1 #ifndef _LINUX_MMZONE_H
2 #define _LINUX_MMZONE_H
3 
4 #ifndef __ASSEMBLY__
5 #ifndef __GENERATING_BOUNDS_H
6 
7 #include <linux/spinlock.h>
8 #include <linux/list.h>
9 #include <linux/wait.h>
10 #include <linux/bitops.h>
11 #include <linux/cache.h>
12 #include <linux/threads.h>
13 #include <linux/numa.h>
14 #include <linux/init.h>
15 #include <linux/seqlock.h>
16 #include <linux/nodemask.h>
17 #include <linux/pageblock-flags.h>
18 #include <linux/page-flags-layout.h>
19 #include <linux/atomic.h>
20 #include <asm/page.h>
21 
22 /* Free memory management - zoned buddy allocator.  */
23 #ifndef CONFIG_FORCE_MAX_ZONEORDER
24 #define MAX_ORDER 11
25 #else
26 #define MAX_ORDER CONFIG_FORCE_MAX_ZONEORDER
27 #endif
28 #define MAX_ORDER_NR_PAGES (1 << (MAX_ORDER - 1))
29 
30 /*
31  * PAGE_ALLOC_COSTLY_ORDER is the order at which allocations are deemed
32  * costly to service.  That is between allocation orders which should
33  * coalesce naturally under reasonable reclaim pressure and those which
34  * will not.
35  */
36 #define PAGE_ALLOC_COSTLY_ORDER 3
37 
38 enum {
39 	MIGRATE_UNMOVABLE,
40 	MIGRATE_MOVABLE,
41 	MIGRATE_RECLAIMABLE,
42 	MIGRATE_PCPTYPES,	/* the number of types on the pcp lists */
43 	MIGRATE_HIGHATOMIC = MIGRATE_PCPTYPES,
44 #ifdef CONFIG_CMA
45 	/*
46 	 * MIGRATE_CMA migration type is designed to mimic the way
47 	 * ZONE_MOVABLE works.  Only movable pages can be allocated
48 	 * from MIGRATE_CMA pageblocks and page allocator never
49 	 * implicitly change migration type of MIGRATE_CMA pageblock.
50 	 *
51 	 * The way to use it is to change migratetype of a range of
52 	 * pageblocks to MIGRATE_CMA which can be done by
53 	 * __free_pageblock_cma() function.  What is important though
54 	 * is that a range of pageblocks must be aligned to
55 	 * MAX_ORDER_NR_PAGES should biggest page be bigger then
56 	 * a single pageblock.
57 	 */
58 	MIGRATE_CMA,
59 #endif
60 #ifdef CONFIG_MEMORY_ISOLATION
61 	MIGRATE_ISOLATE,	/* can't allocate from here */
62 #endif
63 	MIGRATE_TYPES
64 };
65 
66 #ifdef CONFIG_CMA
67 #  define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA)
68 #else
69 #  define is_migrate_cma(migratetype) false
70 #endif
71 
72 #define for_each_migratetype_order(order, type) \
73 	for (order = 0; order < MAX_ORDER; order++) \
74 		for (type = 0; type < MIGRATE_TYPES; type++)
75 
76 extern int page_group_by_mobility_disabled;
77 
78 #define NR_MIGRATETYPE_BITS (PB_migrate_end - PB_migrate + 1)
79 #define MIGRATETYPE_MASK ((1UL << NR_MIGRATETYPE_BITS) - 1)
80 
81 #define get_pageblock_migratetype(page)					\
82 	get_pfnblock_flags_mask(page, page_to_pfn(page),		\
83 			PB_migrate_end, MIGRATETYPE_MASK)
84 
get_pfnblock_migratetype(struct page * page,unsigned long pfn)85 static inline int get_pfnblock_migratetype(struct page *page, unsigned long pfn)
86 {
87 	BUILD_BUG_ON(PB_migrate_end - PB_migrate != 2);
88 	return get_pfnblock_flags_mask(page, pfn, PB_migrate_end,
89 					MIGRATETYPE_MASK);
90 }
91 
92 struct free_area {
93 	struct list_head	free_list[MIGRATE_TYPES];
94 	unsigned long		nr_free;
95 };
96 
97 struct pglist_data;
98 
99 /*
100  * zone->lock and zone->lru_lock are two of the hottest locks in the kernel.
101  * So add a wild amount of padding here to ensure that they fall into separate
102  * cachelines.  There are very few zone structures in the machine, so space
103  * consumption is not a concern here.
104  */
105 #if defined(CONFIG_SMP)
106 struct zone_padding {
107 	char x[0];
108 } ____cacheline_internodealigned_in_smp;
109 #define ZONE_PADDING(name)	struct zone_padding name;
110 #else
111 #define ZONE_PADDING(name)
