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1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_MMZONE_H
3 #define _LINUX_MMZONE_H
4 
5 #ifndef __ASSEMBLY__
6 #ifndef __GENERATING_BOUNDS_H
7 
8 #include <linux/spinlock.h>
9 #include <linux/list.h>
10 #include <linux/list_nulls.h>
11 #include <linux/wait.h>
12 #include <linux/bitops.h>
13 #include <linux/cache.h>
14 #include <linux/threads.h>
15 #include <linux/numa.h>
16 #include <linux/init.h>
17 #include <linux/seqlock.h>
18 #include <linux/nodemask.h>
19 #include <linux/pageblock-flags.h>
20 #include <linux/page-flags-layout.h>
21 #include <linux/atomic.h>
22 #include <linux/mm_types.h>
23 #include <linux/page-flags.h>
24 #include <linux/local_lock.h>
25 #include <linux/android_kabi.h>
26 #include <asm/page.h>
27 
28 /* Free memory management - zoned buddy allocator.  */
29 #ifndef CONFIG_FORCE_MAX_ZONEORDER
30 #define MAX_ORDER 11
31 #else
32 #define MAX_ORDER CONFIG_FORCE_MAX_ZONEORDER
33 #endif
34 #define MAX_ORDER_NR_PAGES (1 << (MAX_ORDER - 1))
35 
36 /*
37  * PAGE_ALLOC_COSTLY_ORDER is the order at which allocations are deemed
38  * costly to service.  That is between allocation orders which should
39  * coalesce naturally under reasonable reclaim pressure and those which
40  * will not.
41  */
42 #define PAGE_ALLOC_COSTLY_ORDER 3
43 
44 #define MAX_KSWAPD_THREADS 16
45 
46 enum migratetype {
47 	MIGRATE_UNMOVABLE,
48 	MIGRATE_MOVABLE,
49 	MIGRATE_RECLAIMABLE,
50 #ifdef CONFIG_CMA
51 	/*
52 	 * MIGRATE_CMA migration type is designed to mimic the way
53 	 * ZONE_MOVABLE works.  Only movable pages can be allocated
54 	 * from MIGRATE_CMA pageblocks and page allocator never
55 	 * implicitly change migration type of MIGRATE_CMA pageblock.
56 	 *
57 	 * The way to use it is to change migratetype of a range of
58 	 * pageblocks to MIGRATE_CMA which can be done by
59 	 * __free_pageblock_cma() function.  What is important though
60 	 * is that a range of pageblocks must be aligned to
61 	 * MAX_ORDER_NR_PAGES should biggest page be bigger than
62 	 * a single pageblock.
63 	 */
64 	MIGRATE_CMA,
65 #endif
66 	MIGRATE_PCPTYPES, /* the number of types on the pcp lists */
67 	MIGRATE_HIGHATOMIC = MIGRATE_PCPTYPES,
68 #ifdef CONFIG_MEMORY_ISOLATION
69 	MIGRATE_ISOLATE,	/* can't allocate from here */
70 #endif
71 	MIGRATE_TYPES
72 };
73 
74 /* In mm/page_alloc.c; keep in sync also with show_migration_types() there */
75 extern const char * const migratetype_names[MIGRATE_TYPES];
76 
77 #ifdef CONFIG_CMA
78 #  define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA)
79 #  define is_migrate_cma_page(_page) ({						\
80 	int mt = get_pageblock_migratetype(_page);				\
81 	bool ret = (mt == MIGRATE_ISOLATE || mt == MIGRATE_CMA) ? true : false;	\
82 	ret;									\
83 })
84 #  define get_cma_migrate_type() MIGRATE_CMA
85 #else
86 #  define is_migrate_cma(migratetype) false
87 #  define is_migrate_cma_page(_page) false
88 #  define get_cma_migrate_type() MIGRATE_MOVABLE
89 #endif
90 
is_migrate_movable(int mt)91 static inline bool is_migrate_movable(int mt)
92 {
93 	return is_migrate_cma(mt) || mt == MIGRATE_MOVABLE;
94 }
95 
96 #define for_each_migratetype_order(order, type) \
97 	for (order = 0; order < MAX_ORDER; order++) \
98 		for (type = 0; type < MIGRATE_TYPES; type++)
99 
100 extern int page_group_by_mobility_disabled;
101 
102 #define MIGRATETYPE_MASK ((1UL << PB_migratetype_bits) - 1)
103 
104 #define get_pageblock_migratetype(page)					\
105 	get_pfnblock_flags_mask(page, page_to_pfn(page), MIGRATETYPE_MASK)
106 
107 struct free_area {
108 	struct list_head	free_list[MIGRATE_TYPES];
109 	unsigned long		nr_free;
110 };
111 
get_page_from_free_area(struct free_area * area,int migratetype)112 static inline struct page *get_page_from_free_area(struct free_area *area,
113 					    int migratetype)
114 {
115 	return list_first_entry_or_null(&area->free_list[migratetype],
116 					struct page, lru);
117 }
118 
free_area_empty(struct free_area * area,int migratetype)119 static inline bool free_area_empty(struct free_area *area, int migratetype)
120 {
121 	return list_empty(&area->free_list[migratetype]);
122 }
123 
124 struct pglist_data;
125 
126 /*
127  * Add a wild amount of padding here to ensure data fall into separate
128  * cachelines.  There are very few zone structures in the machine, so space
129  * consumption is not a concern here.
130  */
131 #if defined(CONFIG_SMP)
132 struct zone_padding {
133 	char x[0];
134 } ____cacheline_internodealigned_in_smp;
135 #define ZONE_PADDING(name)	struct zone_padding name;
136 #else
137 #define ZONE_PADDING(name)
138 #endif
139 
140 #ifdef CONFIG_NUMA
141 enum numa_stat_item {
142 	NUMA_HIT,		/* allocated in intended node */
143 	NUMA_MISS,		/* allocated in non intended node */
144 	NUMA_FOREIGN,		/* was intended here, hit elsewhere */
145 	NUMA_INTERLEAVE_HIT,	/* interleaver preferred this zone */
146 	NUMA_LOCAL,		/* allocation from local node */
147 	NUMA_OTHER,		/* allocation from other node */
148 	NR_VM_NUMA_EVENT_ITEMS
149 };
150 #else
151 #define NR_VM_NUMA_EVENT_ITEMS 0
152 #endif
153 
154 enum zone_stat_item {
155 	/* First 128 byte cacheline (assuming 64 bit words) */
156 	NR_FREE_PAGES,
157 	NR_ZONE_LRU_BASE, /* Used only for compaction and reclaim retry */
158 	NR_ZONE_INACTIVE_ANON = NR_ZONE_LRU_BASE,
159 	NR_ZONE_ACTIVE_ANON,
160 	NR_ZONE_INACTIVE_FILE,
161 	NR_ZONE_ACTIVE_FILE,
162 	NR_ZONE_UNEVICTABLE,
163 	NR_ZONE_WRITE_PENDING,	/* Count of dirty, writeback and unstable pages */
164 	NR_MLOCK,		/* mlock()ed pages found and moved off LRU */
165 	/* Second 128 byte cacheline */
166 	NR_BOUNCE,
167 	NR_ZSPAGES,		/* allocated in zsmalloc */
168 	NR_FREE_CMA_PAGES,
169 	NR_VM_ZONE_STAT_ITEMS };
170 
171 enum node_stat_item {
172 	NR_LRU_BASE,
173 	NR_INACTIVE_ANON = NR_LRU_BASE, /* must match order of LRU_[IN]ACTIVE */
174 	NR_ACTIVE_ANON,		/*  "     "     "   "       "         */
175 	NR_INACTIVE_FILE,	/*  "     "     "   "       "         */
176 	NR_ACTIVE_FILE,		/*  "     "     "   "       "         */
177 	NR_UNEVICTABLE,		/*  "     "     "   "       "         */
178 	NR_SLAB_RECLAIMABLE_B,
179 	NR_SLAB_UNRECLAIMABLE_B,
180 	NR_ISOLATED_ANON,	/* Temporary isolated pages from anon lru */
181 	NR_ISOLATED_FILE,	/* Temporary isolated pages from file lru */
182 	WORKINGSET_NODES,
183 	WORKINGSET_REFAULT_BASE,
184 	WORKINGSET_REFAULT_ANON = WORKINGSET_REFAULT_BASE,
185 	WORKINGSET_REFAULT_FILE,
186 	WORKINGSET_ACTIVATE_BASE,
187 	WORKINGSET_ACTIVATE_ANON = WORKINGSET_ACTIVATE_BASE,
188 	WORKINGSET_ACTIVATE_FILE,
189 	WORKINGSET_RESTORE_BASE,
190 	WORKINGSET_RESTORE_ANON = WORKINGSET_RESTORE_BASE,
191 	WORKINGSET_RESTORE_FILE,
192 	WORKINGSET_NODERECLAIM,
193 	NR_ANON_MAPPED,	/* Mapped anonymous pages */
194 	NR_FILE_MAPPED,	/* pagecache pages mapped into pagetables.
195 			   only modified from process context */
196 	NR_FILE_PAGES,
197 	NR_FILE_DIRTY,
198 	NR_WRITEBACK,
199 	NR_WRITEBACK_TEMP,	/* Writeback using temporary buffers */
200 	NR_SHMEM,		/* shmem pages (included tmpfs/GEM pages) */
201 	NR_SHMEM_THPS,
202 	NR_SHMEM_PMDMAPPED,
203 	NR_FILE_THPS,
204 	NR_FILE_PMDMAPPED,
205 	NR_ANON_THPS,
206 	NR_VMSCAN_WRITE,
207 	NR_VMSCAN_IMMEDIATE,	/* Prioritise for reclaim when writeback ends */
208 	NR_DIRTIED,		/* page dirtyings since bootup */
209 	NR_WRITTEN,		/* page writings since bootup */
210 	NR_KERNEL_MISC_RECLAIMABLE,	/* reclaimable non-slab kernel pages */
211 	NR_FOLL_PIN_ACQUIRED,	/* via: pin_user_page(), gup flag: FOLL_PIN */
212 	NR_FOLL_PIN_RELEASED,	/* pages returned via unpin_user_page() */
213 	NR_KERNEL_STACK_KB,	/* measured in KiB */
214 #if IS_ENABLED(CONFIG_SHADOW_CALL_STACK)
215 	NR_KERNEL_SCS_KB,	/* measured in KiB */
216 #endif
217 	NR_PAGETABLE,		/* used for pagetables */
218 	NR_SECONDARY_PAGETABLE, /* secondary pagetables, e.g. KVM pagetables */
219 #ifdef CONFIG_SWAP
220 	NR_SWAPCACHE,
221 #endif
222 	NR_VM_NODE_STAT_ITEMS
223 };
224 
225 /*
226  * Returns true if the item should be printed in THPs (/proc/vmstat
227  * currently prints number of anon, file and shmem THPs. But the item
228  * is charged in pages).
