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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/bounds.h>
19 #include <asm/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  * coelesce naturally under reasonable reclaim pressure and those which
34  * will not.
35  */
36 #define PAGE_ALLOC_COSTLY_ORDER 3
37 
38 #define MIGRATE_UNMOVABLE     0
39 #define MIGRATE_RECLAIMABLE   1
40 #define MIGRATE_MOVABLE       2
41 #define MIGRATE_RESERVE       3
42 #define MIGRATE_ISOLATE       4 /* can't allocate from here */
43 #define MIGRATE_TYPES         5
44 
45 #define for_each_migratetype_order(order, type) \
46 	for (order = 0; order < MAX_ORDER; order++) \
47 		for (type = 0; type < MIGRATE_TYPES; type++)
48 
49 extern int page_group_by_mobility_disabled;
50 
get_pageblock_migratetype(struct page * page)51 static inline int get_pageblock_migratetype(struct page *page)
52 {
53 	if (unlikely(page_group_by_mobility_disabled))
54 		return MIGRATE_UNMOVABLE;
55 
56 	return get_pageblock_flags_group(page, PB_migrate, PB_migrate_end);
57 }
58 
59 struct free_area {
60 	struct list_head	free_list[MIGRATE_TYPES];
61 	unsigned long		nr_free;
62 };
63 
64 struct pglist_data;
65 
66 /*
67  * zone->lock and zone->lru_lock are two of the hottest locks in the kernel.
68  * So add a wild amount of padding here to ensure that they fall into separate
69  * cachelines.  There are very few zone structures in the machine, so space
70  * consumption is not a concern here.
71  */
72 #if defined(CONFIG_SMP)
73 struct zone_padding {
74 	char x[0];
75 } ____cacheline_internodealigned_in_smp;
76 #define ZONE_PADDING(name)	struct zone_padding name;
77 #else
78 #define ZONE_PADDING(name)
79 #endif
80 
81 enum zone_stat_item {
82 	/* First 128 byte cacheline (assuming 64 bit words) */
83 	NR_FREE_PAGES,
84 	NR_LRU_BASE,
85 	NR_INACTIVE_ANON = NR_LRU_BASE, /* must match order of LRU_[IN]ACTIVE */
86 	NR_ACTIVE_ANON,		/*  "     "     "   "       "         */
87 	NR_INACTIVE_FILE,	/*  "     "     "   "       "         */
88 	NR_ACTIVE_FILE,		/*  "     "     "   "       "         */
89 #ifdef CONFIG_UNEVICTABLE_LRU
90 	NR_UNEVICTABLE,		/*  "     "     "   "       "         */
91 	NR_MLOCK,		/* mlock()ed pages found and moved off LRU */
92 #else
93 	NR_UNEVICTABLE = NR_ACTIVE_FILE, /* avoid compiler errors in dead code */
94 	NR_MLOCK = NR_ACTIVE_FILE,
95 #endif
96 	NR_ANON_PAGES,	/* Mapped anonymous pages */
97 	NR_FILE_MAPPED,	/* pagecache pages mapped into pagetables.
98 			   only modified from process context */
99 	NR_FILE_PAGES,
100 	NR_FILE_DIRTY,
101 	NR_WRITEBACK,
102 	NR_SLAB_RECLAIMABLE,
103 	NR_SLAB_UNRECLAIMABLE,
104 	NR_PAGETABLE,		/* used for pagetables */
105 	NR_UNSTABLE_NFS,	/* NFS unstable pages */
106 	NR_BOUNCE,
107 	NR_VMSCAN_WRITE,
108 	/* Second 128 byte cacheline */
109 	NR_WRITEBACK_TEMP,	/* Writeback using temporary buffers */
110 #ifdef CONFIG_NUMA
111 	NUMA_HIT,		/* allocated in intended node */
112 	NUMA_MISS,		/* allocated in non intended node */
113 	NUMA_FOREIGN,		/* was intended here, hit elsewhere */
114 	NUMA_INTERLEAVE_HIT,	/* interleaver preferred this zone */
115 	NUMA_LOCAL,		/* allocation from local node */
116 	NUMA_OTHER,		/* allocation from other node */
117 #endif
118 	NR_VM_ZONE_STAT_ITEMS };
119 
120 /*
121  * We do arithmetic on the LRU lists in various places in the code,
122  * so it is important to keep the active lists LRU_ACTIVE higher in
123  * the array than the corresponding inactive lists, and to keep
124  * the *_FILE lists LRU_FILE higher than the corresponding _ANON lists.
