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Linux/include/linux/gfp.h

  1 #ifndef __LINUX_GFP_H
  2 #define __LINUX_GFP_H
  3 
  4 #include <linux/mmdebug.h>
  5 #include <linux/mmzone.h>
  6 #include <linux/stddef.h>
  7 #include <linux/linkage.h>
  8 #include <linux/topology.h>
  9 
 10 struct vm_area_struct;
 11 
 12 /* Plain integer GFP bitmasks. Do not use this directly. */
 13 #define ___GFP_DMA              0x01u
 14 #define ___GFP_HIGHMEM          0x02u
 15 #define ___GFP_DMA32            0x04u
 16 #define ___GFP_MOVABLE          0x08u
 17 #define ___GFP_RECLAIMABLE      0x10u
 18 #define ___GFP_HIGH             0x20u
 19 #define ___GFP_IO               0x40u
 20 #define ___GFP_FS               0x80u
 21 #define ___GFP_COLD             0x100u
 22 #define ___GFP_NOWARN           0x200u
 23 #define ___GFP_REPEAT           0x400u
 24 #define ___GFP_NOFAIL           0x800u
 25 #define ___GFP_NORETRY          0x1000u
 26 #define ___GFP_MEMALLOC         0x2000u
 27 #define ___GFP_COMP             0x4000u
 28 #define ___GFP_ZERO             0x8000u
 29 #define ___GFP_NOMEMALLOC       0x10000u
 30 #define ___GFP_HARDWALL         0x20000u
 31 #define ___GFP_THISNODE         0x40000u
 32 #define ___GFP_ATOMIC           0x80000u
 33 #define ___GFP_NOACCOUNT        0x100000u
 34 #define ___GFP_NOTRACK          0x200000u
 35 #define ___GFP_DIRECT_RECLAIM   0x400000u
 36 #define ___GFP_OTHER_NODE       0x800000u
 37 #define ___GFP_WRITE            0x1000000u
 38 #define ___GFP_KSWAPD_RECLAIM   0x2000000u
 39 /* If the above are modified, __GFP_BITS_SHIFT may need updating */
 40 
 41 /*
 42  * Physical address zone modifiers (see linux/mmzone.h - low four bits)
 43  *
 44  * Do not put any conditional on these. If necessary modify the definitions
 45  * without the underscores and use them consistently. The definitions here may
 46  * be used in bit comparisons.
 47  */
 48 #define __GFP_DMA       ((__force gfp_t)___GFP_DMA)
 49 #define __GFP_HIGHMEM   ((__force gfp_t)___GFP_HIGHMEM)
 50 #define __GFP_DMA32     ((__force gfp_t)___GFP_DMA32)
 51 #define __GFP_MOVABLE   ((__force gfp_t)___GFP_MOVABLE)  /* Page is movable */
 52 #define __GFP_MOVABLE   ((__force gfp_t)___GFP_MOVABLE)  /* ZONE_MOVABLE allowed */
 53 #define GFP_ZONEMASK    (__GFP_DMA|__GFP_HIGHMEM|__GFP_DMA32|__GFP_MOVABLE)
 54 
 55 /*
 56  * Page mobility and placement hints
 57  *
 58  * These flags provide hints about how mobile the page is. Pages with similar
 59  * mobility are placed within the same pageblocks to minimise problems due
 60  * to external fragmentation.
 61  *
 62  * __GFP_MOVABLE (also a zone modifier) indicates that the page can be
 63  *   moved by page migration during memory compaction or can be reclaimed.
 64  *
 65  * __GFP_RECLAIMABLE is used for slab allocations that specify
 66  *   SLAB_RECLAIM_ACCOUNT and whose pages can be freed via shrinkers.
 67  *
 68  * __GFP_WRITE indicates the caller intends to dirty the page. Where possible,
 69  *   these pages will be spread between local zones to avoid all the dirty
 70  *   pages being in one zone (fair zone allocation policy).
 71  *
 72  * __GFP_HARDWALL enforces the cpuset memory allocation policy.
 73  *
 74  * __GFP_THISNODE forces the allocation to be satisified from the requested
 75  *   node with no fallbacks or placement policy enforcements.