229  */
vmstat_item_print_in_thp(enum node_stat_item item)230 static __always_inline bool vmstat_item_print_in_thp(enum node_stat_item item)
231 {
232 	if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
233 		return false;
234 
235 	return item == NR_ANON_THPS ||
236 	       item == NR_FILE_THPS ||
237 	       item == NR_SHMEM_THPS ||
238 	       item == NR_SHMEM_PMDMAPPED ||
239 	       item == NR_FILE_PMDMAPPED;
240 }
241 
242 /*
243  * Returns true if the value is measured in bytes (most vmstat values are
244  * measured in pages). This defines the API part, the internal representation
245  * might be different.
246  */
vmstat_item_in_bytes(int idx)247 static __always_inline bool vmstat_item_in_bytes(int idx)
248 {
249 	/*
250 	 * Global and per-node slab counters track slab pages.
251 	 * It's expected that changes are multiples of PAGE_SIZE.
252 	 * Internally values are stored in pages.
253 	 *
254 	 * Per-memcg and per-lruvec counters track memory, consumed
255 	 * by individual slab objects. These counters are actually
256 	 * byte-precise.
257 	 */
258 	return (idx == NR_SLAB_RECLAIMABLE_B ||
259 		idx == NR_SLAB_UNRECLAIMABLE_B);
260 }
261 
262 /*
263  * We do arithmetic on the LRU lists in various places in the code,
264  * so it is important to keep the active lists LRU_ACTIVE higher in
265  * the array than the corresponding inactive lists, and to keep
266  * the *_FILE lists LRU_FILE higher than the corresponding _ANON lists.
267  *
268  * This has to be kept in sync with the statistics in zone_stat_item
269  * above and the descriptions in vmstat_text in mm/vmstat.c
270  */
271 #define LRU_BASE 0
272 #define LRU_ACTIVE 1
273 #define LRU_FILE 2
274 
275 enum lru_list {
276 	LRU_INACTIVE_ANON = LRU_BASE,
277 	LRU_ACTIVE_ANON = LRU_BASE + LRU_ACTIVE,
278 	LRU_INACTIVE_FILE = LRU_BASE + LRU_FILE,
279 	LRU_ACTIVE_FILE = LRU_BASE + LRU_FILE + LRU_ACTIVE,
280 	LRU_UNEVICTABLE,
281 	NR_LRU_LISTS
282 };
283 
284 #define for_each_lru(lru) for (lru = 0; lru < NR_LRU_LISTS; lru++)
285 
286 #define for_each_evictable_lru(lru) for (lru = 0; lru <= LRU_ACTIVE_FILE; lru++)
287 
is_file_lru(enum lru_list lru)288 static inline bool is_file_lru(enum lru_list lru)
289 {
290 	return (lru == LRU_INACTIVE_FILE || lru == LRU_ACTIVE_FILE);
291 }
292 
is_active_lru(enum lru_list lru)293 static inline bool is_active_lru(enum lru_list lru)
294 {
295 	return (lru == LRU_ACTIVE_ANON || lru == LRU_ACTIVE_FILE);
296 }
297 
298 #define ANON_AND_FILE 2
299 
300 enum lruvec_flags {
301 	LRUVEC_CONGESTED,		/* lruvec has many dirty pages
302 					 * backed by a congested BDI
303 					 */
304 };
305 
306 #endif /* !__GENERATING_BOUNDS_H */
307 
308 /*
309  * Evictable pages are divided into multiple generations. The youngest and the
310  * oldest generation numbers, max_seq and min_seq, are monotonically increasing.
311  * They form a sliding window of a variable size [MIN_NR_GENS, MAX_NR_GENS]. An
312  * offset within MAX_NR_GENS, i.e., gen, indexes the LRU list of the
313  * corresponding generation. The gen counter in page->flags stores gen+1 while
314  * a page is on one of lrugen->pages[]. Otherwise it stores 0.
315  *
316  * A page is added to the youngest generation on faulting. The aging needs to
317  * check the accessed bit at least twice before handing this page over to the
318  * eviction. The first check takes care of the accessed bit set on the initial
319  * fault; the second check makes sure this page hasn't been used since then.
320  * This process, AKA second chance, requires a minimum of two generations,
321  * hence MIN_NR_GENS. And to maintain ABI compatibility with the active/inactive
322  * LRU, e.g., /proc/vmstat, these two generations are considered active; the
323  * rest of generations, if they exist, are considered inactive. See
324  * lru_gen_is_active().
325  *
326  * PG_active is always cleared while a page is on one of lrugen->pages[] so
327  * that the aging needs not to worry about it. And it's set again when a page
328  * considered active is isolated for non-reclaiming purposes, e.g., migration.
329  * See lru_gen_add_page() and lru_gen_del_page().
330  *
331  * MAX_NR_GENS is set to 4 so that the multi-gen LRU can support twice the
332  * number of categories of the active/inactive LRU when keeping track of
333  * accesses through page tables. This requires order_base_2(MAX_NR_GENS+1) bits
334  * in page->flags.
335  */
336 #define MIN_NR_GENS		2U
337 #define MAX_NR_GENS		4U
338 
339 /*
340  * Each generation is divided into multiple tiers. A page accessed N times
341  * through file descriptors is in tier order_base_2(N). A page in the first tier
342  * (N=0,1) is marked by PG_referenced unless it was faulted in through page
343  * tables or read ahead. A page in any other tier (N>1) is marked by
344  * PG_referenced and PG_workingset. This implies a minimum of two tiers is
345  * supported without using additional bits in page->flags.
346  *
347  * In contrast to moving across generations which requires the LRU lock, moving
348  * across tiers only involves atomic operations on page->flags and therefore
349  * has a negligible cost in the buffered access path. In the eviction path,
350  * comparisons of refaulted/(evicted+protected) from the first tier and the
351  * rest infer whether pages accessed multiple times through file descriptors
352  * are statistically hot and thus worth protecting.
353  *
354  * MAX_NR_TIERS is set to 4 so that the multi-gen LRU can support twice the
355  * number of categories of the active/inactive LRU when keeping track of
356  * accesses through file descriptors. This uses MAX_NR_TIERS-2 spare bits in
357  * page->flags.
358  */
359 #define MAX_NR_TIERS		4U
360 
361 #ifndef __GENERATING_BOUNDS_H
362 
363 struct lruvec;
364 struct page_vma_mapped_walk;
365 
366 #define LRU_GEN_MASK		((BIT(LRU_GEN_WIDTH) - 1) << LRU_GEN_PGOFF)
367 #define LRU_REFS_MASK		((BIT(LRU_REFS_WIDTH) - 1) << LRU_REFS_PGOFF)
368 
369 /* see the comment on MEMCG_NR_GENS */
370 enum {
371 	MEMCG_LRU_NOP,
372 	MEMCG_LRU_HEAD,
373 	MEMCG_LRU_TAIL,
374 	MEMCG_LRU_OLD,
375 	MEMCG_LRU_YOUNG,
376 };
377 
378 #ifdef CONFIG_LRU_GEN
379 
380 enum {
381 	LRU_GEN_ANON,
382 	LRU_GEN_FILE,
383 };
384 
385 enum {
386 	LRU_GEN_CORE,
387 	LRU_GEN_MM_WALK,
388 	LRU_GEN_NONLEAF_YOUNG,
389 	NR_LRU_GEN_CAPS
390 };
391 
392 #define MIN_LRU_BATCH		BITS_PER_LONG
393 #define MAX_LRU_BATCH		(MIN_LRU_BATCH * 64)
394 
395 /* whether to keep historical stats from evicted generations */
396 #ifdef CONFIG_LRU_GEN_STATS
397 #define NR_HIST_GENS		MAX_NR_GENS
398 #else
399 #define NR_HIST_GENS		1U
400 #endif
401 
402 /*
403  * The youngest generation number is stored in max_seq for both anon and file
404  * types as they are aged on an equal footing. The oldest generation numbers are
405  * stored in min_seq[] separately for anon and file types as clean file pages
406  * can be evicted regardless of swap constraints.
407  *
408  * Normally anon and file min_seq are in sync. But if swapping is constrained,
409  * e.g., out of swap space, file min_seq is allowed to advance and leave anon
410  * min_seq behind.
411  *
412  * The number of pages in each generation is eventually consistent and therefore
413  * can be transiently negative when reset_batch_size() is pending.
414  */
415 struct lru_gen_page {
416 	/* the aging increments the youngest generation number */
417 	unsigned long max_seq;
418 	/* the eviction increments the oldest generation numbers */
419 	unsigned long min_seq[ANON_AND_FILE];
420 	/* the birth time of each generation in jiffies */
421 	unsigned long timestamps[MAX_NR_GENS];
422 	/* the multi-gen LRU lists, lazily sorted on eviction */
423 	struct list_head pages[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES];
424 	/* the multi-gen LRU sizes, eventually consistent */
425 	long nr_pages[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES];
426 	/* the exponential moving average of refaulted */
427 	unsigned long avg_refaulted[ANON_AND_FILE][MAX_NR_TIERS];
428 	/* the exponential moving average of evicted+protected */
429 	unsigned long avg_total[ANON_AND_FILE][MAX_NR_TIERS];
430 	/* the first tier doesn't need protection, hence the minus one */
431 	unsigned long protected[NR_HIST_GENS][ANON_AND_FILE][MAX_NR_TIERS - 1];
432 	/* can be modified without holding the LRU lock */
433 	atomic_long_t evicted[NR_HIST_GENS][ANON_AND_FILE][MAX_NR_TIERS];
434 	atomic_long_t refaulted[NR_HIST_GENS][ANON_AND_FILE][MAX_NR_TIERS];
435 	/* whether the multi-gen LRU is enabled */
436 	bool enabled;
437 #ifdef CONFIG_MEMCG
438 	/* the memcg generation this lru_gen_page belongs to */
439 	u8 gen;
440 	/* the list segment this lru_gen_page belongs to */
441 	u8 seg;
442 	/* per-node lru_gen_page list for global reclaim */
443 	struct hlist_nulls_node list;
444 #endif
445 
446 	ANDROID_KABI_RESERVE(1);
447 	ANDROID_KABI_RESERVE(2);
448 };
449 
450 enum {
451 	MM_LEAF_TOTAL,		/* total leaf entries */
452 	MM_LEAF_OLD,		/* old leaf entries */
453 	MM_LEAF_YOUNG,		/* young leaf entries */
454 	MM_NONLEAF_TOTAL,	/* total non-leaf entries */
455 	MM_NONLEAF_FOUND,	/* non-leaf entries found in Bloom filters */
456 	MM_NONLEAF_ADDED,	/* non-leaf entries added to Bloom filters */
457 	NR_MM_STATS
458 };
459 
460 /* double-buffering Bloom filters */
461 #define NR_BLOOM_FILTERS	2
462 
463 struct lru_gen_mm_state {
464 	/* set to max_seq after each iteration */
465 	unsigned long seq;
466 	/* where the current iteration continues after */
467 	struct list_head *head;
468 	/* where the last iteration ended before */
469 	struct list_head *tail;
470 	/* Bloom filters flip after each iteration */
471 	unsigned long *filters[NR_BLOOM_FILTERS];
472 	/* the mm stats for debugging */
473 	unsigned long stats[NR_HIST_GENS][NR_MM_STATS];
474 
475 	ANDROID_KABI_RESERVE(1);
476 };
477 
478 struct lru_gen_mm_walk {
479 	/* the lruvec under reclaim */
480 	struct lruvec *lruvec;
481 	/* unstable max_seq from lru_gen_page */
482 	unsigned long max_seq;
483 	/* the next address within an mm to scan */
484 	unsigned long next_addr;
485 	/* to batch promoted pages */
486 	int nr_pages[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES];
487 	/* to batch the mm stats */
488 	int mm_stats[NR_MM_STATS];
489 	/* total batched items */
490 	int batched;
491 	bool can_swap;
492 	bool force_scan;
493 
494 	ANDROID_KABI_RESERVE(1);
495 	ANDROID_KABI_RESERVE(2);
496 };
497 
498 void lru_gen_init_lruvec(struct lruvec *lruvec);
499 void lru_gen_look_around(struct page_vma_mapped_walk *pvmw);
500 
501 #ifdef CONFIG_MEMCG
502 
503 /*
504  * For each node, memcgs are divided into two generations: the old and the
505  * young. For each generation, memcgs are randomly sharded into multiple bins
506  * to improve scalability. For each bin, the hlist_nulls is virtually divided
507  * into three segments: the head, the tail and the default.
