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1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /* internal.h: mm/ internal definitions
3 *
4 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7 #ifndef __MM_INTERNAL_H
8 #define __MM_INTERNAL_H
9
10 #include <linux/fs.h>
11 #include <linux/mm.h>
12 #include <linux/pagemap.h>
13 #include <linux/tracepoint-defs.h>
14
15 /*
16 * The set of flags that only affect watermark checking and reclaim
17 * behaviour. This is used by the MM to obey the caller constraints
18 * about IO, FS and watermark checking while ignoring placement
19 * hints such as HIGHMEM usage.
20 */
21 #define GFP_RECLAIM_MASK (__GFP_RECLAIM|__GFP_HIGH|__GFP_IO|__GFP_FS|\
22 __GFP_NOWARN|__GFP_RETRY_MAYFAIL|__GFP_NOFAIL|\
23 __GFP_NORETRY|__GFP_MEMALLOC|__GFP_NOMEMALLOC|\
24 __GFP_ATOMIC)
25
26 /* The GFP flags allowed during early boot */
27 #define GFP_BOOT_MASK (__GFP_BITS_MASK & ~(__GFP_RECLAIM|__GFP_IO|__GFP_FS))
28
29 /* Control allocation cpuset and node placement constraints */
30 #define GFP_CONSTRAINT_MASK (__GFP_HARDWALL|__GFP_THISNODE)
31
32 /* Do not use these with a slab allocator */
33 #define GFP_SLAB_BUG_MASK (__GFP_DMA32|__GFP_HIGHMEM|~__GFP_BITS_MASK)
34
35 void page_writeback_init(void);
36
37 vm_fault_t do_swap_page(struct vm_fault *vmf);
38
39 void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
40 unsigned long floor, unsigned long ceiling);
41
42 static inline bool can_madv_lru_vma(struct vm_area_struct *vma)
43 {
44 return !(vma->vm_flags & (VM_LOCKED|VM_HUGETLB|VM_PFNMAP));
45 }
46
47 void unmap_page_range(struct mmu_gather *tlb,
48 struct vm_area_struct *vma,
49 unsigned long addr, unsigned long end,
50 struct zap_details *details);
51
52 void do_page_cache_ra(struct readahead_control *, unsigned long nr_to_read,
53 unsigned long lookahead_size);
54 void force_page_cache_ra(struct readahead_control *, struct file_ra_state *,
55 unsigned long nr);
56 static inline void force_page_cache_readahead(struct address_space *mapping,
57 struct file *file, pgoff_t index, unsigned long nr_to_read)
58 {
59 DEFINE_READAHEAD(ractl, file, mapping, index);
60 force_page_cache_ra(&ractl, &file->f_ra, nr_to_read);
61 }
62
63 struct page *find_get_entry(struct address_space *mapping, pgoff_t index);
64 struct page *find_lock_entry(struct address_space *mapping, pgoff_t index);
65
66 /**
67 * page_evictable - test whether a page is evictable
68 * @page: the page to test
69 *
70 * Test whether page is evictable--i.e., should be placed on active/inactive
71 * lists vs unevictable list.
72 *
73 * Reasons page might not be evictable:
74 * (1) page's mapping marked unevictable
75 * (2) page is part of an mlocked VMA
76 *
77 */
78 static inline bool page_evictable(struct page *page)
79 {
80 bool ret;
81
82 /* Prevent address_space of inode and swap cache from being freed */
83 rcu_read_lock();
84 ret = !mapping_unevictable(page_mapping(page)) && !PageMlocked(page);
85 rcu_read_unlock();
86 return ret;
87 }
88
89 /*
90 * Turn a non-refcounted page (->_refcount == 0) into refcounted with
91 * a count of one.
92 */
93 static inline void set_page_refcounted(struct page *page)
94 {
95 VM_BUG_ON_PAGE(PageTail(page), page);
96 VM_BUG_ON_PAGE(page_ref_count(page), page);
97 set_page_count(page, 1);
98 }
99
100 extern unsigned long highest_memmap_pfn;
101
102 /*
103 * Maximum number of reclaim retries without progress before the OOM
104 * killer is consider the only way forward.
