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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_ZERO             0x100u
 28 #define ___GFP_ATOMIC           0x200u
 29 #define ___GFP_DIRECT_RECLAIM   0x400u
 30 #define ___GFP_KSWAPD_RECLAIM   0x800u
 31 #define ___GFP_WRITE            0x1000u
 32 #define ___GFP_NOWARN           0x2000u
 33 #define ___GFP_RETRY_MAYFAIL    0x4000u
 34 #define ___GFP_NOFAIL           0x8000u
 35 #define ___GFP_NORETRY          0x10000u
 36 #define ___GFP_MEMALLOC         0x20000u
 37 #define ___GFP_COMP             0x40000u
 38 #define ___GFP_NOMEMALLOC       0x80000u
 39 #define ___GFP_HARDWALL         0x100000u
 40 #define ___GFP_THISNODE         0x200000u
 41 #define ___GFP_ACCOUNT          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  * DOC: Page mobility and placement hints
 64  *
 65  * Page mobility and placement hints
 66  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 67  *
 68  * These flags provide hints about how mobile the page is. Pages with similar
 69  * mobility are placed within the same pageblocks to minimise problems due
 70  * to external fragmentation.
 71  *
 72  * %__GFP_MOVABLE (also a zone modifier) indicates that the page can be
 73  * moved by page migration during memory compaction or can be reclaimed.
 74  *
 75  * %__GFP_RECLAIMABLE is used for slab allocations that specify
 76  * SLAB_RECLAIM_ACCOUNT and whose pages can be freed via shrinkers.
 77  *
 78  * %__GFP_WRITE indicates the caller intends to dirty the page. Where possible,
 79  * these pages will be spread between local zones to avoid all the dirty
 80  * pages being in one zone (fair zone allocation policy).
 81  *
 82  * %__GFP_HARDWALL enforces the cpuset memory allocation policy.
 83  *
 84  * %__GFP_THISNODE forces the allocation to be satisfied from the requested
 85  * node with no fallbacks or placement policy enforcements.
 86  *
 87  * %__GFP_ACCOUNT causes the allocation to be accounted to kmemcg.
 88  */
 89 #define __GFP_RECLAIMABLE ((__force gfp_t)___GFP_RECLAIMABLE)
 90 #define __GFP_WRITE     ((__force gfp_t)___GFP_WRITE)
 91 #define __GFP_HARDWALL   ((__force gfp_t)___GFP_HARDWALL)
 92 #define __GFP_THISNODE  ((__force gfp_t)___GFP_THISNODE)
 93 #define __GFP_ACCOUNT   ((__force gfp_t)___GFP_ACCOUNT)
 94 
 95 /**
 96  * DOC: Watermark modifiers
 97  *
 98  * Watermark modifiers -- controls access to emergency reserves
 99  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
100  *
101  * %__GFP_HIGH indicates that the caller is high-priority and that granting
102  * the request is necessary before the system can make forward progress.
103  * For example, creating an IO context to clean pages.
104  *
105  * %__GFP_ATOMIC indicates that the caller cannot reclaim or sleep and is
106  * high priority. Users are typically interrupt handlers. This may be
107  * used in conjunction with %__GFP_HIGH
108  *
109  * %__GFP_MEMALLOC allows access to all memory. This should only be used when
110  * the caller guarantees the allocation will allow more memory to be freed
111  * very shortly e.g. process exiting or swapping. Users either should
112  * be the MM or co-ordinating closely with the VM (e.g. swap over NFS).
113  * Users of this flag have to be extremely careful to not deplete the reserve
114  * completely and implement a throttling mechanism which controls the
115  * consumption of the reserve based on the amount of freed memory.
116  * Usage of a pre-allocated pool (e.g. mempool) should be always considered
117  * before using this flag.
118  *
119  * %__GFP_NOMEMALLOC is used to explicitly forbid access to emergency reserves.
120  * This takes precedence over the %__GFP_MEMALLOC flag if both are set.