508  *
509  * An onlining memcg is added to the tail of a random bin in the old generation.
510  * The eviction starts at the head of a random bin in the old generation. The
511  * per-node memcg generation counter, whose reminder (mod MEMCG_NR_GENS) indexes
512  * the old generation, is incremented when all its bins become empty.
513  *
514  * There are four operations:
515  * 1. MEMCG_LRU_HEAD, which moves an memcg to the head of a random bin in its
516  *    current generation (old or young) and updates its "seg" to "head";
517  * 2. MEMCG_LRU_TAIL, which moves an memcg to the tail of a random bin in its
518  *    current generation (old or young) and updates its "seg" to "tail";
519  * 3. MEMCG_LRU_OLD, which moves an memcg to the head of a random bin in the old
520  *    generation, updates its "gen" to "old" and resets its "seg" to "default";
521  * 4. MEMCG_LRU_YOUNG, which moves an memcg to the tail of a random bin in the
522  *    young generation, updates its "gen" to "young" and resets its "seg" to
523  *    "default".
524  *
525  * The events that trigger the above operations are:
526  * 1. Exceeding the soft limit, which triggers MEMCG_LRU_HEAD;
527  * 2. The first attempt to reclaim an memcg below low, which triggers
528  *    MEMCG_LRU_TAIL;
529  * 3. The first attempt to reclaim an memcg below reclaimable size threshold,
530  *    which triggers MEMCG_LRU_TAIL;
531  * 4. The second attempt to reclaim an memcg below reclaimable size threshold,
532  *    which triggers MEMCG_LRU_YOUNG;
533  * 5. Attempting to reclaim an memcg below min, which triggers MEMCG_LRU_YOUNG;
534  * 6. Finishing the aging on the eviction path, which triggers MEMCG_LRU_YOUNG;
535  * 7. Offlining an memcg, which triggers MEMCG_LRU_OLD.
536  *
537  * Note that memcg LRU only applies to global reclaim, and the round-robin
538  * incrementing of their max_seq counters ensures the eventual fairness to all
539  * eligible memcgs. For memcg reclaim, it still relies on mem_cgroup_iter().
540  */
541 #define MEMCG_NR_GENS	2
542 #define MEMCG_NR_BINS	8
543 
544 struct lru_gen_memcg {
545 	/* the per-node memcg generation counter */
546 	unsigned long seq;
547 	/* each memcg has one lru_gen_page per node */
548 	unsigned long nr_memcgs[MEMCG_NR_GENS];
549 	/* per-node lru_gen_page list for global reclaim */
550 	struct hlist_nulls_head	fifo[MEMCG_NR_GENS][MEMCG_NR_BINS];
551 	/* protects the above */
552 	spinlock_t lock;
553 
554 	ANDROID_KABI_RESERVE(1);
555 	ANDROID_KABI_RESERVE(2);
556 };
557 
558 void lru_gen_init_pgdat(struct pglist_data *pgdat);
559 
560 void lru_gen_init_memcg(struct mem_cgroup *memcg);
561 void lru_gen_exit_memcg(struct mem_cgroup *memcg);
562 void lru_gen_online_memcg(struct mem_cgroup *memcg);
563 void lru_gen_offline_memcg(struct mem_cgroup *memcg);
564 void lru_gen_release_memcg(struct mem_cgroup *memcg);
565 void lru_gen_rotate_memcg(struct lruvec *lruvec, int op);
566 
567 #else /* !CONFIG_MEMCG */
568 
569 #define MEMCG_NR_GENS	1
570 
571 struct lru_gen_memcg {
572 };
573 
lru_gen_init_pgdat(struct pglist_data * pgdat)574 static inline void lru_gen_init_pgdat(struct pglist_data *pgdat)
575 {
576 }
577 
578 #endif /* CONFIG_MEMCG */
579 
580 #else /* !CONFIG_LRU_GEN */
581 
lru_gen_init_pgdat(struct pglist_data * pgdat)582 static inline void lru_gen_init_pgdat(struct pglist_data *pgdat)
583 {
584 }
585 
lru_gen_init_lruvec(struct lruvec * lruvec)586 static inline void lru_gen_init_lruvec(struct lruvec *lruvec)
587 {
588 }
589 
lru_gen_look_around(struct page_vma_mapped_walk * pvmw)590 static inline void lru_gen_look_around(struct page_vma_mapped_walk *pvmw)
591 {
592 }
593 
594 #ifdef CONFIG_MEMCG
595 
lru_gen_init_memcg(struct mem_cgroup * memcg)596 static inline void lru_gen_init_memcg(struct mem_cgroup *memcg)
597 {
598 }
599 
lru_gen_exit_memcg(struct mem_cgroup * memcg)600 static inline void lru_gen_exit_memcg(struct mem_cgroup *memcg)
601 {
602 }
603 
lru_gen_online_memcg(struct mem_cgroup * memcg)604 static inline void lru_gen_online_memcg(struct mem_cgroup *memcg)
605 {
606 }
607 
lru_gen_offline_memcg(struct mem_cgroup * memcg)608 static inline void lru_gen_offline_memcg(struct mem_cgroup *memcg)
609 {
610 }
611 
lru_gen_release_memcg(struct mem_cgroup * memcg)612 static inline void lru_gen_release_memcg(struct mem_cgroup *memcg)
613 {
614 }
615 
lru_gen_rotate_memcg(struct lruvec * lruvec,int op)616 static inline void lru_gen_rotate_memcg(struct lruvec *lruvec, int op)
617 {
618 }
619 
620 #endif /* CONFIG_MEMCG */
621 
622 #endif /* CONFIG_LRU_GEN */
623 
624 struct lruvec {
625 	struct list_head		lists[NR_LRU_LISTS];
626 	/* per lruvec lru_lock for memcg */
627 	spinlock_t			lru_lock;
628 	/*
629 	 * These track the cost of reclaiming one LRU - file or anon -
630 	 * over the other. As the observed cost of reclaiming one LRU
631 	 * increases, the reclaim scan balance tips toward the other.
632 	 */
633 	unsigned long			anon_cost;
634 	unsigned long			file_cost;
635 	/* Non-resident age, driven by LRU movement */
636 	atomic_long_t			nonresident_age;
637 	/* Refaults at the time of last reclaim cycle */
638 	unsigned long			refaults[ANON_AND_FILE];
639 	/* Various lruvec state flags (enum lruvec_flags) */
640 	unsigned long			flags;
641 #ifdef CONFIG_LRU_GEN
642 	/* evictable pages divided into generations */
643 	struct lru_gen_page		lrugen;
644 	/* to concurrently iterate lru_gen_mm_list */
645 	struct lru_gen_mm_state		mm_state;
646 #endif
647 #ifdef CONFIG_MEMCG
648 	struct pglist_data *pgdat;
649 #endif
650 	ANDROID_VENDOR_DATA(1);
651 	ANDROID_KABI_RESERVE(1);
652 	ANDROID_KABI_RESERVE(2);
653 };
654 
655 /* Isolate unmapped pages */
656 #define ISOLATE_UNMAPPED	((__force isolate_mode_t)0x2)
657 /* Isolate for asynchronous migration */
658 #define ISOLATE_ASYNC_MIGRATE	((__force isolate_mode_t)0x4)
659 /* Isolate unevictable pages */
660 #define ISOLATE_UNEVICTABLE	((__force isolate_mode_t)0x8)
661 
662 /* LRU Isolation modes. */
663 typedef unsigned __bitwise isolate_mode_t;
664 
665 enum zone_watermarks {
666 	WMARK_MIN,
667 	WMARK_LOW,
668 	WMARK_HIGH,
669 	NR_WMARK
670 };
671 
672 /*
673  * One per migratetype for each PAGE_ALLOC_COSTLY_ORDER. One additional list
674  * for THP which will usually be GFP_MOVABLE. Even if it is another type,
675  * it should not contribute to serious fragmentation causing THP allocation
676  * failures.
677  */
678 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
679 #define NR_PCP_THP 1
680 #else
681 #define NR_PCP_THP 0
682 #endif
683 #define NR_LOWORDER_PCP_LISTS (MIGRATE_PCPTYPES * (PAGE_ALLOC_COSTLY_ORDER + 1))
684 #define NR_PCP_LISTS (NR_LOWORDER_PCP_LISTS + NR_PCP_THP)
685 
686 /*
687  * Shift to encode migratetype and order in the same integer, with order
688  * in the least significant bits.
