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TOMOYO Linux Cross Reference
Linux/include/linux/gfp.h

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  1 /* SPDX-License-Identifier: GPL-2.0 */
  2 #ifndef __LINUX_GFP_H
  3 #define __LINUX_GFP_H
  4 
  5 #include <linux/mmdebug.h>
  6 #include <linux/mmzone.h>
  7 #include <linux/stddef.h>
  8 #include <linux/linkage.h>
  9 #include <linux/topology.h>
 10 
 11 struct vm_area_struct;
 12 
 13 /*
 14  * In case of changes, please don't forget to update
 15  * include/trace/events/mmflags.h and tools/perf/builtin-kmem.c
 16  */
 17 
 18 /* Plain integer GFP bitmasks. Do not use this directly. */
 19 #define ___GFP_DMA              0x01u
 20 #define ___GFP_HIGHMEM          0x02u
 21 #define ___GFP_DMA32            0x04u
 22 #define ___GFP_MOVABLE          0x08u
 23 #define ___GFP_RECLAIMABLE      0x10u
 24 #define ___GFP_HIGH             0x20u
 25 #define ___GFP_IO               0x40u
 26 #define ___GFP_FS               0x80u
 27 #define ___GFP_WRITE            0x100u
 28 #define ___GFP_NOWARN           0x200u
 29 #define ___GFP_RETRY_MAYFAIL    0x400u
 30 #define ___GFP_NOFAIL           0x800u
 31 #define ___GFP_NORETRY          0x1000u
 32 #define ___GFP_MEMALLOC         0x2000u
 33 #define ___GFP_COMP             0x4000u
 34 #define ___GFP_ZERO             0x8000u
 35 #define ___GFP_NOMEMALLOC       0x10000u
 36 #define ___GFP_HARDWALL         0x20000u
 37 #define ___GFP_THISNODE         0x40000u
 38 #define ___GFP_ATOMIC           0x80000u
 39 #define ___GFP_ACCOUNT          0x100000u
 40 #define ___GFP_DIRECT_RECLAIM   0x200000u
 41 #define ___GFP_KSWAPD_RECLAIM   0x400000u
 42 #ifdef CONFIG_LOCKDEP
 43 #define ___GFP_NOLOCKDEP        0x800000u
 44 #else
 45 #define ___GFP_NOLOCKDEP        0
 46 #endif
 47 /* If the above are modified, __GFP_BITS_SHIFT may need updating */
 48 
 49 /*
 50  * Physical address zone modifiers (see linux/mmzone.h - low four bits)
 51  *
 52  * Do not put any conditional on these. If necessary modify the definitions
 53  * without the underscores and use them consistently. The definitions here may
 54  * be used in bit comparisons.
 55  */
 56 #define __GFP_DMA       ((__force gfp_t)___GFP_DMA)
 57 #define __GFP_HIGHMEM   ((__force gfp_t)___GFP_HIGHMEM)
 58 #define __GFP_DMA32     ((__force gfp_t)___GFP_DMA32)
 59 #define __GFP_MOVABLE   ((__force gfp_t)___GFP_MOVABLE)  /* ZONE_MOVABLE allowed */
 60 #define GFP_ZONEMASK    (__GFP_DMA|__GFP_HIGHMEM|__GFP_DMA32|__GFP_MOVABLE)
 61 
 62 /*
 63  * Page mobility and placement hints
 64  *
 65  * These flags provide hints about how mobile the page is. Pages with similar
 66  * mobility are placed within the same pageblocks to minimise problems due
 67  * to external fragmentation.
 68  *
 69  * __GFP_MOVABLE (also a zone modifier) indicates that the page can be
 70  *   moved by page migration during memory compaction or can be reclaimed.
 71  *
 72  * __GFP_RECLAIMABLE is used for slab allocations that specify
 73  *   SLAB_RECLAIM_ACCOUNT and whose pages can be freed via shrinkers.