 76  */
 77 #define __GFP_RECLAIMABLE ((__force gfp_t)___GFP_RECLAIMABLE)
 78 #define __GFP_WRITE     ((__force gfp_t)___GFP_WRITE)
 79 #define __GFP_HARDWALL   ((__force gfp_t)___GFP_HARDWALL)
 80 #define __GFP_THISNODE  ((__force gfp_t)___GFP_THISNODE)
 81 
 82 /*
 83  * Watermark modifiers -- controls access to emergency reserves
 84  *
 85  * __GFP_HIGH indicates that the caller is high-priority and that granting
 86  *   the request is necessary before the system can make forward progress.
 87  *   For example, creating an IO context to clean pages.
 88  *
 89  * __GFP_ATOMIC indicates that the caller cannot reclaim or sleep and is
 90  *   high priority. Users are typically interrupt handlers. This may be
 91  *   used in conjunction with __GFP_HIGH
 92  *
 93  * __GFP_MEMALLOC allows access to all memory. This should only be used when
 94  *   the caller guarantees the allocation will allow more memory to be freed
 95  *   very shortly e.g. process exiting or swapping. Users either should
 96  *   be the MM or co-ordinating closely with the VM (e.g. swap over NFS).
 97  *
 98  * __GFP_NOMEMALLOC is used to explicitly forbid access to emergency reserves.
 99  *   This takes precedence over the __GFP_MEMALLOC flag if both are set.
100  *
101  * __GFP_NOACCOUNT ignores the accounting for kmemcg limit enforcement.
102  */
103 #define __GFP_ATOMIC    ((__force gfp_t)___GFP_ATOMIC)
104 #define __GFP_HIGH      ((__force gfp_t)___GFP_HIGH)
105 #define __GFP_MEMALLOC  ((__force gfp_t)___GFP_MEMALLOC)
106 #define __GFP_NOMEMALLOC ((__force gfp_t)___GFP_NOMEMALLOC)
107 #define __GFP_NOACCOUNT ((__force gfp_t)___GFP_NOACCOUNT)
108 
109 /*
110  * Reclaim modifiers
111  *
112  * __GFP_IO can start physical IO.
113  *
114  * __GFP_FS can call down to the low-level FS. Clearing the flag avoids the
115  *   allocator recursing into the filesystem which might already be holding
116  *   locks.
117  *
118  * __GFP_DIRECT_RECLAIM indicates that the caller may enter direct reclaim.
119  *   This flag can be cleared to avoid unnecessary delays when a fallback
120  *   option is available.
121  *
122  * __GFP_KSWAPD_RECLAIM indicates that the caller wants to wake kswapd when
123  *   the low watermark is reached and have it reclaim pages until the high
124  *   watermark is reached. A caller may wish to clear this flag when fallback
125  *   options are available and the reclaim is likely to disrupt the system. The
126  *   canonical example is THP allocation where a fallback is cheap but
127  *   reclaim/compaction may cause indirect stalls.
128  *
129  * __GFP_RECLAIM is shorthand to allow/forbid both direct and kswapd reclaim.
130  *
131  * __GFP_REPEAT: Try hard to allocate the memory, but the allocation attempt
132  *   _might_ fail.  This depends upon the particular VM implementation.
133  *
134  * __GFP_NOFAIL: The VM implementation _must_ retry infinitely: the caller
135  *   cannot handle allocation failures. New users should be evaluated carefully
136  *   (and the flag should be used only when there is no reasonable failure
137  *   policy) but it is definitely preferable to use the flag rather than
138  *   opencode endless loop around allocator.
139  *
140  * __GFP_NORETRY: The VM implementation must not retry indefinitely and will
141  *   return NULL when direct reclaim and memory compaction have failed to allow
142  *   the allocation to succeed.  The OOM killer is not called with the current
143  *   implementation.