689  */
690 #define NR_PCP_ORDER_WIDTH 8
691 #define NR_PCP_ORDER_MASK ((1<<NR_PCP_ORDER_WIDTH) - 1)
692 
693 #define min_wmark_pages(z) (z->_watermark[WMARK_MIN] + z->watermark_boost)
694 #define low_wmark_pages(z) (z->_watermark[WMARK_LOW] + z->watermark_boost)
695 #define high_wmark_pages(z) (z->_watermark[WMARK_HIGH] + z->watermark_boost)
696 #define wmark_pages(z, i) (z->_watermark[i] + z->watermark_boost)
697 
698 /* Fields and list protected by pagesets local_lock in page_alloc.c */
699 struct per_cpu_pages {
700 	spinlock_t lock;	/* Protects lists field */
701 	int count;		/* number of pages in the list */
702 	int high;		/* high watermark, emptying needed */
703 	int batch;		/* chunk size for buddy add/remove */
704 	short free_factor;	/* batch scaling factor during free */
705 #ifdef CONFIG_NUMA
706 	short expire;		/* When 0, remote pagesets are drained */
707 #endif
708 
709 	/* Lists of pages, one per migrate type stored on the pcp-lists */
710 	struct list_head lists[NR_PCP_LISTS];
711 } ____cacheline_aligned_in_smp;
712 
713 struct per_cpu_zonestat {
714 #ifdef CONFIG_SMP
715 	s8 vm_stat_diff[NR_VM_ZONE_STAT_ITEMS];
716 	s8 stat_threshold;
717 #endif
718 #ifdef CONFIG_NUMA
719 	/*
720 	 * Low priority inaccurate counters that are only folded
721 	 * on demand. Use a large type to avoid the overhead of
722 	 * folding during refresh_cpu_vm_stats.
723 	 */
724 	unsigned long vm_numa_event[NR_VM_NUMA_EVENT_ITEMS];
725 #endif
726 };
727 
728 struct per_cpu_nodestat {
729 	s8 stat_threshold;
730 	s8 vm_node_stat_diff[NR_VM_NODE_STAT_ITEMS];
731 };
732 
733 #endif /* !__GENERATING_BOUNDS.H */
734 
735 enum zone_type {
736 	/*
737 	 * ZONE_DMA and ZONE_DMA32 are used when there are peripherals not able
738 	 * to DMA to all of the addressable memory (ZONE_NORMAL).
739 	 * On architectures where this area covers the whole 32 bit address
740 	 * space ZONE_DMA32 is used. ZONE_DMA is left for the ones with smaller
741 	 * DMA addressing constraints. This distinction is important as a 32bit
742 	 * DMA mask is assumed when ZONE_DMA32 is defined. Some 64-bit
743 	 * platforms may need both zones as they support peripherals with
744 	 * different DMA addressing limitations.
745 	 */
746 #ifdef CONFIG_ZONE_DMA
747 	ZONE_DMA,
748 #endif
749 #ifdef CONFIG_ZONE_DMA32
750 	ZONE_DMA32,
751 #endif
752 	/*
753 	 * Normal addressable memory is in ZONE_NORMAL. DMA operations can be
754 	 * performed on pages in ZONE_NORMAL if the DMA devices support
755 	 * transfers to all addressable memory.
756 	 */
757 	ZONE_NORMAL,
758 #ifdef CONFIG_HIGHMEM
759 	/*
760 	 * A memory area that is only addressable by the kernel through
761 	 * mapping portions into its own address space. This is for example
762 	 * used by i386 to allow the kernel to address the memory beyond
763 	 * 900MB. The kernel will set up special mappings (page
764 	 * table entries on i386) for each page that the kernel needs to
765 	 * access.
766 	 */
767 	ZONE_HIGHMEM,
768 #endif
769 	/*
770 	 * ZONE_MOVABLE is similar to ZONE_NORMAL, except that it contains
771 	 * movable pages with few exceptional cases described below. Main use
772 	 * cases for ZONE_MOVABLE are to make memory offlining/unplug more
773 	 * likely to succeed, and to locally limit unmovable allocations - e.g.,
774 	 * to increase the number of THP/huge pages. Notable special cases are:
775 	 *
776 	 * 1. Pinned pages: (long-term) pinning of movable pages might
777 	 *    essentially turn such pages unmovable. Therefore, we do not allow
778 	 *    pinning long-term pages in ZONE_MOVABLE. When pages are pinned and
779 	 *    faulted, they come from the right zone right away. However, it is
780 	 *    still possible that address space already has pages in
781 	 *    ZONE_MOVABLE at the time when pages are pinned (i.e. user has
782 	 *    touches that memory before pinning). In such case we migrate them
783 	 *    to a different zone. When migration fails - pinning fails.
784 	 * 2. memblock allocations: kernelcore/movablecore setups might create
785 	 *    situations where ZONE_MOVABLE contains unmovable allocations
786 	 *    after boot. Memory offlining and allocations fail early.
787 	 * 3. Memory holes: kernelcore/movablecore setups might create very rare
788 	 *    situations where ZONE_MOVABLE contains memory holes after boot,
789 	 *    for example, if we have sections that are only partially
790 	 *    populated. Memory offlining and allocations fail early.
791 	 * 4. PG_hwpoison pages: while poisoned pages can be skipped during
792 	 *    memory offlining, such pages cannot be allocated.
793 	 * 5. Unmovable PG_offline pages: in paravirtualized environments,
794 	 *    hotplugged memory blocks might only partially be managed by the
795 	 *    buddy (e.g., via XEN-balloon, Hyper-V balloon, virtio-mem). The
796 	 *    parts not manged by the buddy are unmovable PG_offline pages. In
797 	 *    some cases (virtio-mem), such pages can be skipped during
798 	 *    memory offlining, however, cannot be moved/allocated. These
799 	 *    techniques might use alloc_contig_range() to hide previously
800 	 *    exposed pages from the buddy again (e.g., to implement some sort
801 	 *    of memory unplug in virtio-mem).
802 	 * 6. ZERO_PAGE(0), kernelcore/movablecore setups might create
803 	 *    situations where ZERO_PAGE(0) which is allocated differently
804 	 *    on different platforms may end up in a movable zone. ZERO_PAGE(0)
805 	 *    cannot be migrated.
806 	 * 7. Memory-hotplug: when using memmap_on_memory and onlining the
807 	 *    memory to the MOVABLE zone, the vmemmap pages are also placed in
808 	 *    such zone. Such pages cannot be really moved around as they are
809 	 *    self-stored in the range, but they are treated as movable when
810 	 *    the range they describe is about to be offlined.
811 	 *
812 	 * In general, no unmovable allocations that degrade memory offlining
813 	 * should end up in ZONE_MOVABLE. Allocators (like alloc_contig_range())
814 	 * have to expect that migrating pages in ZONE_MOVABLE can fail (even
815 	 * if has_unmovable_pages() states that there are no unmovable pages,
816 	 * there can be false negatives).
817 	 */
818 	ZONE_MOVABLE,
819 #ifdef CONFIG_ZONE_DEVICE
820 	ZONE_DEVICE,
821 #endif
822 	__MAX_NR_ZONES
823 
824 };
825 
826 #ifndef __GENERATING_BOUNDS_H
827 
828 #define ASYNC_AND_SYNC 2
829 
830 struct zone {
831 	/* Read-mostly fields */
832 
833 	/* zone watermarks, access with *_wmark_pages(zone) macros */
834 	unsigned long _watermark[NR_WMARK];
835 	unsigned long watermark_boost;
836 
837 	unsigned long nr_reserved_highatomic;
838 
839 	/*
840 	 * We don't know if the memory that we're going to allocate will be
841 	 * freeable or/and it will be released eventually, so to avoid totally
842 	 * wasting several GB of ram we must reserve some of the lower zone
843 	 * memory (otherwise we risk to run OOM on the lower zones despite
844 	 * there being tons of freeable ram on the higher zones).  This array is
845 	 * recalculated at runtime if the sysctl_lowmem_reserve_ratio sysctl
846 	 * changes.
847 	 */
848 	long lowmem_reserve[MAX_NR_ZONES];
849 
850 #ifdef CONFIG_NUMA
851 	int node;
852 #endif
853 	struct pglist_data	*zone_pgdat;
854 	struct per_cpu_pages	__percpu *per_cpu_pageset;
855 	struct per_cpu_zonestat	__percpu *per_cpu_zonestats;
856 	/*
857 	 * the high and batch values are copied to individual pagesets for
858 	 * faster access
859 	 */
860 	int pageset_high;
861 	int pageset_batch;
862 
863 #ifndef CONFIG_SPARSEMEM
864 	/*
865 	 * Flags for a pageblock_nr_pages block. See pageblock-flags.h.
866 	 * In SPARSEMEM, this map is stored in struct mem_section
867 	 */
868 	unsigned long		*pageblock_flags;
869 #endif /* CONFIG_SPARSEMEM */
870 
871 	/* zone_start_pfn == zone_start_paddr >> PAGE_SHIFT */
872 	unsigned long		zone_start_pfn;
873 
874 	/*
875 	 * spanned_pages is the total pages spanned by the zone, including
876 	 * holes, which is calculated as:
877 	 * 	spanned_pages = zone_end_pfn - zone_start_pfn;
878 	 *
879 	 * present_pages is physical pages existing within the zone, which
880 	 * is calculated as:
881 	 *	present_pages = spanned_pages - absent_pages(pages in holes);
882 	 *
883 	 * present_early_pages is present pages existing within the zone
884 	 * located on memory available since early boot, excluding hotplugged
885 	 * memory.
886 	 *
887 	 * managed_pages is present pages managed by the buddy system, which
888 	 * is calculated as (reserved_pages includes pages allocated by the
889 	 * bootmem allocator):
890 	 *	managed_pages = present_pages - reserved_pages;
891 	 *
892 	 * cma pages is present pages that are assigned for CMA use
893 	 * (MIGRATE_CMA).
894 	 *
895 	 * So present_pages may be used by memory hotplug or memory power
896 	 * management logic to figure out unmanaged pages by checking
897 	 * (present_pages - managed_pages). And managed_pages should be used
898 	 * by page allocator and vm scanner to calculate all kinds of watermarks
899 	 * and thresholds.
900 	 *
901 	 * Locking rules:
902 	 *
903 	 * zone_start_pfn and spanned_pages are protected by span_seqlock.
904 	 * It is a seqlock because it has to be read outside of zone->lock,
905 	 * and it is done in the main allocator path.  But, it is written
906 	 * quite infrequently.
907 	 *
908 	 * The span_seq lock is declared along with zone->lock because it is
909 	 * frequently read in proximity to zone->lock.  It's good to
910 	 * give them a chance of being in the same cacheline.
911 	 *
912 	 * Write access to present_pages at runtime should be protected by
913 	 * mem_hotplug_begin/end(). Any reader who can't tolerant drift of
914 	 * present_pages should get_online_mems() to get a stable value.
