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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 Lameter9223b412008-04-28 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 Lameter9223b412008-04-28 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 Lameter9223b412008-04-28 02:12:48 -070067 * N-1 ^ 0
68 * (NR_PAGEFLAGS)
Andy Whitcroft91fc8ab2006-04-10 22:53:01 -070069 *
Christoph Lameter9223b412008-04-28 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#ifdef CONFIG_PAGEFLAGS_EXTENDED
90 PG_head, /* A head page */
91 PG_tail, /* A tail page */
92#else
Christoph Lametere2683182008-04-28 02:12:47 -070093 PG_compound, /* A compound page */
Christoph Lametere20b8cc2008-04-28 02:12:55 -070094#endif
Christoph Lametere2683182008-04-28 02:12:47 -070095 PG_swapcache, /* Swap page: swp_entry_t in private */
96 PG_mappedtodisk, /* Has blocks allocated on-disk */
97 PG_reclaim, /* To be reclaimed asap */
Rik van Rielb2e18532008-10-18 20:26:30 -070098 PG_swapbacked, /* Page is backed by RAM/swap */
Lee Schermerhorn894bc312008-10-18 20:26:39 -070099 PG_unevictable, /* Page is "unevictable" */
Hugh Dickinsaf8e3352009-12-14 17:58:59 -0800100#ifdef CONFIG_MMU
Nick Pigginb291f002008-10-18 20:26:44 -0700101 PG_mlocked, /* Page is vma mlocked */
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700102#endif
Venkatesh Pallipadi46cf98c2009-07-10 09:57:37 -0700103#ifdef CONFIG_ARCH_USES_PG_UNCACHED
Christoph Lameter602c4d12008-04-28 02:12:52 -0700104 PG_uncached, /* Page has been mapped as uncached */
Andrew Mortonf886ed42006-06-23 02:03:06 -0700105#endif
Andi Kleend466f2f2009-09-16 11:50:03 +0200106#ifdef CONFIG_MEMORY_FAILURE
107 PG_hwpoison, /* hardware poisoned page. Don't touch */
108#endif
Andrea Arcangelie9da73d2011-01-13 15:46:32 -0800109#ifdef CONFIG_TRANSPARENT_HUGEPAGE
110 PG_compound_lock,
111#endif
Andy Whitcroft0cad47c2008-07-23 21:27:16 -0700112 __NR_PAGEFLAGS,
113
114 /* Filesystems */
115 PG_checked = PG_owner_priv_1,
116
David Howells266cf652009-04-03 16:42:36 +0100117 /* Two page bits are conscripted by FS-Cache to maintain local caching
118 * state. These bits are set on pages belonging to the netfs's inodes
119 * when those inodes are being locally cached.
120 */
121 PG_fscache = PG_private_2, /* page backed by cache */
122
Andy Whitcroft0cad47c2008-07-23 21:27:16 -0700123 /* XEN */
124 PG_pinned = PG_owner_priv_1,
125 PG_savepinned = PG_dirty,
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 Lameter9223b412008-04-28 02:12:48 -0700131#ifndef __GENERATING_BOUNDS_H
132
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133/*
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700134 * Macros to create function definitions for page flags
135 */
136#define TESTPAGEFLAG(uname, lname) \
Ian Campbell67db3922011-07-25 17:11:52 -0700137static inline int Page##uname(const struct page *page) \
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700138 { return test_bit(PG_##lname, &page->flags); }
139
140#define SETPAGEFLAG(uname, lname) \
141static inline void SetPage##uname(struct page *page) \
142 { set_bit(PG_##lname, &page->flags); }
143
144#define CLEARPAGEFLAG(uname, lname) \
145static inline void ClearPage##uname(struct page *page) \
146 { clear_bit(PG_##lname, &page->flags); }
147
148#define __SETPAGEFLAG(uname, lname) \
149static inline void __SetPage##uname(struct page *page) \
150 { __set_bit(PG_##lname, &page->flags); }
151
152#define __CLEARPAGEFLAG(uname, lname) \
153static inline void __ClearPage##uname(struct page *page) \
