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/zswap.h>
26	#include <asm/page.h>
27
28	/* Free memory management - zoned buddy allocator. */
29	#ifndef CONFIG_ARCH_FORCE_MAX_ORDER
30	#define MAX_PAGE_ORDER 10
31	#else
32	#define MAX_PAGE_ORDER CONFIG_ARCH_FORCE_MAX_ORDER
33	#endif
34	#define MAX_ORDER_NR_PAGES (1 << MAX_PAGE_ORDER)
35
36	#define IS_MAX_ORDER_ALIGNED(pfn) IS_ALIGNED(pfn, MAX_ORDER_NR_PAGES)
37
38	#define NR_PAGE_ORDERS (MAX_PAGE_ORDER + 1)
39
40	/*
41	* PAGE_ALLOC_COSTLY_ORDER is the order at which allocations are deemed
42	* costly to service. That is between allocation orders which should
43	* coalesce naturally under reasonable reclaim pressure and those which
44	* will not.
45	*/
46	#define PAGE_ALLOC_COSTLY_ORDER 3
47
48	enum migratetype {
49	MIGRATE_UNMOVABLE,
50	MIGRATE_MOVABLE,
51	MIGRATE_RECLAIMABLE,
52	MIGRATE_PCPTYPES, /* the number of types on the pcp lists */
53	MIGRATE_HIGHATOMIC = MIGRATE_PCPTYPES,
54	#ifdef CONFIG_CMA
55	/*
56	* MIGRATE_CMA migration type is designed to mimic the way
57	* ZONE_MOVABLE works. Only movable pages can be allocated
58	* from MIGRATE_CMA pageblocks and page allocator never
59	* implicitly change migration type of MIGRATE_CMA pageblock.
60	*
61	* The way to use it is to change migratetype of a range of
62	* pageblocks to MIGRATE_CMA which can be done by
63	* __free_pageblock_cma() function.
64	*/
65	MIGRATE_CMA,
66	#endif
67	#ifdef CONFIG_MEMORY_ISOLATION
68	MIGRATE_ISOLATE, /* can't allocate from here */
69	#endif
70	MIGRATE_TYPES
71	};
72
73	/* In mm/page_alloc.c; keep in sync also with show_migration_types() there */
74	extern const char * const migratetype_names[MIGRATE_TYPES];
75
76	#ifdef CONFIG_CMA
77	# define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA)
78	# define is_migrate_cma_page(_page) (get_pageblock_migratetype(_page) == MIGRATE_CMA)
79	# define is_migrate_cma_folio(folio, pfn) (MIGRATE_CMA == \
80	get_pfnblock_flags_mask(&folio->page, pfn, MIGRATETYPE_MASK))
81	#else
82	# define is_migrate_cma(migratetype) false
83	# define is_migrate_cma_page(_page) false
84	# define is_migrate_cma_folio(folio, pfn) false
85	#endif
86
87	static inline bool is_migrate_movable(int mt)
88	{
89	return is_migrate_cma(mt) || mt == MIGRATE_MOVABLE;
90	}
91
92	/*
93	* Check whether a migratetype can be merged with another migratetype.
94	*
95	* It is only mergeable when it can fall back to other migratetypes for
96	* allocation. See fallbacks[MIGRATE_TYPES][3] in page_alloc.c.
97	*/
98	static inline bool migratetype_is_mergeable(int mt)
99	{
100	return mt < MIGRATE_PCPTYPES;
101	}
102
103	#define for_each_migratetype_order(order, type) \
104	for (order = 0; order < NR_PAGE_ORDERS; order++) \
105	for (type = 0; type < MIGRATE_TYPES; type++)
106
107	extern int page_group_by_mobility_disabled;
108
109	#define MIGRATETYPE_MASK ((1UL << PB_migratetype_bits) - 1)
110
111	#define get_pageblock_migratetype(page) \
112	get_pfnblock_flags_mask(page, page_to_pfn(page), MIGRATETYPE_MASK)
113
114	#define folio_migratetype(folio) \
115	get_pfnblock_flags_mask(&folio->page, folio_pfn(folio), \
116	MIGRATETYPE_MASK)
117	struct free_area {
118	struct list_head free_list[MIGRATE_TYPES];
119	unsigned long nr_free;
120	};
121
122	struct pglist_data;
123
124	#ifdef CONFIG_NUMA
125	enum numa_stat_item {
126	NUMA_HIT, /* allocated in intended node */
127	NUMA_MISS, /* allocated in non intended node */
128	NUMA_FOREIGN, /* was intended here, hit elsewhere */
129	NUMA_INTERLEAVE_HIT, /* interleaver preferred this zone */
130	NUMA_LOCAL, /* allocation from local node */
131	NUMA_OTHER, /* allocation from other node */
132	NR_VM_NUMA_EVENT_ITEMS
133	};
134	#else
135	#define NR_VM_NUMA_EVENT_ITEMS 0
136	#endif
137
138	enum zone_stat_item {
139	/* First 128 byte cacheline (assuming 64 bit words) */
140	NR_FREE_PAGES,
141	NR_ZONE_LRU_BASE, /* Used only for compaction and reclaim retry */
142	NR_ZONE_INACTIVE_ANON = NR_ZONE_LRU_BASE,
143	NR_ZONE_ACTIVE_ANON,
144	NR_ZONE_INACTIVE_FILE,
145	NR_ZONE_ACTIVE_FILE,
146	NR_ZONE_UNEVICTABLE,
147	NR_ZONE_WRITE_PENDING, /* Count of dirty, writeback and unstable pages */
148	NR_MLOCK, /* mlock()ed pages found and moved off LRU */
149	/* Second 128 byte cacheline */
150	NR_BOUNCE,
151	#if IS_ENABLED(CONFIG_ZSMALLOC)