915 	 */
916 	atomic_long_t		managed_pages;
917 	unsigned long		spanned_pages;
918 	unsigned long		present_pages;
919 #if defined(CONFIG_MEMORY_HOTPLUG)
920 	unsigned long		present_early_pages;
921 #endif
922 #ifdef CONFIG_CMA
923 	unsigned long		cma_pages;
924 #endif
925 
926 	const char		*name;
927 
928 #ifdef CONFIG_MEMORY_ISOLATION
929 	/*
930 	 * Number of isolated pageblock. It is used to solve incorrect
931 	 * freepage counting problem due to racy retrieving migratetype
932 	 * of pageblock. Protected by zone->lock.
933 	 */
934 	unsigned long		nr_isolate_pageblock;
935 #endif
936 
937 #ifdef CONFIG_MEMORY_HOTPLUG
938 	/* see spanned/present_pages for more description */
939 	seqlock_t		span_seqlock;
940 #endif
941 
942 	int initialized;
943 
944 	/* Write-intensive fields used from the page allocator */
945 	ZONE_PADDING(_pad1_)
946 
947 	/* free areas of different sizes */
948 	struct free_area	free_area[MAX_ORDER];
949 
950 	/* zone flags, see below */
951 	unsigned long		flags;
952 
953 	/* Primarily protects free_area */
954 	spinlock_t		lock;
955 
956 	/* Write-intensive fields used by compaction and vmstats. */
957 	ZONE_PADDING(_pad2_)
958 
959 	/*
960 	 * When free pages are below this point, additional steps are taken
961 	 * when reading the number of free pages to avoid per-cpu counter
962 	 * drift allowing watermarks to be breached
963 	 */
964 	unsigned long percpu_drift_mark;
965 
966 #if defined CONFIG_COMPACTION || defined CONFIG_CMA
967 	/* pfn where compaction free scanner should start */
968 	unsigned long		compact_cached_free_pfn;
969 	/* pfn where compaction migration scanner should start */
970 	unsigned long		compact_cached_migrate_pfn[ASYNC_AND_SYNC];
971 	unsigned long		compact_init_migrate_pfn;
972 	unsigned long		compact_init_free_pfn;
973 #endif
974 
975 #ifdef CONFIG_COMPACTION
976 	/*
977 	 * On compaction failure, 1<<compact_defer_shift compactions
978 	 * are skipped before trying again. The number attempted since
979 	 * last failure is tracked with compact_considered.
980 	 * compact_order_failed is the minimum compaction failed order.
981 	 */
982 	unsigned int		compact_considered;
983 	unsigned int		compact_defer_shift;
984 	int			compact_order_failed;
985 #endif
986 
987 #if defined CONFIG_COMPACTION || defined CONFIG_CMA
988 	/* Set to true when the PG_migrate_skip bits should be cleared */
989 	bool			compact_blockskip_flush;
990 #endif
991 
992 	bool			contiguous;
993 
994 	ZONE_PADDING(_pad3_)
995 	/* Zone statistics */
996 	atomic_long_t		vm_stat[NR_VM_ZONE_STAT_ITEMS];
997 	atomic_long_t		vm_numa_event[NR_VM_NUMA_EVENT_ITEMS];
998 
999 	ANDROID_KABI_RESERVE(1);
1000 	ANDROID_KABI_RESERVE(2);
1001 	ANDROID_KABI_RESERVE(3);
1002 	ANDROID_KABI_RESERVE(4);
1003 } ____cacheline_internodealigned_in_smp;
1004 
1005 enum pgdat_flags {
1006 	PGDAT_DIRTY,			/* reclaim scanning has recently found
1007 					 * many dirty file pages at the tail
1008 					 * of the LRU.
1009 					 */
1010 	PGDAT_WRITEBACK,		/* reclaim scanning has recently found
1011 					 * many pages under writeback
1012 					 */
1013 	PGDAT_RECLAIM_LOCKED,		/* prevents concurrent reclaim */
1014 };
1015 
1016 enum zone_flags {
1017 	ZONE_BOOSTED_WATERMARK,		/* zone recently boosted watermarks.
1018 					 * Cleared when kswapd is woken.
1019 					 */
1020 	ZONE_RECLAIM_ACTIVE,		/* kswapd may be scanning the zone. */
1021 };
1022 
zone_managed_pages(struct zone * zone)1023 static inline unsigned long zone_managed_pages(struct zone *zone)
1024 {
1025 	return (unsigned long)atomic_long_read(&zone->managed_pages);
1026 }
1027 
zone_cma_pages(struct zone * zone)1028 static inline unsigned long zone_cma_pages(struct zone *zone)
1029 {
1030 #ifdef CONFIG_CMA
1031 	return zone->cma_pages;
1032 #else
1033 	return 0;
1034 #endif
1035 }
1036 
zone_end_pfn(const struct zone * zone)1037 static inline unsigned long zone_end_pfn(const struct zone *zone)
1038 {
1039 	return zone->zone_start_pfn + zone->spanned_pages;
1040 }
1041 
zone_spans_pfn(const struct zone * zone,unsigned long pfn)1042 static inline bool zone_spans_pfn(const struct zone *zone, unsigned long pfn)
1043 {
1044 	return zone->zone_start_pfn <= pfn && pfn < zone_end_pfn(zone);
1045 }
1046 
zone_is_initialized(struct zone * zone)1047 static inline bool zone_is_initialized(struct zone *zone)
1048 {
1049 	return zone->initialized;
1050 }
1051 
zone_is_empty(struct zone * zone)1052 static inline bool zone_is_empty(struct zone *zone)
1053 {
1054 	return zone->spanned_pages == 0;
1055 }
1056 
1057 /*
1058  * Return true if [start_pfn, start_pfn + nr_pages) range has a non-empty
1059  * intersection with the given zone
1060  */
zone_intersects(struct zone * zone,unsigned long start_pfn,unsigned long nr_pages)1061 static inline bool zone_intersects(struct zone *zone,
1062 		unsigned long start_pfn, unsigned long nr_pages)
1063 {
1064 	if (zone_is_empty(zone))
1065 		return false;
1066 	if (start_pfn >= zone_end_pfn(zone) ||
1067 	    start_pfn + nr_pages <= zone->zone_start_pfn)
1068 		return false;
1069 
1070 	return true;
1071 }
1072 
1073 /*
1074  * The "priority" of VM scanning is how much of the queues we will scan in one
1075  * go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the
1076  * queues ("queue_length >> 12") during an aging round.
1077  */
1078 #define DEF_PRIORITY 12
1079 
1080 /* Maximum number of zones on a zonelist */
1081 #define MAX_ZONES_PER_ZONELIST (MAX_NUMNODES * MAX_NR_ZONES)
1082 
1083 enum {
1084 	ZONELIST_FALLBACK,	/* zonelist with fallback */
1085 #ifdef CONFIG_NUMA
1086 	/*
1087 	 * The NUMA zonelists are doubled because we need zonelists that
1088 	 * restrict the allocations to a single node for __GFP_THISNODE.
1089 	 */
1090 	ZONELIST_NOFALLBACK,	/* zonelist without fallback (__GFP_THISNODE) */
1091 #endif
1092 	MAX_ZONELISTS
1093 };
1094 
1095 /*
1096  * This struct contains information about a zone in a zonelist. It is stored
1097  * here to avoid dereferences into large structures and lookups of tables
1098  */
1099 struct zoneref {
1100 	struct zone *zone;	/* Pointer to actual zone */
1101 	int zone_idx;		/* zone_idx(zoneref->zone) */
1102 };
1103 
1104 /*
1105  * One allocation request operates on a zonelist. A zonelist
1106  * is a list of zones, the first one is the 'goal' of the
1107  * allocation, the other zones are fallback zones, in decreasing
1108  * priority.
1109  *
1110  * To speed the reading of the zonelist, the zonerefs contain the zone index
1111  * of the entry being read. Helper functions to access information given
1112  * a struct zoneref are
1113  *
1114  * zonelist_zone()	- Return the struct zone * for an entry in _zonerefs
1115  * zonelist_zone_idx()	- Return the index of the zone for an entry
1116  * zonelist_node_idx()	- Return the index of the node for an entry
1117  */
1118 struct zonelist {
1119 	struct zoneref _zonerefs[MAX_ZONES_PER_ZONELIST + 1];
1120 };
1121 
1122 /*
1123  * The array of struct pages for flatmem.
1124  * It must be declared for SPARSEMEM as well because there are configurations
1125  * that rely on that.
1126  */
1127 extern struct page *mem_map;
1128 
1129 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1130 struct deferred_split {
1131 	spinlock_t split_queue_lock;
1132 	struct list_head split_queue;
1133 	unsigned long split_queue_len;
1134 };
1135 #endif
1136 
1137 /*
1138  * On NUMA machines, each NUMA node would have a pg_data_t to describe
1139  * it's memory layout. On UMA machines there is a single pglist_data which
1140  * describes the whole memory.
1141  *
1142  * Memory statistics and page replacement data structures are maintained on a
1143  * per-zone basis.
1144  */
1145 typedef struct pglist_data {
1146 	/*
1147 	 * node_zones contains just the zones for THIS node. Not all of the
1148 	 * zones may be populated, but it is the full list. It is referenced by
1149 	 * this node's node_zonelists as well as other node's node_zonelists.
1150 	 */
1151 	struct zone node_zones[MAX_NR_ZONES];
1152 
1153 	/*
1154 	 * node_zonelists contains references to all zones in all nodes.
1155 	 * Generally the first zones will be references to this node's
1156 	 * node_zones.
1157 	 */
1158 	struct zonelist node_zonelists[MAX_ZONELISTS];
1159 
1160 	int nr_zones; /* number of populated zones in this node */
1161 #ifdef CONFIG_FLATMEM	/* means !SPARSEMEM */
1162 	struct page *node_mem_map;
1163 #ifdef CONFIG_PAGE_EXTENSION
1164 	struct page_ext *node_page_ext;
1165 #endif
1166 #endif
1167 #if defined(CONFIG_MEMORY_HOTPLUG) || defined(CONFIG_DEFERRED_STRUCT_PAGE_INIT)
1168 	/*
1169 	 * Must be held any time you expect node_start_pfn,
1170 	 * node_present_pages, node_spanned_pages or nr_zones to stay constant.
1171 	 * Also synchronizes pgdat->first_deferred_pfn during deferred page
1172 	 * init.
1173 	 *
1174 	 * pgdat_resize_lock() and pgdat_resize_unlock() are provided to
1175 	 * manipulate node_size_lock without checking for CONFIG_MEMORY_HOTPLUG
1176 	 * or CONFIG_DEFERRED_STRUCT_PAGE_INIT.