 74  *
 75  * __GFP_WRITE indicates the caller intends to dirty the page. Where possible,
 76  *   these pages will be spread between local zones to avoid all the dirty
 77  *   pages being in one zone (fair zone allocation policy).
 78  *
 79  * __GFP_HARDWALL enforces the cpuset memory allocation policy.
 80  *
 81  * __GFP_THISNODE forces the allocation to be satisified from the requested
 82  *   node with no fallbacks or placement policy enforcements.
 83  *
 84  * __GFP_ACCOUNT causes the allocation to be accounted to kmemcg.
 85  */
 86 #define __GFP_RECLAIMABLE ((__force gfp_t)___GFP_RECLAIMABLE)
 87 #define __GFP_WRITE     ((__force gfp_t)___GFP_WRITE)
 88 #define __GFP_HARDWALL   ((__force gfp_t)___GFP_HARDWALL)
 89 #define __GFP_THISNODE  ((__force gfp_t)___GFP_THISNODE)
 90 #define __GFP_ACCOUNT   ((__force gfp_t)___GFP_ACCOUNT)
 91 
 92 /*
 93  * Watermark modifiers -- controls access to emergency reserves
 94  *
 95  * __GFP_HIGH indicates that the caller is high-priority and that granting
 96  *   the request is necessary before the system can make forward progress.
 97  *   For example, creating an IO context to clean pages.
 98  *
 99  * __GFP_ATOMIC indicates that the caller cannot reclaim or sleep and is
100  *   high priority. Users are typically interrupt handlers. This may be
101  *   used in conjunction with __GFP_HIGH
102  *
103  * __GFP_MEMALLOC allows access to all memory. This should only be used when
104  *   the caller guarantees the allocation will allow more memory to be freed
105  *   very shortly e.g. process exiting or swapping. Users either should
106  *   be the MM or co-ordinating closely with the VM (e.g. swap over NFS).
107  *
108  * __GFP_NOMEMALLOC is used to explicitly forbid access to emergency reserves.
109  *   This takes precedence over the __GFP_MEMALLOC flag if both are set.
110  */
111 #define __GFP_ATOMIC    ((__force gfp_t)___GFP_ATOMIC)
112 #define __GFP_HIGH      ((__force gfp_t)___GFP_HIGH)
113 #define __GFP_MEMALLOC  ((__force gfp_t)___GFP_MEMALLOC)
114 #define __GFP_NOMEMALLOC ((__force gfp_t)___GFP_NOMEMALLOC)
115 
116 /*
117  * Reclaim modifiers
118  *
119  * __GFP_IO can start physical IO.
120  *
121  * __GFP_FS can call down to the low-level FS. Clearing the flag avoids the
122  *   allocator recursing into the filesystem which might already be holding
123  *   locks.
124  *
125  * __GFP_DIRECT_RECLAIM indicates that the caller may enter direct reclaim.
126  *   This flag can be cleared to avoid unnecessary delays when a fallback
127  *   option is available.
128  *
129  * __GFP_KSWAPD_RECLAIM indicates that the caller wants to wake kswapd when
130  *   the low watermark is reached and have it reclaim pages until the high
131  *   watermark is reached. A caller may wish to clear this flag when fallback
132  *   options are available and the reclaim is likely to disrupt the system. The
133  *   canonical example is THP allocation where a fallback is cheap but
134  *   reclaim/compaction may cause indirect stalls.
135  *
136  * __GFP_RECLAIM is shorthand to allow/forbid both direct and kswapd reclaim.
137  *
138  * The default allocator behavior depends on the request size. We have a concept
139  * of so called costly allocations (with order > PAGE_ALLOC_COSTLY_ORDER).
140  * !costly allocations are too essential to fail so they are implicitly
141  * non-failing by default (with some exceptions like OOM victims might fail so
142  * the caller still has to check for failures) while costly requests try to be
143  * not disruptive and back off even without invoking the OOM killer.