144  */
145 #define __GFP_IO        ((__force gfp_t)___GFP_IO)
146 #define __GFP_FS        ((__force gfp_t)___GFP_FS)
147 #define __GFP_DIRECT_RECLAIM    ((__force gfp_t)___GFP_DIRECT_RECLAIM) /* Caller can reclaim */
148 #define __GFP_KSWAPD_RECLAIM    ((__force gfp_t)___GFP_KSWAPD_RECLAIM) /* kswapd can wake */
149 #define __GFP_RECLAIM ((__force gfp_t)(___GFP_DIRECT_RECLAIM|___GFP_KSWAPD_RECLAIM))
150 #define __GFP_REPEAT    ((__force gfp_t)___GFP_REPEAT)
151 #define __GFP_NOFAIL    ((__force gfp_t)___GFP_NOFAIL)
152 #define __GFP_NORETRY   ((__force gfp_t)___GFP_NORETRY)
153 
154 /*
155  * Action modifiers
156  *
157  * __GFP_COLD indicates that the caller does not expect to be used in the near
158  *   future. Where possible, a cache-cold page will be returned.
159  *
160  * __GFP_NOWARN suppresses allocation failure reports.
161  *
162  * __GFP_COMP address compound page metadata.
163  *
164  * __GFP_ZERO returns a zeroed page on success.
165  *
166  * __GFP_NOTRACK avoids tracking with kmemcheck.
167  *
168  * __GFP_NOTRACK_FALSE_POSITIVE is an alias of __GFP_NOTRACK. It's a means of
169  *   distinguishing in the source between false positives and allocations that
170  *   cannot be supported (e.g. page tables).
171  *
172  * __GFP_OTHER_NODE is for allocations that are on a remote node but that
173  *   should not be accounted for as a remote allocation in vmstat. A
174  *   typical user would be khugepaged collapsing a huge page on a remote
175  *   node.
176  */
177 #define __GFP_COLD      ((__force gfp_t)___GFP_COLD)
178 #define __GFP_NOWARN    ((__force gfp_t)___GFP_NOWARN)
179 #define __GFP_COMP      ((__force gfp_t)___GFP_COMP)
180 #define __GFP_ZERO      ((__force gfp_t)___GFP_ZERO)
181 #define __GFP_NOTRACK   ((__force gfp_t)___GFP_NOTRACK)
182 #define __GFP_NOTRACK_FALSE_POSITIVE (__GFP_NOTRACK)
183 #define __GFP_OTHER_NODE ((__force gfp_t)___GFP_OTHER_NODE)
184 
185 /* Room for N __GFP_FOO bits */
186 #define __GFP_BITS_SHIFT 26
187 #define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1))
188 
189 /*
190  * Useful GFP flag combinations that are commonly used. It is recommended
191  * that subsystems start with one of these combinations and then set/clear
192  * __GFP_FOO flags as necessary.
193  *
194  * GFP_ATOMIC users can not sleep and need the allocation to succeed. A lower
195  *   watermark is applied to allow access to "atomic reserves"
196  *
197  * GFP_KERNEL is typical for kernel-internal allocations. The caller requires
198  *   ZONE_NORMAL or a lower zone for direct access but can direct reclaim.
199  *
200  * GFP_NOWAIT is for kernel allocations that should not stall for direct
201  *   reclaim, start physical IO or use any filesystem callback.
202  *
203  * GFP_NOIO will use direct reclaim to discard clean pages or slab pages
204  *   that do not require the starting of any physical IO.
205  *
206  * GFP_NOFS will use direct reclaim but will not use any filesystem interfaces.
207  *
208  * GFP_USER is for userspace allocations that also need to be directly
209  *   accessibly by the kernel or hardware. It is typically used by hardware
210  *   for buffers that are mapped to userspace (e.g. graphics) that hardware
211  *   still must DMA to. cpuset limits are enforced for these allocations.
212  *
213  * GFP_DMA exists for historical reasons and should be avoided where possible.
214  *   The flags indicates that the caller requires that the lowest zone be
215  *   used (ZONE_DMA or 16M on x86-64). Ideally, this would be removed but
216  *   it would require careful auditing as some users really require it and
217  *   others use the flag to avoid lowmem reserves in ZONE_DMA and treat the
218  *   lowest zone as a type of emergency reserve.
219  *
220  * GFP_DMA32 is similar to GFP_DMA except that the caller requires a 32-bit
221  *   address.
222  *
223  * GFP_HIGHUSER is for userspace allocations that may be mapped to userspace,
224  *   do not need to be directly accessible by the kernel but that cannot
225  *   move once in use. An example may be a hardware allocation that maps
226  *   data directly into userspace but has no addressing limitations.