1177 	 *
1178 	 * Nests above zone->lock and zone->span_seqlock
1179 	 */
1180 	spinlock_t node_size_lock;
1181 #endif
1182 	unsigned long node_start_pfn;
1183 	unsigned long node_present_pages; /* total number of physical pages */
1184 	unsigned long node_spanned_pages; /* total size of physical page
1185 					     range, including holes */
1186 	int node_id;
1187 	wait_queue_head_t kswapd_wait;
1188 	wait_queue_head_t pfmemalloc_wait;
1189 	struct task_struct *kswapd;	/* Protected by
1190 					   mem_hotplug_begin/end() */
1191 	struct task_struct *mkswapd[MAX_KSWAPD_THREADS];
1192 	int kswapd_order;
1193 	enum zone_type kswapd_highest_zoneidx;
1194 
1195 	int kswapd_failures;		/* Number of 'reclaimed == 0' runs */
1196 
1197 	ANDROID_OEM_DATA(1);
1198 #ifdef CONFIG_COMPACTION
1199 	int kcompactd_max_order;
1200 	enum zone_type kcompactd_highest_zoneidx;
1201 	wait_queue_head_t kcompactd_wait;
1202 	struct task_struct *kcompactd;
1203 	bool proactive_compact_trigger;
1204 #endif
1205 	/*
1206 	 * This is a per-node reserve of pages that are not available
1207 	 * to userspace allocations.
1208 	 */
1209 	unsigned long		totalreserve_pages;
1210 
1211 #ifdef CONFIG_NUMA
1212 	/*
1213 	 * node reclaim becomes active if more unmapped pages exist.
1214 	 */
1215 	unsigned long		min_unmapped_pages;
1216 	unsigned long		min_slab_pages;
1217 #endif /* CONFIG_NUMA */
1218 
1219 	/* Write-intensive fields used by page reclaim */
1220 	ZONE_PADDING(_pad1_)
1221 
1222 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
1223 	/*
1224 	 * If memory initialisation on large machines is deferred then this
1225 	 * is the first PFN that needs to be initialised.
1226 	 */
1227 	unsigned long first_deferred_pfn;
1228 #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
1229 
1230 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1231 	struct deferred_split deferred_split_queue;
1232 #endif
1233 
1234 	/* Fields commonly accessed by the page reclaim scanner */
1235 
1236 	/*
1237 	 * NOTE: THIS IS UNUSED IF MEMCG IS ENABLED.
1238 	 *
1239 	 * Use mem_cgroup_lruvec() to look up lruvecs.
1240 	 */
1241 	struct lruvec		__lruvec;
1242 
1243 	unsigned long		flags;
1244 
1245 #ifdef CONFIG_LRU_GEN
1246 	/* kswap mm walk data */
1247 	struct lru_gen_mm_walk	mm_walk;
1248 	/* lru_gen_page list */
1249 	struct lru_gen_memcg memcg_lru;
1250 #endif
1251 
1252 	ZONE_PADDING(_pad2_)
1253 
1254 	/* Per-node vmstats */
1255 	struct per_cpu_nodestat __percpu *per_cpu_nodestats;
1256 	atomic_long_t		vm_stat[NR_VM_NODE_STAT_ITEMS];
1257 } pg_data_t;
1258 
1259 #define node_present_pages(nid)	(NODE_DATA(nid)->node_present_pages)
1260 #define node_spanned_pages(nid)	(NODE_DATA(nid)->node_spanned_pages)
1261 #ifdef CONFIG_FLATMEM
1262 #define pgdat_page_nr(pgdat, pagenr)	((pgdat)->node_mem_map + (pagenr))
1263 #else
1264 #define pgdat_page_nr(pgdat, pagenr)	pfn_to_page((pgdat)->node_start_pfn + (pagenr))
1265 #endif
1266 #define nid_page_nr(nid, pagenr) 	pgdat_page_nr(NODE_DATA(nid),(pagenr))
1267 
1268 #define node_start_pfn(nid)	(NODE_DATA(nid)->node_start_pfn)
1269 #define node_end_pfn(nid) pgdat_end_pfn(NODE_DATA(nid))
1270 
pgdat_end_pfn(pg_data_t * pgdat)1271 static inline unsigned long pgdat_end_pfn(pg_data_t *pgdat)
1272 {
1273 	return pgdat->node_start_pfn + pgdat->node_spanned_pages;
1274 }
1275 
pgdat_is_empty(pg_data_t * pgdat)1276 static inline bool pgdat_is_empty(pg_data_t *pgdat)
1277 {
1278 	return !pgdat->node_start_pfn && !pgdat->node_spanned_pages;
1279 }
1280 
1281 #include <linux/memory_hotplug.h>
1282 
1283 void build_all_zonelists(pg_data_t *pgdat);
1284 void wakeup_kswapd(struct zone *zone, gfp_t gfp_mask, int order,
1285 		   enum zone_type highest_zoneidx);
1286 bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
1287 			 int highest_zoneidx, unsigned int alloc_flags,
1288 			 long free_pages);
1289 bool zone_watermark_ok(struct zone *z, unsigned int order,
1290 		unsigned long mark, int highest_zoneidx,
1291 		unsigned int alloc_flags);
1292 bool zone_watermark_ok_safe(struct zone *z, unsigned int order,
1293 		unsigned long mark, int highest_zoneidx);
1294 /*
1295  * Memory initialization context, use to differentiate memory added by
1296  * the platform statically or via memory hotplug interface.
1297  */
1298 enum meminit_context {
1299 	MEMINIT_EARLY,
1300 	MEMINIT_HOTPLUG,
1301 };
1302 
1303 extern void init_currently_empty_zone(struct zone *zone, unsigned long start_pfn,
1304 				     unsigned long size);
1305 
1306 extern void lruvec_init(struct lruvec *lruvec);
1307 
lruvec_pgdat(struct lruvec * lruvec)1308 static inline struct pglist_data *lruvec_pgdat(struct lruvec *lruvec)
1309 {
1310 #ifdef CONFIG_MEMCG
1311 	return lruvec->pgdat;
1312 #else
1313 	return container_of(lruvec, struct pglist_data, __lruvec);
1314 #endif
1315 }
1316 
1317 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
1318 int local_memory_node(int node_id);
1319 #else
local_memory_node(int node_id)1320 static inline int local_memory_node(int node_id) { return node_id; };
1321 #endif
1322 
1323 /*
1324  * zone_idx() returns 0 for the ZONE_DMA zone, 1 for the ZONE_NORMAL zone, etc.
1325  */
1326 #define zone_idx(zone)		((zone) - (zone)->zone_pgdat->node_zones)
1327 
1328 #ifdef CONFIG_ZONE_DEVICE
zone_is_zone_device(struct zone * zone)1329 static inline bool zone_is_zone_device(struct zone *zone)
1330 {
1331 	return zone_idx(zone) == ZONE_DEVICE;
1332 }
1333 #else
zone_is_zone_device(struct zone * zone)1334 static inline bool zone_is_zone_device(struct zone *zone)
1335 {
1336 	return false;
1337 }
1338 #endif
1339 
1340 /*
1341  * Returns true if a zone has pages managed by the buddy allocator.
1342  * All the reclaim decisions have to use this function rather than
1343  * populated_zone(). If the whole zone is reserved then we can easily
1344  * end up with populated_zone() && !managed_zone().
1345  */
managed_zone(struct zone * zone)1346 static inline bool managed_zone(struct zone *zone)
1347 {
1348 	return zone_managed_pages(zone);
1349 }
1350 
1351 /* Returns true if a zone has memory */
populated_zone(struct zone * zone)1352 static inline bool populated_zone(struct zone *zone)
1353 {
1354 	return zone->present_pages;
1355 }
1356 
1357 #ifdef CONFIG_NUMA
zone_to_nid(struct zone * zone)1358 static inline int zone_to_nid(struct zone *zone)
1359 {
1360 	return zone->node;
1361 }
1362 
zone_set_nid(struct zone * zone,int nid)1363 static inline void zone_set_nid(struct zone *zone, int nid)
1364 {
1365 	zone->node = nid;
1366 }
1367 #else
zone_to_nid(struct zone * zone)1368 static inline int zone_to_nid(struct zone *zone)
1369 {
1370 	return 0;
1371 }
1372 
zone_set_nid(struct zone * zone,int nid)1373 static inline void zone_set_nid(struct zone *zone, int nid) {}
1374 #endif
1375 
1376 extern int movable_zone;
1377 
is_highmem_idx(enum zone_type idx)1378 static inline int is_highmem_idx(enum zone_type idx)
1379 {
1380 #ifdef CONFIG_HIGHMEM
1381 	return (idx == ZONE_HIGHMEM ||
1382 		(idx == ZONE_MOVABLE && movable_zone == ZONE_HIGHMEM));
1383 #else
1384 	return 0;
1385 #endif
1386 }
1387 
1388 #ifdef CONFIG_ZONE_DMA
1389 bool has_managed_dma(void);
1390 #else
has_managed_dma(void)1391 static inline bool has_managed_dma(void)
1392 {
1393 	return false;
1394 }
1395 #endif
1396 
1397 /**
1398  * is_highmem - helper function to quickly check if a struct zone is a
1399  *              highmem zone or not.  This is an attempt to keep references
1400  *              to ZONE_{DMA/NORMAL/HIGHMEM/etc} in general code to a minimum.