152	NR_ZSPAGES, /* allocated in zsmalloc */
153	#endif
154	NR_FREE_CMA_PAGES,
155	#ifdef CONFIG_UNACCEPTED_MEMORY
156	NR_UNACCEPTED,
157	#endif
158	NR_VM_ZONE_STAT_ITEMS };
159
160	enum node_stat_item {
161	NR_LRU_BASE,
162	NR_INACTIVE_ANON = NR_LRU_BASE, /* must match order of LRU_[IN]ACTIVE */
163	NR_ACTIVE_ANON, /* " " " " " */
164	NR_INACTIVE_FILE, /* " " " " " */
165	NR_ACTIVE_FILE, /* " " " " " */
166	NR_UNEVICTABLE, /* " " " " " */
167	NR_SLAB_RECLAIMABLE_B,
168	NR_SLAB_UNRECLAIMABLE_B,
169	NR_ISOLATED_ANON, /* Temporary isolated pages from anon lru */
170	NR_ISOLATED_FILE, /* Temporary isolated pages from file lru */
171	WORKINGSET_NODES,
172	WORKINGSET_REFAULT_BASE,
173	WORKINGSET_REFAULT_ANON = WORKINGSET_REFAULT_BASE,
174	WORKINGSET_REFAULT_FILE,
175	WORKINGSET_ACTIVATE_BASE,
176	WORKINGSET_ACTIVATE_ANON = WORKINGSET_ACTIVATE_BASE,
177	WORKINGSET_ACTIVATE_FILE,
178	WORKINGSET_RESTORE_BASE,
179	WORKINGSET_RESTORE_ANON = WORKINGSET_RESTORE_BASE,
180	WORKINGSET_RESTORE_FILE,
181	WORKINGSET_NODERECLAIM,
182	NR_ANON_MAPPED, /* Mapped anonymous pages */
183	NR_FILE_MAPPED, /* pagecache pages mapped into pagetables.
184	only modified from process context */
185	NR_FILE_PAGES,
186	NR_FILE_DIRTY,
187	NR_WRITEBACK,
188	NR_WRITEBACK_TEMP, /* Writeback using temporary buffers */
189	NR_SHMEM, /* shmem pages (included tmpfs/GEM pages) */
190	NR_SHMEM_THPS,
191	NR_SHMEM_PMDMAPPED,
192	NR_FILE_THPS,
193	NR_FILE_PMDMAPPED,
194	NR_ANON_THPS,
195	NR_VMSCAN_WRITE,
196	NR_VMSCAN_IMMEDIATE, /* Prioritise for reclaim when writeback ends */
197	NR_DIRTIED, /* page dirtyings since bootup */
198	NR_WRITTEN, /* page writings since bootup */
199	NR_THROTTLED_WRITTEN, /* NR_WRITTEN while reclaim throttled */
200	NR_KERNEL_MISC_RECLAIMABLE, /* reclaimable non-slab kernel pages */
201	NR_FOLL_PIN_ACQUIRED, /* via: pin_user_page(), gup flag: FOLL_PIN */
202	NR_FOLL_PIN_RELEASED, /* pages returned via unpin_user_page() */
203	NR_KERNEL_STACK_KB, /* measured in KiB */
204	#if IS_ENABLED(CONFIG_SHADOW_CALL_STACK)
205	NR_KERNEL_SCS_KB, /* measured in KiB */
206	#endif
207	NR_PAGETABLE, /* used for pagetables */
208	NR_SECONDARY_PAGETABLE, /* secondary pagetables, e.g. KVM pagetables */
209	#ifdef CONFIG_SWAP
210	NR_SWAPCACHE,
211	#endif
212	#ifdef CONFIG_NUMA_BALANCING
213	PGPROMOTE_SUCCESS, /* promote successfully */
214	PGPROMOTE_CANDIDATE, /* candidate pages to promote */
215	#endif
216	/* PGDEMOTE_*: pages demoted */
217	PGDEMOTE_KSWAPD,
218	PGDEMOTE_DIRECT,
219	PGDEMOTE_KHUGEPAGED,
220	NR_VM_NODE_STAT_ITEMS
221	};
222
223	/*
224	* Returns true if the item should be printed in THPs (/proc/vmstat
225	* currently prints number of anon, file and shmem THPs. But the item
226	* is charged in pages).
227	*/
228	static __always_inline bool vmstat_item_print_in_thp(enum node_stat_item item)
229	{
230	if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
231	return false;
232
233	return item == NR_ANON_THPS ||
234	item == NR_FILE_THPS ||
235	item == NR_SHMEM_THPS ||
236	item == NR_SHMEM_PMDMAPPED ||
237	item == NR_FILE_PMDMAPPED;
238	}
239
240	/*
241	* Returns true if the value is measured in bytes (most vmstat values are
242	* measured in pages). This defines the API part, the internal representation
243	* might be different.
244	*/
245	static __always_inline bool vmstat_item_in_bytes(int idx)
246	{
247	/*
248	* Global and per-node slab counters track slab pages.
249	* It's expected that changes are multiples of PAGE_SIZE.
250	* Internally values are stored in pages.
251	*
252	* Per-memcg and per-lruvec counters track memory, consumed
253	* by individual slab objects. These counters are actually
254	* byte-precise.
255	*/
256	return (idx == NR_SLAB_RECLAIMABLE_B ||
257	idx == NR_SLAB_UNRECLAIMABLE_B);
258	}
259
260	/*
261	* We do arithmetic on the LRU lists in various places in the code,
262	* so it is important to keep the active lists LRU_ACTIVE higher in
263	* the array than the corresponding inactive lists, and to keep
264	* the *_FILE lists LRU_FILE higher than the corresponding _ANON lists.