125  *
126  * This has to be kept in sync with the statistics in zone_stat_item
127  * above and the descriptions in vmstat_text in mm/vmstat.c
128  */
129 #define LRU_BASE 0
130 #define LRU_ACTIVE 1
131 #define LRU_FILE 2
132 
133 enum lru_list {
134 	LRU_INACTIVE_ANON = LRU_BASE,
135 	LRU_ACTIVE_ANON = LRU_BASE + LRU_ACTIVE,
136 	LRU_INACTIVE_FILE = LRU_BASE + LRU_FILE,
137 	LRU_ACTIVE_FILE = LRU_BASE + LRU_FILE + LRU_ACTIVE,
138 #ifdef CONFIG_UNEVICTABLE_LRU
139 	LRU_UNEVICTABLE,
140 #else
141 	LRU_UNEVICTABLE = LRU_ACTIVE_FILE, /* avoid compiler errors in dead code */
142 #endif
143 	NR_LRU_LISTS
144 };
145 
146 #define for_each_lru(l) for (l = 0; l < NR_LRU_LISTS; l++)
147 
148 #define for_each_evictable_lru(l) for (l = 0; l <= LRU_ACTIVE_FILE; l++)
149 
is_file_lru(enum lru_list l)150 static inline int is_file_lru(enum lru_list l)
151 {
152 	return (l == LRU_INACTIVE_FILE || l == LRU_ACTIVE_FILE);
153 }
154 
is_active_lru(enum lru_list l)155 static inline int is_active_lru(enum lru_list l)
156 {
157 	return (l == LRU_ACTIVE_ANON || l == LRU_ACTIVE_FILE);
158 }
159 
is_unevictable_lru(enum lru_list l)160 static inline int is_unevictable_lru(enum lru_list l)
161 {
162 #ifdef CONFIG_UNEVICTABLE_LRU
163 	return (l == LRU_UNEVICTABLE);
164 #else
165 	return 0;
166 #endif
167 }
168 
169 struct per_cpu_pages {
170 	int count;		/* number of pages in the list */
171 	int high;		/* high watermark, emptying needed */
172 	int batch;		/* chunk size for buddy add/remove */
173 	struct list_head list;	/* the list of pages */
174 };
175 
176 struct per_cpu_pageset {
177 	struct per_cpu_pages pcp;
178 #ifdef CONFIG_NUMA
179 	s8 expire;
180 #endif
181 #ifdef CONFIG_SMP
182 	s8 stat_threshold;
183 	s8 vm_stat_diff[NR_VM_ZONE_STAT_ITEMS];
184 #endif
185 } ____cacheline_aligned_in_smp;
186 
187 #ifdef CONFIG_NUMA
188 #define zone_pcp(__z, __cpu) ((__z)->pageset[(__cpu)])
189 #else
190 #define zone_pcp(__z, __cpu) (&(__z)->pageset[(__cpu)])
191 #endif
192 
193 #endif /* !__GENERATING_BOUNDS.H */
194 
195 enum zone_type {
196 #ifdef CONFIG_ZONE_DMA
197 	/*
198 	 * ZONE_DMA is used when there are devices that are not able
199 	 * to do DMA to all of addressable memory (ZONE_NORMAL). Then we
200 	 * carve out the portion of memory that is needed for these devices.
201 	 * The range is arch specific.
202 	 *
203 	 * Some examples
204 	 *
205 	 * Architecture		Limit
206 	 * ---------------------------
207 	 * parisc, ia64, sparc	<4G
208 	 * s390			<2G
209 	 * arm			Various
210 	 * alpha		Unlimited or 0-16MB.
211 	 *
212 	 * i386, x86_64 and multiple other arches
213 	 * 			<16M.
214 	 */
215 	ZONE_DMA,
216 #endif
217 #ifdef CONFIG_ZONE_DMA32
218 	/*
219 	 * x86_64 needs two ZONE_DMAs because it supports devices that are
220 	 * only able to do DMA to the lower 16M but also 32 bit devices that
221 	 * can only do DMA areas below 4G.
222 	 */
223 	ZONE_DMA32,
224 #endif
225 	/*
226 	 * Normal addressable memory is in ZONE_NORMAL. DMA operations can be
227 	 * performed on pages in ZONE_NORMAL if the DMA devices support
228 	 * transfers to all addressable memory.
229 	 */
230 	ZONE_NORMAL,
231 #ifdef CONFIG_HIGHMEM
232 	/*
233 	 * A memory area that is only addressable by the kernel through
234 	 * mapping portions into its own address space. This is for example
235 	 * used by i386 to allow the kernel to address the memory beyond
236 	 * 900MB. The kernel will set up special mappings (page
237 	 * table entries on i386) for each page that the kernel needs to
238 	 * access.
239 	 */
240 	ZONE_HIGHMEM,
241 #endif
242 	ZONE_MOVABLE,
243 	__MAX_NR_ZONES
244 };
245 
246 #ifndef __GENERATING_BOUNDS_H
247 
248 /*
249  * When a memory allocation must conform to specific limitations (such
250  * as being suitable for DMA) the caller will pass in hints to the
251  * allocator in the gfp_mask, in the zone modifier bits.  These bits
252  * are used to select a priority ordered list of memory zones which
253  * match the requested limits. See gfp_zone() in include/linux/gfp.h
254  */
255 
256 #if MAX_NR_ZONES < 2
257 #define ZONES_SHIFT 0
258 #elif MAX_NR_ZONES <= 2
259 #define ZONES_SHIFT 1
260 #elif MAX_NR_ZONES <= 4
261 #define ZONES_SHIFT 2
262 #else
263 #error ZONES_SHIFT -- too many zones configured adjust calculation
264 #endif
265 
266 struct zone_reclaim_stat {
267 	/*
268 	 * The pageout code in vmscan.c keeps track of how many of the
269 	 * mem/swap backed and file backed pages are refeferenced.
270 	 * The higher the rotated/scanned ratio, the more valuable
271 	 * that cache is.
272 	 *
273 	 * The anon LRU stats live in [0], file LRU stats in [1]
274 	 */
275 	unsigned long		recent_rotated[2];
276 	unsigned long		recent_scanned[2];
277 };
278 
279 struct zone {
280 	/* Fields commonly accessed by the page allocator */
281 	unsigned long		pages_min, pages_low, pages_high;
282 	/*
283 	 * We don't know if the memory that we're going to allocate will be freeable
284 	 * or/and it will be released eventually, so to avoid totally wasting several
285 	 * GB of ram we must reserve some of the lower zone memory (otherwise we risk
286 	 * to run OOM on the lower zones despite there's tons of freeable ram
287 	 * on the higher zones). This array is recalculated at runtime if the
288 	 * sysctl_lowmem_reserve_ratio sysctl changes.
289 	 */
290 	unsigned long		lowmem_reserve[MAX_NR_ZONES];
291 
292 #ifdef CONFIG_NUMA
293 	int node;
294 	/*
295 	 * zone reclaim becomes active if more unmapped pages exist.
