blob: 0db8037e27256a8aa04fb81afa543a5db806482b [file] [log] [blame]
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,
127
Andy Whitcroft8a380822008-07-23 21:27:18 -0700128 /* SLUB */
129 PG_slub_frozen = PG_active,
Christoph Lametere2683182008-04-28 02:12:47 -0700130};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131
Christoph Lameter9223b412008-04-28 02:12:48 -0700132#ifndef __GENERATING_BOUNDS_H
133
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134/*
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700135 * Macros to create function definitions for page flags
136 */
137#define TESTPAGEFLAG(uname, lname) \
138static inline int Page##uname(struct page *page) \
139 { return test_bit(PG_##lname, &page->flags); }
140
141#define SETPAGEFLAG(uname, lname) \
142static inline void SetPage##uname(struct page *page) \
143 { set_bit(PG_##lname, &page->flags); }
144
145#define CLEARPAGEFLAG(uname, lname) \
146static inline void ClearPage##uname(struct page *page) \
147 { clear_bit(PG_##lname, &page->flags); }
148
149#define __SETPAGEFLAG(uname, lname) \
150static inline void __SetPage##uname(struct page *page) \
151 { __set_bit(PG_##lname, &page->flags); }
152
153#define __CLEARPAGEFLAG(uname, lname) \
154static inline void __ClearPage##uname(struct page *page) \
155 { __clear_bit(PG_##lname, &page->flags); }
156
157#define TESTSETFLAG(uname, lname) \
158static inline int TestSetPage##uname(struct page *page) \
159 { return test_and_set_bit(PG_##lname, &page->flags); }
160
161#define TESTCLEARFLAG(uname, lname) \
162static inline int TestClearPage##uname(struct page *page) \
163 { return test_and_clear_bit(PG_##lname, &page->flags); }
164
Johannes Weiner451ea252009-09-21 17:01:48 -0700165#define __TESTCLEARFLAG(uname, lname) \
166static inline int __TestClearPage##uname(struct page *page) \
167 { return __test_and_clear_bit(PG_##lname, &page->flags); }
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700168
169#define PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \
170 SETPAGEFLAG(uname, lname) CLEARPAGEFLAG(uname, lname)
171
172#define __PAGEFLAG(uname, lname) TESTPAGEFLAG(uname, lname) \
173 __SETPAGEFLAG(uname, lname) __CLEARPAGEFLAG(uname, lname)
174
Christoph Lameterec7cade2008-04-28 02:12:53 -0700175#define PAGEFLAG_FALSE(uname) \
176static inline int Page##uname(struct page *page) \
177 { return 0; }
178
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700179#define TESTSCFLAG(uname, lname) \
180 TESTSETFLAG(uname, lname) TESTCLEARFLAG(uname, lname)
181
Lee Schermerhorn8a7a8542008-10-18 20:26:37 -0700182#define SETPAGEFLAG_NOOP(uname) \
183static inline void SetPage##uname(struct page *page) { }
184
185#define CLEARPAGEFLAG_NOOP(uname) \
186static inline void ClearPage##uname(struct page *page) { }
187
188#define __CLEARPAGEFLAG_NOOP(uname) \
189static inline void __ClearPage##uname(struct page *page) { }
190
191#define TESTCLEARFLAG_FALSE(uname) \
192static inline int TestClearPage##uname(struct page *page) { return 0; }
193
Johannes Weiner451ea252009-09-21 17:01:48 -0700194#define __TESTCLEARFLAG_FALSE(uname) \