265	*
266	* This has to be kept in sync with the statistics in zone_stat_item
267	* above and the descriptions in vmstat_text in mm/vmstat.c
268	*/
269	#define LRU_BASE 0
270	#define LRU_ACTIVE 1
271	#define LRU_FILE 2
272
273	enum lru_list {
274	LRU_INACTIVE_ANON = LRU_BASE,
275	LRU_ACTIVE_ANON = LRU_BASE + LRU_ACTIVE,
276	LRU_INACTIVE_FILE = LRU_BASE + LRU_FILE,
277	LRU_ACTIVE_FILE = LRU_BASE + LRU_FILE + LRU_ACTIVE,
278	LRU_UNEVICTABLE,
279	NR_LRU_LISTS
280	};
281
282	enum vmscan_throttle_state {
283	VMSCAN_THROTTLE_WRITEBACK,
284	VMSCAN_THROTTLE_ISOLATED,
285	VMSCAN_THROTTLE_NOPROGRESS,
286	VMSCAN_THROTTLE_CONGESTED,
287	NR_VMSCAN_THROTTLE,
288	};
289
290	#define for_each_lru(lru) for (lru = 0; lru < NR_LRU_LISTS; lru++)
291
292	#define for_each_evictable_lru(lru) for (lru = 0; lru <= LRU_ACTIVE_FILE; lru++)
293
294	static inline bool is_file_lru(enum lru_list lru)
295	{
296	return (lru == LRU_INACTIVE_FILE || lru == LRU_ACTIVE_FILE);
297	}
298
299	static inline bool is_active_lru(enum lru_list lru)
300	{
301	return (lru == LRU_ACTIVE_ANON || lru == LRU_ACTIVE_FILE);
302	}
303
304	#define WORKINGSET_ANON 0
305	#define WORKINGSET_FILE 1
306	#define ANON_AND_FILE 2
307
308	enum lruvec_flags {
309	/*
310	* An lruvec has many dirty pages backed by a congested BDI:
311	* 1. LRUVEC_CGROUP_CONGESTED is set by cgroup-level reclaim.
312	* It can be cleared by cgroup reclaim or kswapd.
313	* 2. LRUVEC_NODE_CONGESTED is set by kswapd node-level reclaim.
314	* It can only be cleared by kswapd.
315	*
316	* Essentially, kswapd can unthrottle an lruvec throttled by cgroup
317	* reclaim, but not vice versa. This only applies to the root cgroup.
318	* The goal is to prevent cgroup reclaim on the root cgroup (e.g.
319	* memory.reclaim) to unthrottle an unbalanced node (that was throttled
320	* by kswapd).
321	*/
322	LRUVEC_CGROUP_CONGESTED,
323	LRUVEC_NODE_CONGESTED,
324	};
325
326	#endif /* !__GENERATING_BOUNDS_H */
327
328	/*
329	* Evictable pages are divided into multiple generations. The youngest and the
330	* oldest generation numbers, max_seq and min_seq, are monotonically increasing.
331	* They form a sliding window of a variable size [MIN_NR_GENS, MAX_NR_GENS]. An
332	* offset within MAX_NR_GENS, i.e., gen, indexes the LRU list of the
333	* corresponding generation. The gen counter in folio->flags stores gen+1 while
334	* a page is on one of lrugen->folios[]. Otherwise it stores 0.
335	*
336	* A page is added to the youngest generation on faulting. The aging needs to
337	* check the accessed bit at least twice before handing this page over to the
338	* eviction. The first check takes care of the accessed bit set on the initial
339	* fault; the second check makes sure this page hasn't been used since then.
340	* This process, AKA second chance, requires a minimum of two generations,
341	* hence MIN_NR_GENS. And to maintain ABI compatibility with the active/inactive
342	* LRU, e.g., /proc/vmstat, these two generations are considered active; the
343	* rest of generations, if they exist, are considered inactive. See
344	* lru_gen_is_active().
345	*
346	* PG_active is always cleared while a page is on one of lrugen->folios[] so
347	* that the aging needs not to worry about it. And it's set again when a page
348	* considered active is isolated for non-reclaiming purposes, e.g., migration.
349	* See lru_gen_add_folio() and lru_gen_del_folio().
350	*
351	* MAX_NR_GENS is set to 4 so that the multi-gen LRU can support twice the
352	* number of categories of the active/inactive LRU when keeping track of
353	* accesses through page tables. This requires order_base_2(MAX_NR_GENS+1) bits
354	* in folio->flags.
355	*/
356	#define MIN_NR_GENS 2U
357	#define MAX_NR_GENS 4U
358
359	/*
360	* Each generation is divided into multiple tiers. A page accessed N times
361	* through file descriptors is in tier order_base_2(N). A page in the first tier
362	* (N=0,1) is marked by PG_referenced unless it was faulted in through page
363	* tables or read ahead. A page in any other tier (N>1) is marked by
364	* PG_referenced and PG_workingset. This implies a minimum of two tiers is
365	* supported without using additional bits in folio->flags.
366	*
367	* In contrast to moving across generations which requires the LRU lock, moving
368	* across tiers only involves atomic operations on folio->flags and therefore
369	* has a negligible cost in the buffered access path. In the eviction path,
370	* comparisons of refaulted/(evicted+protected) from the first tier and the
371	* rest infer whether pages accessed multiple times through file descriptors
372	* are statistically hot and thus worth protecting.
373	*
374	* MAX_NR_TIERS is set to 4 so that the multi-gen LRU can support twice the
375	* number of categories of the active/inactive LRU when keeping track of
376	* accesses through file descriptors. This uses MAX_NR_TIERS-2 spare bits in
377	* folio->flags.
378	*/
379	#define MAX_NR_TIERS 4U
380
381	#ifndef __GENERATING_BOUNDS_H
382
383	struct lruvec;
384	struct page_vma_mapped_walk;
385
386	#define LRU_GEN_MASK ((BIT(LRU_GEN_WIDTH) - 1) << LRU_GEN_PGOFF)
387	#define LRU_REFS_MASK ((BIT(LRU_REFS_WIDTH) - 1) << LRU_REFS_PGOFF)
388
389	#ifdef CONFIG_LRU_GEN
390
391	enum {
392	LRU_GEN_ANON,
393	LRU_GEN_FILE,
394	};
395
396	enum {
397	LRU_GEN_CORE,
398	LRU_GEN_MM_WALK,
399	LRU_GEN_NONLEAF_YOUNG,
400	NR_LRU_GEN_CAPS
401	};
402
403	#define MIN_LRU_BATCH BITS_PER_LONG
404	#define MAX_LRU_BATCH (MIN_LRU_BATCH * 64)
405
406	/* whether to keep historical stats from evicted generations */
407	#ifdef CONFIG_LRU_GEN_STATS
408	#define NR_HIST_GENS MAX_NR_GENS
409	#else
410	#define NR_HIST_GENS 1U
411	#endif
412
413	/*
414	* The youngest generation number is stored in max_seq for both anon and file
415	* types as they are aged on an equal footing. The oldest generation numbers are
416	* stored in min_seq[] separately for anon and file types as clean file pages
417	* can be evicted regardless of swap constraints.