121  */
122 #define __GFP_ATOMIC    ((__force gfp_t)___GFP_ATOMIC)
123 #define __GFP_HIGH      ((__force gfp_t)___GFP_HIGH)
124 #define __GFP_MEMALLOC  ((__force gfp_t)___GFP_MEMALLOC)
125 #define __GFP_NOMEMALLOC ((__force gfp_t)___GFP_NOMEMALLOC)
126 
127 /**
128  * DOC: Reclaim modifiers
129  *
130  * Reclaim modifiers
131  * ~~~~~~~~~~~~~~~~~
132  * Please note that all the following flags are only applicable to sleepable
133  * allocations (e.g. %GFP_NOWAIT and %GFP_ATOMIC will ignore them).
134  *
135  * %__GFP_IO can start physical IO.
136  *
137  * %__GFP_FS can call down to the low-level FS. Clearing the flag avoids the
138  * allocator recursing into the filesystem which might already be holding
139  * locks.
140  *
141  * %__GFP_DIRECT_RECLAIM indicates that the caller may enter direct reclaim.
142  * This flag can be cleared to avoid unnecessary delays when a fallback
143  * option is available.
144  *
145  * %__GFP_KSWAPD_RECLAIM indicates that the caller wants to wake kswapd when
146  * the low watermark is reached and have it reclaim pages until the high
147  * watermark is reached. A caller may wish to clear this flag when fallback
148  * options are available and the reclaim is likely to disrupt the system. The
149  * canonical example is THP allocation where a fallback is cheap but
150  * reclaim/compaction may cause indirect stalls.
151  *
152  * %__GFP_RECLAIM is shorthand to allow/forbid both direct and kswapd reclaim.
153  *
154  * The default allocator behavior depends on the request size. We have a concept
155  * of so called costly allocations (with order > %PAGE_ALLOC_COSTLY_ORDER).
156  * !costly allocations are too essential to fail so they are implicitly
157  * non-failing by default (with some exceptions like OOM victims might fail so
158  * the caller still has to check for failures) while costly requests try to be
159  * not disruptive and back off even without invoking the OOM killer.
160  * The following three modifiers might be used to override some of these
161  * implicit rules
162  *
163  * %__GFP_NORETRY: The VM implementation will try only very lightweight
164  * memory direct reclaim to get some memory under memory pressure (thus
165  * it can sleep). It will avoid disruptive actions like OOM killer. The
166  * caller must handle the failure which is quite likely to happen under
167  * heavy memory pressure. The flag is suitable when failure can easily be
168  * handled at small cost, such as reduced throughput
169  *
170  * %__GFP_RETRY_MAYFAIL: The VM implementation will retry memory reclaim
171  * procedures that have previously failed if there is some indication
172  * that progress has been made else where.  It can wait for other
173  * tasks to attempt high level approaches to freeing memory such as
174  * compaction (which removes fragmentation) and page-out.
175  * There is still a definite limit to the number of retries, but it is
176  * a larger limit than with %__GFP_NORETRY.
177  * Allocations with this flag may fail, but only when there is
178  * genuinely little unused memory. While these allocations do not
179  * directly trigger the OOM killer, their failure indicates that
180  * the system is likely to need to use the OOM killer soon.  The
181  * caller must handle failure, but can reasonably do so by failing
182  * a higher-level request, or completing it only in a much less
183  * efficient manner.
184  * If the allocation does fail, and the caller is in a position to
185  * free some non-essential memory, doing so could benefit the system
186  * as a whole.
187  *
188  * %__GFP_NOFAIL: The VM implementation _must_ retry infinitely: the caller
189  * cannot handle allocation failures. The allocation could block
190  * indefinitely but will never return with failure. Testing for
191  * failure is pointless.
192  * New users should be evaluated carefully (and the flag should be
193  * used only when there is no reasonable failure policy) but it is
194  * definitely preferable to use the flag rather than opencode endless
195  * loop around allocator.