227  *
228  * GFP_HIGHUSER_MOVABLE is for userspace allocations that the kernel does not
229  *   need direct access to but can use kmap() when access is required. They
230  *   are expected to be movable via page reclaim or page migration. Typically,
231  *   pages on the LRU would also be allocated with GFP_HIGHUSER_MOVABLE.
232  *
233  * GFP_TRANSHUGE is used for THP allocations. They are compound allocations
234  *   that will fail quickly if memory is not available and will not wake
235  *   kswapd on failure.
236  */
237 #define GFP_ATOMIC      (__GFP_HIGH|__GFP_ATOMIC|__GFP_KSWAPD_RECLAIM)
238 #define GFP_KERNEL      (__GFP_RECLAIM | __GFP_IO | __GFP_FS)
239 #define GFP_NOWAIT      (__GFP_KSWAPD_RECLAIM)
240 #define GFP_NOIO        (__GFP_RECLAIM)
241 #define GFP_NOFS        (__GFP_RECLAIM | __GFP_IO)
242 #define GFP_TEMPORARY   (__GFP_RECLAIM | __GFP_IO | __GFP_FS | \
243                          __GFP_RECLAIMABLE)
244 #define GFP_USER        (__GFP_RECLAIM | __GFP_IO | __GFP_FS | __GFP_HARDWALL)
245 #define GFP_DMA         __GFP_DMA
246 #define GFP_DMA32       __GFP_DMA32
247 #define GFP_HIGHUSER    (GFP_USER | __GFP_HIGHMEM)
248 #define GFP_HIGHUSER_MOVABLE    (GFP_HIGHUSER | __GFP_MOVABLE)
249 #define GFP_TRANSHUGE   ((GFP_HIGHUSER_MOVABLE | __GFP_COMP | \
250                          __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN) & \
251                          ~__GFP_KSWAPD_RECLAIM)
252 
253 /* Convert GFP flags to their corresponding migrate type */
254 #define GFP_MOVABLE_MASK (__GFP_RECLAIMABLE|__GFP_MOVABLE)
255 #define GFP_MOVABLE_SHIFT 3
256 
257 static inline int gfpflags_to_migratetype(const gfp_t gfp_flags)
258 {
259         VM_WARN_ON((gfp_flags & GFP_MOVABLE_MASK) == GFP_MOVABLE_MASK);
260         BUILD_BUG_ON((1UL << GFP_MOVABLE_SHIFT) != ___GFP_MOVABLE);
261         BUILD_BUG_ON((___GFP_MOVABLE >> GFP_MOVABLE_SHIFT) != MIGRATE_MOVABLE);
262 
263         if (unlikely(page_group_by_mobility_disabled))
264                 return MIGRATE_UNMOVABLE;
265 
266         /* Group based on mobility */
267         return (gfp_flags & GFP_MOVABLE_MASK) >> GFP_MOVABLE_SHIFT;
268 }
269 #undef GFP_MOVABLE_MASK
270 #undef GFP_MOVABLE_SHIFT
271 
272 static inline bool gfpflags_allow_blocking(const gfp_t gfp_flags)
273 {
274         return (bool __force)(gfp_flags & __GFP_DIRECT_RECLAIM);
275 }
276 
277 #ifdef CONFIG_HIGHMEM
278 #define OPT_ZONE_HIGHMEM ZONE_HIGHMEM
279 #else
280 #define OPT_ZONE_HIGHMEM ZONE_NORMAL
281 #endif
282 
283 #ifdef CONFIG_ZONE_DMA
284 #define OPT_ZONE_DMA ZONE_DMA
285 #else
286 #define OPT_ZONE_DMA ZONE_NORMAL
287 #endif
288 
289 #ifdef CONFIG_ZONE_DMA32
290 #define OPT_ZONE_DMA32 ZONE_DMA32
291 #else
292 #define OPT_ZONE_DMA32 ZONE_NORMAL
293 #endif
294 
295 /*
296  * GFP_ZONE_TABLE is a word size bitstring that is used for looking up the
297  * zone to use given the lowest 4 bits of gfp_t. Entries are ZONE_SHIFT long
298  * and there are 16 of them to cover all possible combinations of
299  * __GFP_DMA, __GFP_DMA32, __GFP_MOVABLE and __GFP_HIGHMEM.