296 	 */
297 	unsigned long		min_unmapped_pages;
298 	unsigned long		min_slab_pages;
299 	struct per_cpu_pageset	*pageset[NR_CPUS];
300 #else
301 	struct per_cpu_pageset	pageset[NR_CPUS];
302 #endif
303 	/*
304 	 * free areas of different sizes
305 	 */
306 	spinlock_t		lock;
307 #ifdef CONFIG_MEMORY_HOTPLUG
308 	/* see spanned/present_pages for more description */
309 	seqlock_t		span_seqlock;
310 #endif
311 	struct free_area	free_area[MAX_ORDER];
312 
313 #ifndef CONFIG_SPARSEMEM
314 	/*
315 	 * Flags for a pageblock_nr_pages block. See pageblock-flags.h.
316 	 * In SPARSEMEM, this map is stored in struct mem_section
317 	 */
318 	unsigned long		*pageblock_flags;
319 #endif /* CONFIG_SPARSEMEM */
320 
321 
322 	ZONE_PADDING(_pad1_)
323 
324 	/* Fields commonly accessed by the page reclaim scanner */
325 	spinlock_t		lru_lock;
326 	struct {
327 		struct list_head list;
328 		unsigned long nr_scan;
329 	} lru[NR_LRU_LISTS];
330 
331 	struct zone_reclaim_stat reclaim_stat;
332 
333 	unsigned long		pages_scanned;	   /* since last reclaim */
334 	unsigned long		flags;		   /* zone flags, see below */
335 
336 	/* Zone statistics */
337 	atomic_long_t		vm_stat[NR_VM_ZONE_STAT_ITEMS];
338 
339 	/*
340 	 * prev_priority holds the scanning priority for this zone.  It is
341 	 * defined as the scanning priority at which we achieved our reclaim
342 	 * target at the previous try_to_free_pages() or balance_pgdat()
343 	 * invokation.
344 	 *
345 	 * We use prev_priority as a measure of how much stress page reclaim is
346 	 * under - it drives the swappiness decision: whether to unmap mapped
347 	 * pages.
348 	 *
349 	 * Access to both this field is quite racy even on uniprocessor.  But
350 	 * it is expected to average out OK.
351 	 */
352 	int prev_priority;
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 
361 	ZONE_PADDING(_pad2_)
362 	/* Rarely used or read-mostly fields */
363 
364 	/*
365 	 * wait_table		-- the array holding the hash table
366 	 * wait_table_hash_nr_entries	-- the size of the hash table array
367 	 * wait_table_bits	-- wait_table_size == (1 << wait_table_bits)
368 	 *
369 	 * The purpose of all these is to keep track of the people
370 	 * waiting for a page to become available and make them
371 	 * runnable again when possible. The trouble is that this
372 	 * consumes a lot of space, especially when so few things
373 	 * wait on pages at a given time. So instead of using
374 	 * per-page waitqueues, we use a waitqueue hash table.
375 	 *
376 	 * The bucket discipline is to sleep on the same queue when
377 	 * colliding and wake all in that wait queue when removing.
378 	 * When something wakes, it must check to be sure its page is
379 	 * truly available, a la thundering herd. The cost of a
380 	 * collision is great, but given the expected load of the
381 	 * table, they should be so rare as to be outweighed by the
382 	 * benefits from the saved space.
383 	 *
384 	 * __wait_on_page_locked() and unlock_page() in mm/filemap.c, are the
385 	 * primary users of these fields, and in mm/page_alloc.c
386 	 * free_area_init_core() performs the initialization of them.
387 	 */
388 	wait_queue_head_t	* wait_table;
389 	unsigned long		wait_table_hash_nr_entries;
390 	unsigned long		wait_table_bits;
391 
392 	/*
393 	 * Discontig memory support fields.
394 	 */
395 	struct pglist_data	*zone_pgdat;
396 	/* zone_start_pfn == zone_start_paddr >> PAGE_SHIFT */
397 	unsigned long		zone_start_pfn;
398 
399 	/*
400 	 * zone_start_pfn, spanned_pages and present_pages are all
401 	 * protected by span_seqlock.  It is a seqlock because it has
402 	 * to be read outside of zone->lock, and it is done in the main
403 	 * allocator path.  But, it is written quite infrequently.
404 	 *
405 	 * The lock is declared along with zone->lock because it is
406 	 * frequently read in proximity to zone->lock.  It's good to
407 	 * give them a chance of being in the same cacheline.
408 	 */
409 	unsigned long		spanned_pages;	/* total size, including holes */
410 	unsigned long		present_pages;	/* amount of memory (excluding holes) */
411 
412 	/*
413 	 * rarely used fields:
414 	 */
415 	const char		*name;
416 } ____cacheline_internodealigned_in_smp;
417 
418 typedef enum {
419 	ZONE_ALL_UNRECLAIMABLE,		/* all pages pinned */
420 	ZONE_RECLAIM_LOCKED,		/* prevents concurrent reclaim */
421 	ZONE_OOM_LOCKED,		/* zone is in OOM killer zonelist */
422 } zone_flags_t;
423 
zone_set_flag(struct zone * zone,zone_flags_t flag)424 static inline void zone_set_flag(struct zone *zone, zone_flags_t flag)
425 {
426 	set_bit(flag, &zone->flags);
427 }
428 
zone_test_and_set_flag(struct zone * zone,zone_flags_t flag)429 static inline int zone_test_and_set_flag(struct zone *zone, zone_flags_t flag)
430 {
431 	return test_and_set_bit(flag, &zone->flags);
432 }
433 
zone_clear_flag(struct zone * zone,zone_flags_t flag)434 static inline void zone_clear_flag(struct zone *zone, zone_flags_t flag)
435 {
436 	clear_bit(flag, &zone->flags);
437 }
438 
zone_is_all_unreclaimable(const struct zone * zone)439 static inline int zone_is_all_unreclaimable(const struct zone *zone)
440 {
441 	return test_bit(ZONE_ALL_UNRECLAIMABLE, &zone->flags);
442 }
443 
zone_is_reclaim_locked(const struct zone * zone)444 static inline int zone_is_reclaim_locked(const struct zone *zone)
445 {
446 	return test_bit(ZONE_RECLAIM_LOCKED, &zone->flags);
447 }
448 
zone_is_oom_locked(const struct zone * zone)449 static inline int zone_is_oom_locked(const struct zone *zone)
450 {
451 	return test_bit(ZONE_OOM_LOCKED, &zone->flags);
452 }
453 
454 /*
455  * The "priority" of VM scanning is how much of the queues we will scan in one
456  * go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the
457  * queues ("queue_length >> 12") during an aging round.