196  * Using this flag for costly allocations is _highly_ discouraged.
197  */
198 #define __GFP_IO        ((__force gfp_t)___GFP_IO)
199 #define __GFP_FS        ((__force gfp_t)___GFP_FS)
200 #define __GFP_DIRECT_RECLAIM    ((__force gfp_t)___GFP_DIRECT_RECLAIM) /* Caller can reclaim */
201 #define __GFP_KSWAPD_RECLAIM    ((__force gfp_t)___GFP_KSWAPD_RECLAIM) /* kswapd can wake */
202 #define __GFP_RECLAIM ((__force gfp_t)(___GFP_DIRECT_RECLAIM|___GFP_KSWAPD_RECLAIM))
203 #define __GFP_RETRY_MAYFAIL     ((__force gfp_t)___GFP_RETRY_MAYFAIL)
204 #define __GFP_NOFAIL    ((__force gfp_t)___GFP_NOFAIL)
205 #define __GFP_NORETRY   ((__force gfp_t)___GFP_NORETRY)
206 
207 /**
208  * DOC: Action modifiers
209  *
210  * Action modifiers
211  * ~~~~~~~~~~~~~~~~
212  *
213  * %__GFP_NOWARN suppresses allocation failure reports.
214  *
215  * %__GFP_COMP address compound page metadata.
216  *
217  * %__GFP_ZERO returns a zeroed page on success.
218  */
219 #define __GFP_NOWARN    ((__force gfp_t)___GFP_NOWARN)
220 #define __GFP_COMP      ((__force gfp_t)___GFP_COMP)
221 #define __GFP_ZERO      ((__force gfp_t)___GFP_ZERO)
222 
223 /* Disable lockdep for GFP context tracking */
224 #define __GFP_NOLOCKDEP ((__force gfp_t)___GFP_NOLOCKDEP)
225 
226 /* Room for N __GFP_FOO bits */
227 #define __GFP_BITS_SHIFT (23 + IS_ENABLED(CONFIG_LOCKDEP))
228 #define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1))
229 
230 /**
231  * DOC: Useful GFP flag combinations
232  *
233  * Useful GFP flag combinations
234  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
235  *
236  * Useful GFP flag combinations that are commonly used. It is recommended
237  * that subsystems start with one of these combinations and then set/clear
238  * %__GFP_FOO flags as necessary.
239  *
240  * %GFP_ATOMIC users can not sleep and need the allocation to succeed. A lower
241  * watermark is applied to allow access to "atomic reserves"
242  *
243  * %GFP_KERNEL is typical for kernel-internal allocations. The caller requires
244  * %ZONE_NORMAL or a lower zone for direct access but can direct reclaim.
245  *
246  * %GFP_KERNEL_ACCOUNT is the same as GFP_KERNEL, except the allocation is
247  * accounted to kmemcg.
248  *
249  * %GFP_NOWAIT is for kernel allocations that should not stall for direct
250  * reclaim, start physical IO or use any filesystem callback.
251  *
252  * %GFP_NOIO will use direct reclaim to discard clean pages or slab pages
253  * that do not require the starting of any physical IO.
254  * Please try to avoid using this flag directly and instead use
255  * memalloc_noio_{save,restore} to mark the whole scope which cannot
256  * perform any IO with a short explanation why. All allocation requests
257  * will inherit GFP_NOIO implicitly.
258  *
259  * %GFP_NOFS will use direct reclaim but will not use any filesystem interfaces.
260  * Please try to avoid using this flag directly and instead use
261  * memalloc_nofs_{save,restore} to mark the whole scope which cannot/shouldn't
262  * recurse into the FS layer with a short explanation why. All allocation
263  * requests will inherit GFP_NOFS implicitly.