418	*
419	* Normally anon and file min_seq are in sync. But if swapping is constrained,
420	* e.g., out of swap space, file min_seq is allowed to advance and leave anon
421	* min_seq behind.
422	*
423	* The number of pages in each generation is eventually consistent and therefore
424	* can be transiently negative when reset_batch_size() is pending.
425	*/
426	struct lru_gen_folio {
427	/* the aging increments the youngest generation number */
428	unsigned long max_seq;
429	/* the eviction increments the oldest generation numbers */
430	unsigned long min_seq[ANON_AND_FILE];
431	/* the birth time of each generation in jiffies */
432	unsigned long timestamps[MAX_NR_GENS];
433	/* the multi-gen LRU lists, lazily sorted on eviction */
434	struct list_head folios[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES];
435	/* the multi-gen LRU sizes, eventually consistent */
436	long nr_pages[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES];
437	/* the exponential moving average of refaulted */
438	unsigned long avg_refaulted[ANON_AND_FILE][MAX_NR_TIERS];
439	/* the exponential moving average of evicted+protected */
440	unsigned long avg_total[ANON_AND_FILE][MAX_NR_TIERS];
441	/* the first tier doesn't need protection, hence the minus one */
442	unsigned long protected[NR_HIST_GENS][ANON_AND_FILE][MAX_NR_TIERS - 1];
443	/* can be modified without holding the LRU lock */
444	atomic_long_t evicted[NR_HIST_GENS][ANON_AND_FILE][MAX_NR_TIERS];
445	atomic_long_t refaulted[NR_HIST_GENS][ANON_AND_FILE][MAX_NR_TIERS];
446	/* whether the multi-gen LRU is enabled */
447	bool enabled;
448	/* the memcg generation this lru_gen_folio belongs to */
449	u8 gen;
450	/* the list segment this lru_gen_folio belongs to */
451	u8 seg;
452	/* per-node lru_gen_folio list for global reclaim */
453	struct hlist_nulls_node list;
454	};
455
456	enum {
457	MM_LEAF_TOTAL, /* total leaf entries */
458	MM_LEAF_OLD, /* old leaf entries */
459	MM_LEAF_YOUNG, /* young leaf entries */
460	MM_NONLEAF_TOTAL, /* total non-leaf entries */
461	MM_NONLEAF_FOUND, /* non-leaf entries found in Bloom filters */
462	MM_NONLEAF_ADDED, /* non-leaf entries added to Bloom filters */
463	NR_MM_STATS
464	};
465
466	/* double-buffering Bloom filters */
467	#define NR_BLOOM_FILTERS 2
468
469	struct lru_gen_mm_state {
470	/* synced with max_seq after each iteration */
471	unsigned long seq;
472	/* where the current iteration continues after */
473	struct list_head *head;
474	/* where the last iteration ended before */
475	struct list_head *tail;
476	/* Bloom filters flip after each iteration */
477	unsigned long *filters[NR_BLOOM_FILTERS];
478	/* the mm stats for debugging */
479	unsigned long stats[NR_HIST_GENS][NR_MM_STATS];
480	};
481
482	struct lru_gen_mm_walk {
483	/* the lruvec under reclaim */
484	struct lruvec *lruvec;
485	/* max_seq from lru_gen_folio: can be out of date */
486	unsigned long seq;
487	/* the next address within an mm to scan */
488	unsigned long next_addr;
489	/* to batch promoted pages */
490	int nr_pages[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES];
491	/* to batch the mm stats */
492	int mm_stats[NR_MM_STATS];
493	/* total batched items */
494	int batched;
495	bool can_swap;
496	bool force_scan;
497	};
498
499	/*
500	* For each node, memcgs are divided into two generations: the old and the
501	* young. For each generation, memcgs are randomly sharded into multiple bins
502	* to improve scalability. For each bin, the hlist_nulls is virtually divided
503	* into three segments: the head, the tail and the default.
504	*
505	* An onlining memcg is added to the tail of a random bin in the old generation.
506	* The eviction starts at the head of a random bin in the old generation. The
507	* per-node memcg generation counter, whose reminder (mod MEMCG_NR_GENS) indexes
508	* the old generation, is incremented when all its bins become empty.
509	*
510	* There are four operations:
511	* 1. MEMCG_LRU_HEAD, which moves a memcg to the head of a random bin in its
512	* current generation (old or young) and updates its "seg" to "head";
513	* 2. MEMCG_LRU_TAIL, which moves a memcg to the tail of a random bin in its
514	* current generation (old or young) and updates its "seg" to "tail";
515	* 3. MEMCG_LRU_OLD, which moves a memcg to the head of a random bin in the old
516	* generation, updates its "gen" to "old" and resets its "seg" to "default";
517	* 4. MEMCG_LRU_YOUNG, which moves a memcg to the tail of a random bin in the
518	* young generation, updates its "gen" to "young" and resets its "seg" to
519	* "default".
520	*
521	* The events that trigger the above operations are:
522	* 1. Exceeding the soft limit, which triggers MEMCG_LRU_HEAD;
523	* 2. The first attempt to reclaim a memcg below low, which triggers
524	* MEMCG_LRU_TAIL;
525	* 3. The first attempt to reclaim a memcg offlined or below reclaimable size
526	* threshold, which triggers MEMCG_LRU_TAIL;
527	* 4. The second attempt to reclaim a memcg offlined or below reclaimable size
528	* threshold, which triggers MEMCG_LRU_YOUNG;
529	* 5. Attempting to reclaim a memcg below min, which triggers MEMCG_LRU_YOUNG;
530	* 6. Finishing the aging on the eviction path, which triggers MEMCG_LRU_YOUNG;
531	* 7. Offlining a memcg, which triggers MEMCG_LRU_OLD.