458  */
459 #define DEF_PRIORITY 12
460 
461 /* Maximum number of zones on a zonelist */
462 #define MAX_ZONES_PER_ZONELIST (MAX_NUMNODES * MAX_NR_ZONES)
463 
464 #ifdef CONFIG_NUMA
465 
466 /*
467  * The NUMA zonelists are doubled becausse we need zonelists that restrict the
468  * allocations to a single node for GFP_THISNODE.
469  *
470  * [0]	: Zonelist with fallback
471  * [1]	: No fallback (GFP_THISNODE)
472  */
473 #define MAX_ZONELISTS 2
474 
475 
476 /*
477  * We cache key information from each zonelist for smaller cache
478  * footprint when scanning for free pages in get_page_from_freelist().
479  *
480  * 1) The BITMAP fullzones tracks which zones in a zonelist have come
481  *    up short of free memory since the last time (last_fullzone_zap)
482  *    we zero'd fullzones.
483  * 2) The array z_to_n[] maps each zone in the zonelist to its node
484  *    id, so that we can efficiently evaluate whether that node is
485  *    set in the current tasks mems_allowed.
486  *
487  * Both fullzones and z_to_n[] are one-to-one with the zonelist,
488  * indexed by a zones offset in the zonelist zones[] array.
489  *
490  * The get_page_from_freelist() routine does two scans.  During the
491  * first scan, we skip zones whose corresponding bit in 'fullzones'
492  * is set or whose corresponding node in current->mems_allowed (which
493  * comes from cpusets) is not set.  During the second scan, we bypass
494  * this zonelist_cache, to ensure we look methodically at each zone.
495  *
496  * Once per second, we zero out (zap) fullzones, forcing us to
497  * reconsider nodes that might have regained more free memory.
498  * The field last_full_zap is the time we last zapped fullzones.
499  *
500  * This mechanism reduces the amount of time we waste repeatedly
501  * reexaming zones for free memory when they just came up low on
502  * memory momentarilly ago.
503  *
504  * The zonelist_cache struct members logically belong in struct
505  * zonelist.  However, the mempolicy zonelists constructed for
506  * MPOL_BIND are intentionally variable length (and usually much
507  * shorter).  A general purpose mechanism for handling structs with
508  * multiple variable length members is more mechanism than we want
509  * here.  We resort to some special case hackery instead.
510  *
511  * The MPOL_BIND zonelists don't need this zonelist_cache (in good
512  * part because they are shorter), so we put the fixed length stuff
513  * at the front of the zonelist struct, ending in a variable length
514  * zones[], as is needed by MPOL_BIND.
515  *
516  * Then we put the optional zonelist cache on the end of the zonelist
517  * struct.  This optional stuff is found by a 'zlcache_ptr' pointer in
518  * the fixed length portion at the front of the struct.  This pointer
519  * both enables us to find the zonelist cache, and in the case of
520  * MPOL_BIND zonelists, (which will just set the zlcache_ptr to NULL)
521  * to know that the zonelist cache is not there.
522  *
523  * The end result is that struct zonelists come in two flavors:
524  *  1) The full, fixed length version, shown below, and
525  *  2) The custom zonelists for MPOL_BIND.
526  * The custom MPOL_BIND zonelists have a NULL zlcache_ptr and no zlcache.
527  *
528  * Even though there may be multiple CPU cores on a node modifying
529  * fullzones or last_full_zap in the same zonelist_cache at the same
530  * time, we don't lock it.  This is just hint data - if it is wrong now
531  * and then, the allocator will still function, perhaps a bit slower.
532  */
533 
534 
535 struct zonelist_cache {
536 	unsigned short z_to_n[MAX_ZONES_PER_ZONELIST];		/* zone->nid */
537 	DECLARE_BITMAP(fullzones, MAX_ZONES_PER_ZONELIST);	/* zone full? */
538 	unsigned long last_full_zap;		/* when last zap'd (jiffies) */
539 };
540 #else
541 #define MAX_ZONELISTS 1
542 struct zonelist_cache;
543 #endif
544 
545 /*
546  * This struct contains information about a zone in a zonelist. It is stored
547  * here to avoid dereferences into large structures and lookups of tables
548  */
549 struct zoneref {
550 	struct zone *zone;	/* Pointer to actual zone */
551 	int zone_idx;		/* zone_idx(zoneref->zone) */
552 };
553 
554 /*
555  * One allocation request operates on a zonelist. A zonelist
556  * is a list of zones, the first one is the 'goal' of the
557  * allocation, the other zones are fallback zones, in decreasing
558  * priority.
559  *
560  * If zlcache_ptr is not NULL, then it is just the address of zlcache,
561  * as explained above.  If zlcache_ptr is NULL, there is no zlcache.