300  *
301  * The zone fallback order is MOVABLE=>HIGHMEM=>NORMAL=>DMA32=>DMA.
302  * But GFP_MOVABLE is not only a zone specifier but also an allocation
303  * policy. Therefore __GFP_MOVABLE plus another zone selector is valid.
304  * Only 1 bit of the lowest 3 bits (DMA,DMA32,HIGHMEM) can be set to "1".
305  *
306  *       bit       result
307  *       =================
308  *       0x0    => NORMAL
309  *       0x1    => DMA or NORMAL
310  *       0x2    => HIGHMEM or NORMAL
311  *       0x3    => BAD (DMA+HIGHMEM)
312  *       0x4    => DMA32 or DMA or NORMAL
313  *       0x5    => BAD (DMA+DMA32)
314  *       0x6    => BAD (HIGHMEM+DMA32)
315  *       0x7    => BAD (HIGHMEM+DMA32+DMA)
316  *       0x8    => NORMAL (MOVABLE+0)
317  *       0x9    => DMA or NORMAL (MOVABLE+DMA)
318  *       0xa    => MOVABLE (Movable is valid only if HIGHMEM is set too)
319  *       0xb    => BAD (MOVABLE+HIGHMEM+DMA)
320  *       0xc    => DMA32 (MOVABLE+DMA32)
321  *       0xd    => BAD (MOVABLE+DMA32+DMA)
322  *       0xe    => BAD (MOVABLE+DMA32+HIGHMEM)
323  *       0xf    => BAD (MOVABLE+DMA32+HIGHMEM+DMA)
324  *
325  * ZONES_SHIFT must be <= 2 on 32 bit platforms.
326  */
327 
328 #if 16 * ZONES_SHIFT > BITS_PER_LONG
329 #error ZONES_SHIFT too large to create GFP_ZONE_TABLE integer
330 #endif
331 
332 #define GFP_ZONE_TABLE ( \
333         (ZONE_NORMAL << 0 * ZONES_SHIFT)                                      \
334         | (OPT_ZONE_DMA << ___GFP_DMA * ZONES_SHIFT)                          \
335         | (OPT_ZONE_HIGHMEM << ___GFP_HIGHMEM * ZONES_SHIFT)                  \
336         | (OPT_ZONE_DMA32 << ___GFP_DMA32 * ZONES_SHIFT)                      \
337         | (ZONE_NORMAL << ___GFP_MOVABLE * ZONES_SHIFT)                       \
338         | (OPT_ZONE_DMA << (___GFP_MOVABLE | ___GFP_DMA) * ZONES_SHIFT)       \
339         | (ZONE_MOVABLE << (___GFP_MOVABLE | ___GFP_HIGHMEM) * ZONES_SHIFT)   \
340         | (OPT_ZONE_DMA32 << (___GFP_MOVABLE | ___GFP_DMA32) * ZONES_SHIFT)   \
341 )
342 
343 /*
344  * GFP_ZONE_BAD is a bitmap for all combinations of __GFP_DMA, __GFP_DMA32
345  * __GFP_HIGHMEM and __GFP_MOVABLE that are not permitted. One flag per
346  * entry starting with bit 0. Bit is set if the combination is not
347  * allowed.