144  * The following three modifiers might be used to override some of these
145  * implicit rules
146  *
147  * __GFP_NORETRY: The VM implementation will try only very lightweight
148  *   memory direct reclaim to get some memory under memory pressure (thus
149  *   it can sleep). It will avoid disruptive actions like OOM killer. The
150  *   caller must handle the failure which is quite likely to happen under
151  *   heavy memory pressure. The flag is suitable when failure can easily be
152  *   handled at small cost, such as reduced throughput
153  *
154  * __GFP_RETRY_MAYFAIL: The VM implementation will retry memory reclaim
155  *   procedures that have previously failed if there is some indication
156  *   that progress has been made else where.  It can wait for other
157  *   tasks to attempt high level approaches to freeing memory such as
158  *   compaction (which removes fragmentation) and page-out.
159  *   There is still a definite limit to the number of retries, but it is
160  *   a larger limit than with __GFP_NORETRY.
161  *   Allocations with this flag may fail, but only when there is
162  *   genuinely little unused memory. While these allocations do not
163  *   directly trigger the OOM killer, their failure indicates that
164  *   the system is likely to need to use the OOM killer soon.  The
165  *   caller must handle failure, but can reasonably do so by failing
166  *   a higher-level request, or completing it only in a much less
167  *   efficient manner.
168  *   If the allocation does fail, and the caller is in a position to
169  *   free some non-essential memory, doing so could benefit the system
170  *   as a whole.
171  *
172  * __GFP_NOFAIL: The VM implementation _must_ retry infinitely: the caller
173  *   cannot handle allocation failures. The allocation could block
174  *   indefinitely but will never return with failure. Testing for
175  *   failure is pointless.
176  *   New users should be evaluated carefully (and the flag should be
177  *   used only when there is no reasonable failure policy) but it is
178  *   definitely preferable to use the flag rather than opencode endless
179  *   loop around allocator.
180  *   Using this flag for costly allocations is _highly_ discouraged.
181  */
182 #define __GFP_IO        ((__force gfp_t)___GFP_IO)
183 #define __GFP_FS        ((__force gfp_t)___GFP_FS)
184 #define __GFP_DIRECT_RECLAIM    ((__force gfp_t)___GFP_DIRECT_RECLAIM) /* Caller can reclaim */
185 #define __GFP_KSWAPD_RECLAIM    ((__force gfp_t)___GFP_KSWAPD_RECLAIM) /* kswapd can wake */
186 #define __GFP_RECLAIM ((__force gfp_t)(___GFP_DIRECT_RECLAIM|___GFP_KSWAPD_RECLAIM))
187 #define __GFP_RETRY_MAYFAIL     ((__force gfp_t)___GFP_RETRY_MAYFAIL)
188 #define __GFP_NOFAIL    ((__force gfp_t)___GFP_NOFAIL)
189 #define __GFP_NORETRY   ((__force gfp_t)___GFP_NORETRY)
190 
191 /*
192  * Action modifiers
193  *
194  * __GFP_NOWARN suppresses allocation failure reports.
195  *
196  * __GFP_COMP address compound page metadata.
197  *
198  * __GFP_ZERO returns a zeroed page on success.
199  */
200 #define __GFP_NOWARN    ((__force gfp_t)___GFP_NOWARN)
201 #define __GFP_COMP      ((__force gfp_t)___GFP_COMP)
202 #define __GFP_ZERO      ((__force gfp_t)___GFP_ZERO)
203 
204 /* Disable lockdep for GFP context tracking */
205 #define __GFP_NOLOCKDEP ((__force gfp_t)___GFP_NOLOCKDEP)
206 
207 /* Room for N __GFP_FOO bits */
208 #define __GFP_BITS_SHIFT (23 + IS_ENABLED(CONFIG_LOCKDEP))
209 #define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1))
210 
211 /*
212  * Useful GFP flag combinations that are commonly used. It is recommended
213  * that subsystems start with one of these combinations and then set/clear
214  * __GFP_FOO flags as necessary.