154 { __clear_bit(PG_##lname, &page->flags); }
155
156#define TESTSETFLAG(uname, lname) \
157static inline int TestSetPage##uname(struct page *page) \
158 { return test_and_set_bit(PG_##lname, &page->flags); }
159
160#define TESTCLEARFLAG(uname, lname) \
161static inline int TestClearPage##uname(struct page *page) \
162 { return test_and_clear_bit(PG_##lname, &page->flags); }
163
Johannes Weiner451ea252009-09-21 17:01:48 -0700164#define __TESTCLEARFLAG(uname, lname) \
165static inline int __TestClearPage##uname(struct page *page) \
166 { return __test_and_clear_bit(PG_##lname, &page->flags); }
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700167
168#define PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \
169 SETPAGEFLAG(uname, lname) CLEARPAGEFLAG(uname, lname)
170
171#define __PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \
172 __SETPAGEFLAG(uname, lname) __CLEARPAGEFLAG(uname, lname)
173
Christoph Lameterec7cade2008-04-28 02:12:53 -0700174#define PAGEFLAG_FALSE(uname) \
Ian Campbell67db3922011-07-25 17:11:52 -0700175static inline int Page##uname(const struct page *page) \
Christoph Lameterec7cade2008-04-28 02:12:53 -0700176 { return 0; }
177
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700178#define TESTSCFLAG(uname, lname) \
179 TESTSETFLAG(uname, lname) TESTCLEARFLAG(uname, lname)
180
Lee Schermerhorn8a7a8542008-10-18 20:26:37 -0700181#define SETPAGEFLAG_NOOP(uname) \
182static inline void SetPage##uname(struct page *page) { }
183
184#define CLEARPAGEFLAG_NOOP(uname) \
185static inline void ClearPage##uname(struct page *page) { }
186
187#define __CLEARPAGEFLAG_NOOP(uname) \
188static inline void __ClearPage##uname(struct page *page) { }
189
190#define TESTCLEARFLAG_FALSE(uname) \
191static inline int TestClearPage##uname(struct page *page) { return 0; }
192
Johannes Weiner451ea252009-09-21 17:01:48 -0700193#define __TESTCLEARFLAG_FALSE(uname) \
194static inline int __TestClearPage##uname(struct page *page) { return 0; }
195
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700196struct page; /* forward declaration */
197
Michel Lespinassecb240452011-03-22 16:32:49 -0700198TESTPAGEFLAG(Locked, locked)
Rik van Riel212260a2011-01-13 15:46:06 -0800199PAGEFLAG(Error, error) TESTCLEARFLAG(Error, error)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700200PAGEFLAG(Referenced, referenced) TESTCLEARFLAG(Referenced, referenced)
201PAGEFLAG(Dirty, dirty) TESTSCFLAG(Dirty, dirty) __CLEARPAGEFLAG(Dirty, dirty)
202PAGEFLAG(LRU, lru) __CLEARPAGEFLAG(LRU, lru)
203PAGEFLAG(Active, active) __CLEARPAGEFLAG(Active, active)
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700204 TESTCLEARFLAG(Active, active)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700205__PAGEFLAG(Slab, slab)
Andy Whitcroft0cad47c2008-07-23 21:27:16 -0700206PAGEFLAG(Checked, checked) /* Used by some filesystems */
207PAGEFLAG(Pinned, pinned) TESTSCFLAG(Pinned, pinned) /* Xen */
208PAGEFLAG(SavePinned, savepinned); /* Xen */
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700209PAGEFLAG(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved)
Rik van Rielb2e18532008-10-18 20:26:30 -0700210PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700211
Andy Whitcroft9023cb72008-07-23 21:27:19 -0700212__PAGEFLAG(SlobFree, slob_free)
213
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700214/*
David Howells266cf652009-04-03 16:42:36 +0100215 * Private page markings that may be used by the filesystem that owns the page
216 * for its own purposes.