1401  * @zone: pointer to struct zone variable
1402  * Return: 1 for a highmem zone, 0 otherwise
1403  */
is_highmem(struct zone * zone)1404 static inline int is_highmem(struct zone *zone)
1405 {
1406 #ifdef CONFIG_HIGHMEM
1407 	return is_highmem_idx(zone_idx(zone));
1408 #else
1409 	return 0;
1410 #endif
1411 }
1412 
1413 /* These two functions are used to setup the per zone pages min values */
1414 struct ctl_table;
1415 
1416 int min_free_kbytes_sysctl_handler(struct ctl_table *, int, void *, size_t *,
1417 		loff_t *);
1418 int watermark_scale_factor_sysctl_handler(struct ctl_table *, int, void *,
1419 		size_t *, loff_t *);
1420 extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES];
1421 int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int, void *,
1422 		size_t *, loff_t *);
1423 int percpu_pagelist_high_fraction_sysctl_handler(struct ctl_table *, int,
1424 		void *, size_t *, loff_t *);
1425 int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *, int,
1426 		void *, size_t *, loff_t *);
1427 int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *, int,
1428 		void *, size_t *, loff_t *);
1429 int numa_zonelist_order_handler(struct ctl_table *, int,
1430 		void *, size_t *, loff_t *);
1431 extern int percpu_pagelist_high_fraction;
1432 extern char numa_zonelist_order[];
1433 #define NUMA_ZONELIST_ORDER_LEN	16
1434 
1435 #ifndef CONFIG_NUMA
1436 
1437 extern struct pglist_data contig_page_data;
NODE_DATA(int nid)1438 static inline struct pglist_data *NODE_DATA(int nid)
1439 {
1440 	return &contig_page_data;
1441 }
1442 #define NODE_MEM_MAP(nid)	mem_map
1443 
1444 #else /* CONFIG_NUMA */
1445 
1446 #include <asm/mmzone.h>
1447 
1448 #endif /* !CONFIG_NUMA */
1449 
1450 extern struct pglist_data *first_online_pgdat(void);
1451 extern struct pglist_data *next_online_pgdat(struct pglist_data *pgdat);
1452 extern struct zone *next_zone(struct zone *zone);
1453 extern int isolate_anon_lru_page(struct page *page);
1454 
1455 /**
1456  * for_each_online_pgdat - helper macro to iterate over all online nodes
1457  * @pgdat: pointer to a pg_data_t variable
1458  */
1459 #define for_each_online_pgdat(pgdat)			\
1460 	for (pgdat = first_online_pgdat();		\
1461 	     pgdat;					\
1462 	     pgdat = next_online_pgdat(pgdat))
1463 /**
1464  * for_each_zone - helper macro to iterate over all memory zones
1465  * @zone: pointer to struct zone variable
1466  *
1467  * The user only needs to declare the zone variable, for_each_zone
1468  * fills it in.
1469  */
1470 #define for_each_zone(zone)			        \
1471 	for (zone = (first_online_pgdat())->node_zones; \
1472 	     zone;					\
1473 	     zone = next_zone(zone))
1474 
1475 #define for_each_populated_zone(zone)		        \
1476 	for (zone = (first_online_pgdat())->node_zones; \
1477 	     zone;					\
1478 	     zone = next_zone(zone))			\
1479 		if (!populated_zone(zone))		\
1480 			; /* do nothing */		\
1481 		else
1482 
zonelist_zone(struct zoneref * zoneref)1483 static inline struct zone *zonelist_zone(struct zoneref *zoneref)
1484 {
1485 	return zoneref->zone;
1486 }
1487 
zonelist_zone_idx(struct zoneref * zoneref)1488 static inline int zonelist_zone_idx(struct zoneref *zoneref)
1489 {
1490 	return zoneref->zone_idx;
1491 }
1492 
zonelist_node_idx(struct zoneref * zoneref)1493 static inline int zonelist_node_idx(struct zoneref *zoneref)
1494 {
1495 	return zone_to_nid(zoneref->zone);
1496 }
1497 
1498 struct zoneref *__next_zones_zonelist(struct zoneref *z,
1499 					enum zone_type highest_zoneidx,
1500 					nodemask_t *nodes);
1501 
1502 /**
1503  * 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
1504  * @z: The cursor used as a starting point for the search
1505  * @highest_zoneidx: The zone index of the highest zone to return
1506  * @nodes: An optional nodemask to filter the zonelist with
1507  *
1508  * This function returns the next zone at or below a given zone index that is
1509  * within the allowed nodemask using a cursor as the starting point for the
1510  * search. The zoneref returned is a cursor that represents the current zone
1511  * being examined. It should be advanced by one before calling
1512  * next_zones_zonelist again.
1513  *
1514  * Return: the next zone at or below highest_zoneidx within the allowed
1515  * nodemask using a cursor within a zonelist as a starting point
1516  */
next_zones_zonelist(struct zoneref * z,enum zone_type highest_zoneidx,nodemask_t * nodes)1517 static __always_inline struct zoneref *next_zones_zonelist(struct zoneref *z,
1518 					enum zone_type highest_zoneidx,
1519 					nodemask_t *nodes)
1520 {
1521 	if (likely(!nodes && zonelist_zone_idx(z) <= highest_zoneidx))
1522 		return z;
1523 	return __next_zones_zonelist(z, highest_zoneidx, nodes);
1524 }
1525 
1526 /**
1527  * first_zones_zonelist - Returns the first zone at or below highest_zoneidx within the allowed nodemask in a zonelist
1528  * @zonelist: The zonelist to search for a suitable zone
1529  * @highest_zoneidx: The zone index of the highest zone to return
1530  * @nodes: An optional nodemask to filter the zonelist with
1531  *
1532  * This function returns the first zone at or below a given zone index that is
1533  * within the allowed nodemask. The zoneref returned is a cursor that can be
1534  * used to iterate the zonelist with next_zones_zonelist by advancing it by
1535  * one before calling.
1536  *
1537  * When no eligible zone is found, zoneref->zone is NULL (zoneref itself is
1538  * never NULL). This may happen either genuinely, or due to concurrent nodemask
1539  * update due to cpuset modification.
1540  *
1541  * Return: Zoneref pointer for the first suitable zone found
1542  */
first_zones_zonelist(struct zonelist * zonelist,enum zone_type highest_zoneidx,nodemask_t * nodes)1543 static inline struct zoneref *first_zones_zonelist(struct zonelist *zonelist,
1544 					enum zone_type highest_zoneidx,
1545 					nodemask_t *nodes)
1546 {
1547 	return next_zones_zonelist(zonelist->_zonerefs,
1548 							highest_zoneidx, nodes);
1549 }
1550 
1551 /**
1552  * 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
1553  * @zone: The current zone in the iterator
1554  * @z: The current pointer within zonelist->_zonerefs being iterated
1555  * @zlist: The zonelist being iterated
1556  * @highidx: The zone index of the highest zone to return
1557  * @nodemask: Nodemask allowed by the allocator
1558  *
1559  * This iterator iterates though all zones at or below a given zone index and
1560  * within a given nodemask
1561  */
1562 #define for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, nodemask) \
1563 	for (z = first_zones_zonelist(zlist, highidx, nodemask), zone = zonelist_zone(z);	\
1564 		zone;							\
1565 		z = next_zones_zonelist(++z, highidx, nodemask),	\
1566 			zone = zonelist_zone(z))
1567 
1568 #define for_next_zone_zonelist_nodemask(zone, z, highidx, nodemask) \
1569 	for (zone = z->zone;	\
1570 		zone;							\
1571 		z = next_zones_zonelist(++z, highidx, nodemask),	\
1572 			zone = zonelist_zone(z))
1573 
1574 
1575 /**
1576  * for_each_zone_zonelist - helper macro to iterate over valid zones in a zonelist at or below a given zone index
1577  * @zone: The current zone in the iterator
1578  * @z: The current pointer within zonelist->zones being iterated
1579  * @zlist: The zonelist being iterated
1580  * @highidx: The zone index of the highest zone to return
1581  *
1582  * This iterator iterates though all zones at or below a given zone index.
1583  */
1584 #define for_each_zone_zonelist(zone, z, zlist, highidx) \
1585 	for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, NULL)
1586 
1587 #ifdef CONFIG_SPARSEMEM
1588 #include <asm/sparsemem.h>
1589 #endif
1590 
1591 #ifdef CONFIG_FLATMEM
1592 #define pfn_to_nid(pfn)		(0)
1593 #endif
1594 
1595 #ifdef CONFIG_SPARSEMEM
1596 
1597 /*
1598  * PA_SECTION_SHIFT		physical address to/from section number
1599  * PFN_SECTION_SHIFT		pfn to/from section number
1600  */
1601 #define PA_SECTION_SHIFT	(SECTION_SIZE_BITS)
1602 #define PFN_SECTION_SHIFT	(SECTION_SIZE_BITS - PAGE_SHIFT)
1603 
1604 #define NR_MEM_SECTIONS		(1UL << SECTIONS_SHIFT)
1605 
1606 #define PAGES_PER_SECTION       (1UL << PFN_SECTION_SHIFT)
1607 #define PAGE_SECTION_MASK	(~(PAGES_PER_SECTION-1))
1608 
1609 #define SECTION_BLOCKFLAGS_BITS \
1610 	((1UL << (PFN_SECTION_SHIFT - pageblock_order)) * NR_PAGEBLOCK_BITS)
1611 
1612 #if (MAX_ORDER - 1 + PAGE_SHIFT) > SECTION_SIZE_BITS
1613 #error Allocator MAX_ORDER exceeds SECTION_SIZE
1614 #endif
1615 
pfn_to_section_nr(unsigned long pfn)1616 static inline unsigned long pfn_to_section_nr(unsigned long pfn)
1617 {
1618 	return pfn >> PFN_SECTION_SHIFT;
1619 }
section_nr_to_pfn(unsigned long sec)1620 static inline unsigned long section_nr_to_pfn(unsigned long sec)
1621 {
1622 	return sec << PFN_SECTION_SHIFT;
1623 }
1624 
1625 #define SECTION_ALIGN_UP(pfn)	(((pfn) + PAGES_PER_SECTION - 1) & PAGE_SECTION_MASK)
1626 #define SECTION_ALIGN_DOWN(pfn)	((pfn) & PAGE_SECTION_MASK)
1627 
1628 #define SUBSECTION_SHIFT 21
1629 #define SUBSECTION_SIZE (1UL << SUBSECTION_SHIFT)
1630 
1631 #define PFN_SUBSECTION_SHIFT (SUBSECTION_SHIFT - PAGE_SHIFT)
1632 #define PAGES_PER_SUBSECTION (1UL << PFN_SUBSECTION_SHIFT)
1633 #define PAGE_SUBSECTION_MASK (~(PAGES_PER_SUBSECTION-1))
1634 
1635 #if SUBSECTION_SHIFT > SECTION_SIZE_BITS
1636 #error Subsection size exceeds section size
1637 #else
1638 #define SUBSECTIONS_PER_SECTION (1UL << (SECTION_SIZE_BITS - SUBSECTION_SHIFT))
1639 #endif
1640 
1641 #define SUBSECTION_ALIGN_UP(pfn) ALIGN((pfn), PAGES_PER_SUBSECTION)
1642 #define SUBSECTION_ALIGN_DOWN(pfn) ((pfn) & PAGE_SUBSECTION_MASK)
1643 
1644 struct mem_section_usage {
1645 #ifdef CONFIG_SPARSEMEM_VMEMMAP
1646 	DECLARE_BITMAP(subsection_map, SUBSECTIONS_PER_SECTION);
1647 #endif
1648 	/* See declaration of similar field in struct zone */
1649 	unsigned long pageblock_flags[0];
1650 };
1651 
1652 void subsection_map_init(unsigned long pfn, unsigned long nr_pages);
1653 
1654 struct page;
1655 struct page_ext;
1656 struct mem_section {
1657 	/*
1658 	 * This is, logically, a pointer to an array of struct
1659 	 * pages.  However, it is stored with some other magic.