562  * *
563  * To speed the reading of the zonelist, the zonerefs contain the zone index
564  * of the entry being read. Helper functions to access information given
565  * a struct zoneref are
566  *
567  * zonelist_zone()	- Return the struct zone * for an entry in _zonerefs
568  * zonelist_zone_idx()	- Return the index of the zone for an entry
569  * zonelist_node_idx()	- Return the index of the node for an entry
570  */
571 struct zonelist {
572 	struct zonelist_cache *zlcache_ptr;		     // NULL or &zlcache
573 	struct zoneref _zonerefs[MAX_ZONES_PER_ZONELIST + 1];
574 #ifdef CONFIG_NUMA
575 	struct zonelist_cache zlcache;			     // optional ...
576 #endif
577 };
578 
579 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP
580 struct node_active_region {
581 	unsigned long start_pfn;
582 	unsigned long end_pfn;
583 	int nid;
584 };
585 #endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
586 
587 #ifndef CONFIG_DISCONTIGMEM
588 /* The array of struct pages - for discontigmem use pgdat->lmem_map */
589 extern struct page *mem_map;
590 #endif
591 
592 /*
593  * The pg_data_t structure is used in machines with CONFIG_DISCONTIGMEM
594  * (mostly NUMA machines?) to denote a higher-level memory zone than the
595  * zone denotes.
596  *
597  * On NUMA machines, each NUMA node would have a pg_data_t to describe
598  * it's memory layout.
599  *
600  * Memory statistics and page replacement data structures are maintained on a
601  * per-zone basis.
602  */
603 struct bootmem_data;
604 typedef struct pglist_data {
605 	struct zone node_zones[MAX_NR_ZONES];
606 	struct zonelist node_zonelists[MAX_ZONELISTS];
607 	int nr_zones;
608 #ifdef CONFIG_FLAT_NODE_MEM_MAP	/* means !SPARSEMEM */
609 	struct page *node_mem_map;
610 #ifdef CONFIG_CGROUP_MEM_RES_CTLR
611 	struct page_cgroup *node_page_cgroup;
612 #endif
613 #endif
614 	struct bootmem_data *bdata;
615 #ifdef CONFIG_MEMORY_HOTPLUG
616 	/*
617 	 * Must be held any time you expect node_start_pfn, node_present_pages
618 	 * or node_spanned_pages stay constant.  Holding this will also
619 	 * guarantee that any pfn_valid() stays that way.
620 	 *
621 	 * Nests above zone->lock and zone->size_seqlock.
622 	 */
623 	spinlock_t node_size_lock;
624 #endif
625 	unsigned long node_start_pfn;
626 	unsigned long node_present_pages; /* total number of physical pages */
627 	unsigned long node_spanned_pages; /* total size of physical page
628 					     range, including holes */
629 	int node_id;
630 	wait_queue_head_t kswapd_wait;
631 	struct task_struct *kswapd;
632 	int kswapd_max_order;
633 } pg_data_t;
634 
635 #define node_present_pages(nid)	(NODE_DATA(nid)->node_present_pages)
636 #define node_spanned_pages(nid)	(NODE_DATA(nid)->node_spanned_pages)
637 #ifdef CONFIG_FLAT_NODE_MEM_MAP
638 #define pgdat_page_nr(pgdat, pagenr)	((pgdat)->node_mem_map + (pagenr))
639 #else
640 #define pgdat_page_nr(pgdat, pagenr)	pfn_to_page((pgdat)->node_start_pfn + (pagenr))
641 #endif
642 #define nid_page_nr(nid, pagenr) 	pgdat_page_nr(NODE_DATA(nid),(pagenr))
643 
644 #include <linux/memory_hotplug.h>
645 
646 void get_zone_counts(unsigned long *active, unsigned long *inactive,
647 			unsigned long *free);
648 void build_all_zonelists(void);
649 void wakeup_kswapd(struct zone *zone, int order);
650 int zone_watermark_ok(struct zone *z, int order, unsigned long mark,
651 		int classzone_idx, int alloc_flags);
652 enum memmap_context {
653 	MEMMAP_EARLY,
654 	MEMMAP_HOTPLUG,
655 };
656 extern int init_currently_empty_zone(struct zone *zone, unsigned long start_pfn,
657 				     unsigned long size,
658 				     enum memmap_context context);
659 
660 #ifdef CONFIG_HAVE_MEMORY_PRESENT
661 void memory_present(int nid, unsigned long start, unsigned long end);
662 #else
memory_present(int nid,unsigned long start,unsigned long end)663 static inline void memory_present(int nid, unsigned long start, unsigned long end) {}
664 #endif
665 
666 #ifdef CONFIG_NEED_NODE_MEMMAP_SIZE
667 unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long);
668 #endif
669 
670 /*
671  * zone_idx() returns 0 for the ZONE_DMA zone, 1 for the ZONE_NORMAL zone, etc.
672  */
673 #define zone_idx(zone)		((zone) - (zone)->zone_pgdat->node_zones)
674 
populated_zone(struct zone * zone)675 static inline int populated_zone(struct zone *zone)
676 {
677 	return (!!zone->present_pages);
678 }
679 
680 extern int movable_zone;
681 
zone_movable_is_highmem(void)682 static inline int zone_movable_is_highmem(void)
683 {
684 #if defined(CONFIG_HIGHMEM) && defined(CONFIG_ARCH_POPULATES_NODE_MAP)
685 	return movable_zone == ZONE_HIGHMEM;
686 #else
687 	return 0;
688 #endif
689 }
690 
is_highmem_idx(enum zone_type idx)691 static inline int is_highmem_idx(enum zone_type idx)
692 {
693 #ifdef CONFIG_HIGHMEM
694 	return (idx == ZONE_HIGHMEM ||
695 		(idx == ZONE_MOVABLE && zone_movable_is_highmem()));
696 #else
697 	return 0;
698 #endif
699 }
700 
is_normal_idx(enum zone_type idx)701 static inline int is_normal_idx(enum zone_type idx)
702 {
703 	return (idx == ZONE_NORMAL);
704 }
705 
706 /**
707  * is_highmem - helper function to quickly check if a struct zone is a
708  *              highmem zone or not.  This is an attempt to keep references
709  *              to ZONE_{DMA/NORMAL/HIGHMEM/etc} in general code to a minimum.