264  *
265  * %GFP_USER is for userspace allocations that also need to be directly
266  * accessibly by the kernel or hardware. It is typically used by hardware
267  * for buffers that are mapped to userspace (e.g. graphics) that hardware
268  * still must DMA to. cpuset limits are enforced for these allocations.
269  *
270  * %GFP_DMA exists for historical reasons and should be avoided where possible.
271  * The flags indicates that the caller requires that the lowest zone be
272  * used (%ZONE_DMA or 16M on x86-64). Ideally, this would be removed but
273  * it would require careful auditing as some users really require it and
274  * others use the flag to avoid lowmem reserves in %ZONE_DMA and treat the
275  * lowest zone as a type of emergency reserve.
276  *
277  * %GFP_DMA32 is similar to %GFP_DMA except that the caller requires a 32-bit
278  * address.
279  *
280  * %GFP_HIGHUSER is for userspace allocations that may be mapped to userspace,
281  * do not need to be directly accessible by the kernel but that cannot
282  * move once in use. An example may be a hardware allocation that maps
283  * data directly into userspace but has no addressing limitations.
284  *
285  * %GFP_HIGHUSER_MOVABLE is for userspace allocations that the kernel does not
286  * need direct access to but can use kmap() when access is required. They
287  * are expected to be movable via page reclaim or page migration. Typically,
288  * pages on the LRU would also be allocated with %GFP_HIGHUSER_MOVABLE.
289  *
290  * %GFP_TRANSHUGE and %GFP_TRANSHUGE_LIGHT are used for THP allocations. They
291  * are compound allocations that will generally fail quickly if memory is not
292  * available and will not wake kswapd/kcompactd on failure. The _LIGHT
293  * version does not attempt reclaim/compaction at all and is by default used
294  * in page fault path, while the non-light is used by khugepaged.
295  */
296 #define GFP_ATOMIC      (__GFP_HIGH|__GFP_ATOMIC|__GFP_KSWAPD_RECLAIM)
297 #define GFP_KERNEL      (__GFP_RECLAIM | __GFP_IO | __GFP_FS)
298 #define GFP_KERNEL_ACCOUNT (GFP_KERNEL | __GFP_ACCOUNT)
299 #define GFP_NOWAIT      (__GFP_KSWAPD_RECLAIM)
300 #define GFP_NOIO        (__GFP_RECLAIM)
301 #define GFP_NOFS        (__GFP_RECLAIM | __GFP_IO)
302 #define GFP_USER        (__GFP_RECLAIM | __GFP_IO | __GFP_FS | __GFP_HARDWALL)
303 #define GFP_DMA         __GFP_DMA
304 #define GFP_DMA32       __GFP_DMA32
305 #define GFP_HIGHUSER    (GFP_USER | __GFP_HIGHMEM)
306 #define GFP_HIGHUSER_MOVABLE    (GFP_HIGHUSER | __GFP_MOVABLE)
307 #define GFP_TRANSHUGE_LIGHT     ((GFP_HIGHUSER_MOVABLE | __GFP_COMP | \
308                          __GFP_NOMEMALLOC | __GFP_NOWARN) & ~__GFP_RECLAIM)
309 #define GFP_TRANSHUGE   (GFP_TRANSHUGE_LIGHT | __GFP_DIRECT_RECLAIM)
310 
311 /* Convert GFP flags to their corresponding migrate type */
312 #define GFP_MOVABLE_MASK (__GFP_RECLAIMABLE|__GFP_MOVABLE)
313 #define GFP_MOVABLE_SHIFT 3
314 
315 static inline int gfp_migratetype(const gfp_t gfp_flags)
316 {
317         VM_WARN_ON((gfp_flags & GFP_MOVABLE_MASK) == GFP_MOVABLE_MASK);
318         BUILD_BUG_ON((1UL << GFP_MOVABLE_SHIFT) != ___GFP_MOVABLE);
319         BUILD_BUG_ON((___GFP_MOVABLE >> GFP_MOVABLE_SHIFT) != MIGRATE_MOVABLE);
320 
321         if (unlikely(page_group_by_mobility_disabled))
322                 return MIGRATE_UNMOVABLE;
323 
324         /* Group based on mobility */
325         return (gfp_flags & GFP_MOVABLE_MASK) >> GFP_MOVABLE_SHIFT;
326 }
327 #undef GFP_MOVABLE_MASK
328 #undef GFP_MOVABLE_SHIFT
329 
330 static inline bool gfpflags_allow_blocking(const gfp_t gfp_flags)
331 {
332         return !!(gfp_flags & __GFP_DIRECT_RECLAIM);
333 }
334 
335 /**
336  * gfpflags_normal_context - is gfp_flags a normal sleepable context?