1660 	 * (see sparse.c::sparse_init_one_section())
1661 	 *
1662 	 * Additionally during early boot we encode node id of
1663 	 * the location of the section here to guide allocation.
1664 	 * (see sparse.c::memory_present())
1665 	 *
1666 	 * Making it a UL at least makes someone do a cast
1667 	 * before using it wrong.
1668 	 */
1669 	unsigned long section_mem_map;
1670 
1671 	struct mem_section_usage *usage;
1672 #ifdef CONFIG_PAGE_EXTENSION
1673 	/*
1674 	 * If SPARSEMEM, pgdat doesn't have page_ext pointer. We use
1675 	 * section. (see page_ext.h about this.)
1676 	 */
1677 	struct page_ext *page_ext;
1678 	unsigned long pad;
1679 #endif
1680 	/*
1681 	 * WARNING: mem_section must be a power-of-2 in size for the
1682 	 * calculation and use of SECTION_ROOT_MASK to make sense.
1683 	 */
1684 };
1685 
1686 #ifdef CONFIG_SPARSEMEM_EXTREME
1687 #define SECTIONS_PER_ROOT       (PAGE_SIZE / sizeof (struct mem_section))
1688 #else
1689 #define SECTIONS_PER_ROOT	1
1690 #endif
1691 
1692 #define SECTION_NR_TO_ROOT(sec)	((sec) / SECTIONS_PER_ROOT)
1693 #define NR_SECTION_ROOTS	DIV_ROUND_UP(NR_MEM_SECTIONS, SECTIONS_PER_ROOT)
1694 #define SECTION_ROOT_MASK	(SECTIONS_PER_ROOT - 1)
1695 
1696 #ifdef CONFIG_SPARSEMEM_EXTREME
1697 extern struct mem_section **mem_section;
1698 #else
1699 extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT];
1700 #endif
1701 
section_to_usemap(struct mem_section * ms)1702 static inline unsigned long *section_to_usemap(struct mem_section *ms)
1703 {
1704 	return ms->usage->pageblock_flags;
1705 }
1706 
__nr_to_section(unsigned long nr)1707 static inline struct mem_section *__nr_to_section(unsigned long nr)
1708 {
1709 	unsigned long root = SECTION_NR_TO_ROOT(nr);
1710 
1711 	if (unlikely(root >= NR_SECTION_ROOTS))
1712 		return NULL;
1713 
1714 #ifdef CONFIG_SPARSEMEM_EXTREME
1715 	if (!mem_section || !mem_section[root])
1716 		return NULL;
1717 #endif
1718 	return &mem_section[root][nr & SECTION_ROOT_MASK];
1719 }
1720 extern size_t mem_section_usage_size(void);
1721 
1722 /*
1723  * We use the lower bits of the mem_map pointer to store
1724  * a little bit of information.  The pointer is calculated
1725  * as mem_map - section_nr_to_pfn(pnum).  The result is
1726  * aligned to the minimum alignment of the two values:
1727  *   1. All mem_map arrays are page-aligned.
1728  *   2. section_nr_to_pfn() always clears PFN_SECTION_SHIFT
1729  *      lowest bits.  PFN_SECTION_SHIFT is arch-specific
1730  *      (equal SECTION_SIZE_BITS - PAGE_SHIFT), and the
1731  *      worst combination is powerpc with 256k pages,
1732  *      which results in PFN_SECTION_SHIFT equal 6.
1733  * To sum it up, at least 6 bits are available.
1734  */
1735 #define SECTION_MARKED_PRESENT		(1UL<<0)
1736 #define SECTION_HAS_MEM_MAP		(1UL<<1)
1737 #define SECTION_IS_ONLINE		(1UL<<2)
1738 #define SECTION_IS_EARLY		(1UL<<3)
1739 #define SECTION_TAINT_ZONE_DEVICE	(1UL<<4)
1740 #define SECTION_MAP_LAST_BIT		(1UL<<5)
1741 #define SECTION_MAP_MASK		(~(SECTION_MAP_LAST_BIT-1))
1742 #define SECTION_NID_SHIFT		6
1743 
__section_mem_map_addr(struct mem_section * section)1744 static inline struct page *__section_mem_map_addr(struct mem_section *section)
1745 {
1746 	unsigned long map = section->section_mem_map;
1747 	map &= SECTION_MAP_MASK;
1748 	return (struct page *)map;
1749 }
1750 
present_section(struct mem_section * section)1751 static inline int present_section(struct mem_section *section)
1752 {
1753 	return (section && (section->section_mem_map & SECTION_MARKED_PRESENT));
1754 }
1755 
present_section_nr(unsigned long nr)1756 static inline int present_section_nr(unsigned long nr)
1757 {
1758 	return present_section(__nr_to_section(nr));
1759 }
1760 
valid_section(struct mem_section * section)1761 static inline int valid_section(struct mem_section *section)
1762 {
1763 	return (section && (section->section_mem_map & SECTION_HAS_MEM_MAP));
1764 }
1765 
early_section(struct mem_section * section)1766 static inline int early_section(struct mem_section *section)
1767 {
1768 	return (section && (section->section_mem_map & SECTION_IS_EARLY));
1769 }
1770 
valid_section_nr(unsigned long nr)1771 static inline int valid_section_nr(unsigned long nr)
1772 {
1773 	return valid_section(__nr_to_section(nr));
1774 }
1775 
online_section(struct mem_section * section)1776 static inline int online_section(struct mem_section *section)
1777 {
1778 	return (section && (section->section_mem_map & SECTION_IS_ONLINE));
1779 }
1780 
online_device_section(struct mem_section * section)1781 static inline int online_device_section(struct mem_section *section)
1782 {
1783 	unsigned long flags = SECTION_IS_ONLINE | SECTION_TAINT_ZONE_DEVICE;
1784 
1785 	return section && ((section->section_mem_map & flags) == flags);
1786 }
1787 
online_section_nr(unsigned long nr)1788 static inline int online_section_nr(unsigned long nr)
1789 {
1790 	return online_section(__nr_to_section(nr));
1791 }
1792 
1793 #ifdef CONFIG_MEMORY_HOTPLUG
1794 void online_mem_sections(unsigned long start_pfn, unsigned long end_pfn);
1795 void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn);
1796 #endif
1797 
__pfn_to_section(unsigned long pfn)1798 static inline struct mem_section *__pfn_to_section(unsigned long pfn)
1799 {
1800 	return __nr_to_section(pfn_to_section_nr(pfn));
1801 }
1802 
1803 extern unsigned long __highest_present_section_nr;
1804 
subsection_map_index(unsigned long pfn)1805 static inline int subsection_map_index(unsigned long pfn)
1806 {
1807 	return (pfn & ~(PAGE_SECTION_MASK)) / PAGES_PER_SUBSECTION;
1808 }
1809 
1810 #ifdef CONFIG_SPARSEMEM_VMEMMAP
pfn_section_valid(struct mem_section * ms,unsigned long pfn)1811 static inline int pfn_section_valid(struct mem_section *ms, unsigned long pfn)
1812 {
1813 	int idx = subsection_map_index(pfn);
1814 
1815 	return test_bit(idx, ms->usage->subsection_map);
1816 }
1817 #else
pfn_section_valid(struct mem_section * ms,unsigned long pfn)1818 static inline int pfn_section_valid(struct mem_section *ms, unsigned long pfn)
1819 {
1820 	return 1;
1821 }
1822 #endif
1823 
1824 #ifndef CONFIG_HAVE_ARCH_PFN_VALID
1825 /**
1826  * pfn_valid - check if there is a valid memory map entry for a PFN
1827  * @pfn: the page frame number to check
1828  *
1829  * Check if there is a valid memory map entry aka struct page for the @pfn.
1830  * Note, that availability of the memory map entry does not imply that
1831  * there is actual usable memory at that @pfn. The struct page may
1832  * represent a hole or an unusable page frame.
1833  *
1834  * Return: 1 for PFNs that have memory map entries and 0 otherwise
1835  */
pfn_valid(unsigned long pfn)1836 static inline int pfn_valid(unsigned long pfn)
1837 {
1838 	struct mem_section *ms;
1839 
1840 	/*
1841 	 * Ensure the upper PAGE_SHIFT bits are clear in the
1842 	 * pfn. Else it might lead to false positives when
1843 	 * some of the upper bits are set, but the lower bits
1844 	 * match a valid pfn.
1845 	 */
1846 	if (PHYS_PFN(PFN_PHYS(pfn)) != pfn)
1847 		return 0;
1848 
1849 	if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
1850 		return 0;
1851 	ms = __pfn_to_section(pfn);
1852 	if (!valid_section(ms))
1853 		return 0;
1854 	/*
1855 	 * Traditionally early sections always returned pfn_valid() for
1856 	 * the entire section-sized span.
1857 	 */
1858 	return early_section(ms) || pfn_section_valid(ms, pfn);
1859 }
1860 #endif
1861 
pfn_in_present_section(unsigned long pfn)1862 static inline int pfn_in_present_section(unsigned long pfn)
1863 {
1864 	if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
1865 		return 0;
1866 	return present_section(__pfn_to_section(pfn));
1867 }
1868 
next_present_section_nr(unsigned long section_nr)1869 static inline unsigned long next_present_section_nr(unsigned long section_nr)
1870 {
1871 	while (++section_nr <= __highest_present_section_nr) {
1872 		if (present_section_nr(section_nr))
1873 			return section_nr;
1874 	}
1875 
1876 	return -1;
1877 }
1878 
1879 /*
1880  * These are _only_ used during initialisation, therefore they
1881  * can use __initdata ...  They could have names to indicate
1882  * this restriction.
1883  */
1884 #ifdef CONFIG_NUMA
1885 #define pfn_to_nid(pfn)							\
1886 ({									\
1887 	unsigned long __pfn_to_nid_pfn = (pfn);				\
1888 	page_to_nid(pfn_to_page(__pfn_to_nid_pfn));			\
1889 })
1890 #else
1891 #define pfn_to_nid(pfn)		(0)
1892 #endif
1893 
1894 void sparse_init(void);
1895 #else
1896 #define sparse_init()	do {} while (0)
1897 #define sparse_index_init(_sec, _nid)  do {} while (0)
1898 #define pfn_in_present_section pfn_valid
1899 #define subsection_map_init(_pfn, _nr_pages) do {} while (0)
1900 #endif /* CONFIG_SPARSEMEM */
1901 
1902 #endif /* !__GENERATING_BOUNDS.H */
1903 #endif /* !__ASSEMBLY__ */
1904 #endif /* _LINUX_MMZONE_H */
1905