710  * @zone - pointer to struct zone variable
711  */
is_highmem(struct zone * zone)712 static inline int is_highmem(struct zone *zone)
713 {
714 #ifdef CONFIG_HIGHMEM
715 	int zone_off = (char *)zone - (char *)zone->zone_pgdat->node_zones;
716 	return zone_off == ZONE_HIGHMEM * sizeof(*zone) ||
717 	       (zone_off == ZONE_MOVABLE * sizeof(*zone) &&
718 		zone_movable_is_highmem());
719 #else
720 	return 0;
721 #endif
722 }
723 
is_normal(struct zone * zone)724 static inline int is_normal(struct zone *zone)
725 {
726 	return zone == zone->zone_pgdat->node_zones + ZONE_NORMAL;
727 }
728 
is_dma32(struct zone * zone)729 static inline int is_dma32(struct zone *zone)
730 {
731 #ifdef CONFIG_ZONE_DMA32
732 	return zone == zone->zone_pgdat->node_zones + ZONE_DMA32;
733 #else
734 	return 0;
735 #endif
736 }
737 
is_dma(struct zone * zone)738 static inline int is_dma(struct zone *zone)
739 {
740 #ifdef CONFIG_ZONE_DMA
741 	return zone == zone->zone_pgdat->node_zones + ZONE_DMA;
742 #else
743 	return 0;
744 #endif
745 }
746 
747 /* These two functions are used to setup the per zone pages min values */
748 struct ctl_table;
749 struct file;
750 int min_free_kbytes_sysctl_handler(struct ctl_table *, int, struct file *,
751 					void __user *, size_t *, loff_t *);
752 extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1];
753 int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int, struct file *,
754 					void __user *, size_t *, loff_t *);
755 int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *, int, struct file *,
756 					void __user *, size_t *, loff_t *);
757 int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *, int,
758 			struct file *, void __user *, size_t *, loff_t *);
759 int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *, int,
760 			struct file *, void __user *, size_t *, loff_t *);
761 
762 extern int numa_zonelist_order_handler(struct ctl_table *, int,
763 			struct file *, void __user *, size_t *, loff_t *);
764 extern char numa_zonelist_order[];
765 #define NUMA_ZONELIST_ORDER_LEN 16	/* string buffer size */
766 
767 #include <linux/topology.h>
768 /* Returns the number of the current Node. */
769 #ifndef numa_node_id
770 #define numa_node_id()		(cpu_to_node(raw_smp_processor_id()))
771 #endif
772 
773 #ifndef CONFIG_NEED_MULTIPLE_NODES
774 
775 extern struct pglist_data contig_page_data;
776 #define NODE_DATA(nid)		(&contig_page_data)
777 #define NODE_MEM_MAP(nid)	mem_map
778 
779 #else /* CONFIG_NEED_MULTIPLE_NODES */
780 
781 #include <asm/mmzone.h>
782 
783 #endif /* !CONFIG_NEED_MULTIPLE_NODES */
784 
785 extern struct pglist_data *first_online_pgdat(void);
786 extern struct pglist_data *next_online_pgdat(struct pglist_data *pgdat);
787 extern struct zone *next_zone(struct zone *zone);
788 
789 /**
790  * for_each_online_pgdat - helper macro to iterate over all online nodes
791  * @pgdat - pointer to a pg_data_t variable
792  */
793 #define for_each_online_pgdat(pgdat)			\
794 	for (pgdat = first_online_pgdat();		\
795 	     pgdat;					\
796 	     pgdat = next_online_pgdat(pgdat))
797 /**
798  * for_each_zone - helper macro to iterate over all memory zones
799  * @zone - pointer to struct zone variable
800  *
801  * The user only needs to declare the zone variable, for_each_zone
802  * fills it in.
803  */
804 #define for_each_zone(zone)			        \
805 	for (zone = (first_online_pgdat())->node_zones; \
806 	     zone;					\
807 	     zone = next_zone(zone))
808 
zonelist_zone(struct zoneref * zoneref)809 static inline struct zone *zonelist_zone(struct zoneref *zoneref)
810 {
811 	return zoneref->zone;
812 }
813 
zonelist_zone_idx(struct zoneref * zoneref)814 static inline int zonelist_zone_idx(struct zoneref *zoneref)
815 {
816 	return zoneref->zone_idx;
817 }
818 
zonelist_node_idx(struct zoneref * zoneref)819 static inline int zonelist_node_idx(struct zoneref *zoneref)
820 {
821 #ifdef CONFIG_NUMA
822 	/* zone_to_nid not available in this context */
823 	return zoneref->zone->node;
824 #else
825 	return 0;
826 #endif /* CONFIG_NUMA */
827 }
828 
829 /**
830  * 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
831  * @z - The cursor used as a starting point for the search
832  * @highest_zoneidx - The zone index of the highest zone to return
833  * @nodes - An optional nodemask to filter the zonelist with
834  * @zone - The first suitable zone found is returned via this parameter
835  *
836  * This function returns the next zone at or below a given zone index that is
837  * within the allowed nodemask using a cursor as the starting point for the
838  * search. The zoneref returned is a cursor that represents the current zone
839  * being examined. It should be advanced by one before calling
840  * next_zones_zonelist again.