112 #endif
113 
114 enum zone_stat_item {
115 	/* First 128 byte cacheline (assuming 64 bit words) */
116 	NR_FREE_PAGES,
117 	NR_ALLOC_BATCH,
118 	NR_LRU_BASE,
119 	NR_INACTIVE_ANON = NR_LRU_BASE, /* must match order of LRU_[IN]ACTIVE */
120 	NR_ACTIVE_ANON,		/*  "     "     "   "       "         */
121 	NR_INACTIVE_FILE,	/*  "     "     "   "       "         */
122 	NR_ACTIVE_FILE,		/*  "     "     "   "       "         */
123 	NR_UNEVICTABLE,		/*  "     "     "   "       "         */
124 	NR_MLOCK,		/* mlock()ed pages found and moved off LRU */
125 	NR_ANON_PAGES,	/* Mapped anonymous pages */
126 	NR_FILE_MAPPED,	/* pagecache pages mapped into pagetables.
127 			   only modified from process context */
128 	NR_FILE_PAGES,
129 	NR_FILE_DIRTY,
130 	NR_WRITEBACK,
131 	NR_SLAB_RECLAIMABLE,
132 	NR_SLAB_UNRECLAIMABLE,
133 	NR_PAGETABLE,		/* used for pagetables */
134 	NR_KERNEL_STACK,
135 	/* Second 128 byte cacheline */
136 	NR_UNSTABLE_NFS,	/* NFS unstable pages */
137 	NR_BOUNCE,
138 	NR_VMSCAN_WRITE,
139 	NR_VMSCAN_IMMEDIATE,	/* Prioritise for reclaim when writeback ends */
140 	NR_WRITEBACK_TEMP,	/* Writeback using temporary buffers */
141 	NR_ISOLATED_ANON,	/* Temporary isolated pages from anon lru */
142 	NR_ISOLATED_FILE,	/* Temporary isolated pages from file lru */
143 	NR_SHMEM,		/* shmem pages (included tmpfs/GEM pages) */
144 	NR_DIRTIED,		/* page dirtyings since bootup */
145 	NR_WRITTEN,		/* page writings since bootup */
146 	NR_PAGES_SCANNED,	/* pages scanned since last reclaim */
147 #ifdef CONFIG_NUMA
148 	NUMA_HIT,		/* allocated in intended node */
149 	NUMA_MISS,		/* allocated in non intended node */
150 	NUMA_FOREIGN,		/* was intended here, hit elsewhere */
151 	NUMA_INTERLEAVE_HIT,	/* interleaver preferred this zone */
152 	NUMA_LOCAL,		/* allocation from local node */
153 	NUMA_OTHER,		/* allocation from other node */
154 #endif
155 	WORKINGSET_REFAULT,
156 	WORKINGSET_ACTIVATE,
157 	WORKINGSET_NODERECLAIM,
158 	NR_ANON_TRANSPARENT_HUGEPAGES,
159 	NR_FREE_CMA_PAGES,
160 	NR_VM_ZONE_STAT_ITEMS };
161 
162 /*
163  * We do arithmetic on the LRU lists in various places in the code,
164  * so it is important to keep the active lists LRU_ACTIVE higher in
165  * the array than the corresponding inactive lists, and to keep
166  * the *_FILE lists LRU_FILE higher than the corresponding _ANON lists.
167  *
168  * This has to be kept in sync with the statistics in zone_stat_item
169  * above and the descriptions in vmstat_text in mm/vmstat.c
170  */
171 #define LRU_BASE 0
172 #define LRU_ACTIVE 1
173 #define LRU_FILE 2
174 
175 enum lru_list {
176 	LRU_INACTIVE_ANON = LRU_BASE,
177 	LRU_ACTIVE_ANON = LRU_BASE + LRU_ACTIVE,
178 	LRU_INACTIVE_FILE = LRU_BASE + LRU_FILE,
179 	LRU_ACTIVE_FILE = LRU_BASE + LRU_FILE + LRU_ACTIVE,
180 	LRU_UNEVICTABLE,
181 	NR_LRU_LISTS
182 };
183 
184 #define for_each_lru(lru) for (lru = 0; lru < NR_LRU_LISTS; lru++)
185 
186 #define for_each_evictable_lru(lru) for (lru = 0; lru <= LRU_ACTIVE_FILE; lru++)
187 
is_file_lru(enum lru_list lru)188 static inline int is_file_lru(enum lru_list lru)
189 {
190 	return (lru == LRU_INACTIVE_FILE || lru == LRU_ACTIVE_FILE);
191 }
192 
is_active_lru(enum lru_list lru)193 static inline int is_active_lru(enum lru_list lru)
194 {
195 	return (lru == LRU_ACTIVE_ANON || lru == LRU_ACTIVE_FILE);
196 }
197 
is_unevictable_lru(enum lru_list lru)198 static inline int is_unevictable_lru(enum lru_list lru)
199 {
200 	return (lru == LRU_UNEVICTABLE);
201 }
202 
203 struct zone_reclaim_stat {
204 	/*
205 	 * The pageout code in vmscan.c keeps track of how many of the
206 	 * mem/swap backed and file backed pages are referenced.
207 	 * The higher the rotated/scanned ratio, the more valuable
208 	 * that cache is.
209 	 *
210 	 * The anon LRU stats live in [0], file LRU stats in [1]
211 	 */
212 	unsigned long		recent_rotated[2];
213 	unsigned long		recent_scanned[2];
214 };
215 
216 struct lruvec {
217 	struct list_head lists[NR_LRU_LISTS];
218 	struct zone_reclaim_stat reclaim_stat;
219 #ifdef CONFIG_MEMCG
220 	struct zone *zone;
221 #endif
222 };
223 
224 /* Mask used at gathering information at once (see memcontrol.c) */
225 #define LRU_ALL_FILE (BIT(LRU_INACTIVE_FILE) | BIT(LRU_ACTIVE_FILE))
226 #define LRU_ALL_ANON (BIT(LRU_INACTIVE_ANON) | BIT(LRU_ACTIVE_ANON))
227 #define LRU_ALL	     ((1 << NR_LRU_LISTS) - 1)
228 
229 /* Isolate clean file */
230 #define ISOLATE_CLEAN		((__force isolate_mode_t)0x1)
231 /* Isolate unmapped file */
232 #define ISOLATE_UNMAPPED	((__force isolate_mode_t)0x2)
233 /* Isolate for asynchronous migration */
234 #define ISOLATE_ASYNC_MIGRATE	((__force isolate_mode_t)0x4)
235 /* Isolate unevictable pages */
236 #define ISOLATE_UNEVICTABLE	((__force isolate_mode_t)0x8)
237 
238 /* LRU Isolation modes. */
239 typedef unsigned __bitwise__ isolate_mode_t;
240 
241 enum zone_watermarks {
242 	WMARK_MIN,
243 	WMARK_LOW,
244 	WMARK_HIGH,
245 	NR_WMARK
246 };
247 
248 #define min_wmark_pages(z) (z->watermark[WMARK_MIN])
249 #define low_wmark_pages(z) (z->watermark[WMARK_LOW])
250 #define high_wmark_pages(z) (z->watermark[WMARK_HIGH])
251 
252 struct per_cpu_pages {
253 	int count;		/* number of pages in the list */
254 	int high;		/* high watermark, emptying needed */
255 	int batch;		/* chunk size for buddy add/remove */
256 
257 	/* Lists of pages, one per migrate type stored on the pcp-lists */
258 	struct list_head lists[MIGRATE_PCPTYPES];
259 };
260 
261 struct per_cpu_pageset {
262 	struct per_cpu_pages pcp;
263 #ifdef CONFIG_NUMA
264 	s8 expire;
265 #endif
266 #ifdef CONFIG_SMP
267 	s8 stat_threshold;
268 	s8 vm_stat_diff[NR_VM_ZONE_STAT_ITEMS];
269 #endif
270 };
271 
272 #endif /* !__GENERATING_BOUNDS.H */
273 
274 enum zone_type {
275 #ifdef CONFIG_ZONE_DMA
276 	/*
277 	 * ZONE_DMA is used when there are devices that are not able
278 	 * to do DMA to all of addressable memory (ZONE_NORMAL). Then we
279 	 * carve out the portion of memory that is needed for these devices.
280 	 * The range is arch specific.