105 */
106 #define MAX_RECLAIM_RETRIES 16
107
108 /*
109 * in mm/vmscan.c:
110 */
111 extern int isolate_lru_page(struct page *page);
112 extern void putback_lru_page(struct page *page);
113
114 /*
115 * in mm/rmap.c:
116 */
117 extern pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address);
118
119 /*
120 * in mm/page_alloc.c
121 */
122
123 /*
124 * Structure for holding the mostly immutable allocation parameters passed
125 * between functions involved in allocations, including the alloc_pages*
126 * family of functions.
127 *
128 * nodemask, migratetype and highest_zoneidx are initialized only once in
129 * __alloc_pages_nodemask() and then never change.
130 *
131 * zonelist, preferred_zone and highest_zoneidx are set first in
132 * __alloc_pages_nodemask() for the fast path, and might be later changed
133 * in __alloc_pages_slowpath(). All other functions pass the whole structure
134 * by a const pointer.
135 */
136 struct alloc_context {
137 struct zonelist *zonelist;
138 nodemask_t *nodemask;
139 struct zoneref *preferred_zoneref;
140 int migratetype;
141
142 /*
143 * highest_zoneidx represents highest usable zone index of
144 * the allocation request. Due to the nature of the zone,
145 * memory on lower zone than the highest_zoneidx will be
146 * protected by lowmem_reserve[highest_zoneidx].
147 *
148 * highest_zoneidx is also used by reclaim/compaction to limit
149 * the target zone since higher zone than this index cannot be
150 * usable for this allocation request.
151 */
152 enum zone_type highest_zoneidx;
153 bool spread_dirty_pages;
154 };
155
156 /*
157 * Locate the struct page for both the matching buddy in our
158 * pair (buddy1) and the combined O(n+1) page they form (page).
159 *
160 * 1) Any buddy B1 will have an order O twin B2 which satisfies
161 * the following equation:
162 * B2 = B1 ^ (1 << O)
163 * For example, if the starting buddy (buddy2) is #8 its order
164 * 1 buddy is #10:
165 * B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
166 *
167 * 2) Any buddy B will have an order O+1 parent P which
168 * satisfies the following equation:
169 * P = B & ~(1 << O)
170 *
171 * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
172 */
173 static inline unsigned long
174 __find_buddy_pfn(unsigned long page_pfn, unsigned int order)
175 {
176 return page_pfn ^ (1 << order);
177 }
178
179 extern struct page *__pageblock_pfn_to_page(unsigned long start_pfn,
180 unsigned long end_pfn, struct zone *zone);
181
182 static inline struct page *pageblock_pfn_to_page(unsigned long start_pfn,
183 unsigned long end_pfn, struct zone *zone)
184 {
185 if (zone->contiguous)
186 return pfn_to_page(start_pfn);
187
188 return __pageblock_pfn_to_page(start_pfn, end_pfn, zone);
189 }
190
191 extern int __isolate_free_page(struct page *page, unsigned int order);
192 extern void __putback_isolated_page(struct page *page, unsigned int order,
193 int mt);
194 extern void memblock_free_pages(struct page *page, unsigned long pfn,
195 unsigned int order);
196 extern void __free_pages_core(struct page *page, unsigned int order);
197 extern void prep_compound_page(struct page *page, unsigned int order);
198 extern void post_alloc_hook(struct page *page, unsigned int order,
199 gfp_t gfp_flags);
200 extern int user_min_free_kbytes;
201
202 extern void free_unref_page(struct page *page);
203 extern void free_unref_page_list(struct list_head *list);
204
205 extern void zone_pcp_update(struct zone *zone);
206 extern void zone_pcp_reset(struct zone *zone);
207 extern void zone_pcp_disable(struct zone *zone);
208 extern void zone_pcp_enable(struct zone *zone);
209
210 #if defined CONFIG_COMPACTION || defined CONFIG_CMA
211
212 /*
213 * in mm/compaction.c
214 */
215 /*
216 * compact_control is used to track pages being migrated and the free pages