841  */
842 struct zoneref *next_zones_zonelist(struct zoneref *z,
843 					enum zone_type highest_zoneidx,
844 					nodemask_t *nodes,
845 					struct zone **zone);
846 
847 /**
848  * first_zones_zonelist - Returns the first zone at or below highest_zoneidx within the allowed nodemask in a zonelist
849  * @zonelist - The zonelist to search for a suitable zone
850  * @highest_zoneidx - The zone index of the highest zone to return
851  * @nodes - An optional nodemask to filter the zonelist with
852  * @zone - The first suitable zone found is returned via this parameter
853  *
854  * This function returns the first zone at or below a given zone index that is
855  * within the allowed nodemask. The zoneref returned is a cursor that can be
856  * used to iterate the zonelist with next_zones_zonelist by advancing it by
857  * one before calling.
858  */
first_zones_zonelist(struct zonelist * zonelist,enum zone_type highest_zoneidx,nodemask_t * nodes,struct zone ** zone)859 static inline struct zoneref *first_zones_zonelist(struct zonelist *zonelist,
860 					enum zone_type highest_zoneidx,
861 					nodemask_t *nodes,
862 					struct zone **zone)
863 {
864 	return next_zones_zonelist(zonelist->_zonerefs, highest_zoneidx, nodes,
865 								zone);
866 }
867 
868 /**
869  * 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
870  * @zone - The current zone in the iterator
871  * @z - The current pointer within zonelist->zones being iterated
872  * @zlist - The zonelist being iterated
873  * @highidx - The zone index of the highest zone to return
874  * @nodemask - Nodemask allowed by the allocator
875  *
876  * This iterator iterates though all zones at or below a given zone index and
877  * within a given nodemask
878  */
879 #define for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, nodemask) \
880 	for (z = first_zones_zonelist(zlist, highidx, nodemask, &zone);	\
881 		zone;							\
882 		z = next_zones_zonelist(++z, highidx, nodemask, &zone))	\
883 
884 /**
885  * for_each_zone_zonelist - helper macro to iterate over valid zones in a zonelist at or below a given zone index
886  * @zone - The current zone in the iterator
887  * @z - The current pointer within zonelist->zones being iterated
888  * @zlist - The zonelist being iterated
889  * @highidx - The zone index of the highest zone to return
890  *
891  * This iterator iterates though all zones at or below a given zone index.
892  */
893 #define for_each_zone_zonelist(zone, z, zlist, highidx) \
894 	for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, NULL)
895 
896 #ifdef CONFIG_SPARSEMEM
897 #include <asm/sparsemem.h>
898 #endif
899 
900 #if !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) && \
901 	!defined(CONFIG_ARCH_POPULATES_NODE_MAP)
early_pfn_to_nid(unsigned long pfn)902 static inline unsigned long early_pfn_to_nid(unsigned long pfn)
903 {
904 	return 0;
905 }
906 #endif
907 
908 #ifdef CONFIG_FLATMEM
909 #define pfn_to_nid(pfn)		(0)
910 #endif
911 
912 #define pfn_to_section_nr(pfn) ((pfn) >> PFN_SECTION_SHIFT)
913 #define section_nr_to_pfn(sec) ((sec) << PFN_SECTION_SHIFT)
914 
915 #ifdef CONFIG_SPARSEMEM
916 
917 /*
918  * SECTION_SHIFT    		#bits space required to store a section #
919  *
920  * PA_SECTION_SHIFT		physical address to/from section number
921  * PFN_SECTION_SHIFT		pfn to/from section number
922  */
923 #define SECTIONS_SHIFT		(MAX_PHYSMEM_BITS - SECTION_SIZE_BITS)
924 
925 #define PA_SECTION_SHIFT	(SECTION_SIZE_BITS)
926 #define PFN_SECTION_SHIFT	(SECTION_SIZE_BITS - PAGE_SHIFT)
927 
928 #define NR_MEM_SECTIONS		(1UL << SECTIONS_SHIFT)
929 
930 #define PAGES_PER_SECTION       (1UL << PFN_SECTION_SHIFT)
931 #define PAGE_SECTION_MASK	(~(PAGES_PER_SECTION-1))
932 
933 #define SECTION_BLOCKFLAGS_BITS \
934 	((1UL << (PFN_SECTION_SHIFT - pageblock_order)) * NR_PAGEBLOCK_BITS)
935 
936 #if (MAX_ORDER - 1 + PAGE_SHIFT) > SECTION_SIZE_BITS
937 #error Allocator MAX_ORDER exceeds SECTION_SIZE
938 #endif
939 
940 struct page;
941 struct page_cgroup;
942 struct mem_section {
943 	/*
944 	 * This is, logically, a pointer to an array of struct
945 	 * pages.  However, it is stored with some other magic.
946 	 * (see sparse.c::sparse_init_one_section())
947 	 *
948 	 * Additionally during early boot we encode node id of
949 	 * the location of the section here to guide allocation.
950 	 * (see sparse.c::memory_present())
951 	 *
952 	 * Making it a UL at least makes someone do a cast
953 	 * before using it wrong.
954 	 */
955 	unsigned long section_mem_map;
956 
957 	/* See declaration of similar field in struct zone */
958 	unsigned long *pageblock_flags;
959 #ifdef CONFIG_CGROUP_MEM_RES_CTLR
960 	/*
961 	 * If !SPARSEMEM, pgdat doesn't have page_cgroup pointer. We use
962 	 * section. (see memcontrol.h/page_cgroup.h about this.)