337  * @gfp_flags: gfp_flags to test
338  *
339  * Test whether @gfp_flags indicates that the allocation is from the
340  * %current context and allowed to sleep.
341  *
342  * An allocation being allowed to block doesn't mean it owns the %current
343  * context.  When direct reclaim path tries to allocate memory, the
344  * allocation context is nested inside whatever %current was doing at the
345  * time of the original allocation.  The nested allocation may be allowed
346  * to block but modifying anything %current owns can corrupt the outer
347  * context's expectations.
348  *
349  * %true result from this function indicates that the allocation context
350  * can sleep and use anything that's associated with %current.
351  */
352 static inline bool gfpflags_normal_context(const gfp_t gfp_flags)
353 {
354         return (gfp_flags & (__GFP_DIRECT_RECLAIM | __GFP_MEMALLOC)) ==
355                 __GFP_DIRECT_RECLAIM;
356 }
357 
358 #ifdef CONFIG_HIGHMEM
359 #define OPT_ZONE_HIGHMEM ZONE_HIGHMEM
360 #else
361 #define OPT_ZONE_HIGHMEM ZONE_NORMAL
362 #endif
363 
364 #ifdef CONFIG_ZONE_DMA
365 #define OPT_ZONE_DMA ZONE_DMA
366 #else
367 #define OPT_ZONE_DMA ZONE_NORMAL
368 #endif
369 
370 #ifdef CONFIG_ZONE_DMA32
371 #define OPT_ZONE_DMA32 ZONE_DMA32
372 #else
373 #define OPT_ZONE_DMA32 ZONE_NORMAL
374 #endif
375 
376 /*
377  * GFP_ZONE_TABLE is a word size bitstring that is used for looking up the
378  * zone to use given the lowest 4 bits of gfp_t. Entries are GFP_ZONES_SHIFT
379  * bits long and there are 16 of them to cover all possible combinations of
380  * __GFP_DMA, __GFP_DMA32, __GFP_MOVABLE and __GFP_HIGHMEM.
381  *
382  * The zone fallback order is MOVABLE=>HIGHMEM=>NORMAL=>DMA32=>DMA.
383  * But GFP_MOVABLE is not only a zone specifier but also an allocation
384  * policy. Therefore __GFP_MOVABLE plus another zone selector is valid.
385  * Only 1 bit of the lowest 3 bits (DMA,DMA32,HIGHMEM) can be set to "1".
386  *
387  *       bit       result
388  *       =================
389  *       0x0    => NORMAL
390  *       0x1    => DMA or NORMAL
391  *       0x2    => HIGHMEM or NORMAL
392  *       0x3    => BAD (DMA+HIGHMEM)
393  *       0x4    => DMA32 or NORMAL
394  *       0x5    => BAD (DMA+DMA32)
395  *       0x6    => BAD (HIGHMEM+DMA32)
396  *       0x7    => BAD (HIGHMEM+DMA32+DMA)
397  *       0x8    => NORMAL (MOVABLE+0)
398  *       0x9    => DMA or NORMAL (MOVABLE+DMA)
399  *       0xa    => MOVABLE (Movable is valid only if HIGHMEM is set too)
400  *       0xb    => BAD (MOVABLE+HIGHMEM+DMA)
401  *       0xc    => DMA32 or NORMAL (MOVABLE+DMA32)
402  *       0xd    => BAD (MOVABLE+DMA32+DMA)
403  *       0xe    => BAD (MOVABLE+DMA32+HIGHMEM)
404  *       0xf    => BAD (MOVABLE+DMA32+HIGHMEM+DMA)
405  *
406  * GFP_ZONES_SHIFT must be <= 2 on 32 bit platforms.