217 * they are being migrated to during memory compaction. The free_pfn starts
218 * at the end of a zone and migrate_pfn begins at the start. Movable pages
219 * are moved to the end of a zone during a compaction run and the run
220 * completes when free_pfn <= migrate_pfn
221 */
222 struct compact_control {
223 struct list_head freepages; /* List of free pages to migrate to */
224 struct list_head migratepages; /* List of pages being migrated */
225 unsigned int nr_freepages; /* Number of isolated free pages */
226 unsigned int nr_migratepages; /* Number of pages to migrate */
227 unsigned long free_pfn; /* isolate_freepages search base */
228 unsigned long migrate_pfn; /* isolate_migratepages search base */
229 unsigned long fast_start_pfn; /* a pfn to start linear scan from */
230 struct zone *zone;
231 unsigned long total_migrate_scanned;
232 unsigned long total_free_scanned;
233 unsigned short fast_search_fail;/* failures to use free list searches */
234 short search_order; /* order to start a fast search at */
235 const gfp_t gfp_mask; /* gfp mask of a direct compactor */
236 int order; /* order a direct compactor needs */
237 int migratetype; /* migratetype of direct compactor */
238 const unsigned int alloc_flags; /* alloc flags of a direct compactor */
239 const int highest_zoneidx; /* zone index of a direct compactor */
240 enum migrate_mode mode; /* Async or sync migration mode */
241 bool ignore_skip_hint; /* Scan blocks even if marked skip */
242 bool no_set_skip_hint; /* Don't mark blocks for skipping */
243 bool ignore_block_suitable; /* Scan blocks considered unsuitable */
244 bool direct_compaction; /* False from kcompactd or /proc/... */
245 bool proactive_compaction; /* kcompactd proactive compaction */
246 bool whole_zone; /* Whole zone should/has been scanned */
247 bool contended; /* Signal lock or sched contention */
248 bool rescan; /* Rescanning the same pageblock */
249 bool alloc_contig; /* alloc_contig_range allocation */
250 };
251
252 /*
253 * Used in direct compaction when a page should be taken from the freelists
254 * immediately when one is created during the free path.
255 */
256 struct capture_control {
257 struct compact_control *cc;
258 struct page *page;
259 };
260
261 unsigned long
262 isolate_freepages_range(struct compact_control *cc,
263 unsigned long start_pfn, unsigned long end_pfn);
264 unsigned long
265 isolate_migratepages_range(struct compact_control *cc,
266 unsigned long low_pfn, unsigned long end_pfn);
267 int find_suitable_fallback(struct free_area *area, unsigned int order,
268 int migratetype, bool only_stealable, bool *can_steal);
269
270 #endif
271
272 /*
273 * This function returns the order of a free page in the buddy system. In
274 * general, page_zone(page)->lock must be held by the caller to prevent the
275 * page from being allocated in parallel and returning garbage as the order.
276 * If a caller does not hold page_zone(page)->lock, it must guarantee that the
277 * page cannot be allocated or merged in parallel. Alternatively, it must
278 * handle invalid values gracefully, and use buddy_order_unsafe() below.
279 */
280 static inline unsigned int buddy_order(struct page *page)
281 {
282 /* PageBuddy() must be checked by the caller */
283 return page_private(page);
284 }
285
286 /*
287 * Like buddy_order(), but for callers who cannot afford to hold the zone lock.
288 * PageBuddy() should be checked first by the caller to minimize race window,
289 * and invalid values must be handled gracefully.
290 *
291 * READ_ONCE is used so that if the caller assigns the result into a local
292 * variable and e.g. tests it for valid range before using, the compiler cannot
293 * decide to remove the variable and inline the page_private(page) multiple
294 * times, potentially observing different values in the tests and the actual
295 * use of the result.