348  */
349 #define GFP_ZONE_BAD ( \
350         1 << (___GFP_DMA | ___GFP_HIGHMEM)                                    \
351         | 1 << (___GFP_DMA | ___GFP_DMA32)                                    \
352         | 1 << (___GFP_DMA32 | ___GFP_HIGHMEM)                                \
353         | 1 << (___GFP_DMA | ___GFP_DMA32 | ___GFP_HIGHMEM)                   \
354         | 1 << (___GFP_MOVABLE | ___GFP_HIGHMEM | ___GFP_DMA)                 \
355         | 1 << (___GFP_MOVABLE | ___GFP_DMA32 | ___GFP_DMA)                   \
356         | 1 << (___GFP_MOVABLE | ___GFP_DMA32 | ___GFP_HIGHMEM)               \
357         | 1 << (___GFP_MOVABLE | ___GFP_DMA32 | ___GFP_DMA | ___GFP_HIGHMEM)  \
358 )
359 
360 static inline enum zone_type gfp_zone(gfp_t flags)
361 {
362         enum zone_type z;
363         int bit = (__force int) (flags & GFP_ZONEMASK);
364 
365         z = (GFP_ZONE_TABLE >> (bit * ZONES_SHIFT)) &
366                                          ((1 << ZONES_SHIFT) - 1);
367         VM_BUG_ON((GFP_ZONE_BAD >> bit) & 1);
368         return z;
369 }
370 
371 /*
372  * There is only one page-allocator function, and two main namespaces to
373  * it. The alloc_page*() variants return 'struct page *' and as such
374  * can allocate highmem pages, the *get*page*() variants return
375  * virtual kernel addresses to the allocated page(s).
376  */
377 
378 static inline int gfp_zonelist(gfp_t flags)
379 {
380         if (IS_ENABLED(CONFIG_NUMA) && unlikely(flags & __GFP_THISNODE))
381                 return 1;
382 
383         return 0;
384 }
385 
386 /*
387  * We get the zone list from the current node and the gfp_mask.
388  * This zone list contains a maximum of MAXNODES*MAX_NR_ZONES zones.
389  * There are two zonelists per node, one for all zones with memory and
390  * one containing just zones from the node the zonelist belongs to.
391  *
392  * For the normal case of non-DISCONTIGMEM systems the NODE_DATA() gets
393  * optimized to &contig_page_data at compile-time.
394  */
395 static inline struct zonelist *node_zonelist(int nid, gfp_t flags)
396 {
397         return NODE_DATA(nid)->node_zonelists + gfp_zonelist(flags);
398 }
399 
400 #ifndef HAVE_ARCH_FREE_PAGE
401 static inline void arch_free_page(struct page *page, int order) { }
402 #endif
403 #ifndef HAVE_ARCH_ALLOC_PAGE
404 static inline void arch_alloc_page(struct page *page, int order) { }
405 #endif
406 
407 struct page *
408 __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
409                        struct zonelist *zonelist, nodemask_t *nodemask);
410 
411 static inline struct page *
412 __alloc_pages(gfp_t gfp_mask, unsigned int order,
413                 struct zonelist *zonelist)
414 {
415         return __alloc_pages_nodemask(gfp_mask, order, zonelist, NULL);
416 }
417 
418 /*
419  * Allocate pages, preferring the node given as nid. The node must be valid and
420  * online. For more general interface, see alloc_pages_node().
421  */
422 static inline struct page *
423 __alloc_pages_node(int nid, gfp_t gfp_mask, unsigned int order)
424 {
425         VM_BUG_ON(nid < 0 || nid >= MAX_NUMNODES);
426         VM_WARN_ON(!node_online(nid));
427 
428         return __alloc_pages(gfp_mask, order, node_zonelist(nid, gfp_mask));
429 }
430 
431 /*
432  * Allocate pages, preferring the node given as nid. When nid == NUMA_NO_NODE,
433  * prefer the current CPU's closest node. Otherwise node must be valid and
434  * online.