195static inline int __TestClearPage##uname(struct page *page) { return 0; }
196
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700197struct page; /* forward declaration */
198
David Howells03fb3d22009-04-03 16:42:35 +0100199TESTPAGEFLAG(Locked, locked) TESTSETFLAG(Locked, locked)
Rik van Riel212260a2011-01-13 15:46:06 -0800200PAGEFLAG(Error, error) TESTCLEARFLAG(Error, error)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700201PAGEFLAG(Referenced, referenced) TESTCLEARFLAG(Referenced, referenced)
202PAGEFLAG(Dirty, dirty) TESTSCFLAG(Dirty, dirty) __CLEARPAGEFLAG(Dirty, dirty)
203PAGEFLAG(LRU, lru) __CLEARPAGEFLAG(LRU, lru)
204PAGEFLAG(Active, active) __CLEARPAGEFLAG(Active, active)
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700205 TESTCLEARFLAG(Active, active)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700206__PAGEFLAG(Slab, slab)
Andy Whitcroft0cad47c2008-07-23 21:27:16 -0700207PAGEFLAG(Checked, checked) /* Used by some filesystems */
208PAGEFLAG(Pinned, pinned) TESTSCFLAG(Pinned, pinned) /* Xen */
209PAGEFLAG(SavePinned, savepinned); /* Xen */
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700210PAGEFLAG(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved)
Rik van Rielb2e18532008-10-18 20:26:30 -0700211PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700212
Andy Whitcroft9023cb72008-07-23 21:27:19 -0700213__PAGEFLAG(SlobFree, slob_free)
214
Andy Whitcroft8a380822008-07-23 21:27:18 -0700215__PAGEFLAG(SlubFrozen, slub_frozen)
Andy Whitcroft8a380822008-07-23 21:27:18 -0700216
Christoph Lameterf94a62e2008-04-28 02:12:49 -0700217/*
David Howells266cf652009-04-03 16:42:36 +0100218 * Private page markings that may be used by the filesystem that owns the page
219 * for its own purposes.
220 * - PG_private and PG_private_2 cause releasepage() and co to be invoked
221 */
222PAGEFLAG(Private, private) __SETPAGEFLAG(Private, private)
223 __CLEARPAGEFLAG(Private, private)
224PAGEFLAG(Private2, private_2) TESTSCFLAG(Private2, private_2)
225PAGEFLAG(OwnerPriv1, owner_priv_1) TESTCLEARFLAG(OwnerPriv1, owner_priv_1)
226
227/*
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700228 * Only test-and-set exist for PG_writeback. The unconditional operators are
229 * risky: they bypass page accounting.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230 */
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700231TESTPAGEFLAG(Writeback, writeback) TESTSCFLAG(Writeback, writeback)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700232PAGEFLAG(MappedToDisk, mappedtodisk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700234/* PG_readahead is only used for file reads; PG_reclaim is only for writes */
235PAGEFLAG(Reclaim, reclaim) TESTCLEARFLAG(Reclaim, reclaim)
Christoph Lameter0a128b22008-04-28 02:12:52 -0700236PAGEFLAG(Readahead, reclaim) /* Reminder to do async read-ahead */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700238#ifdef CONFIG_HIGHMEM
239/*
240 * Must use a macro here due to header dependency issues. page_zone() is not
241 * available at this point.