281 	 *
282 	 * Some examples
283 	 *
284 	 * Architecture		Limit
285 	 * ---------------------------
286 	 * parisc, ia64, sparc	<4G
287 	 * s390			<2G
288 	 * arm			Various
289 	 * alpha		Unlimited or 0-16MB.
290 	 *
291 	 * i386, x86_64 and multiple other arches
292 	 * 			<16M.
293 	 */
294 	ZONE_DMA,
295 #endif
296 #ifdef CONFIG_ZONE_DMA32
297 	/*
298 	 * x86_64 needs two ZONE_DMAs because it supports devices that are
299 	 * only able to do DMA to the lower 16M but also 32 bit devices that
300 	 * can only do DMA areas below 4G.
301 	 */
302 	ZONE_DMA32,
303 #endif
304 	/*
305 	 * Normal addressable memory is in ZONE_NORMAL. DMA operations can be
306 	 * performed on pages in ZONE_NORMAL if the DMA devices support
307 	 * transfers to all addressable memory.
308 	 */
309 	ZONE_NORMAL,
310 #ifdef CONFIG_HIGHMEM
311 	/*
312 	 * A memory area that is only addressable by the kernel through
313 	 * mapping portions into its own address space. This is for example
314 	 * used by i386 to allow the kernel to address the memory beyond
315 	 * 900MB. The kernel will set up special mappings (page
316 	 * table entries on i386) for each page that the kernel needs to
317 	 * access.
318 	 */
319 	ZONE_HIGHMEM,
320 #endif
321 	ZONE_MOVABLE,
322 #ifdef CONFIG_ZONE_DEVICE
323 	ZONE_DEVICE,
324 #endif
325 	__MAX_NR_ZONES
326 
327 };
328 
329 #ifndef __GENERATING_BOUNDS_H
330 
331 struct zone {
332 	/* Read-mostly fields */
333 
334 	/* zone watermarks, access with *_wmark_pages(zone) macros */
335 	unsigned long watermark[NR_WMARK];
336 
337 	unsigned long nr_reserved_highatomic;
338 
339 	/*
340 	 * We don't know if the memory that we're going to allocate will be
341 	 * freeable or/and it will be released eventually, so to avoid totally
342 	 * wasting several GB of ram we must reserve some of the lower zone
343 	 * memory (otherwise we risk to run OOM on the lower zones despite
344 	 * there being tons of freeable ram on the higher zones).  This array is
345 	 * recalculated at runtime if the sysctl_lowmem_reserve_ratio sysctl
346 	 * changes.
347 	 */
348 	long lowmem_reserve[MAX_NR_ZONES];
349 
350 #ifdef CONFIG_NUMA
351 	int node;
352 #endif
353 
354 	/*
355 	 * The target ratio of ACTIVE_ANON to INACTIVE_ANON pages on
356 	 * this zone's LRU.  Maintained by the pageout code.
357 	 */
358 	unsigned int inactive_ratio;
359 
360 	struct pglist_data	*zone_pgdat;
361 	struct per_cpu_pageset __percpu *pageset;
362 
363 	/*
364 	 * This is a per-zone reserve of pages that should not be
365 	 * considered dirtyable memory.
366 	 */
367 	unsigned long		dirty_balance_reserve;
368 
369 #ifndef CONFIG_SPARSEMEM
370 	/*
371 	 * Flags for a pageblock_nr_pages block. See pageblock-flags.h.
372 	 * In SPARSEMEM, this map is stored in struct mem_section
373 	 */
374 	unsigned long		*pageblock_flags;
375 #endif /* CONFIG_SPARSEMEM */
376 
377 #ifdef CONFIG_NUMA
378 	/*
379 	 * zone reclaim becomes active if more unmapped pages exist.
380 	 */
381 	unsigned long		min_unmapped_pages;
382 	unsigned long		min_slab_pages;
383 #endif /* CONFIG_NUMA */
384 
385 	/* zone_start_pfn == zone_start_paddr >> PAGE_SHIFT */
386 	unsigned long		zone_start_pfn;
387 
388 	/*
389 	 * spanned_pages is the total pages spanned by the zone, including
390 	 * holes, which is calculated as:
391 	 * 	spanned_pages = zone_end_pfn - zone_start_pfn;
392 	 *
393 	 * present_pages is physical pages existing within the zone, which
394 	 * is calculated as:
395 	 *	present_pages = spanned_pages - absent_pages(pages in holes);
396 	 *
397 	 * managed_pages is present pages managed by the buddy system, which
398 	 * is calculated as (reserved_pages includes pages allocated by the
399 	 * bootmem allocator):
400 	 *	managed_pages = present_pages - reserved_pages;
401 	 *
402 	 * So present_pages may be used by memory hotplug or memory power
403 	 * management logic to figure out unmanaged pages by checking
404 	 * (present_pages - managed_pages). And managed_pages should be used
405 	 * by page allocator and vm scanner to calculate all kinds of watermarks
406 	 * and thresholds.
407 	 *
408 	 * Locking rules:
409 	 *
410 	 * zone_start_pfn and spanned_pages are protected by span_seqlock.
411 	 * It is a seqlock because it has to be read outside of zone->lock,
412 	 * and it is done in the main allocator path.  But, it is written
413 	 * quite infrequently.
414 	 *
415 	 * The span_seq lock is declared along with zone->lock because it is
416 	 * frequently read in proximity to zone->lock.  It's good to
417 	 * give them a chance of being in the same cacheline.
418 	 *
419 	 * Write access to present_pages at runtime should be protected by
420 	 * mem_hotplug_begin/end(). Any reader who can't tolerant drift of
421 	 * present_pages should get_online_mems() to get a stable value.
422 	 *
423 	 * Read access to managed_pages should be safe because it's unsigned
424 	 * long. Write access to zone->managed_pages and totalram_pages are
425 	 * protected by managed_page_count_lock at runtime. Idealy only
426 	 * adjust_managed_page_count() should be used instead of directly
427 	 * touching zone->managed_pages and totalram_pages.
428 	 */
429 	unsigned long		managed_pages;
430 	unsigned long		spanned_pages;
431 	unsigned long		present_pages;
432 
433 	const char		*name;
434 
435 #ifdef CONFIG_MEMORY_ISOLATION
436 	/*
437 	 * Number of isolated pageblock. It is used to solve incorrect
438 	 * freepage counting problem due to racy retrieving migratetype
439 	 * of pageblock. Protected by zone->lock.