435  */
436 static inline struct page *alloc_pages_node(int nid, gfp_t gfp_mask,
437                                                 unsigned int order)
438 {
439         if (nid == NUMA_NO_NODE)
440                 nid = numa_mem_id();
441 
442         return __alloc_pages_node(nid, gfp_mask, order);
443 }
444 
445 #ifdef CONFIG_NUMA
446 extern struct page *alloc_pages_current(gfp_t gfp_mask, unsigned order);
447 
448 static inline struct page *
449 alloc_pages(gfp_t gfp_mask, unsigned int order)
450 {
451         return alloc_pages_current(gfp_mask, order);
452 }
453 extern struct page *alloc_pages_vma(gfp_t gfp_mask, int order,
454                         struct vm_area_struct *vma, unsigned long addr,
455                         int node, bool hugepage);
456 #define alloc_hugepage_vma(gfp_mask, vma, addr, order)  \
457         alloc_pages_vma(gfp_mask, order, vma, addr, numa_node_id(), true)
458 #else
459 #define alloc_pages(gfp_mask, order) \
460                 alloc_pages_node(numa_node_id(), gfp_mask, order)
461 #define alloc_pages_vma(gfp_mask, order, vma, addr, node, false)\
462         alloc_pages(gfp_mask, order)
463 #define alloc_hugepage_vma(gfp_mask, vma, addr, order)  \
464         alloc_pages(gfp_mask, order)
465 #endif
466 #define alloc_page(gfp_mask) alloc_pages(gfp_mask, 0)
467 #define alloc_page_vma(gfp_mask, vma, addr)                     \
468         alloc_pages_vma(gfp_mask, 0, vma, addr, numa_node_id(), false)
469 #define alloc_page_vma_node(gfp_mask, vma, addr, node)          \
470         alloc_pages_vma(gfp_mask, 0, vma, addr, node, false)
471 
472 extern struct page *alloc_kmem_pages(gfp_t gfp_mask, unsigned int order);
473 extern struct page *alloc_kmem_pages_node(int nid, gfp_t gfp_mask,
474                                           unsigned int order);
475 
476 extern unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order);
477 extern unsigned long get_zeroed_page(gfp_t gfp_mask);
478 
479 void *alloc_pages_exact(size_t size, gfp_t gfp_mask);
480 void free_pages_exact(void *virt, size_t size);
481 void * __meminit alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask);
482 
483 #define __get_free_page(gfp_mask) \
484                 __get_free_pages((gfp_mask), 0)
485 
486 #define __get_dma_pages(gfp_mask, order) \
487                 __get_free_pages((gfp_mask) | GFP_DMA, (order))
488 
489 extern void __free_pages(struct page *page, unsigned int order);
490 extern void free_pages(unsigned long addr, unsigned int order);
491 extern void free_hot_cold_page(struct page *page, bool cold);
492 extern void free_hot_cold_page_list(struct list_head *list, bool cold);
493 
494 struct page_frag_cache;
495 extern void *__alloc_page_frag(struct page_frag_cache *nc,
496                                unsigned int fragsz, gfp_t gfp_mask);
497 extern void __free_page_frag(void *addr);
498 
499 extern void __free_kmem_pages(struct page *page, unsigned int order);
500 extern void free_kmem_pages(unsigned long addr, unsigned int order);
501 
502 #define __free_page(page) __free_pages((page), 0)
503 #define free_page(addr) free_pages((addr), 0)
504 
505 void page_alloc_init(void);
506 void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp);
507 void drain_all_pages(struct zone *zone);
508 void drain_local_pages(struct zone *zone);
509 
510 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
511 void page_alloc_init_late(void);
512 #else
513 static inline void page_alloc_init_late(void)
514 {
515 }
516 #endif
517 
518 /*
519  * gfp_allowed_mask is set to GFP_BOOT_MASK during early boot to restrict what
520  * GFP flags are used before interrupts are enabled. Once interrupts are
521  * enabled, it is set to __GFP_BITS_MASK while the system is running. During
522  * hibernation, it is used by PM to avoid I/O during memory allocation while
523  * devices are suspended.
524  */
525 extern gfp_t gfp_allowed_mask;
526 
527 /* Returns true if the gfp_mask allows use of ALLOC_NO_WATERMARK */
528 bool gfp_pfmemalloc_allowed(gfp_t gfp_mask);
529 
530 extern void pm_restrict_gfp_mask(void);
531 extern void pm_restore_gfp_mask(void);
532 
533 #ifdef CONFIG_PM_SLEEP
534 extern bool pm_suspended_storage(void);
535 #else
536 static inline bool pm_suspended_storage(void)
537 {
538         return false;
539 }
540 #endif /* CONFIG_PM_SLEEP */
541 
542 #ifdef CONFIG_CMA
543 
544 /* The below functions must be run on a range from a single zone. */
545 extern int alloc_contig_range(unsigned long start, unsigned long end,
546                               unsigned migratetype);
547 extern void free_contig_range(unsigned long pfn, unsigned nr_pages);
548 
549 /* CMA stuff */
550 extern void init_cma_reserved_pageblock(struct page *page);
551 
552 #endif
553 
554 #endif /* __LINUX_GFP_H */
555 

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