407  */
408 
409 #if defined(CONFIG_ZONE_DEVICE) && (MAX_NR_ZONES-1) <= 4
410 /* ZONE_DEVICE is not a valid GFP zone specifier */
411 #define GFP_ZONES_SHIFT 2
412 #else
413 #define GFP_ZONES_SHIFT ZONES_SHIFT
414 #endif
415 
416 #if 16 * GFP_ZONES_SHIFT > BITS_PER_LONG
417 #error GFP_ZONES_SHIFT too large to create GFP_ZONE_TABLE integer
418 #endif
419 
420 #define GFP_ZONE_TABLE ( \
421         (ZONE_NORMAL << 0 * GFP_ZONES_SHIFT)                                   \
422         | (OPT_ZONE_DMA << ___GFP_DMA * GFP_ZONES_SHIFT)                       \
423         | (OPT_ZONE_HIGHMEM << ___GFP_HIGHMEM * GFP_ZONES_SHIFT)               \
424         | (OPT_ZONE_DMA32 << ___GFP_DMA32 * GFP_ZONES_SHIFT)                   \
425         | (ZONE_NORMAL << ___GFP_MOVABLE * GFP_ZONES_SHIFT)                    \
426         | (OPT_ZONE_DMA << (___GFP_MOVABLE | ___GFP_DMA) * GFP_ZONES_SHIFT)    \
427         | (ZONE_MOVABLE << (___GFP_MOVABLE | ___GFP_HIGHMEM) * GFP_ZONES_SHIFT)\
428         | (OPT_ZONE_DMA32 << (___GFP_MOVABLE | ___GFP_DMA32) * GFP_ZONES_SHIFT)\
429 )
430 
431 /*
432  * GFP_ZONE_BAD is a bitmap for all combinations of __GFP_DMA, __GFP_DMA32
433  * __GFP_HIGHMEM and __GFP_MOVABLE that are not permitted. One flag per
434  * entry starting with bit 0. Bit is set if the combination is not
435  * allowed.
436  */
437 #define GFP_ZONE_BAD ( \
438         1 << (___GFP_DMA | ___GFP_HIGHMEM)                                    \
439         | 1 << (___GFP_DMA | ___GFP_DMA32)                                    \
440         | 1 << (___GFP_DMA32 | ___GFP_HIGHMEM)                                \
441         | 1 << (___GFP_DMA | ___GFP_DMA32 | ___GFP_HIGHMEM)                   \
442         | 1 << (___GFP_MOVABLE | ___GFP_HIGHMEM | ___GFP_DMA)                 \
443         | 1 << (___GFP_MOVABLE | ___GFP_DMA32 | ___GFP_DMA)                   \
444         | 1 << (___GFP_MOVABLE | ___GFP_DMA32 | ___GFP_HIGHMEM)               \
445         | 1 << (___GFP_MOVABLE | ___GFP_DMA32 | ___GFP_DMA | ___GFP_HIGHMEM)  \
446 )
447 
448 static inline enum zone_type gfp_zone(gfp_t flags)
449 {
450         enum zone_type z;
451         int bit = (__force int) (flags & GFP_ZONEMASK);
452 
453         z = (GFP_ZONE_TABLE >> (bit * GFP_ZONES_SHIFT)) &
454                                          ((1 << GFP_ZONES_SHIFT) - 1);
455         VM_BUG_ON((GFP_ZONE_BAD >> bit) & 1);
456         return z;
457 }
458 
459 /*
460  * There is only one page-allocator function, and two main namespaces to
461  * it. The alloc_page*() variants return 'struct page *' and as such
462  * can allocate highmem pages, the *get*page*() variants return
463  * virtual kernel addresses to the allocated page(s).