217 * - PG_private and PG_private_2 cause releasepage() and co to be invoked
218 */
219PAGEFLAG(Private, private) __SETPAGEFLAG(Private, private)
220 __CLEARPAGEFLAG(Private, private)
221PAGEFLAG(Private2, private_2) TESTSCFLAG(Private2, private_2)
222PAGEFLAG(OwnerPriv1, owner_priv_1) TESTCLEARFLAG(OwnerPriv1, owner_priv_1)
223
224/*
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700225 * Only test-and-set exist for PG_writeback. The unconditional operators are
226 * risky: they bypass page accounting.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 */
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700228TESTPAGEFLAG(Writeback, writeback) TESTSCFLAG(Writeback, writeback)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700229PAGEFLAG(MappedToDisk, mappedtodisk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700231/* PG_readahead is only used for file reads; PG_reclaim is only for writes */
232PAGEFLAG(Reclaim, reclaim) TESTCLEARFLAG(Reclaim, reclaim)
Christoph Lameter0a128b22008-04-28 02:12:52 -0700233PAGEFLAG(Readahead, reclaim) /* Reminder to do async read-ahead */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700235#ifdef CONFIG_HIGHMEM
236/*
237 * Must use a macro here due to header dependency issues. page_zone() is not
238 * available at this point.
239 */
Christoph Lameter0a128b22008-04-28 02:12:52 -0700240#define PageHighMem(__p) is_highmem(page_zone(__p))
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700241#else
Christoph Lameterec7cade2008-04-28 02:12:53 -0700242PAGEFLAG_FALSE(HighMem)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700243#endif
244
245#ifdef CONFIG_SWAP
246PAGEFLAG(SwapCache, swapcache)
247#else
Christoph Lameterec7cade2008-04-28 02:12:53 -0700248PAGEFLAG_FALSE(SwapCache)
Hugh Dickins6d91add2009-01-06 14:39:24 -0800249 SETPAGEFLAG_NOOP(SwapCache) CLEARPAGEFLAG_NOOP(SwapCache)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700250#endif
251
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700252PAGEFLAG(Unevictable, unevictable) __CLEARPAGEFLAG(Unevictable, unevictable)
253 TESTCLEARFLAG(Unevictable, unevictable)
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700254
Hugh Dickinsaf8e3352009-12-14 17:58:59 -0800255#ifdef CONFIG_MMU
David Howells33925b22009-03-31 15:23:26 -0700256PAGEFLAG(Mlocked, mlocked) __CLEARPAGEFLAG(Mlocked, mlocked)
Johannes Weiner451ea252009-09-21 17:01:48 -0700257 TESTSCFLAG(Mlocked, mlocked) __TESTCLEARFLAG(Mlocked, mlocked)
David Howells33925b22009-03-31 15:23:26 -0700258#else
Johannes Weiner451ea252009-09-21 17:01:48 -0700259PAGEFLAG_FALSE(Mlocked) SETPAGEFLAG_NOOP(Mlocked)
260 TESTCLEARFLAG_FALSE(Mlocked) __TESTCLEARFLAG_FALSE(Mlocked)
David Howells33925b22009-03-31 15:23:26 -0700261#endif
262
Venkatesh Pallipadi46cf98c2009-07-10 09:57:37 -0700263#ifdef CONFIG_ARCH_USES_PG_UNCACHED
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700264PAGEFLAG(Uncached, uncached)
Christoph Lameter602c4d12008-04-28 02:12:52 -0700265#else
Christoph Lameterec7cade2008-04-28 02:12:53 -0700266PAGEFLAG_FALSE(Uncached)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700267#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268
Andi Kleend466f2f2009-09-16 11:50:03 +0200269#ifdef CONFIG_MEMORY_FAILURE
270PAGEFLAG(HWPoison, hwpoison)
Wu Fengguang847ce402009-12-16 12:19:58 +0100271TESTSCFLAG(HWPoison, hwpoison)
Andi Kleend466f2f2009-09-16 11:50:03 +0200272#define __PG_HWPOISON (1UL << PG_hwpoison)
273#else
274PAGEFLAG_FALSE(HWPoison)
275#define __PG_HWPOISON 0
276#endif
277
Wu Fengguang1a9b5b72009-12-16 12:19:59 +0100278u64 stable_page_flags(struct page *page);
279
Nick Piggin0ed361d2008-02-04 22:29:34 -0800280static inline int PageUptodate(struct page *page)
281{
282 int ret = test_bit(PG_uptodate, &(page)->flags);
283
284 /*
285 * Must ensure that the data we read out of the page is loaded
286 * _after_ we've loaded page->flags to check for PageUptodate.