440 	 */
441 	unsigned long		nr_isolate_pageblock;
442 #endif
443 
444 #ifdef CONFIG_MEMORY_HOTPLUG
445 	/* see spanned/present_pages for more description */
446 	seqlock_t		span_seqlock;
447 #endif
448 
449 	/*
450 	 * wait_table		-- the array holding the hash table
451 	 * wait_table_hash_nr_entries	-- the size of the hash table array
452 	 * wait_table_bits	-- wait_table_size == (1 << wait_table_bits)
453 	 *
454 	 * The purpose of all these is to keep track of the people
455 	 * waiting for a page to become available and make them
456 	 * runnable again when possible. The trouble is that this
457 	 * consumes a lot of space, especially when so few things
458 	 * wait on pages at a given time. So instead of using
459 	 * per-page waitqueues, we use a waitqueue hash table.
460 	 *
461 	 * The bucket discipline is to sleep on the same queue when
462 	 * colliding and wake all in that wait queue when removing.
463 	 * When something wakes, it must check to be sure its page is
464 	 * truly available, a la thundering herd. The cost of a
465 	 * collision is great, but given the expected load of the
466 	 * table, they should be so rare as to be outweighed by the
467 	 * benefits from the saved space.
468 	 *
469 	 * __wait_on_page_locked() and unlock_page() in mm/filemap.c, are the
470 	 * primary users of these fields, and in mm/page_alloc.c
471 	 * free_area_init_core() performs the initialization of them.
472 	 */
473 	wait_queue_head_t	*wait_table;
474 	unsigned long		wait_table_hash_nr_entries;
475 	unsigned long		wait_table_bits;
476 
477 	ZONE_PADDING(_pad1_)
478 	/* free areas of different sizes */
479 	struct free_area	free_area[MAX_ORDER];
480 
481 	/* zone flags, see below */
482 	unsigned long		flags;
483 
484 	/* Write-intensive fields used from the page allocator */
485 	spinlock_t		lock;
486 
487 	ZONE_PADDING(_pad2_)
488 
489 	/* Write-intensive fields used by page reclaim */
490 
491 	/* Fields commonly accessed by the page reclaim scanner */
492 	spinlock_t		lru_lock;
493 	struct lruvec		lruvec;
494 
495 	/* Evictions & activations on the inactive file list */
496 	atomic_long_t		inactive_age;
497 
498 	/*
499 	 * When free pages are below this point, additional steps are taken
500 	 * when reading the number of free pages to avoid per-cpu counter
501 	 * drift allowing watermarks to be breached
502 	 */
503 	unsigned long percpu_drift_mark;
504 
505 #if defined CONFIG_COMPACTION || defined CONFIG_CMA
506 	/* pfn where compaction free scanner should start */
507 	unsigned long		compact_cached_free_pfn;
508 	/* pfn where async and sync compaction migration scanner should start */
509 	unsigned long		compact_cached_migrate_pfn[2];
510 #endif
511 
512 #ifdef CONFIG_COMPACTION
513 	/*
514 	 * On compaction failure, 1<<compact_defer_shift compactions
515 	 * are skipped before trying again. The number attempted since
516 	 * last failure is tracked with compact_considered.
517 	 */
518 	unsigned int		compact_considered;
519 	unsigned int		compact_defer_shift;
520 	int			compact_order_failed;
521 #endif
522 
523 #if defined CONFIG_COMPACTION || defined CONFIG_CMA
524 	/* Set to true when the PG_migrate_skip bits should be cleared */
525 	bool			compact_blockskip_flush;
526 #endif
527 
528 	ZONE_PADDING(_pad3_)
529 	/* Zone statistics */
530 	atomic_long_t		vm_stat[NR_VM_ZONE_STAT_ITEMS];
531 } ____cacheline_internodealigned_in_smp;
532 
533 enum zone_flags {
534 	ZONE_RECLAIM_LOCKED,		/* prevents concurrent reclaim */
535 	ZONE_OOM_LOCKED,		/* zone is in OOM killer zonelist */
536 	ZONE_CONGESTED,			/* zone has many dirty pages backed by
537 					 * a congested BDI
538 					 */
539 	ZONE_DIRTY,			/* reclaim scanning has recently found
540 					 * many dirty file pages at the tail
541 					 * of the LRU.
542 					 */
543 	ZONE_WRITEBACK,			/* reclaim scanning has recently found
544 					 * many pages under writeback
545 					 */
546 	ZONE_FAIR_DEPLETED,		/* fair zone policy batch depleted */
547 };
548 
zone_end_pfn(const struct zone * zone)549 static inline unsigned long zone_end_pfn(const struct zone *zone)
550 {
551 	return zone->zone_start_pfn + zone->spanned_pages;
552 }
553 
zone_spans_pfn(const struct zone * zone,unsigned long pfn)554 static inline bool zone_spans_pfn(const struct zone *zone, unsigned long pfn)
555 {
556 	return zone->zone_start_pfn <= pfn && pfn < zone_end_pfn(zone);
557 }
558 
zone_is_initialized(struct zone * zone)559 static inline bool zone_is_initialized(struct zone *zone)
560 {
561 	return !!zone->wait_table;
562 }
563 
zone_is_empty(struct zone * zone)564 static inline bool zone_is_empty(struct zone *zone)
565 {
566 	return zone->spanned_pages == 0;
567 }
568 
569 /*
570  * The "priority" of VM scanning is how much of the queues we will scan in one
571  * go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the
572  * queues ("queue_length >> 12") during an aging round.
573  */
574 #define DEF_PRIORITY 12
575 
576 /* Maximum number of zones on a zonelist */
577 #define MAX_ZONES_PER_ZONELIST (MAX_NUMNODES * MAX_NR_ZONES)
578 
579 #ifdef CONFIG_NUMA
580 
581 /*
582  * The NUMA zonelists are doubled because we need zonelists that restrict the
583  * allocations to a single node for __GFP_THISNODE.
584  *
585  * [0]	: Zonelist with fallback
586  * [1]	: No fallback (__GFP_THISNODE)
587  */
588 #define MAX_ZONELISTS 2
589 #else
590 #define MAX_ZONELISTS 1
591 #endif
592 
593 /*
594  * This struct contains information about a zone in a zonelist. It is stored
595  * here to avoid dereferences into large structures and lookups of tables
596  */
597 struct zoneref {
598 	struct zone *zone;	/* Pointer to actual zone */
599 	int zone_idx;		/* zone_idx(zoneref->zone) */
600 };
601 
602 /*
603  * One allocation request operates on a zonelist. A zonelist
604  * is a list of zones, the first one is the 'goal' of the
605  * allocation, the other zones are fallback zones, in decreasing
606  * priority.