532	*
533	* Notes:
534	* 1. Memcg LRU only applies to global reclaim, and the round-robin incrementing
535	* of their max_seq counters ensures the eventual fairness to all eligible
536	* memcgs. For memcg reclaim, it still relies on mem_cgroup_iter().
537	* 2. There are only two valid generations: old (seq) and young (seq+1).
538	* MEMCG_NR_GENS is set to three so that when reading the generation counter
539	* locklessly, a stale value (seq-1) does not wraparound to young.
540	*/
541	#define MEMCG_NR_GENS 3
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_folio per node */
548	unsigned long nr_memcgs[MEMCG_NR_GENS];
549	/* per-node lru_gen_folio 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
555	void lru_gen_init_pgdat(struct pglist_data *pgdat);
556	void lru_gen_init_lruvec(struct lruvec *lruvec);
557	void lru_gen_look_around(struct page_vma_mapped_walk *pvmw);
558
559	void lru_gen_init_memcg(struct mem_cgroup *memcg);
560	void lru_gen_exit_memcg(struct mem_cgroup *memcg);
561	void lru_gen_online_memcg(struct mem_cgroup *memcg);
562	void lru_gen_offline_memcg(struct mem_cgroup *memcg);
563	void lru_gen_release_memcg(struct mem_cgroup *memcg);
564	void lru_gen_soft_reclaim(struct mem_cgroup *memcg, int nid);
565
566	#else /* !CONFIG_LRU_GEN */
567
568	static inline void lru_gen_init_pgdat(struct pglist_data *pgdat)
569	{
570	}
571
572	static inline void lru_gen_init_lruvec(struct lruvec *lruvec)
573	{
574	}
575
576	static inline void lru_gen_look_around(struct page_vma_mapped_walk *pvmw)
577	{
578	}
579
580	static inline void lru_gen_init_memcg(struct mem_cgroup *memcg)
581	{
582	}
583
584	static inline void lru_gen_exit_memcg(struct mem_cgroup *memcg)
585	{
586	}
587
588	static inline void lru_gen_online_memcg(struct mem_cgroup *memcg)
589	{
590	}
591
592	static inline void lru_gen_offline_memcg(struct mem_cgroup *memcg)
593	{
594	}
595
596	static inline void lru_gen_release_memcg(struct mem_cgroup *memcg)
597	{
598	}
599
600	static inline void lru_gen_soft_reclaim(struct mem_cgroup *memcg, int nid)
601	{
602	}
603
604	#endif /* CONFIG_LRU_GEN */
605
606	struct lruvec {
607	struct list_head lists[NR_LRU_LISTS];
608	/* per lruvec lru_lock for memcg */
609	spinlock_t lru_lock;
610	/*
611	* These track the cost of reclaiming one LRU - file or anon -
612	* over the other. As the observed cost of reclaiming one LRU
613	* increases, the reclaim scan balance tips toward the other.
614	*/
615	unsigned long anon_cost;
616	unsigned long file_cost;
617	/* Non-resident age, driven by LRU movement */
618	atomic_long_t nonresident_age;
619	/* Refaults at the time of last reclaim cycle */
620	unsigned long refaults[ANON_AND_FILE];
621	/* Various lruvec state flags (enum lruvec_flags) */
622	unsigned long flags;
623	#ifdef CONFIG_LRU_GEN
624	/* evictable pages divided into generations */
625	struct lru_gen_folio lrugen;
626	#ifdef CONFIG_LRU_GEN_WALKS_MMU
627	/* to concurrently iterate lru_gen_mm_list */
628	struct lru_gen_mm_state mm_state;
629	#endif
630	#endif /* CONFIG_LRU_GEN */
631	#ifdef CONFIG_MEMCG
632	struct pglist_data *pgdat;
633	#endif
634	struct zswap_lruvec_state zswap_lruvec_state;
635	};
636
637	/* Isolate for asynchronous migration */
638	#define ISOLATE_ASYNC_MIGRATE ((__force isolate_mode_t)0x4)
639	/* Isolate unevictable pages */
640	#define ISOLATE_UNEVICTABLE ((__force isolate_mode_t)0x8)
641
642	/* LRU Isolation modes. */
643	typedef unsigned __bitwise isolate_mode_t;
644
645	enum zone_watermarks {
646	WMARK_MIN,
647	WMARK_LOW,
648	WMARK_HIGH,
649	WMARK_PROMO,
650	NR_WMARK
651	};
652
653	/*
654	* One per migratetype for each PAGE_ALLOC_COSTLY_ORDER. One additional list
655	* for THP which will usually be GFP_MOVABLE. Even if it is another type,
656	* it should not contribute to serious fragmentation causing THP allocation
657	* failures.
658	*/
659	#ifdef CONFIG_TRANSPARENT_HUGEPAGE
660	#define NR_PCP_THP 1
661	#else
662	#define NR_PCP_THP 0
663	#endif
664	#define NR_LOWORDER_PCP_LISTS (MIGRATE_PCPTYPES * (PAGE_ALLOC_COSTLY_ORDER + 1))
665	#define NR_PCP_LISTS (NR_LOWORDER_PCP_LISTS + NR_PCP_THP)
666
667	#define min_wmark_pages(z) (z->_watermark[WMARK_MIN] + z->watermark_boost)
668	#define low_wmark_pages(z) (z->_watermark[WMARK_LOW] + z->watermark_boost)
669	#define high_wmark_pages(z) (z->_watermark[WMARK_HIGH] + z->watermark_boost)
670	#define wmark_pages(z, i) (z->_watermark[i] + z->watermark_boost)
671
672	/*
673	* Flags used in pcp->flags field.
674	*
675	* PCPF_PREV_FREE_HIGH_ORDER: a high-order page is freed in the
676	* previous page freeing. To avoid to drain PCP for an accident
677	* high-order page freeing.
678	*
679	* PCPF_FREE_HIGH_BATCH: preserve "pcp->batch" pages in PCP before
680	* draining PCP for consecutive high-order pages freeing without
681	* allocation if data cache slice of CPU is large enough. To reduce
682	* zone lock contention and keep cache-hot pages reusing.