242 */
Christoph Lameter0a128b22008-04-28 02:12:52 -0700243#define PageHighMem(__p) is_highmem(page_zone(__p))
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700244#else
Christoph Lameterec7cade2008-04-28 02:12:53 -0700245PAGEFLAG_FALSE(HighMem)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700246#endif
247
248#ifdef CONFIG_SWAP
249PAGEFLAG(SwapCache, swapcache)
250#else
Christoph Lameterec7cade2008-04-28 02:12:53 -0700251PAGEFLAG_FALSE(SwapCache)
Hugh Dickins6d91add2009-01-06 14:39:24 -0800252 SETPAGEFLAG_NOOP(SwapCache) CLEARPAGEFLAG_NOOP(SwapCache)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700253#endif
254
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700255PAGEFLAG(Unevictable, unevictable) __CLEARPAGEFLAG(Unevictable, unevictable)
256 TESTCLEARFLAG(Unevictable, unevictable)
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700257
Hugh Dickinsaf8e3352009-12-14 17:58:59 -0800258#ifdef CONFIG_MMU
David Howells33925b22009-03-31 15:23:26 -0700259PAGEFLAG(Mlocked, mlocked) __CLEARPAGEFLAG(Mlocked, mlocked)
Johannes Weiner451ea252009-09-21 17:01:48 -0700260 TESTSCFLAG(Mlocked, mlocked) __TESTCLEARFLAG(Mlocked, mlocked)
David Howells33925b22009-03-31 15:23:26 -0700261#else
Johannes Weiner451ea252009-09-21 17:01:48 -0700262PAGEFLAG_FALSE(Mlocked) SETPAGEFLAG_NOOP(Mlocked)
263 TESTCLEARFLAG_FALSE(Mlocked) __TESTCLEARFLAG_FALSE(Mlocked)
David Howells33925b22009-03-31 15:23:26 -0700264#endif
265
Venkatesh Pallipadi46cf98c2009-07-10 09:57:37 -0700266#ifdef CONFIG_ARCH_USES_PG_UNCACHED
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700267PAGEFLAG(Uncached, uncached)
Christoph Lameter602c4d12008-04-28 02:12:52 -0700268#else
Christoph Lameterec7cade2008-04-28 02:12:53 -0700269PAGEFLAG_FALSE(Uncached)
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700270#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271
Andi Kleend466f2f2009-09-16 11:50:03 +0200272#ifdef CONFIG_MEMORY_FAILURE
273PAGEFLAG(HWPoison, hwpoison)
Wu Fengguang847ce402009-12-16 12:19:58 +0100274TESTSCFLAG(HWPoison, hwpoison)
Andi Kleend466f2f2009-09-16 11:50:03 +0200275#define __PG_HWPOISON (1UL << PG_hwpoison)
276#else
277PAGEFLAG_FALSE(HWPoison)
278#define __PG_HWPOISON 0
279#endif
280
Wu Fengguang1a9b5b72009-12-16 12:19:59 +0100281u64 stable_page_flags(struct page *page);
282
Nick Piggin0ed361d2008-02-04 22:29:34 -0800283static inline int PageUptodate(struct page *page)
284{
285 int ret = test_bit(PG_uptodate, &(page)->flags);
286
287 /*
288 * Must ensure that the data we read out of the page is loaded
289 * _after_ we've loaded page->flags to check for PageUptodate.
290 * We can skip the barrier if the page is not uptodate, because
291 * we wouldn't be reading anything from it.
292 *
293 * See SetPageUptodate() for the other side of the story.
294 */
295 if (ret)
296 smp_rmb();
297
298 return ret;
299}
300
301static inline void __SetPageUptodate(struct page *page)
302{
303 smp_wmb();
304 __set_bit(PG_uptodate, &(page)->flags);
Nick Piggin0ed361d2008-02-04 22:29:34 -0800305}
306
Heiko Carstens2dcea572006-09-29 01:58:41 -0700307static inline void SetPageUptodate(struct page *page)
308{
Nick Piggin0ed361d2008-02-04 22:29:34 -0800309#ifdef CONFIG_S390
Heiko Carstens2dcea572006-09-29 01:58:41 -0700310 if (!test_and_set_bit(PG_uptodate, &page->flags))
Martin Schwidefskye2b8d7a2010-10-25 16:10:14 +0200311 page_clear_dirty(page, 0);
Christoph Lameterf6ac2352006-06-30 01:55:32 -0700312#else
Nick Piggin0ed361d2008-02-04 22:29:34 -0800313 /*
314 * Memory barrier must be issued before setting the PG_uptodate bit,
315 * so that all previous stores issued in order to bring the page
316 * uptodate are actually visible before PageUptodate becomes true.
317 *
318 * s390 doesn't need an explicit smp_wmb here because the test and
319 * set bit already provides full barriers.