607  *
608  * To speed the reading of the zonelist, the zonerefs contain the zone index
609  * of the entry being read. Helper functions to access information given
610  * a struct zoneref are
611  *
612  * zonelist_zone()	- Return the struct zone * for an entry in _zonerefs
613  * zonelist_zone_idx()	- Return the index of the zone for an entry
614  * zonelist_node_idx()	- Return the index of the node for an entry
615  */
616 struct zonelist {
617 	struct zoneref _zonerefs[MAX_ZONES_PER_ZONELIST + 1];
618 };
619 
620 #ifndef CONFIG_DISCONTIGMEM
621 /* The array of struct pages - for discontigmem use pgdat->lmem_map */
622 extern struct page *mem_map;
623 #endif
624 
625 /*
626  * The pg_data_t structure is used in machines with CONFIG_DISCONTIGMEM
627  * (mostly NUMA machines?) to denote a higher-level memory zone than the
628  * zone denotes.
629  *
630  * On NUMA machines, each NUMA node would have a pg_data_t to describe
631  * it's memory layout.
632  *
633  * Memory statistics and page replacement data structures are maintained on a
634  * per-zone basis.
635  */
636 struct bootmem_data;
637 typedef struct pglist_data {
638 	struct zone node_zones[MAX_NR_ZONES];
639 	struct zonelist node_zonelists[MAX_ZONELISTS];
640 	int nr_zones;
641 #ifdef CONFIG_FLAT_NODE_MEM_MAP	/* means !SPARSEMEM */
642 	struct page *node_mem_map;
643 #ifdef CONFIG_PAGE_EXTENSION
644 	struct page_ext *node_page_ext;
645 #endif
646 #endif
647 #ifndef CONFIG_NO_BOOTMEM
648 	struct bootmem_data *bdata;
649 #endif
650 #ifdef CONFIG_MEMORY_HOTPLUG
651 	/*
652 	 * Must be held any time you expect node_start_pfn, node_present_pages
653 	 * or node_spanned_pages stay constant.  Holding this will also
654 	 * guarantee that any pfn_valid() stays that way.
655 	 *
656 	 * pgdat_resize_lock() and pgdat_resize_unlock() are provided to
657 	 * manipulate node_size_lock without checking for CONFIG_MEMORY_HOTPLUG.
658 	 *
659 	 * Nests above zone->lock and zone->span_seqlock
660 	 */
661 	spinlock_t node_size_lock;
662 #endif
663 	unsigned long node_start_pfn;
664 	unsigned long node_present_pages; /* total number of physical pages */
665 	unsigned long node_spanned_pages; /* total size of physical page
666 					     range, including holes */
667 	int node_id;
668 	wait_queue_head_t kswapd_wait;
669 	wait_queue_head_t pfmemalloc_wait;
670 	struct task_struct *kswapd;	/* Protected by
671 					   mem_hotplug_begin/end() */
672 	int kswapd_max_order;
673 	enum zone_type classzone_idx;
674 #ifdef CONFIG_NUMA_BALANCING
675 	/* Lock serializing the migrate rate limiting window */
676 	spinlock_t numabalancing_migrate_lock;
677 
678 	/* Rate limiting time interval */
679 	unsigned long numabalancing_migrate_next_window;
680 
681 	/* Number of pages migrated during the rate limiting time interval */
682 	unsigned long numabalancing_migrate_nr_pages;
683 #endif
684 
685 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
686 	/*
687 	 * If memory initialisation on large machines is deferred then this
688 	 * is the first PFN that needs to be initialised.
689 	 */
690 	unsigned long first_deferred_pfn;
691 #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
692 } pg_data_t;
693 
694 #define node_present_pages(nid)	(NODE_DATA(nid)->node_present_pages)
695 #define node_spanned_pages(nid)	(NODE_DATA(nid)->node_spanned_pages)
696 #ifdef CONFIG_FLAT_NODE_MEM_MAP
697 #define pgdat_page_nr(pgdat, pagenr)	((pgdat)->node_mem_map + (pagenr))
698 #else
699 #define pgdat_page_nr(pgdat, pagenr)	pfn_to_page((pgdat)->node_start_pfn + (pagenr))
700 #endif
701 #define nid_page_nr(nid, pagenr) 	pgdat_page_nr(NODE_DATA(nid),(pagenr))
702 
703 #define node_start_pfn(nid)	(NODE_DATA(nid)->node_start_pfn)
704 #define node_end_pfn(nid) pgdat_end_pfn(NODE_DATA(nid))
705 
pgdat_end_pfn(pg_data_t * pgdat)706 static inline unsigned long pgdat_end_pfn(pg_data_t *pgdat)
707 {
708 	return pgdat->node_start_pfn + pgdat->node_spanned_pages;
709 }
710 
pgdat_is_empty(pg_data_t * pgdat)711 static inline bool pgdat_is_empty(pg_data_t *pgdat)
712 {
713 	return !pgdat->node_start_pfn && !pgdat->node_spanned_pages;
714 }
715 
zone_id(const struct zone * zone)716 static inline int zone_id(const struct zone *zone)
717 {
718 	struct pglist_data *pgdat = zone->zone_pgdat;
719 
720 	return zone - pgdat->node_zones;
721 }
722 
723 #ifdef CONFIG_ZONE_DEVICE
is_dev_zone(const struct zone * zone)724 static inline bool is_dev_zone(const struct zone *zone)
725 {
726 	return zone_id(zone) == ZONE_DEVICE;
727 }
728 #else
is_dev_zone(const struct zone * zone)729 static inline bool is_dev_zone(const struct zone *zone)
730 {
731 	return false;
732 }
733 #endif
734 
735 #include <linux/memory_hotplug.h>
736 
737 extern struct mutex zonelists_mutex;
738 void build_all_zonelists(pg_data_t *pgdat, struct zone *zone);
739 void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx);
740 bool zone_watermark_ok(struct zone *z, unsigned int order,
741 		unsigned long mark, int classzone_idx, int alloc_flags);
742 bool zone_watermark_ok_safe(struct zone *z, unsigned int order,
743 		unsigned long mark, int classzone_idx);
744 enum memmap_context {
745 	MEMMAP_EARLY,
746 	MEMMAP_HOTPLUG,
747 };
748 extern int init_currently_empty_zone(struct zone *zone, unsigned long start_pfn,
749 				     unsigned long size);
750 
751 extern void lruvec_init(struct lruvec *lruvec);
752 
lruvec_zone(struct lruvec * lruvec)753 static inline struct zone *lruvec_zone(struct lruvec *lruvec)
754 {
755 #ifdef CONFIG_MEMCG
756 	return lruvec->zone;
757 #else
758 	return container_of(lruvec, struct zone, lruvec);
759 #endif
760 }
761 
762 #ifdef CONFIG_HAVE_MEMORY_PRESENT
763 void memory_present(int nid, unsigned long start, unsigned long end);
764 #else
memory_present(int nid,unsigned long start,unsigned long end)765 static inline void memory_present(int nid, unsigned long start, unsigned long end) {}
766 #endif
767 
768 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
769 int local_memory_node(int node_id);
770 #else
local_memory_node(int node_id)771 static inline int local_memory_node(int node_id) { return node_id; };
772 #endif
773 
774 #ifdef CONFIG_NEED_NODE_MEMMAP_SIZE
775 unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long);
776 #endif
777 
778 /*
779  * zone_idx() returns 0 for the ZONE_DMA zone, 1 for the ZONE_NORMAL zone, etc.