963 	 */
964 	struct page_cgroup *page_cgroup;
965 	unsigned long pad;
966 #endif
967 };
968 
969 #ifdef CONFIG_SPARSEMEM_EXTREME
970 #define SECTIONS_PER_ROOT       (PAGE_SIZE / sizeof (struct mem_section))
971 #else
972 #define SECTIONS_PER_ROOT	1
973 #endif
974 
975 #define SECTION_NR_TO_ROOT(sec)	((sec) / SECTIONS_PER_ROOT)
976 #define NR_SECTION_ROOTS	(NR_MEM_SECTIONS / SECTIONS_PER_ROOT)
977 #define SECTION_ROOT_MASK	(SECTIONS_PER_ROOT - 1)
978 
979 #ifdef CONFIG_SPARSEMEM_EXTREME
980 extern struct mem_section *mem_section[NR_SECTION_ROOTS];
981 #else
982 extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT];
983 #endif
984 
__nr_to_section(unsigned long nr)985 static inline struct mem_section *__nr_to_section(unsigned long nr)
986 {
987 	if (!mem_section[SECTION_NR_TO_ROOT(nr)])
988 		return NULL;
989 	return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK];
990 }
991 extern int __section_nr(struct mem_section* ms);
992 extern unsigned long usemap_size(void);
993 
994 /*
995  * We use the lower bits of the mem_map pointer to store
996  * a little bit of information.  There should be at least
997  * 3 bits here due to 32-bit alignment.
998  */
999 #define	SECTION_MARKED_PRESENT	(1UL<<0)
1000 #define SECTION_HAS_MEM_MAP	(1UL<<1)
1001 #define SECTION_MAP_LAST_BIT	(1UL<<2)
1002 #define SECTION_MAP_MASK	(~(SECTION_MAP_LAST_BIT-1))
1003 #define SECTION_NID_SHIFT	2
1004 
__section_mem_map_addr(struct mem_section * section)1005 static inline struct page *__section_mem_map_addr(struct mem_section *section)
1006 {
1007 	unsigned long map = section->section_mem_map;
1008 	map &= SECTION_MAP_MASK;
1009 	return (struct page *)map;
1010 }
1011 
present_section(struct mem_section * section)1012 static inline int present_section(struct mem_section *section)
1013 {
1014 	return (section && (section->section_mem_map & SECTION_MARKED_PRESENT));
1015 }
1016 
present_section_nr(unsigned long nr)1017 static inline int present_section_nr(unsigned long nr)
1018 {
1019 	return present_section(__nr_to_section(nr));
1020 }
1021 
valid_section(struct mem_section * section)1022 static inline int valid_section(struct mem_section *section)
1023 {
1024 	return (section && (section->section_mem_map & SECTION_HAS_MEM_MAP));
1025 }
1026 
valid_section_nr(unsigned long nr)1027 static inline int valid_section_nr(unsigned long nr)
1028 {
1029 	return valid_section(__nr_to_section(nr));
1030 }
1031 
__pfn_to_section(unsigned long pfn)1032 static inline struct mem_section *__pfn_to_section(unsigned long pfn)
1033 {
1034 	return __nr_to_section(pfn_to_section_nr(pfn));
1035 }
1036 
pfn_valid(unsigned long pfn)1037 static inline int pfn_valid(unsigned long pfn)
1038 {
1039 	if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
1040 		return 0;
1041 	return valid_section(__nr_to_section(pfn_to_section_nr(pfn)));
1042 }
1043 
pfn_present(unsigned long pfn)1044 static inline int pfn_present(unsigned long pfn)
1045 {
1046 	if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
1047 		return 0;
1048 	return present_section(__nr_to_section(pfn_to_section_nr(pfn)));
1049 }
1050 
1051 /*
1052  * These are _only_ used during initialisation, therefore they
1053  * can use __initdata ...  They could have names to indicate
1054  * this restriction.
1055  */
1056 #ifdef CONFIG_NUMA
1057 #define pfn_to_nid(pfn)							\
1058 ({									\
1059 	unsigned long __pfn_to_nid_pfn = (pfn);				\
1060 	page_to_nid(pfn_to_page(__pfn_to_nid_pfn));			\
1061 })
1062 #else
1063 #define pfn_to_nid(pfn)		(0)
1064 #endif
1065 
1066 #define early_pfn_valid(pfn)	pfn_valid(pfn)
1067 void sparse_init(void);
1068 #else
1069 #define sparse_init()	do {} while (0)
1070 #define sparse_index_init(_sec, _nid)  do {} while (0)
1071 #endif /* CONFIG_SPARSEMEM */
1072 
1073 #ifdef CONFIG_NODES_SPAN_OTHER_NODES
1074 bool early_pfn_in_nid(unsigned long pfn, int nid);
1075 #else
1076 #define early_pfn_in_nid(pfn, nid)	(1)
1077 #endif
1078 
1079 #ifndef early_pfn_valid
1080 #define early_pfn_valid(pfn)	(1)
1081 #endif
1082 
1083 void memory_present(int nid, unsigned long start, unsigned long end);
1084 unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long);
1085 
1086 /*
1087  * If it is possible to have holes within a MAX_ORDER_NR_PAGES, then we
1088  * need to check pfn validility within that MAX_ORDER_NR_PAGES block.
1089  * pfn_valid_within() should be used in this case; we optimise this away
1090  * when we have no holes within a MAX_ORDER_NR_PAGES block.
1091  */
1092 #ifdef CONFIG_HOLES_IN_ZONE
1093 #define pfn_valid_within(pfn) pfn_valid(pfn)
1094 #else
1095 #define pfn_valid_within(pfn) (1)
1096 #endif
1097 
1098 #endif /* !__GENERATING_BOUNDS.H */
1099 #endif /* !__ASSEMBLY__ */
1100 #endif /* _LINUX_MMZONE_H */
1101