320 */
321 smp_wmb();
322 set_bit(PG_uptodate, &(page)->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323#endif
Nick Piggin0ed361d2008-02-04 22:29:34 -0800324}
325
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700326CLEARPAGEFLAG(Uptodate, uptodate)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327
Linus Torvaldsfba25912006-12-20 13:46:42 -0800328extern void cancel_dirty_page(struct page *page, unsigned int account_size);
329
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330int test_clear_page_writeback(struct page *page);
331int test_set_page_writeback(struct page *page);
332
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333static inline void set_page_writeback(struct page *page)
334{
335 test_set_page_writeback(page);
336}
337
Christoph Lametere20b8cc2008-04-28 02:12:55 -0700338#ifdef CONFIG_PAGEFLAGS_EXTENDED
339/*
340 * System with lots of page flags available. This allows separate
341 * flags for PageHead() and PageTail() checks of compound pages so that bit
342 * tests can be used in performance sensitive paths. PageCompound is
343 * generally not used in hot code paths.
344 */
Andrea Arcangeli4e6af672011-01-13 15:46:44 -0800345__PAGEFLAG(Head, head) CLEARPAGEFLAG(Head, head)
Christoph Lametere20b8cc2008-04-28 02:12:55 -0700346__PAGEFLAG(Tail, tail)
347
348static inline int PageCompound(struct page *page)
349{
350 return page->flags & ((1L << PG_head) | (1L << PG_tail));
351
352}
Andrea Arcangeli4e6af672011-01-13 15:46:44 -0800353#ifdef CONFIG_TRANSPARENT_HUGEPAGE
354static inline void ClearPageCompound(struct page *page)
355{
356 BUG_ON(!PageHead(page));
357 ClearPageHead(page);
358}
359#endif
Christoph Lametere20b8cc2008-04-28 02:12:55 -0700360#else
361/*
362 * Reduce page flag use as much as possible by overlapping
363 * compound page flags with the flags used for page cache pages. Possible
364 * because PageCompound is always set for compound pages and not for
365 * pages on the LRU and/or pagecache.
366 */
Christoph Lameter6a1e7f72008-04-28 02:12:50 -0700367TESTPAGEFLAG(Compound, compound)
368__PAGEFLAG(Head, compound)
369
370/*
371 * PG_reclaim is used in combination with PG_compound to mark the
372 * head and tail of a compound page. This saves one page flag
373 * but makes it impossible to use compound pages for the page cache.
374 * The PG_reclaim bit would have to be used for reclaim or readahead
375 * if compound pages enter the page cache.
376 *
377 * PG_compound & PG_reclaim => Tail page
378 * PG_compound & ~PG_reclaim => Head page
379 */
380#define PG_head_tail_mask ((1L << PG_compound) | (1L << PG_reclaim))
381
382static inline int PageTail(struct page *page)
383{
384 return ((page->flags & PG_head_tail_mask) == PG_head_tail_mask);
385}
386
387static inline void __SetPageTail(struct page *page)
388{
389 page->flags |= PG_head_tail_mask;
390}
391
392static inline void __ClearPageTail(struct page *page)
393{
394 page->flags &= ~PG_head_tail_mask;
395}
396
Andrea Arcangeli4e6af672011-01-13 15:46:44 -0800397#ifdef CONFIG_TRANSPARENT_HUGEPAGE
398static inline void ClearPageCompound(struct page *page)
399{
400 BUG_ON((page->flags & PG_head_tail_mask) != (1 << PG_compound));
401 clear_bit(PG_compound, &page->flags);
402}
403#endif
404
Christoph Lametere20b8cc2008-04-28 02:12:55 -0700405#endif /* !PAGEFLAGS_EXTENDED */
Russ Andersondfa7e202008-06-09 11:18:45 -0500406
Andrea Arcangeli936a5fe2011-01-13 15:46:48 -0800407#ifdef CONFIG_TRANSPARENT_HUGEPAGE
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800408/*
409 * PageHuge() only returns true for hugetlbfs pages, but not for
410 * normal or transparent huge pages.