296 */
297 #define buddy_order_unsafe(page) READ_ONCE(page_private(page))
298
299 static inline bool is_cow_mapping(vm_flags_t flags)
300 {
301 return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
302 }
303
304 /*
305 * These three helpers classifies VMAs for virtual memory accounting.
306 */
307
308 /*
309 * Executable code area - executable, not writable, not stack
310 */
311 static inline bool is_exec_mapping(vm_flags_t flags)
312 {
313 return (flags & (VM_EXEC | VM_WRITE | VM_STACK)) == VM_EXEC;
314 }
315
316 /*
317 * Stack area - atomatically grows in one direction
318 *
319 * VM_GROWSUP / VM_GROWSDOWN VMAs are always private anonymous:
320 * do_mmap() forbids all other combinations.
321 */
322 static inline bool is_stack_mapping(vm_flags_t flags)
323 {
324 return (flags & VM_STACK) == VM_STACK;
325 }
326
327 /*
328 * Data area - private, writable, not stack
329 */
330 static inline bool is_data_mapping(vm_flags_t flags)
331 {
332 return (flags & (VM_WRITE | VM_SHARED | VM_STACK)) == VM_WRITE;
333 }
334
335 /* mm/util.c */
336 void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
337 struct vm_area_struct *prev);
338 void __vma_unlink_list(struct mm_struct *mm, struct vm_area_struct *vma);
339
340 #ifdef CONFIG_MMU
341 extern long populate_vma_page_range(struct vm_area_struct *vma,
342 unsigned long start, unsigned long end, int *nonblocking);
343 extern void munlock_vma_pages_range(struct vm_area_struct *vma,
344 unsigned long start, unsigned long end);
345 static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
346 {
347 munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end);
348 }
349
350 /*
351 * must be called with vma's mmap_lock held for read or write, and page locked.
352 */
353 extern void mlock_vma_page(struct page *page);
354 extern unsigned int munlock_vma_page(struct page *page);
355
356 /*
357 * Clear the page's PageMlocked(). This can be useful in a situation where
358 * we want to unconditionally remove a page from the pagecache -- e.g.,
359 * on truncation or freeing.
360 *
361 * It is legal to call this function for any page, mlocked or not.
362 * If called for a page that is still mapped by mlocked vmas, all we do
363 * is revert to lazy LRU behaviour -- semantics are not broken.
364 */
365 extern void clear_page_mlock(struct page *page);
366
367 /*
368 * mlock_migrate_page - called only from migrate_misplaced_transhuge_page()
369 * (because that does not go through the full procedure of migration ptes):
370 * to migrate the Mlocked page flag; update statistics.
371 */
372 static inline void mlock_migrate_page(struct page *newpage, struct page *page)
373 {
374 if (TestClearPageMlocked(page)) {
375 int nr_pages = thp_nr_pages(page);
376
377 /* Holding pmd lock, no change in irq context: __mod is safe */
378 __mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages);
379 SetPageMlocked(newpage);
380 __mod_zone_page_state(page_zone(newpage), NR_MLOCK, nr_pages);
381 }
382 }
383
384 extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma);
385
386 /*
387 * At what user virtual address is page expected in @vma?
388 */
389 static inline unsigned long
390 __vma_address(struct page *page, struct vm_area_struct *vma)
391 {
392 pgoff_t pgoff = page_to_pgoff(page);
393 return vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
394 }
395
396 static inline unsigned long
397 vma_address(struct page *page, struct vm_area_struct *vma)
398 {
399 unsigned long start, end;
400
401 start = __vma_address(page, vma);
402 end = start + thp_size(page) - PAGE_SIZE;
403
404 /* page should be within @vma mapping range */
405 VM_BUG_ON_VMA(end < vma->vm_start || start >= vma->vm_end, vma);
406
407 return max(start, vma->vm_start);
408 }
409
410 static inline struct file *maybe_unlock_mmap_for_io(struct vm_fault *vmf,
411 struct file *fpin)
412 {
413 int flags = vmf->flags;
414
415 if (fpin)
416 return fpin;
417
418 /*
419 * FAULT_FLAG_RETRY_NOWAIT means we don't want to wait on page locks or
420 * anything, so we only pin the file and drop the mmap_lock if only
421 * FAULT_FLAG_ALLOW_RETRY is set, while this is the first attempt.