780  */
781 #define zone_idx(zone)		((zone) - (zone)->zone_pgdat->node_zones)
782 
populated_zone(struct zone * zone)783 static inline int populated_zone(struct zone *zone)
784 {
785 	return (!!zone->present_pages);
786 }
787 
788 extern int movable_zone;
789 
790 #ifdef CONFIG_HIGHMEM
zone_movable_is_highmem(void)791 static inline int zone_movable_is_highmem(void)
792 {
793 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
794 	return movable_zone == ZONE_HIGHMEM;
795 #else
796 	return (ZONE_MOVABLE - 1) == ZONE_HIGHMEM;
797 #endif
798 }
799 #endif
800 
is_highmem_idx(enum zone_type idx)801 static inline int is_highmem_idx(enum zone_type idx)
802 {
803 #ifdef CONFIG_HIGHMEM
804 	return (idx == ZONE_HIGHMEM ||
805 		(idx == ZONE_MOVABLE && zone_movable_is_highmem()));
806 #else
807 	return 0;
808 #endif
809 }
810 
811 /**
812  * is_highmem - helper function to quickly check if a struct zone is a
813  *              highmem zone or not.  This is an attempt to keep references
814  *              to ZONE_{DMA/NORMAL/HIGHMEM/etc} in general code to a minimum.
815  * @zone - pointer to struct zone variable
816  */
is_highmem(struct zone * zone)817 static inline int is_highmem(struct zone *zone)
818 {
819 #ifdef CONFIG_HIGHMEM
820 	int zone_off = (char *)zone - (char *)zone->zone_pgdat->node_zones;
821 	return zone_off == ZONE_HIGHMEM * sizeof(*zone) ||
822 	       (zone_off == ZONE_MOVABLE * sizeof(*zone) &&
823 		zone_movable_is_highmem());
824 #else
825 	return 0;
826 #endif
827 }
828 
829 /* These two functions are used to setup the per zone pages min values */
830 struct ctl_table;
831 int min_free_kbytes_sysctl_handler(struct ctl_table *, int,
832 					void __user *, size_t *, loff_t *);
833 extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1];
834 int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int,
835 					void __user *, size_t *, loff_t *);
836 int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *, int,
837 					void __user *, size_t *, loff_t *);
838 int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *, int,
839 			void __user *, size_t *, loff_t *);
840 int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *, int,
841 			void __user *, size_t *, loff_t *);
842 
843 extern int numa_zonelist_order_handler(struct ctl_table *, int,
844 			void __user *, size_t *, loff_t *);
845 extern char numa_zonelist_order[];
846 #define NUMA_ZONELIST_ORDER_LEN 16	/* string buffer size */
847 
848 #ifndef CONFIG_NEED_MULTIPLE_NODES
849 
850 extern struct pglist_data contig_page_data;
851 #define NODE_DATA(nid)		(&contig_page_data)
852 #define NODE_MEM_MAP(nid)	mem_map
853 
854 #else /* CONFIG_NEED_MULTIPLE_NODES */
855 
856 #include <asm/mmzone.h>
857 
858 #endif /* !CONFIG_NEED_MULTIPLE_NODES */
859 
860 extern struct pglist_data *first_online_pgdat(void);
861 extern struct pglist_data *next_online_pgdat(struct pglist_data *pgdat);
862 extern struct zone *next_zone(struct zone *zone);
863 
864 /**
865  * for_each_online_pgdat - helper macro to iterate over all online nodes
866  * @pgdat - pointer to a pg_data_t variable
867  */
868 #define for_each_online_pgdat(pgdat)			\
869 	for (pgdat = first_online_pgdat();		\
870 	     pgdat;					\
871 	     pgdat = next_online_pgdat(pgdat))
872 /**
873  * for_each_zone - helper macro to iterate over all memory zones
874  * @zone - pointer to struct zone variable
875  *
876  * The user only needs to declare the zone variable, for_each_zone
877  * fills it in.
878  */
879 #define for_each_zone(zone)			        \
880 	for (zone = (first_online_pgdat())->node_zones; \
881 	     zone;					\
882 	     zone = next_zone(zone))
883 
884 #define for_each_populated_zone(zone)		        \
885 	for (zone = (first_online_pgdat())->node_zones; \
886 	     zone;					\
887 	     zone = next_zone(zone))			\
888 		if (!populated_zone(zone))		\
889 			; /* do nothing */		\
890 		else
891 
zonelist_zone(struct zoneref * zoneref)892 static inline struct zone *zonelist_zone(struct zoneref *zoneref)
893 {
894 	return zoneref->zone;
895 }
896 
zonelist_zone_idx(struct zoneref * zoneref)897 static inline int zonelist_zone_idx(struct zoneref *zoneref)
898 {
899 	return zoneref->zone_idx;
900 }
901 
zonelist_node_idx(struct zoneref * zoneref)902 static inline int zonelist_node_idx(struct zoneref *zoneref)
903 {
904 #ifdef CONFIG_NUMA
905 	/* zone_to_nid not available in this context */
906 	return zoneref->zone->node;
907 #else
908 	return 0;
909 #endif /* CONFIG_NUMA */
910 }
911 
912 /**
913  * next_zones_zonelist - Returns the next zone at or below highest_zoneidx within the allowed nodemask using a cursor within a zonelist as a starting point
914  * @z - The cursor used as a starting point for the search
915  * @highest_zoneidx - The zone index of the highest zone to return
916  * @nodes - An optional nodemask to filter the zonelist with
917  *
918  * This function returns the next zone at or below a given zone index that is
919  * within the allowed nodemask using a cursor as the starting point for the
920  * search. The zoneref returned is a cursor that represents the current zone
921  * being examined. It should be advanced by one before calling
922  * next_zones_zonelist again.