215  *
216  * GFP_ATOMIC users can not sleep and need the allocation to succeed. A lower
217  *   watermark is applied to allow access to "atomic reserves"
218  *
219  * GFP_KERNEL is typical for kernel-internal allocations. The caller requires
220  *   ZONE_NORMAL or a lower zone for direct access but can direct reclaim.
221  *
222  * GFP_KERNEL_ACCOUNT is the same as GFP_KERNEL, except the allocation is
223  *   accounted to kmemcg.
224  *
225  * GFP_NOWAIT is for kernel allocations that should not stall for direct
226  *   reclaim, start physical IO or use any filesystem callback.
227  *
228  * GFP_NOIO will use direct reclaim to discard clean pages or slab pages
229  *   that do not require the starting of any physical IO.
230  *   Please try to avoid using this flag directly and instead use
231  *   memalloc_noio_{save,restore} to mark the whole scope which cannot
232  *   perform any IO with a short explanation why. All allocation requests
233  *   will inherit GFP_NOIO implicitly.
234  *
235  * GFP_NOFS will use direct reclaim but will not use any filesystem interfaces.
236  *   Please try to avoid using this flag directly and instead use
237  *   memalloc_nofs_{save,restore} to mark the whole scope which cannot/shouldn't
238  *   recurse into the FS layer with a short explanation why. All allocation
239  *   requests will inherit GFP_NOFS implicitly.
240  *
241  * GFP_USER is for userspace allocations that also need to be directly
242  *   accessibly by the kernel or hardware. It is typically used by hardware
243  *   for buffers that are mapped to userspace (e.g. graphics) that hardware
244  *   still must DMA to. cpuset limits are enforced for these allocations.
245  *
246  * GFP_DMA exists for historical reasons and should be avoided where possible.
247  *   The flags indicates that the caller requires that the lowest zone be
248  *   used (ZONE_DMA or 16M on x86-64). Ideally, this would be removed but
249  *   it would require careful auditing as some users really require it and
250  *   others use the flag to avoid lowmem reserves in ZONE_DMA and treat the
251  *   lowest zone as a type of emergency reserve.
252  *
253  * GFP_DMA32 is similar to GFP_DMA except that the caller requires a 32-bit
254  *   address.
255  *
256  * GFP_HIGHUSER is for userspace allocations that may be mapped to userspace,
257  *   do not need to be directly accessible by the kernel but that cannot
258  *   move once in use. An example may be a hardware allocation that maps
259  *   data directly into userspace but has no addressing limitations.
260  *
261  * GFP_HIGHUSER_MOVABLE is for userspace allocations that the kernel does not
262  *   need direct access to but can use kmap() when access is required. They
263  *   are expected to be movable via page reclaim or page migration. Typically,
264  *   pages on the LRU would also be allocated with GFP_HIGHUSER_MOVABLE.
265  *
266  * GFP_TRANSHUGE and GFP_TRANSHUGE_LIGHT are used for THP allocations. They are
267  *   compound allocations that will generally fail quickly if memory is not
268  *   available and will not wake kswapd/kcompactd on failure. The _LIGHT
269  *   version does not attempt reclaim/compaction at all and is by default used
270  *   in page fault path, while the non-light is used by khugepaged.