411 *
412 * PageTransHuge() returns true for both transparent huge and
413 * hugetlbfs pages, but not normal pages. PageTransHuge() can only be
414 * called only in the core VM paths where hugetlbfs pages can't exist.
415 */
416static inline int PageTransHuge(struct page *page)
417{
418 VM_BUG_ON(PageTail(page));
419 return PageHead(page);
420}
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
Andrea Arcangeli936a5fe2011-01-13 15:46:48 -0800427#else
Andrea Arcangeli71e3aac2011-01-13 15:46:52 -0800428
429static inline int PageTransHuge(struct page *page)
430{
431 return 0;
432}
433
Andrea Arcangeli936a5fe2011-01-13 15:46:48 -0800434static inline int PageTransCompound(struct page *page)
435{
436 return 0;
437}
438#endif
439
Hugh Dickinsaf8e3352009-12-14 17:58:59 -0800440#ifdef CONFIG_MMU
David Howells33925b22009-03-31 15:23:26 -0700441#define __PG_MLOCKED (1 << PG_mlocked)
442#else
Nick Pigginb291f002008-10-18 20:26:44 -0700443#define __PG_MLOCKED 0
Lee Schermerhorn894bc312008-10-18 20:26:39 -0700444#endif
445
Andrea Arcangelie9da73d2011-01-13 15:46:32 -0800446#ifdef CONFIG_TRANSPARENT_HUGEPAGE
447#define __PG_COMPOUND_LOCK (1 << PG_compound_lock)
448#else
449#define __PG_COMPOUND_LOCK 0
450#endif
451
Russ Andersondfa7e202008-06-09 11:18:45 -0500452/*
453 * Flags checked when a page is freed. Pages being freed should not have
454 * these flags set. It they are, there is a problem.
455 */
Hugh Dickins79f4b7b2009-01-06 14:40:05 -0800456#define PAGE_FLAGS_CHECK_AT_FREE \
David Howells266cf652009-04-03 16:42:36 +0100457 (1 << PG_lru | 1 << PG_locked | \
458 1 << PG_private | 1 << PG_private_2 | \
Andrea Arcangeli5f24ce52011-01-13 15:47:00 -0800459 1 << PG_writeback | 1 << PG_reserved | \
David Howells266cf652009-04-03 16:42:36 +0100460 1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \
Andrea Arcangelie9da73d2011-01-13 15:46:32 -0800461 1 << PG_unevictable | __PG_MLOCKED | __PG_HWPOISON | \
462 __PG_COMPOUND_LOCK)
Russ Andersondfa7e202008-06-09 11:18:45 -0500463
464/*
465 * Flags checked when a page is prepped for return by the page allocator.
Hugh Dickins79f4b7b2009-01-06 14:40:05 -0800466 * Pages being prepped should not have any flags set. It they are set,
467 * there has been a kernel bug or struct page corruption.
Russ Andersondfa7e202008-06-09 11:18:45 -0500468 */
Hugh Dickins79f4b7b2009-01-06 14:40:05 -0800469#define PAGE_FLAGS_CHECK_AT_PREP ((1 << NR_PAGEFLAGS) - 1)
Russ Andersondfa7e202008-06-09 11:18:45 -0500470
Johannes Weineredcf4742009-09-21 17:02:59 -0700471#define PAGE_FLAGS_PRIVATE \
472 (1 << PG_private | 1 << PG_private_2)
David Howells266cf652009-04-03 16:42:36 +0100473/**
474 * page_has_private - Determine if page has private stuff
475 * @page: The page to be checked
476 *
477 * Determine if a page has private stuff, indicating that release routines
478 * should be invoked upon it.
479 */
Johannes Weineredcf4742009-09-21 17:02:59 -0700480static inline int page_has_private(struct page *page)
481{
482 return !!(page->flags & PAGE_FLAGS_PRIVATE);
483}
484
485#endif /* !__GENERATING_BOUNDS_H */
David Howells266cf652009-04-03 16:42:36 +0100486
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487#endif /* PAGE_FLAGS_H */