923  */
924 struct zoneref *next_zones_zonelist(struct zoneref *z,
925 					enum zone_type highest_zoneidx,
926 					nodemask_t *nodes);
927 
928 /**
929  * first_zones_zonelist - Returns the first zone at or below highest_zoneidx within the allowed nodemask in a zonelist
930  * @zonelist - The zonelist to search for a suitable zone
931  * @highest_zoneidx - The zone index of the highest zone to return
932  * @nodes - An optional nodemask to filter the zonelist with
933  * @zone - The first suitable zone found is returned via this parameter
934  *
935  * This function returns the first zone at or below a given zone index that is
936  * within the allowed nodemask. The zoneref returned is a cursor that can be
937  * used to iterate the zonelist with next_zones_zonelist by advancing it by
938  * one before calling.
939  */
first_zones_zonelist(struct zonelist * zonelist,enum zone_type highest_zoneidx,nodemask_t * nodes,struct zone ** zone)940 static inline struct zoneref *first_zones_zonelist(struct zonelist *zonelist,
941 					enum zone_type highest_zoneidx,
942 					nodemask_t *nodes,
943 					struct zone **zone)
944 {
945 	struct zoneref *z = next_zones_zonelist(zonelist->_zonerefs,
946 							highest_zoneidx, nodes);
947 	*zone = zonelist_zone(z);
948 	return z;
949 }
950 
951 /**
952  * for_each_zone_zonelist_nodemask - helper macro to iterate over valid zones in a zonelist at or below a given zone index and within a nodemask
953  * @zone - The current zone in the iterator
954  * @z - The current pointer within zonelist->zones being iterated
955  * @zlist - The zonelist being iterated
956  * @highidx - The zone index of the highest zone to return
957  * @nodemask - Nodemask allowed by the allocator
958  *
959  * This iterator iterates though all zones at or below a given zone index and
960  * within a given nodemask
961  */
962 #define for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, nodemask) \
963 	for (z = first_zones_zonelist(zlist, highidx, nodemask, &zone);	\
964 		zone;							\
965 		z = next_zones_zonelist(++z, highidx, nodemask),	\
966 			zone = zonelist_zone(z))			\
967 
968 /**
969  * for_each_zone_zonelist - helper macro to iterate over valid zones in a zonelist at or below a given zone index
970  * @zone - The current zone in the iterator
971  * @z - The current pointer within zonelist->zones being iterated
972  * @zlist - The zonelist being iterated
973  * @highidx - The zone index of the highest zone to return
974  *
975  * This iterator iterates though all zones at or below a given zone index.
976  */
977 #define for_each_zone_zonelist(zone, z, zlist, highidx) \
978 	for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, NULL)
979 
980 #ifdef CONFIG_SPARSEMEM
981 #include <asm/sparsemem.h>
982 #endif
983 
984 #if !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) && \
985 	!defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP)
early_pfn_to_nid(unsigned long pfn)986 static inline unsigned long early_pfn_to_nid(unsigned long pfn)
987 {
988 	return 0;
989 }
990 #endif
991 
992 #ifdef CONFIG_FLATMEM
993 #define pfn_to_nid(pfn)		(0)
994 #endif
995 
996 #ifdef CONFIG_SPARSEMEM
997 
998 /*
999  * SECTION_SHIFT    		#bits space required to store a section #
1000  *
1001  * PA_SECTION_SHIFT		physical address to/from section number
1002  * PFN_SECTION_SHIFT		pfn to/from section number
1003  */
1004 #define PA_SECTION_SHIFT	(SECTION_SIZE_BITS)
1005 #define PFN_SECTION_SHIFT	(SECTION_SIZE_BITS - PAGE_SHIFT)
1006 
1007 #define NR_MEM_SECTIONS		(1UL << SECTIONS_SHIFT)
1008 
1009 #define PAGES_PER_SECTION       (1UL << PFN_SECTION_SHIFT)
1010 #define PAGE_SECTION_MASK	(~(PAGES_PER_SECTION-1))
1011 
1012 #define SECTION_BLOCKFLAGS_BITS \
1013 	((1UL << (PFN_SECTION_SHIFT - pageblock_order)) * NR_PAGEBLOCK_BITS)
1014 
1015 #if (MAX_ORDER - 1 + PAGE_SHIFT) > SECTION_SIZE_BITS
1016 #error Allocator MAX_ORDER exceeds SECTION_SIZE
1017 #endif
1018 
1019 #define pfn_to_section_nr(pfn) ((pfn) >> PFN_SECTION_SHIFT)
1020 #define section_nr_to_pfn(sec) ((sec) << PFN_SECTION_SHIFT)
1021 
1022 #define SECTION_ALIGN_UP(pfn)	(((pfn) + PAGES_PER_SECTION - 1) & PAGE_SECTION_MASK)
1023 #define SECTION_ALIGN_DOWN(pfn)	((pfn) & PAGE_SECTION_MASK)
1024 
1025 struct page;
1026 struct page_ext;
1027 struct mem_section {
1028 	/*
1029 	 * This is, logically, a pointer to an array of struct
1030 	 * pages.  However, it is stored with some other magic.
1031 	 * (see sparse.c::sparse_init_one_section())
1032 	 *
1033 	 * Additionally during early boot we encode node id of
1034 	 * the location of the section here to guide allocation.
1035 	 * (see sparse.c::memory_present())
1036 	 *
1037 	 * Making it a UL at least makes someone do a cast
1038 	 * before using it wrong.
1039 	 */
1040 	unsigned long section_mem_map;
1041 
1042 	/* See declaration of similar field in struct zone */
1043 	unsigned long *pageblock_flags;
1044 #ifdef CONFIG_PAGE_EXTENSION
1045 	/*
1046 	 * If !SPARSEMEM, pgdat doesn't have page_ext pointer. We use
1047 	 * section. (see page_ext.h about this.)
1048 	 */
1049 	struct page_ext *page_ext;
1050 	unsigned long pad;
1051 #endif
1052 	/*
1053 	 * WARNING: mem_section must be a power-of-2 in size for the
1054 	 * calculation and use of SECTION_ROOT_MASK to make sense.