271  */
272 #define GFP_ATOMIC      (__GFP_HIGH|__GFP_ATOMIC|__GFP_KSWAPD_RECLAIM)
273 #define GFP_KERNEL      (__GFP_RECLAIM | __GFP_IO | __GFP_FS)
274 #define GFP_KERNEL_ACCOUNT (GFP_KERNEL | __GFP_ACCOUNT)
275 #define GFP_NOWAIT      (__GFP_KSWAPD_RECLAIM)
276 #define GFP_NOIO        (__GFP_RECLAIM)
277 #define GFP_NOFS        (__GFP_RECLAIM | __GFP_IO)
278 #define GFP_USER        (__GFP_RECLAIM | __GFP_IO | __GFP_FS | __GFP_HARDWALL)
279 #define GFP_DMA         __GFP_DMA
280 #define GFP_DMA32       __GFP_DMA32
281 #define GFP_HIGHUSER    (GFP_USER | __GFP_HIGHMEM)
282 #define GFP_HIGHUSER_MOVABLE    (GFP_HIGHUSER | __GFP_MOVABLE)
283 #define GFP_TRANSHUGE_LIGHT     ((GFP_HIGHUSER_MOVABLE | __GFP_COMP | \
284                          __GFP_NOMEMALLOC | __GFP_NOWARN) & ~__GFP_RECLAIM)
285 #define GFP_TRANSHUGE   (GFP_TRANSHUGE_LIGHT | __GFP_DIRECT_RECLAIM)
286 
287 /* Convert GFP flags to their corresponding migrate type */
288 #define GFP_MOVABLE_MASK (__GFP_RECLAIMABLE|__GFP_MOVABLE)
289 #define GFP_MOVABLE_SHIFT 3
290 
291 static inline int gfpflags_to_migratetype(const gfp_t gfp_flags)
292 {
293         VM_WARN_ON((gfp_flags & GFP_MOVABLE_MASK) == GFP_MOVABLE_MASK);
294         BUILD_BUG_ON((1UL << GFP_MOVABLE_SHIFT) != ___GFP_MOVABLE);
295         BUILD_BUG_ON((___GFP_MOVABLE >> GFP_MOVABLE_SHIFT) != MIGRATE_MOVABLE);
296 
297         if (unlikely(page_group_by_mobility_disabled))
298                 return MIGRATE_UNMOVABLE;
299 
300         /* Group based on mobility */
301         return (gfp_flags & GFP_MOVABLE_MASK) >> GFP_MOVABLE_SHIFT;
302 }
303 #undef GFP_MOVABLE_MASK
304 #undef GFP_MOVABLE_SHIFT
305 
306 static inline bool gfpflags_allow_blocking(const gfp_t gfp_flags)
307 {
308         return !!(gfp_flags & __GFP_DIRECT_RECLAIM);
309 }
310 
311 #ifdef CONFIG_HIGHMEM
312 #define OPT_ZONE_HIGHMEM ZONE_HIGHMEM
313 #else
314 #define OPT_ZONE_HIGHMEM ZONE_NORMAL
315 #endif
316 
317 #ifdef CONFIG_ZONE_DMA
318 #define OPT_ZONE_DMA ZONE_DMA
319 #else
320 #define OPT_ZONE_DMA ZONE_NORMAL
321 #endif
322 
323 #ifdef CONFIG_ZONE_DMA32
324 #define OPT_ZONE_DMA32 ZONE_DMA32
325 #else
326 #define OPT_ZONE_DMA32 ZONE_NORMAL
327 #endif
328 
329 /*
330  * GFP_ZONE_TABLE is a word size bitstring that is used for looking up the
331  * zone to use given the lowest 4 bits of gfp_t. Entries are GFP_ZONES_SHIFT
332  * bits long and there are 16 of them to cover all possible combinations of
333  * __GFP_DMA, __GFP_DMA32, __GFP_MOVABLE and __GFP_HIGHMEM.
334  *
335  * The zone fallback order is MOVABLE=>HIGHMEM=>NORMAL=>DMA32=>DMA.
336  * But GFP_MOVABLE is not only a zone specifier but also an allocation
337  * policy. Therefore __GFP_MOVABLE plus another zone selector is valid.
338  * Only 1 bit of the lowest 3 bits (DMA,DMA32,HIGHMEM) can be set to "1".