464  */
465 
466 static inline int gfp_zonelist(gfp_t flags)
467 {
468 #ifdef CONFIG_NUMA
469         if (unlikely(flags & __GFP_THISNODE))
470                 return ZONELIST_NOFALLBACK;
471 #endif
472         return ZONELIST_FALLBACK;
473 }
474 
475 /*
476  * We get the zone list from the current node and the gfp_mask.
477  * This zone list contains a maximum of MAXNODES*MAX_NR_ZONES zones.
478  * There are two zonelists per node, one for all zones with memory and
479  * one containing just zones from the node the zonelist belongs to.
480  *
481  * For the normal case of non-DISCONTIGMEM systems the NODE_DATA() gets
482  * optimized to &contig_page_data at compile-time.
483  */
484 static inline struct zonelist *node_zonelist(int nid, gfp_t flags)
485 {
486         return NODE_DATA(nid)->node_zonelists + gfp_zonelist(flags);
487 }
488 
489 #ifndef HAVE_ARCH_FREE_PAGE
490 static inline void arch_free_page(struct page *page, int order) { }
491 #endif
492 #ifndef HAVE_ARCH_ALLOC_PAGE
493 static inline void arch_alloc_page(struct page *page, int order) { }
494 #endif
495 #ifndef HAVE_ARCH_MAKE_PAGE_ACCESSIBLE
496 static inline int arch_make_page_accessible(struct page *page)
497 {
498         return 0;
499 }
500 #endif
501 
502 struct page *
503 __alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order, int preferred_nid,
504                                                         nodemask_t *nodemask);
505 
506 static inline struct page *
507 __alloc_pages(gfp_t gfp_mask, unsigned int order, int preferred_nid)
508 {
509         return __alloc_pages_nodemask(gfp_mask, order, preferred_nid, NULL);
510 }
511 
512 /*
513  * Allocate pages, preferring the node given as nid. The node must be valid and
514  * online. For more general interface, see alloc_pages_node().
515  */
516 static inline struct page *
517 __alloc_pages_node(int nid, gfp_t gfp_mask, unsigned int order)
518 {
519         VM_BUG_ON(nid < 0 || nid >= MAX_NUMNODES);
520         VM_WARN_ON((gfp_mask & __GFP_THISNODE) && !node_online(nid));
521 
522         return __alloc_pages(gfp_mask, order, nid);
523 }
524 
525 /*
526  * Allocate pages, preferring the node given as nid. When nid == NUMA_NO_NODE,
527  * prefer the current CPU's closest node. Otherwise node must be valid and
528  * online.