422 */
423 if (fault_flag_allow_retry_first(flags) &&
424 !(flags & FAULT_FLAG_RETRY_NOWAIT)) {
425 fpin = get_file(vmf->vma->vm_file);
426 mmap_read_unlock(vmf->vma->vm_mm);
427 }
428 return fpin;
429 }
430
431 #else /* !CONFIG_MMU */
432 static inline void clear_page_mlock(struct page *page) { }
433 static inline void mlock_vma_page(struct page *page) { }
434 static inline void mlock_migrate_page(struct page *new, struct page *old) { }
435
436 #endif /* !CONFIG_MMU */
437
438 /*
439 * Return the mem_map entry representing the 'offset' subpage within
440 * the maximally aligned gigantic page 'base'. Handle any discontiguity
441 * in the mem_map at MAX_ORDER_NR_PAGES boundaries.
442 */
443 static inline struct page *mem_map_offset(struct page *base, int offset)
444 {
445 if (unlikely(offset >= MAX_ORDER_NR_PAGES))
446 return nth_page(base, offset);
447 return base + offset;
448 }
449
450 /*
451 * Iterator over all subpages within the maximally aligned gigantic
452 * page 'base'. Handle any discontiguity in the mem_map.
453 */
454 static inline struct page *mem_map_next(struct page *iter,
455 struct page *base, int offset)
456 {
457 if (unlikely((offset & (MAX_ORDER_NR_PAGES - 1)) == 0)) {
458 unsigned long pfn = page_to_pfn(base) + offset;
459 if (!pfn_valid(pfn))
460 return NULL;
461 return pfn_to_page(pfn);
462 }
463 return iter + 1;
464 }
465
466 /* Memory initialisation debug and verification */
467 enum mminit_level {
468 MMINIT_WARNING,
469 MMINIT_VERIFY,
470 MMINIT_TRACE
471 };
472
473 #ifdef CONFIG_DEBUG_MEMORY_INIT
474
475 extern int mminit_loglevel;
476
477 #define mminit_dprintk(level, prefix, fmt, arg...) \
478 do { \
479 if (level < mminit_loglevel) { \
480 if (level <= MMINIT_WARNING) \
481 pr_warn("mminit::" prefix " " fmt, ##arg); \
482 else \
483 printk(KERN_DEBUG "mminit::" prefix " " fmt, ##arg); \
484 } \
485 } while (0)
486
487 extern void mminit_verify_pageflags_layout(void);
488 extern void mminit_verify_zonelist(void);
489 #else
490
491 static inline void mminit_dprintk(enum mminit_level level,
492 const char *prefix, const char *fmt, ...)