339  *
340  *       bit       result
341  *       =================
342  *       0x0    => NORMAL
343  *       0x1    => DMA or NORMAL
344  *       0x2    => HIGHMEM or NORMAL
345  *       0x3    => BAD (DMA+HIGHMEM)
346  *       0x4    => DMA32 or NORMAL
347  *       0x5    => BAD (DMA+DMA32)
348  *       0x6    => BAD (HIGHMEM+DMA32)
349  *       0x7    => BAD (HIGHMEM+DMA32+DMA)
350  *       0x8    => NORMAL (MOVABLE+0)
351  *       0x9    => DMA or NORMAL (MOVABLE+DMA)
352  *       0xa    => MOVABLE (Movable is valid only if HIGHMEM is set too)
353  *       0xb    => BAD (MOVABLE+HIGHMEM+DMA)
354  *       0xc    => DMA32 or NORMAL (MOVABLE+DMA32)
355  *       0xd    => BAD (MOVABLE+DMA32+DMA)
356  *       0xe    => BAD (MOVABLE+DMA32+HIGHMEM)
357  *       0xf    => BAD (MOVABLE+DMA32+HIGHMEM+DMA)
358  *
359  * GFP_ZONES_SHIFT must be <= 2 on 32 bit platforms.
360  */
361 
362 #if defined(CONFIG_ZONE_DEVICE) && (MAX_NR_ZONES-1) <= 4
363 /* ZONE_DEVICE is not a valid GFP zone specifier */
364 #define GFP_ZONES_SHIFT 2
365 #else
366 #define GFP_ZONES_SHIFT ZONES_SHIFT
367 #endif
368 
369 #if 16 * GFP_ZONES_SHIFT > BITS_PER_LONG
370 #error GFP_ZONES_SHIFT too large to create GFP_ZONE_TABLE integer
371 #endif
372 
373 #define GFP_ZONE_TABLE ( \
374         (ZONE_NORMAL << 0 * GFP_ZONES_SHIFT)                                   \
375         | (OPT_ZONE_DMA << ___GFP_DMA * GFP_ZONES_SHIFT)                       \
376         | (OPT_ZONE_HIGHMEM << ___GFP_HIGHMEM * GFP_ZONES_SHIFT)               \
377         | (OPT_ZONE_DMA32 << ___GFP_DMA32 * GFP_ZONES_SHIFT)                   \
378         | (ZONE_NORMAL << ___GFP_MOVABLE * GFP_ZONES_SHIFT)                    \
379         | (OPT_ZONE_DMA << (___GFP_MOVABLE | ___GFP_DMA) * GFP_ZONES_SHIFT)    \
380         | (ZONE_MOVABLE << (___GFP_MOVABLE | ___GFP_HIGHMEM) * GFP_ZONES_SHIFT)\
381         | (OPT_ZONE_DMA32 << (___GFP_MOVABLE | ___GFP_DMA32) * GFP_ZONES_SHIFT)\
382 )
383 
384 /*
385  * GFP_ZONE_BAD is a bitmap for all combinations of __GFP_DMA, __GFP_DMA32
386  * __GFP_HIGHMEM and __GFP_MOVABLE that are not permitted. One flag per
387  * entry starting with bit 0. Bit is set if the combination is not
388  * allowed.
389  */
390 #define GFP_ZONE_BAD ( \
391         1 << (___GFP_DMA | ___GFP_HIGHMEM)                                    \
392         | 1 << (___GFP_DMA | ___GFP_DMA32)                                    \
393         | 1 << (___GFP_DMA32 | ___GFP_HIGHMEM)                                \
394         | 1 << (___GFP_DMA | ___GFP_DMA32 | ___GFP_HIGHMEM)                   \
395         | 1 << (___GFP_MOVABLE | ___GFP_HIGHMEM | ___GFP_DMA)                 \
396         | 1 << (___GFP_MOVABLE | ___GFP_DMA32 | ___GFP_DMA)                   \
397         | 1 << (___GFP_MOVABLE | ___GFP_DMA32 | ___GFP_HIGHMEM)               \
398         | 1 << (___GFP_MOVABLE | ___GFP_DMA32 | ___GFP_DMA | ___GFP_HIGHMEM)  \
399 )
400 
401 static inline enum zone_type gfp_zone(gfp_t flags)
402 {
403         enum zone_type z;
404         int bit = (__force int) (flags & GFP_ZONEMASK);
405 
406         z = (GFP_ZONE_TABLE >> (bit * GFP_ZONES_SHIFT)) &
407                                          ((1 << GFP_ZONES_SHIFT) - 1);
408         VM_BUG_ON((GFP_ZONE_BAD >> bit) & 1);
409         return z;
410 }
411 
412 /*
413  * There is only one page-allocator function, and two main namespaces to
414  * it. The alloc_page*() variants return 'struct page *' and as such
415  * can allocate highmem pages, the *get*page*() variants return
416  * virtual kernel addresses to the allocated page(s).
