguang1a9b5b72009-12-16 12:19:59 +0100276u64 stable_page_flags(struct page *page);
277
Nick Piggin0ed361d2008-02-04 22:29:34 -0800278static inline int PageUptodate(struct page *page)
279{
280 int ret = test_bit(PG_uptodate, &(page)->flags);
281
282 /*
283 * Must ensure that the data we read out of the page is loaded
284 * _after_ we've loaded page->flags to check for PageUptodate.
285 * We can skip the barrier if the page is not uptodate, because
286 * we wouldn't be reading anything from it.
287 *
288 * See SetPageUptodate() for the other side of the story.
289 */
290 if (ret)
291 smp_rmb();
292
293 return ret;
294}
295
296static inline void __SetPageUptodate(struct page *page)
297{
298 smp_wmb();
299 __set_bit(PG_uptodate, &(page)->flags);
Nick Piggin0ed361d2008-02-04 22:29:34 -0800300}
301
Heiko Carstens2dcea572006-09-29 01:58:41 -0700302static inline void SetPageUptodate(struct page *page)
303{
Nick Piggin0ed361d2008-02-04 22:29:34 -0800304#ifdef CONFIG_S390
Heiko Carstens2dcea572006-09-29 01:58:41 -0700305 if (!test_and_set_bit(PG_uptodate, &page->flags))
Heiko Carstensa43a9d92011-05-29 12:40:50 +0200306 page_set_storage_key(page_to_phys(page), PAGE_DEFAULT_KEY, 0);
Christoph Lameterf6ac2352006-06-30 01:55:32 -0700307#else
Nick Piggin0ed361d2008-02-04 22:29:34 -0800308 /*
309 * Memory barrier must be issued before setting the PG_uptodate bit,
310 * so that all previous stores issued in order to bring the page
311 * uptodate are actually visible before PageUptodate becomes true.
312 *
313 * s390 doesn't need an explicit smp_wmb here because the test and
314 * set bit already provides full barriers.
315 */
316 smp_wmb();
317 set_bit(PG_uptodate, &(page)->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318#endif
Nick Piggin0ed361d2008-02-04 22:29:34 -0800319}
320
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700321CLEARPAGEFLAG(Uptodate, uptodate)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322
Linus Torvaldsfba25912006-12-20 13:46:42 -0800323extern void cancel_dirty_page(struct page *page, unsigned int account_size);
324
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325int test_clear_page_writeback(struct page *page);
326int test_set_page_writeback(struct page *page);
327
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328static inline void set_page_writeback(struct page *page)
329{
330 test_set_page_writeback(page);
331}
332
Christoph Lametere20b8cc2008-04-28 02:12:55 -0700333#ifdef CONFIG_PAGEFLAGS_EXTENDED
334/*
335 * System with lots of page flags available. This allows separate
336 * flags for PageHead() and PageTail() checks of compound pages so that bit
337 * tests can be used in performance sensitive paths. PageCompound is
338 * generally not used in hot code paths.
339 */
Andrea Arcangeli4e6af672011-01-13 15:46:44 -0800340__PAGEFLAG(Head, head) CLEARPAGEFLAG(Head, head)
Christoph Lametere20b8cc2008-04-28 02:12:55 -0700341__PAGEFLAG(Tail, tail)
342
343static inline int PageCompound(struct page *page)
344{
345 return page->flags & ((1L << PG_head) | (1L << PG_tail));
346
347}
Andrea Arcangeli4e6af672011-01-13 15:46:44 -0800348#ifdef CONFIG_TRANSPARENT_HUGEPAGE
349static inline void ClearPageCompound(struct page *page)
350{
351 BUG_ON(!PageHead(page));
352 ClearPageHead(page);
353}
354#endif
Christoph Lametere20b8cc2008-04-28 02:12:55 -0700355#else
356/*
357 * Reduce page flag use as much as possible by overlapping
358 * compound page flags with the flags used for page cache pages. Possible
359 * because PageCompound is always set for compound pages and not for
360 * pages on the LRU and/or pagecache.
361 */
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700362TESTPAGEFLAG(Compound, compound)
363__PAGEFLAG(Head, compound)
364
365/*
366 * PG_reclaim is used in combination with PG_compound to mark the
367 * head and tail of a compound page. This saves one page flag
368 * but makes it impossible to use compound pages for the page cache.
369 * The PG_reclaim bit would have to be used for reclaim or readahead
370 * if compound pages enter the page cache.
371 *
372 * PG_compound & PG_reclaim => Tail page
373 * PG_compound & ~PG_reclaim => Head page
374 */
375#define PG_head_tail_mask ((1L << PG_compound) | (1L << PG_reclaim))
376
377static inline int PageTail(struct page *page)
378{
379 return ((page->flags & PG_head_tail_mask) == PG_head_tail_mask);
380}
381
382static inline void __SetPageTail(struct page *page)
383{
384 page->flags |= PG_head_tail_mask;
385}
386
387static inline void __ClearPageTail(struct page *page)
388{
389 page->flags &= ~PG_head_tail_mask;
390}
391
Andrea Arcangeli4e6af672011-01-13 15:46:44 -0800392#ifdef CONFIG_TRANSPARENT_HUGEPAGE
393static inline void ClearPageCompound(struct page *page)
394{
395 BUG_ON((page->flags & PG_head_tail_mask) != (1 << PG_compound));
396 clear_bit(PG_compound, &page->flags);
397}
398#endif
399
Christoph Lametere20b8cc2008-04-28 02:12:55 -0700400#endif /* !PAGEFLAGS_EXTENDED */
Russ Andersondfa7e202008-06-09 11:18:45 -0500401
Andrea Arcangeli936a5fe2011-01-13 15:46:48 -0800402#ifdef CONFIG_TRANSPARENT_HUGEPAGE
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800403/*
404 * PageHuge() only returns true for hugetlbfs pages, but not for
405 * normal or transparent huge pages.