529  */
530 static inline struct page *alloc_pages_node(int nid, gfp_t gfp_mask,
531                                                 unsigned int order)
532 {
533         if (nid == NUMA_NO_NODE)
534                 nid = numa_mem_id();
535 
536         return __alloc_pages_node(nid, gfp_mask, order);
537 }
538 
539 #ifdef CONFIG_NUMA
540 extern struct page *alloc_pages_current(gfp_t gfp_mask, unsigned order);
541 
542 static inline struct page *
543 alloc_pages(gfp_t gfp_mask, unsigned int order)
544 {
545         return alloc_pages_current(gfp_mask, order);
546 }
547 extern struct page *alloc_pages_vma(gfp_t gfp_mask, int order,
548                         struct vm_area_struct *vma, unsigned long addr,
549                         int node, bool hugepage);
550 #define alloc_hugepage_vma(gfp_mask, vma, addr, order) \
551         alloc_pages_vma(gfp_mask, order, vma, addr, numa_node_id(), true)
552 #else
553 #define alloc_pages(gfp_mask, order) \
554                 alloc_pages_node(numa_node_id(), gfp_mask, order)
555 #define alloc_pages_vma(gfp_mask, order, vma, addr, node, false)\
556         alloc_pages(gfp_mask, order)
557 #define alloc_hugepage_vma(gfp_mask, vma, addr, order) \
558         alloc_pages(gfp_mask, order)
559 #endif
560 #define alloc_page(gfp_mask) alloc_pages(gfp_mask, 0)
561 #define alloc_page_vma(gfp_mask, vma, addr)                     \
562         alloc_pages_vma(gfp_mask, 0, vma, addr, numa_node_id(), false)
563 #define alloc_page_vma_node(gfp_mask, vma, addr, node)          \
564         alloc_pages_vma(gfp_mask, 0, vma, addr, node, false)
565 
566 extern unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order);
567 extern unsigned long get_zeroed_page(gfp_t gfp_mask);
568 
569 void *alloc_pages_exact(size_t size, gfp_t gfp_mask);
570 void free_pages_exact(void *virt, size_t size);
571 void * __meminit alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask);
572 
573 #define __get_free_page(gfp_mask) \
574                 __get_free_pages((gfp_mask), 0)
575 
576 #define __get_dma_pages(gfp_mask, order) \
577                 __get_free_pages((gfp_mask) | GFP_DMA, (order))
578 
579 extern void __free_pages(struct page *page, unsigned int order);
580 extern void free_pages(unsigned long addr, unsigned int order);
581 extern void free_unref_page(struct page *page);
582 extern void free_unref_page_list(struct list_head *list);
583 
584 struct page_frag_cache;
585 extern void __page_frag_cache_drain(struct page *page, unsigned int count);
586 extern void *page_frag_alloc(struct page_frag_cache *nc,
587                              unsigned int fragsz, gfp_t gfp_mask);
588 extern void page_frag_free(void *addr);
589 
590 #define __free_page(page) __free_pages((page), 0)
591 #define free_page(addr) free_pages((addr), 0)
592 
593 void page_alloc_init(void);
594 void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp);
595 void drain_all_pages(struct zone *zone);
596 void drain_local_pages(struct zone *zone);
597 
598 void page_alloc_init_late(void);
599 
600 /*
601  * gfp_allowed_mask is set to GFP_BOOT_MASK during early boot to restrict what
602  * GFP flags are used before interrupts are enabled. Once interrupts are
603  * enabled, it is set to __GFP_BITS_MASK while the system is running. During
604  * hibernation, it is used by PM to avoid I/O during memory allocation while
605  * devices are suspended.
606  */
607 extern gfp_t gfp_allowed_mask;
608 
609 /* Returns true if the gfp_mask allows use of ALLOC_NO_WATERMARK */
610 bool gfp_pfmemalloc_allowed(gfp_t gfp_mask);
611 
612 extern void pm_restrict_gfp_mask(void);
613 extern void pm_restore_gfp_mask(void);
614 
615 #ifdef CONFIG_PM_SLEEP
616 extern bool pm_suspended_storage(void);
617 #else
618 static inline bool pm_suspended_storage(void)
619 {
620         return false;
621 }
622 #endif /* CONFIG_PM_SLEEP */
623 
624 #ifdef CONFIG_CONTIG_ALLOC
625 /* The below functions must be run on a range from a single zone. */
626 extern int alloc_contig_range(unsigned long start, unsigned long end,
627                               unsigned migratetype, gfp_t gfp_mask);
628 extern struct page *alloc_contig_pages(unsigned long nr_pages, gfp_t gfp_mask,
629                                        int nid, nodemask_t *nodemask);
630 #endif
631 void free_contig_range(unsigned long pfn, unsigned int nr_pages);
632 
633 #ifdef CONFIG_CMA
634 /* CMA stuff */
635 extern void init_cma_reserved_pageblock(struct page *page);
636 #endif
637 
638 #endif /* __LINUX_GFP_H */
639 

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