683	*/
684	#define PCPF_PREV_FREE_HIGH_ORDER BIT(0)
685	#define PCPF_FREE_HIGH_BATCH BIT(1)
686
687	struct per_cpu_pages {
688	spinlock_t lock; /* Protects lists field */
689	int count; /* number of pages in the list */
690	int high; /* high watermark, emptying needed */
691	int high_min; /* min high watermark */
692	int high_max; /* max high watermark */
693	int batch; /* chunk size for buddy add/remove */
694	u8 flags; /* protected by pcp->lock */
695	u8 alloc_factor; /* batch scaling factor during allocate */
696	#ifdef CONFIG_NUMA
697	u8 expire; /* When 0, remote pagesets are drained */
698	#endif
699	short free_count; /* consecutive free count */
700
701	/* Lists of pages, one per migrate type stored on the pcp-lists */
702	struct list_head lists[NR_PCP_LISTS];
703	} ____cacheline_aligned_in_smp;
704
705	struct per_cpu_zonestat {
706	#ifdef CONFIG_SMP
707	s8 vm_stat_diff[NR_VM_ZONE_STAT_ITEMS];
708	s8 stat_threshold;
709	#endif
710	#ifdef CONFIG_NUMA
711	/*
712	* Low priority inaccurate counters that are only folded
713	* on demand. Use a large type to avoid the overhead of
714	* folding during refresh_cpu_vm_stats.
715	*/
716	unsigned long vm_numa_event[NR_VM_NUMA_EVENT_ITEMS];
717	#endif
718	};
719
720	struct per_cpu_nodestat {
721	s8 stat_threshold;
722	s8 vm_node_stat_diff[NR_VM_NODE_STAT_ITEMS];
723	};
724
725	#endif /* !__GENERATING_BOUNDS.H */
726
727	enum zone_type {
728	/*
729	* ZONE_DMA and ZONE_DMA32 are used when there are peripherals not able
730	* to DMA to all of the addressable memory (ZONE_NORMAL).
731	* On architectures where this area covers the whole 32 bit address
732	* space ZONE_DMA32 is used. ZONE_DMA is left for the ones with smaller
733	* DMA addressing constraints. This distinction is important as a 32bit
734	* DMA mask is assumed when ZONE_DMA32 is defined. Some 64-bit
735	* platforms may need both zones as they support peripherals with
736	* different DMA addressing limitations.
737	*/
738	#ifdef CONFIG_ZONE_DMA
739	ZONE_DMA,
740	#endif
741	#ifdef CONFIG_ZONE_DMA32
742	ZONE_DMA32,
743	#endif
744	/*
745	* Normal addressable memory is in ZONE_NORMAL. DMA operations can be
746	* performed on pages in ZONE_NORMAL if the DMA devices support
747	* transfers to all addressable memory.
748	*/
749	ZONE_NORMAL,
750	#ifdef CONFIG_HIGHMEM
751	/*
752	* A memory area that is only addressable by the kernel through
753	* mapping portions into its own address space. This is for example
754	* used by i386 to allow the kernel to address the memory beyond
755	* 900MB. The kernel will set up special mappings (page
756	* table entries on i386) for each page that the kernel needs to
757	* access.
758	*/
759	ZONE_HIGHMEM,
760	#endif
761	/*
762	* ZONE_MOVABLE is similar to ZONE_NORMAL, except that it contains
763	* movable pages with few exceptional cases described below. Main use
764	* cases for ZONE_MOVABLE are to make memory offlining/unplug more
765	* likely to succeed, and to locally limit unmovable allocations - e.g.,
766	* to increase the number of THP/huge pages. Notable special cases are:
767	*
768	* 1. Pinned pages: (long-term) pinning of movable pages might
769	* essentially turn such pages unmovable. Therefore, we do not allow
770	* pinning long-term pages in ZONE_MOVABLE. When pages are pinned and
771	* faulted, they come from the right zone right away. However, it is
772	* still possible that address space already has pages in
773	* ZONE_MOVABLE at the time when pages are pinned (i.e. user has
774	* touches that memory before pinning). In such case we migrate them
775	* to a different zone. When migration fails - pinning fails.
776	* 2. memblock allocations: kernelcore/movablecore setups might create
777	* situations where ZONE_MOVABLE contains unmovable allocations
778	* after boot. Memory offlining and allocations fail early.
779	* 3. Memory holes: kernelcore/movablecore setups might create very rare
780	* situations where ZONE_MOVABLE contains memory holes after boot,
781	* for example, if we have sections that are only partially
782	* populated. Memory offlining and allocations fail early.
783	* 4. PG_hwpoison pages: while poisoned pages can be skipped during
784	* memory offlining, such pages cannot be allocated.
785	* 5. Unmovable PG_offline pages: in paravirtualized environments,
786	* hotplugged memory blocks might only partially be managed by the
787	* buddy (e.g., via XEN-balloon, Hyper-V balloon, virtio-mem). The
788	* parts not manged by the buddy are unmovable PG_offline pages. In
789	* some cases (virtio-mem), such pages can be skipped during
790	* memory offlining, however, cannot be moved/allocated. These
791	* techniques might use alloc_contig_range() to hide previously
792	* exposed pages from the buddy again (e.g., to implement some sort
793	* of memory unplug in virtio-mem).
794	* 6. ZERO_PAGE(0), kernelcore/movablecore setups might create
795	* situations where ZERO_PAGE(0) which is allocated differently
796	* on different platforms may end up in a movable zone. ZERO_PAGE(0)
797	* cannot be migrated.
798	* 7. Memory-hotplug: when using memmap_on_memory and onlining the
799	* memory to the MOVABLE zone, the vmemmap pages are also placed in
800	* such zone. Such pages cannot be really moved around as they are
801	* self-stored in the range, but they are treated as movable when
802	* the range they describe is about to be offlined.
803	*
804	* In general, no unmovable allocations that degrade memory offlining
805	* should end up in ZONE_MOVABLE. Allocators (like alloc_contig_range())
806	* have to expect that migrating pages in ZONE_MOVABLE can fail (even
807	* if has_unmovable_pages() states that there are no unmovable pages,
808	* there can be false negatives).