287 * We can skip the barrier if the page is not uptodate, because
288 * we wouldn't be reading anything from it.
289 *
290 * See SetPageUptodate() for the other side of the story.
291 */
292 if (ret)
293 smp_rmb();
294
295 return ret;
296}
297
298static inline void __SetPageUptodate(struct page *page)
299{
300 smp_wmb();
301 __set_bit(PG_uptodate, &(page)->flags);
Nick Piggin0ed361d2008-02-04 22:29:34 -0800302}
303
Heiko Carstens2dcea572006-09-29 01:58:41 -0700304static inline void SetPageUptodate(struct page *page)
305{
Nick Piggin0ed361d2008-02-04 22:29:34 -0800306#ifdef CONFIG_S390
Heiko Carstens2dcea572006-09-29 01:58:41 -0700307 if (!test_and_set_bit(PG_uptodate, &page->flags))
Heiko Carstensa43a9d92011-05-29 12:40:50 +0200308 page_set_storage_key(page_to_phys(page), PAGE_DEFAULT_KEY, 0);
Christoph Lameterf6ac2352006-06-30 01:55:32 -0700309#else
Nick Piggin0ed361d2008-02-04 22:29:34 -0800310 /*
311 * Memory barrier must be issued before setting the PG_uptodate bit,
312 * so that all previous stores issued in order to bring the page
313 * uptodate are actually visible before PageUptodate becomes true.
314 *
315 * s390 doesn't need an explicit smp_wmb here because the test and
316 * set bit already provides full barriers.
317 */
318 smp_wmb();
319 set_bit(PG_uptodate, &(page)->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320#endif
Nick Piggin0ed361d2008-02-04 22:29:34 -0800321}
322
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700323CLEARPAGEFLAG(Uptodate, uptodate)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324
Linus Torvaldsfba25912006-12-20 13:46:42 -0800325extern void cancel_dirty_page(struct page *page, unsigned int account_size);
326
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327int test_clear_page_writeback(struct page *page);
328int test_set_page_writeback(struct page *page);
329
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330static inline void set_page_writeback(struct page *page)
331{
332 test_set_page_writeback(page);
333}
334
Christoph Lametere20b8cc2008-04-28 02:12:55 -0700335#ifdef CONFIG_PAGEFLAGS_EXTENDED
336/*
337 * System with lots of page flags available. This allows separate
338 * flags for PageHead() and PageTail() checks of compound pages so that bit
339 * tests can be used in performance sensitive paths. PageCompound is
340 * generally not used in hot code paths.
341 */
Andrea Arcangeli4e6af672011-01-13 15:46:44 -0800342__PAGEFLAG(Head, head) CLEARPAGEFLAG(Head, head)
Christoph Lametere20b8cc2008-04-28 02:12:55 -0700343__PAGEFLAG(Tail, tail)
344
345static inline int PageCompound(struct page *page)
346{
347 return page->flags & ((1L << PG_head) | (1L << PG_tail));
348
349}
Andrea Arcangeli4e6af672011-01-13 15:46:44 -0800350#ifdef CONFIG_TRANSPARENT_HUGEPAGE
351static inline void ClearPageCompound(struct page *page)
352{
353 BUG_ON(!PageHead(page));
354 ClearPageHead(page);
355}
356#endif
Christoph Lametere20b8cc2008-04-28 02:12:55 -0700357#else
358/*
359 * Reduce page flag use as much as possible by overlapping
360 * compound page flags with the flags used for page cache pages. Possible
361 * because PageCompound is always set for compound pages and not for
362 * pages on the LRU and/or pagecache.