493 {
494 }
495
496 static inline void mminit_verify_pageflags_layout(void)
497 {
498 }
499
500 static inline void mminit_verify_zonelist(void)
501 {
502 }
503 #endif /* CONFIG_DEBUG_MEMORY_INIT */
504
505 /* mminit_validate_memmodel_limits is independent of CONFIG_DEBUG_MEMORY_INIT */
506 #if defined(CONFIG_SPARSEMEM)
507 extern void mminit_validate_memmodel_limits(unsigned long *start_pfn,
508 unsigned long *end_pfn);
509 #else
510 static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn,
511 unsigned long *end_pfn)
512 {
513 }
514 #endif /* CONFIG_SPARSEMEM */
515
516 #define NODE_RECLAIM_NOSCAN -2
517 #define NODE_RECLAIM_FULL -1
518 #define NODE_RECLAIM_SOME 0
519 #define NODE_RECLAIM_SUCCESS 1
520
521 #ifdef CONFIG_NUMA
522 extern int node_reclaim(struct pglist_data *, gfp_t, unsigned int);
523 #else
524 static inline int node_reclaim(struct pglist_data *pgdat, gfp_t mask,
525 unsigned int order)
526 {
527 return NODE_RECLAIM_NOSCAN;
528 }
529 #endif
530
531 extern int hwpoison_filter(struct page *p);
532
533 extern u32 hwpoison_filter_dev_major;
534 extern u32 hwpoison_filter_dev_minor;
535 extern u64 hwpoison_filter_flags_mask;
536 extern u64 hwpoison_filter_flags_value;
537 extern u64 hwpoison_filter_memcg;
538 extern u32 hwpoison_filter_enable;
539
540 extern unsigned long __must_check vm_mmap_pgoff(struct file *, unsigned long,
541 unsigned long, unsigned long,
542 unsigned long, unsigned long);
543
544 extern void set_pageblock_order(void);
545 unsigned int reclaim_clean_pages_from_list(struct zone *zone,
546 struct list_head *page_list);
547 /* The ALLOC_WMARK bits are used as an index to zone->watermark */
548 #define ALLOC_WMARK_MIN WMARK_MIN
549 #define ALLOC_WMARK_LOW WMARK_LOW
550 #define ALLOC_WMARK_HIGH WMARK_HIGH
551 #define ALLOC_NO_WATERMARKS 0x04 /* don't check watermarks at all */
552
553 /* Mask to get the watermark bits */
554 #define ALLOC_WMARK_MASK (ALLOC_NO_WATERMARKS-1)
555
556 /*
557 * Only MMU archs have async oom victim reclaim - aka oom_reaper so we
558 * cannot assume a reduced access to memory reserves is sufficient for
559 * !MMU
560 */
561 #ifdef CONFIG_MMU
562 #define ALLOC_OOM 0x08
563 #else
564 #define ALLOC_OOM ALLOC_NO_WATERMARKS
565 #endif
566
567 #define ALLOC_HARDER 0x10 /* try to alloc harder */
568 #define ALLOC_HIGH 0x20 /* __GFP_HIGH set */
569 #define ALLOC_CPUSET 0x40 /* check for correct cpuset */
570 #define ALLOC_CMA 0x80 /* allow allocations from CMA areas */
571 #ifdef CONFIG_ZONE_DMA32
572 #define ALLOC_NOFRAGMENT 0x100 /* avoid mixing pageblock types */
573 #else
574 #define ALLOC_NOFRAGMENT 0x0
575 #endif
576 #define ALLOC_KSWAPD 0x800 /* allow waking of kswapd, __GFP_KSWAPD_RECLAIM set */
577
578 enum ttu_flags;
579 struct tlbflush_unmap_batch;
580
581
582 /*
583 * only for MM internal work items which do not depend on
584 * any allocations or locks which might depend on allocations
585 */
586 extern struct workqueue_struct *mm_percpu_wq;
587
588 #ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
589 void try_to_unmap_flush(void);
590 void try_to_unmap_flush_dirty(void);
591 void flush_tlb_batched_pending(struct mm_struct *mm);
592 #else
593 static inline void try_to_unmap_flush(void)
594 {
595 }
596 static inline void try_to_unmap_flush_dirty(void)
597 {
598 }
599 static inline void flush_tlb_batched_pending(struct mm_struct *mm)
600 {
601 }
602 #endif /* CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH */
603
604 extern const struct trace_print_flags pageflag_names[];
605 extern const struct trace_print_flags vmaflag_names[];
606 extern const struct trace_print_flags gfpflag_names[];
607
608 static inline bool is_migrate_highatomic(enum migratetype migratetype)
609 {
610 return migratetype == MIGRATE_HIGHATOMIC;
611 }
612
613 static inline bool is_migrate_highatomic_page(struct page *page)
614 {
615 return get_pageblock_migratetype(page) == MIGRATE_HIGHATOMIC;
616 }
617
618 void setup_zone_pageset(struct zone *zone);
619
620 struct migration_target_control {
621 int nid; /* preferred node id */
622 nodemask_t *nmask;
623 gfp_t gfp_mask;
624 };
625
626 #endif /* __MM_INTERNAL_H */