809	*/
810	ZONE_MOVABLE,
811	#ifdef CONFIG_ZONE_DEVICE
812	ZONE_DEVICE,
813	#endif
814	__MAX_NR_ZONES
815
816	};
817
818	#ifndef __GENERATING_BOUNDS_H
819
820	#define ASYNC_AND_SYNC 2
821
822	struct zone {
823	/* Read-mostly fields */
824
825	/* zone watermarks, access with *_wmark_pages(zone) macros */
826	unsigned long _watermark[NR_WMARK];
827	unsigned long watermark_boost;
828
829	unsigned long nr_reserved_highatomic;
830
831	/*
832	* We don't know if the memory that we're going to allocate will be
833	* freeable or/and it will be released eventually, so to avoid totally
834	* wasting several GB of ram we must reserve some of the lower zone
835	* memory (otherwise we risk to run OOM on the lower zones despite
836	* there being tons of freeable ram on the higher zones). This array is
837	* recalculated at runtime if the sysctl_lowmem_reserve_ratio sysctl
838	* changes.
839	*/
840	long lowmem_reserve[MAX_NR_ZONES];
841
842	#ifdef CONFIG_NUMA
843	int node;
844	#endif
845	struct pglist_data *zone_pgdat;
846	struct per_cpu_pages __percpu *per_cpu_pageset;
847	struct per_cpu_zonestat __percpu *per_cpu_zonestats;
848	/*
849	* the high and batch values are copied to individual pagesets for
850	* faster access
851	*/
852	int pageset_high_min;
853	int pageset_high_max;
854	int pageset_batch;
855
856	#ifndef CONFIG_SPARSEMEM
857	/*
858	* Flags for a pageblock_nr_pages block. See pageblock-flags.h.
859	* In SPARSEMEM, this map is stored in struct mem_section
860	*/
861	unsigned long *pageblock_flags;
862	#endif /* CONFIG_SPARSEMEM */
863
864	/* zone_start_pfn == zone_start_paddr >> PAGE_SHIFT */
865	unsigned long zone_start_pfn;
866
867	/*
868	* spanned_pages is the total pages spanned by the zone, including
869	* holes, which is calculated as:
870	* spanned_pages = zone_end_pfn - zone_start_pfn;
871	*
872	* present_pages is physical pages existing within the zone, which
873	* is calculated as:
874	* present_pages = spanned_pages - absent_pages(pages in holes);
875	*
876	* present_early_pages is present pages existing within the zone
877	* located on memory available since early boot, excluding hotplugged
878	* memory.
879	*
880	* managed_pages is present pages managed by the buddy system, which
881	* is calculated as (reserved_pages includes pages allocated by the
882	* bootmem allocator):
883	* managed_pages = present_pages - reserved_pages;
884	*
885	* cma pages is present pages that are assigned for CMA use
886	* (MIGRATE_CMA).
887	*
888	* So present_pages may be used by memory hotplug or memory power
889	* management logic to figure out unmanaged pages by checking
890	* (present_pages - managed_pages). And managed_pages should be used
891	* by page allocator and vm scanner to calculate all kinds of watermarks
892	* and thresholds.
893	*
894	* Locking rules:
895	*
896	* zone_start_pfn and spanned_pages are protected by span_seqlock.
897	* It is a seqlock because it has to be read outside of zone->lock,
898	* and it is done in the main allocator path. But, it is written
899	* quite infrequently.
900	*
901	* The span_seq lock is declared along with zone->lock because it is
902	* frequently read in proximity to zone->lock. It's good to
903	* give them a chance of being in the same cacheline.
904	*
905	* Write access to present_pages at runtime should be protected by
906	* mem_hotplug_begin/done(). Any reader who can't tolerant drift of
907	* present_pages should use get_online_mems() to get a stable value.
908	*/
909	atomic_long_t managed_pages;
910	unsigned long spanned_pages;
911	unsigned long present_pages;
912	#if defined(CONFIG_MEMORY_HOTPLUG)
913	unsigned long present_early_pages;
914	#endif
915	#ifdef CONFIG_CMA
916	unsigned long cma_pages;
917	#endif
918
919	const char *name;
920
921	#ifdef CONFIG_MEMORY_ISOLATION
922	/*
923	* Number of isolated pageblock. It is used to solve incorrect
924	* freepage counting problem due to racy retrieving migratetype
925	* of pageblock. Protected by zone->lock.
926	*/
927	unsigned long nr_isolate_pageblock;
928	#endif
929
930	#ifdef CONFIG_MEMORY_HOTPLUG
931	/* see spanned/present_pages for more description */
932	seqlock_t span_seqlock;
933	#endif
934
935	int initialized;
936
937	/* Write-intensive fields used from the page allocator */
938	CACHELINE_PADDING(_pad1_);
939
940	/* free areas of different sizes */
941	struct free_area free_area[NR_PAGE_ORDERS];
942
943	#ifdef CONFIG_UNACCEPTED_MEMORY
944	/* Pages to be accepted. All pages on the list are MAX_PAGE_ORDER */
945	struct list_head unaccepted_pages;
946	#endif
947
948	/* zone flags, see below */
949	unsigned long flags;
950
951	/* Primarily protects free_area */
952	spinlock_t lock;
953
954	/* Write-intensive fields used by compaction and vmstats. */
955	CACHELINE_PADDING(_pad2_);
956
957	/*
958	* When free pages are below this point, additional steps are taken
959	* when reading the number of free pages to avoid per-cpu counter
960	* drift allowing watermarks to be breached
961	*/
962	unsigned long percpu_drift_mark;
963
964	#if defined CONFIG_COMPACTION || defined CONFIG_CMA
965	/* pfn where compaction free scanner should start */
966	unsigned long compact_cached_free_pfn;
967	/* pfn where compaction migration scanner should start */
968	unsigned long compact_cached_migrate_pfn[ASYNC_AND_SYNC];
969	unsigned long compact_init_migrate_pfn;
970	unsigned long compact_init_free_pfn;
971	#endif
972
973	#ifdef CONFIG_COMPACTION
974	/*
975	* On compaction failure, 1<<compact_defer_shift compactions
976	* are skipped before trying again. The number attempted since
977	* last failure is tracked with compact_considered.