363 */
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700364TESTPAGEFLAG(Compound, compound)
Christoffer Dallad4b3fb2012-12-21 13:03:50 -0500365__SETPAGEFLAG(Head, compound) __CLEARPAGEFLAG(Head, compound)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700366
367/*
368 * PG_reclaim is used in combination with PG_compound to mark the
369 * head and tail of a compound page. This saves one page flag
370 * but makes it impossible to use compound pages for the page cache.
371 * The PG_reclaim bit would have to be used for reclaim or readahead
372 * if compound pages enter the page cache.
373 *
374 * PG_compound & PG_reclaim => Tail page
375 * PG_compound & ~PG_reclaim => Head page
376 */
Christoffer Dallad4b3fb2012-12-21 13:03:50 -0500377#define PG_head_mask ((1L << PG_compound))
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700378#define PG_head_tail_mask ((1L << PG_compound) | (1L << PG_reclaim))
379
Christoffer Dallad4b3fb2012-12-21 13:03:50 -0500380static inline int PageHead(struct page *page)
381{
382 return ((page->flags & PG_head_tail_mask) == PG_head_mask);
383}
384
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700385static inline int PageTail(struct page *page)
386{
387 return ((page->flags & PG_head_tail_mask) == PG_head_tail_mask);
388}
389
390static inline void __SetPageTail(struct page *page)
391{
392 page->flags |= PG_head_tail_mask;
393}
394
395static inline void __ClearPageTail(struct page *page)
396{
397 page->flags &= ~PG_head_tail_mask;
398}
399
Andrea Arcangeli4e6af672011-01-13 15:46:44 -0800400#ifdef CONFIG_TRANSPARENT_HUGEPAGE
401static inline void ClearPageCompound(struct page *page)
402{
403 BUG_ON((page->flags & PG_head_tail_mask) != (1 << PG_compound));
404 clear_bit(PG_compound, &page->flags);
405}
406#endif
407
Christoph Lametere20b8cc2008-04-28 02:12:55 -0700408#endif /* !PAGEFLAGS_EXTENDED */
Russ Andersondfa7e202008-06-09 11:18:45 -0500409
Andrea Arcangeli936a5fe2011-01-13 15:46:48 -0800410#ifdef CONFIG_TRANSPARENT_HUGEPAGE
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800411/*
412 * PageHuge() only returns true for hugetlbfs pages, but not for
413 * normal or transparent huge pages.
414 *
415 * PageTransHuge() returns true for both transparent huge and
416 * hugetlbfs pages, but not normal pages. PageTransHuge() can only be
417 * called only in the core VM paths where hugetlbfs pages can't exist.
418 */
419static inline int PageTransHuge(struct page *page)
420{
421 VM_BUG_ON(PageTail(page));
422 return PageHead(page);
423}
424
Dean Nelson385de352012-03-21 16:34:05 -0700425/*
426 * PageTransCompound returns true for both transparent huge pages
427 * and hugetlbfs pages, so it should only be called when it's known
428 * that hugetlbfs pages aren't involved.
429 */
Andrea Arcangeli936a5fe2011-01-13 15:46:48 -0800430static inline int PageTransCompound(struct page *page)
431{
432 return PageCompound(page);
433}
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800434
Dean Nelson385de352012-03-21 16:34:05 -0700435/*
436 * PageTransTail returns true for both transparent huge pages
437 * and hugetlbfs pages, so it should only be called when it's known
438 * that hugetlbfs pages aren't involved.
439 */
440static inline int PageTransTail(struct page *page)
441{
442 return PageTail(page);
443}
444
Andrea Arcangeli936a5fe2011-01-13 15:46:48 -0800445#else
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800446
447static inline int PageTransHuge(struct page *page)
448{
449 return 0;
450}
451
Andrea Arcangeli936a5fe2011-01-13 15:46:48 -0800452static inline int PageTransCompound(struct page *page)
453{
454 return 0;
455}
Dean Nelson385de352012-03-21 16:34:05 -0700456
457static inline int PageTransTail(struct page *page)
458{
459 return 0;
460}
Andrea Arcangeli936a5fe2011-01-13 15:46:48 -0800461#endif
462
Mel Gorman072bb0a2012-07-31 16:43:58 -0700463/*
464 * If network-based swap is enabled, sl*b must keep track of whether pages
465 * were allocated from pfmemalloc reserves.