406 *
407 * PageTransHuge() returns true for both transparent huge and
408 * hugetlbfs pages, but not normal pages. PageTransHuge() can only be
409 * called only in the core VM paths where hugetlbfs pages can't exist.
410 */
411static inline int PageTransHuge(struct page *page)
412{
413 VM_BUG_ON(PageTail(page));
414 return PageHead(page);
415}
416
Dean Nelson385de352012-03-21 16:34:05 -0700417/*
418 * PageTransCompound returns true for both transparent huge pages
419 * and hugetlbfs pages, so it should only be called when it's known
420 * that hugetlbfs pages aren't involved.
421 */
Andrea Arcangeli936a5fe2011-01-13 15:46:48 -0800422static inline int PageTransCompound(struct page *page)
423{
424 return PageCompound(page);
425}
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800426
Dean Nelson385de352012-03-21 16:34:05 -0700427/*
428 * PageTransTail returns true for both transparent huge pages
429 * and hugetlbfs pages, so it should only be called when it's known
430 * that hugetlbfs pages aren't involved.
431 */
432static inline int PageTransTail(struct page *page)
433{
434 return PageTail(page);
435}
436
Andrea Arcangeli936a5fe2011-01-13 15:46:48 -0800437#else
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800438
439static inline int PageTransHuge(struct page *page)
440{
441 return 0;
442}
443
Andrea Arcangeli936a5fe2011-01-13 15:46:48 -0800444static inline int PageTransCompound(struct page *page)
445{
446 return 0;
447}
Dean Nelson385de352012-03-21 16:34:05 -0700448
449static inline int PageTransTail(struct page *page)
450{
451 return 0;
452}
Andrea Arcangeli936a5fe2011-01-13 15:46:48 -0800453#endif
454
Hugh Dickinsaf8e3352009-12-14 17:58:59 -0800455#ifdef CONFIG_MMU
David Howells33925b22009-03-31 15:23:26 -0700456#define __PG_MLOCKED (1 << PG_mlocked)
457#else
Nick Pigginb291f002008-10-18 20:26:44 -0700458#define __PG_MLOCKED 0
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700459#endif
460
Andrea Arcangelie9da73d2011-01-13 15:46:32 -0800461#ifdef CONFIG_TRANSPARENT_HUGEPAGE
462#define __PG_COMPOUND_LOCK (1 << PG_compound_lock)
463#else
464#define __PG_COMPOUND_LOCK 0
465#endif
466
Russ Andersondfa7e202008-06-09 11:18:45 -0500467/*
468 * Flags checked when a page is freed. Pages being freed should not have
469 * these flags set. It they are, there is a problem.
470 */
Hugh Dickins79f4b7b2009-01-06 14:40:05 -0800471#define PAGE_FLAGS_CHECK_AT_FREE \
David Howells266cf652009-04-03 16:42:36 +0100472 (1 << PG_lru | 1 << PG_locked | \
473 1 << PG_private | 1 << PG_private_2 | \
Andrea Arcangeli5f24ce52011-01-13 15:47:00 -0800474 1 << PG_writeback | 1 << PG_reserved | \
David Howells266cf652009-04-03 16:42:36 +0100475 1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \
Andrea Arcangelie9da73d2011-01-13 15:46:32 -0800476 1 << PG_unevictable | __PG_MLOCKED | __PG_HWPOISON | \
477 __PG_COMPOUND_LOCK)
Russ Andersondfa7e202008-06-09 11:18:45 -0500478
479/*
480 * Flags checked when a page is prepped for return by the page allocator.
Hugh Dickins79f4b7b2009-01-06 14:40:05 -0800481 * Pages being prepped should not have any flags set. It they are set,
482 * there has been a kernel bug or struct page corruption.
Russ Andersondfa7e202008-06-09 11:18:45 -0500483 */
Hugh Dickins79f4b7b2009-01-06 14:40:05 -0800484#define PAGE_FLAGS_CHECK_AT_PREP ((1 << NR_PAGEFLAGS) - 1)
Russ Andersondfa7e202008-06-09 11:18:45 -0500485
Johannes Weineredcf4742009-09-21 17:02:59 -0700486#define PAGE_FLAGS_PRIVATE \
487 (1 << PG_private | 1 << PG_private_2)
David Howells266cf652009-04-03 16:42:36 +0100488/**
489 * page_has_private - Determine if page has private stuff
490 * @page: The page to be checked
491 *
492 * Determine if a page has private stuff, indicating that release routines
493 * should be invoked upon it.
494 */
Johannes Weineredcf4742009-09-21 17:02:59 -0700495static inline int page_has_private(struct page *page)
496{
497 return !!(page->flags & PAGE_FLAGS_PRIVATE);
498}
499
500#endif /* !__GENERATING_BOUNDS_H */
David Howells266cf652009-04-03 16:42:36 +0100501
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502#endif /* PAGE_FLAGS_H */