417  */
418 
419 static inline int gfp_zonelist(gfp_t flags)
420 {
421 #ifdef CONFIG_NUMA
422         if (unlikely(flags & __GFP_THISNODE))
423                 return ZONELIST_NOFALLBACK;
424 #endif
425         return ZONELIST_FALLBACK;
426 }
427 
428 /*
429  * We get the zone list from the current node and the gfp_mask.
430  * This zone list contains a maximum of MAXNODES*MAX_NR_ZONES zones.
431  * There are two zonelists per node, one for all zones with memory and
432  * one containing just zones from the node the zonelist belongs to.
433  *
434  * For the normal case of non-DISCONTIGMEM systems the NODE_DATA() gets
435  * optimized to &contig_page_data at compile-time.
436  */
437 static inline struct zonelist *node_zonelist(int nid, gfp_t flags)
438 {
439         return NODE_DATA(nid)->node_zonelists + gfp_zonelist(flags);
440 }
441 
442 #ifndef HAVE_ARCH_FREE_PAGE
443 static inline void arch_free_page(struct page *page, int order) { }
444 #endif
445 #ifndef HAVE_ARCH_ALLOC_PAGE
446 static inline void arch_alloc_page(struct page *page, int order) { }
447 #endif
448 
449 struct page *
450 __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, int preferred_nid,
451                                                         nodemask_t *nodemask);
452 
453 static inline struct page *
454 __alloc_pages(gfp_t gfp_mask, unsigned int order, int preferred_nid)
455 {
456         return __alloc_pages_nodemask(gfp_mask, order, preferred_nid, NULL);
457 }
458 
459 /*
460  * Allocate pages, preferring the node given as nid. The node must be valid and
461  * online. For more general interface, see alloc_pages_node().
462  */
463 static inline struct page *
464 __alloc_pages_node(int nid, gfp_t gfp_mask, unsigned int order)
465 {
466         VM_BUG_ON(nid < 0 || nid >= MAX_NUMNODES);
467         VM_WARN_ON((gfp_mask & __GFP_THISNODE) && !node_online(nid));
468 
469         return __alloc_pages(gfp_mask, order, nid);
470 }
471 
472 /*
473  * Allocate pages, preferring the node given as nid. When nid == NUMA_NO_NODE,
474  * prefer the current CPU's closest node. Otherwise node must be valid and
475  * online.