466 */
467static inline int PageSlabPfmemalloc(struct page *page)
468{
469 VM_BUG_ON(!PageSlab(page));
470 return PageActive(page);
471}
472
473static inline void SetPageSlabPfmemalloc(struct page *page)
474{
475 VM_BUG_ON(!PageSlab(page));
476 SetPageActive(page);
477}
478
479static inline void __ClearPageSlabPfmemalloc(struct page *page)
480{
481 VM_BUG_ON(!PageSlab(page));
482 __ClearPageActive(page);
483}
484
485static inline void ClearPageSlabPfmemalloc(struct page *page)
486{
487 VM_BUG_ON(!PageSlab(page));
488 ClearPageActive(page);
489}
490
Hugh Dickinsaf8e3352009-12-14 17:58:59 -0800491#ifdef CONFIG_MMU
David Howells33925b22009-03-31 15:23:26 -0700492#define __PG_MLOCKED (1 << PG_mlocked)
493#else
Nick Pigginb291f002008-10-18 20:26:44 -0700494#define __PG_MLOCKED 0
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700495#endif
496
Andrea Arcangelie9da73d2011-01-13 15:46:32 -0800497#ifdef CONFIG_TRANSPARENT_HUGEPAGE
498#define __PG_COMPOUND_LOCK (1 << PG_compound_lock)
499#else
500#define __PG_COMPOUND_LOCK 0
501#endif
502
Russ Andersondfa7e202008-06-09 11:18:45 -0500503/*
504 * Flags checked when a page is freed. Pages being freed should not have
505 * these flags set. It they are, there is a problem.
506 */
Hugh Dickins79f4b7b2009-01-06 14:40:05 -0800507#define PAGE_FLAGS_CHECK_AT_FREE \
David Howells266cf652009-04-03 16:42:36 +0100508 (1 << PG_lru | 1 << PG_locked | \
509 1 << PG_private | 1 << PG_private_2 | \
Andrea Arcangeli5f24ce52011-01-13 15:47:00 -0800510 1 << PG_writeback | 1 << PG_reserved | \
David Howells266cf652009-04-03 16:42:36 +0100511 1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \
Andrea Arcangelie9da73d2011-01-13 15:46:32 -0800512 1 << PG_unevictable | __PG_MLOCKED | __PG_HWPOISON | \
513 __PG_COMPOUND_LOCK)
Russ Andersondfa7e202008-06-09 11:18:45 -0500514
515/*
516 * Flags checked when a page is prepped for return by the page allocator.
Hugh Dickins79f4b7b2009-01-06 14:40:05 -0800517 * Pages being prepped should not have any flags set. It they are set,
518 * there has been a kernel bug or struct page corruption.
Russ Andersondfa7e202008-06-09 11:18:45 -0500519 */
Hugh Dickins79f4b7b2009-01-06 14:40:05 -0800520#define PAGE_FLAGS_CHECK_AT_PREP ((1 << NR_PAGEFLAGS) - 1)
Russ Andersondfa7e202008-06-09 11:18:45 -0500521
Johannes Weineredcf4742009-09-21 17:02:59 -0700522#define PAGE_FLAGS_PRIVATE \
523 (1 << PG_private | 1 << PG_private_2)
David Howells266cf652009-04-03 16:42:36 +0100524/**
525 * page_has_private - Determine if page has private stuff
526 * @page: The page to be checked
527 *
528 * Determine if a page has private stuff, indicating that release routines
529 * should be invoked upon it.
530 */
Johannes Weineredcf4742009-09-21 17:02:59 -0700531static inline int page_has_private(struct page *page)
532{
533 return !!(page->flags & PAGE_FLAGS_PRIVATE);
534}
535
536#endif /* !__GENERATING_BOUNDS_H */
David Howells266cf652009-04-03 16:42:36 +0100537
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538#endif /* PAGE_FLAGS_H */