1055 	 */
1056 };
1057 
1058 #ifdef CONFIG_SPARSEMEM_EXTREME
1059 #define SECTIONS_PER_ROOT       (PAGE_SIZE / sizeof (struct mem_section))
1060 #else
1061 #define SECTIONS_PER_ROOT	1
1062 #endif
1063 
1064 #define SECTION_NR_TO_ROOT(sec)	((sec) / SECTIONS_PER_ROOT)
1065 #define NR_SECTION_ROOTS	DIV_ROUND_UP(NR_MEM_SECTIONS, SECTIONS_PER_ROOT)
1066 #define SECTION_ROOT_MASK	(SECTIONS_PER_ROOT - 1)
1067 
1068 #ifdef CONFIG_SPARSEMEM_EXTREME
1069 extern struct mem_section *mem_section[NR_SECTION_ROOTS];
1070 #else
1071 extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT];
1072 #endif
1073 
__nr_to_section(unsigned long nr)1074 static inline struct mem_section *__nr_to_section(unsigned long nr)
1075 {
1076 	if (!mem_section[SECTION_NR_TO_ROOT(nr)])
1077 		return NULL;
1078 	return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK];
1079 }
1080 extern int __section_nr(struct mem_section* ms);
1081 extern unsigned long usemap_size(void);
1082 
1083 /*
1084  * We use the lower bits of the mem_map pointer to store
1085  * a little bit of information.  There should be at least
1086  * 3 bits here due to 32-bit alignment.
1087  */
1088 #define	SECTION_MARKED_PRESENT	(1UL<<0)
1089 #define SECTION_HAS_MEM_MAP	(1UL<<1)
1090 #define SECTION_MAP_LAST_BIT	(1UL<<2)
1091 #define SECTION_MAP_MASK	(~(SECTION_MAP_LAST_BIT-1))
1092 #define SECTION_NID_SHIFT	2
1093 
__section_mem_map_addr(struct mem_section * section)1094 static inline struct page *__section_mem_map_addr(struct mem_section *section)
1095 {
1096 	unsigned long map = section->section_mem_map;
1097 	map &= SECTION_MAP_MASK;
1098 	return (struct page *)map;
1099 }
1100 
present_section(struct mem_section * section)1101 static inline int present_section(struct mem_section *section)
1102 {
1103 	return (section && (section->section_mem_map & SECTION_MARKED_PRESENT));
1104 }
1105 
present_section_nr(unsigned long nr)1106 static inline int present_section_nr(unsigned long nr)
1107 {
1108 	return present_section(__nr_to_section(nr));
1109 }
1110 
valid_section(struct mem_section * section)1111 static inline int valid_section(struct mem_section *section)
1112 {
1113 	return (section && (section->section_mem_map & SECTION_HAS_MEM_MAP));
1114 }
1115 
valid_section_nr(unsigned long nr)1116 static inline int valid_section_nr(unsigned long nr)
1117 {
1118 	return valid_section(__nr_to_section(nr));
1119 }
1120 
__pfn_to_section(unsigned long pfn)1121 static inline struct mem_section *__pfn_to_section(unsigned long pfn)
1122 {
1123 	return __nr_to_section(pfn_to_section_nr(pfn));
1124 }
1125 
1126 #ifndef CONFIG_HAVE_ARCH_PFN_VALID
pfn_valid(unsigned long pfn)1127 static inline int pfn_valid(unsigned long pfn)
1128 {
1129 	if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
1130 		return 0;
1131 	return valid_section(__nr_to_section(pfn_to_section_nr(pfn)));
1132 }
1133 #endif
1134 
pfn_present(unsigned long pfn)1135 static inline int pfn_present(unsigned long pfn)
1136 {
1137 	if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
1138 		return 0;
1139 	return present_section(__nr_to_section(pfn_to_section_nr(pfn)));
1140 }
1141 
1142 /*
1143  * These are _only_ used during initialisation, therefore they
1144  * can use __initdata ...  They could have names to indicate
1145  * this restriction.
1146  */
1147 #ifdef CONFIG_NUMA
1148 #define pfn_to_nid(pfn)							\
1149 ({									\
1150 	unsigned long __pfn_to_nid_pfn = (pfn);				\
1151 	page_to_nid(pfn_to_page(__pfn_to_nid_pfn));			\
1152 })
1153 #else
1154 #define pfn_to_nid(pfn)		(0)
1155 #endif
1156 
1157 #define early_pfn_valid(pfn)	pfn_valid(pfn)
1158 void sparse_init(void);
1159 #else
1160 #define sparse_init()	do {} while (0)
1161 #define sparse_index_init(_sec, _nid)  do {} while (0)
1162 #endif /* CONFIG_SPARSEMEM */
1163 
1164 /*
1165  * During memory init memblocks map pfns to nids. The search is expensive and
1166  * this caches recent lookups. The implementation of __early_pfn_to_nid
1167  * may treat start/end as pfns or sections.
1168  */
1169 struct mminit_pfnnid_cache {
1170 	unsigned long last_start;
1171 	unsigned long last_end;
1172 	int last_nid;
1173 };
1174 
1175 #ifndef early_pfn_valid
1176 #define early_pfn_valid(pfn)	(1)
1177 #endif
1178 
1179 void memory_present(int nid, unsigned long start, unsigned long end);
1180 unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long);
1181 
1182 /*
1183  * If it is possible to have holes within a MAX_ORDER_NR_PAGES, then we
1184  * need to check pfn validility within that MAX_ORDER_NR_PAGES block.
1185  * pfn_valid_within() should be used in this case; we optimise this away
1186  * when we have no holes within a MAX_ORDER_NR_PAGES block.
1187  */
1188 #ifdef CONFIG_HOLES_IN_ZONE
1189 #define pfn_valid_within(pfn) pfn_valid(pfn)
1190 #else
1191 #define pfn_valid_within(pfn) (1)
1192 #endif
1193 
1194 #ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL
1195 /*
1196  * pfn_valid() is meant to be able to tell if a given PFN has valid memmap
1197  * associated with it or not. In FLATMEM, it is expected that holes always
1198  * have valid memmap as long as there is valid PFNs either side of the hole.
1199  * In SPARSEMEM, it is assumed that a valid section has a memmap for the
1200  * entire section.
1201  *
1202  * However, an ARM, and maybe other embedded architectures in the future
1203  * free memmap backing holes to save memory on the assumption the memmap is
1204  * never used. The page_zone linkages are then broken even though pfn_valid()
1205  * returns true. A walker of the full memmap must then do this additional
1206  * check to ensure the memmap they are looking at is sane by making sure
1207  * the zone and PFN linkages are still valid. This is expensive, but walkers
1208  * of the full memmap are extremely rare.
1209  */
1210 int memmap_valid_within(unsigned long pfn,
1211 					struct page *page, struct zone *zone);
1212 #else
memmap_valid_within(unsigned long pfn,struct page * page,struct zone * zone)1213 static inline int memmap_valid_within(unsigned long pfn,
1214 					struct page *page, struct zone *zone)
1215 {
1216 	return 1;
1217 }
1218 #endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */
1219 
1220 #endif /* !__GENERATING_BOUNDS.H */
1221 #endif /* !__ASSEMBLY__ */
1222 #endif /* _LINUX_MMZONE_H */
1223