476  */
477 static inline struct page *alloc_pages_node(int nid, gfp_t gfp_mask,
478                                                 unsigned int order)
479 {
480         if (nid == NUMA_NO_NODE)
481                 nid = numa_mem_id();
482 
483         return __alloc_pages_node(nid, gfp_mask, order);
484 }
485 
486 #ifdef CONFIG_NUMA
487 extern struct page *alloc_pages_current(gfp_t gfp_mask, unsigned order);
488 
489 static inline struct page *
490 alloc_pages(gfp_t gfp_mask, unsigned int order)
491 {
492         return alloc_pages_current(gfp_mask, order);
493 }
494 extern struct page *alloc_pages_vma(gfp_t gfp_mask, int order,
495                         struct vm_area_struct *vma, unsigned long addr,
496                         int node, bool hugepage);
497 #define alloc_hugepage_vma(gfp_mask, vma, addr, order)  \
498         alloc_pages_vma(gfp_mask, order, vma, addr, numa_node_id(), true)
499 #else
500 #define alloc_pages(gfp_mask, order) \
501                 alloc_pages_node(numa_node_id(), gfp_mask, order)
502 #define alloc_pages_vma(gfp_mask, order, vma, addr, node, false)\
503         alloc_pages(gfp_mask, order)
504 #define alloc_hugepage_vma(gfp_mask, vma, addr, order)  \
505         alloc_pages(gfp_mask, order)
506 #endif
507 #define alloc_page(gfp_mask) alloc_pages(gfp_mask, 0)
508 #define alloc_page_vma(gfp_mask, vma, addr)                     \
509         alloc_pages_vma(gfp_mask, 0, vma, addr, numa_node_id(), false)
510 #define alloc_page_vma_node(gfp_mask, vma, addr, node)          \
511         alloc_pages_vma(gfp_mask, 0, vma, addr, node, false)
512 
513 extern unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order);
514 extern unsigned long get_zeroed_page(gfp_t gfp_mask);
515 
516 void *alloc_pages_exact(size_t size, gfp_t gfp_mask);
517 void free_pages_exact(void *virt, size_t size);
518 void * __meminit alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask);
519 
520 #define __get_free_page(gfp_mask) \
521                 __get_free_pages((gfp_mask), 0)
522 
523 #define __get_dma_pages(gfp_mask, order) \
524                 __get_free_pages((gfp_mask) | GFP_DMA, (order))
525 
526 extern void __free_pages(struct page *page, unsigned int order);
527 extern void free_pages(unsigned long addr, unsigned int order);
528 extern void free_unref_page(struct page *page);
529 extern void free_unref_page_list(struct list_head *list);
530 
531 struct page_frag_cache;
532 extern void __page_frag_cache_drain(struct page *page, unsigned int count);
533 extern void *page_frag_alloc(struct page_frag_cache *nc,
534                              unsigned int fragsz, gfp_t gfp_mask);
535 extern void page_frag_free(void *addr);
536 
537 #define __free_page(page) __free_pages((page), 0)
538 #define free_page(addr) free_pages((addr), 0)
539 
540 void page_alloc_init(void);
541 void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp);
542 void drain_all_pages(struct zone *zone);
543 void drain_local_pages(struct zone *zone);
544 
545 void page_alloc_init_late(void);
546 
547 /*
548  * gfp_allowed_mask is set to GFP_BOOT_MASK during early boot to restrict what
549  * GFP flags are used before interrupts are enabled. Once interrupts are
550  * enabled, it is set to __GFP_BITS_MASK while the system is running. During
551  * hibernation, it is used by PM to avoid I/O during memory allocation while
552  * devices are suspended.
553  */
554 extern gfp_t gfp_allowed_mask;
555 
556 /* Returns true if the gfp_mask allows use of ALLOC_NO_WATERMARK */
557 bool gfp_pfmemalloc_allowed(gfp_t gfp_mask);
558 
559 extern void pm_restrict_gfp_mask(void);
560 extern void pm_restore_gfp_mask(void);
561 
562 #ifdef CONFIG_PM_SLEEP
563 extern bool pm_suspended_storage(void);
564 #else
565 static inline bool pm_suspended_storage(void)
566 {
567         return false;
568 }
569 #endif /* CONFIG_PM_SLEEP */
570 
571 #if (defined(CONFIG_MEMORY_ISOLATION) && defined(CONFIG_COMPACTION)) || defined(CONFIG_CMA)
572 /* The below functions must be run on a range from a single zone. */
573 extern int alloc_contig_range(unsigned long start, unsigned long end,
574                               unsigned migratetype, gfp_t gfp_mask);
575 extern void free_contig_range(unsigned long pfn, unsigned nr_pages);
576 #endif
577 
578 #ifdef CONFIG_CMA
579 /* CMA stuff */
580 extern void init_cma_reserved_pageblock(struct page *page);
581 #endif
582 
583 #endif /* __LINUX_GFP_H */
584 

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