978	* compact_order_failed is the minimum compaction failed order.
979	*/
980	unsigned int compact_considered;
981	unsigned int compact_defer_shift;
982	int compact_order_failed;
983	#endif
984
985	#if defined CONFIG_COMPACTION || defined CONFIG_CMA
986	/* Set to true when the PG_migrate_skip bits should be cleared */
987	bool compact_blockskip_flush;
988	#endif
989
990	bool contiguous;
991
992	CACHELINE_PADDING(_pad3_);
993	/* Zone statistics */
994	atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
995	atomic_long_t vm_numa_event[NR_VM_NUMA_EVENT_ITEMS];
996	} ____cacheline_internodealigned_in_smp;
997
998	enum pgdat_flags {
999	PGDAT_DIRTY, /* reclaim scanning has recently found
1000	* many dirty file pages at the tail
1001	* of the LRU.
1002	*/
1003	PGDAT_WRITEBACK, /* reclaim scanning has recently found
1004	* many pages under writeback
1005	*/
1006	PGDAT_RECLAIM_LOCKED, /* prevents concurrent reclaim */
1007	};
1008
1009	enum zone_flags {
1010	ZONE_BOOSTED_WATERMARK, /* zone recently boosted watermarks.
1011	* Cleared when kswapd is woken.
1012	*/
1013	ZONE_RECLAIM_ACTIVE, /* kswapd may be scanning the zone. */
1014	ZONE_BELOW_HIGH, /* zone is below high watermark. */
1015	};
1016
1017	static inline unsigned long zone_managed_pages(struct zone *zone)
1018	{
1019	return (unsigned long)atomic_long_read(v: &zone->managed_pages);
1020	}
1021
1022	static inline unsigned long zone_cma_pages(struct zone *zone)
1023	{
1024	#ifdef CONFIG_CMA
1025	return zone->cma_pages;
1026	#else
1027	return 0;
1028	#endif
1029	}
1030
1031	static inline unsigned long zone_end_pfn(const struct zone *zone)
1032	{
1033	return zone->zone_start_pfn + zone->spanned_pages;
1034	}
1035
1036	static inline bool zone_spans_pfn(const struct zone *zone, unsigned long pfn)
1037	{
1038	return zone->zone_start_pfn <= pfn && pfn < zone_end_pfn(zone);
1039	}
1040
1041	static inline bool zone_is_initialized(struct zone *zone)
1042	{
1043	return zone->initialized;
1044	}
1045
1046	static inline bool zone_is_empty(struct zone *zone)
1047	{
1048	return zone->spanned_pages == 0;
1049	}
1050
1051	#ifndef BUILD_VDSO32_64
1052	/*
1053	* The zone field is never updated after free_area_init_core()
1054	* sets it, so none of the operations on it need to be atomic.
1055	*/
1056
1057	/* Page flags: | [SECTION] | [NODE] | ZONE | [LAST_CPUPID] | ... | FLAGS | */
1058	#define SECTIONS_PGOFF ((sizeof(unsigned long)*8) - SECTIONS_WIDTH)
1059	#define NODES_PGOFF (SECTIONS_PGOFF - NODES_WIDTH)
1060	#define ZONES_PGOFF (NODES_PGOFF - ZONES_WIDTH)
1061	#define LAST_CPUPID_PGOFF (ZONES_PGOFF - LAST_CPUPID_WIDTH)
1062	#define KASAN_TAG_PGOFF (LAST_CPUPID_PGOFF - KASAN_TAG_WIDTH)
1063	#define LRU_GEN_PGOFF (KASAN_TAG_PGOFF - LRU_GEN_WIDTH)
1064	#define LRU_REFS_PGOFF (LRU_GEN_PGOFF - LRU_REFS_WIDTH)
1065
1066	/*
1067	* Define the bit shifts to access each section. For non-existent
1068	* sections we define the shift as 0; that plus a 0 mask ensures
1069	* the compiler will optimise away reference to them.
1070	*/
1071	#define SECTIONS_PGSHIFT (SECTIONS_PGOFF * (SECTIONS_WIDTH != 0))
1072	#define NODES_PGSHIFT (NODES_PGOFF * (NODES_WIDTH != 0))
1073	#define ZONES_PGSHIFT (ZONES_PGOFF * (ZONES_WIDTH != 0))
1074	#define LAST_CPUPID_PGSHIFT (LAST_CPUPID_PGOFF * (LAST_CPUPID_WIDTH != 0))
1075	#define KASAN_TAG_PGSHIFT (KASAN_TAG_PGOFF * (KASAN_TAG_WIDTH != 0))
1076
1077	/* NODE:ZONE or SECTION:ZONE is used to ID a zone for the buddy allocator */
1078	#ifdef NODE_NOT_IN_PAGE_FLAGS
1079	#define ZONEID_SHIFT (SECTIONS_SHIFT + ZONES_SHIFT)
1080	#define ZONEID_PGOFF ((SECTIONS_PGOFF < ZONES_PGOFF) ? \
1081	SECTIONS_PGOFF : ZONES_PGOFF)
1082	#else
1083	#define ZONEID_SHIFT (NODES_SHIFT + ZONES_SHIFT)
1084	#define ZONEID_PGOFF ((NODES_PGOFF < ZONES_PGOFF) ? \
1085	NODES_PGOFF : ZONES_PGOFF)
1086	#endif
1087
1088	#define ZONEID_PGSHIFT (ZONEID_PGOFF * (ZONEID_SHIFT != 0))
1089
1090	#define ZONES_MASK ((1UL << ZONES_WIDTH) - 1)
1091	#define NODES_MASK ((1UL << NODES_WIDTH) - 1)
1092	#define SECTIONS_MASK ((1UL << SECTIONS_WIDTH) - 1)
1093	#define LAST_CPUPID_MASK ((1UL << LAST_CPUPID_SHIFT) - 1)
1094	#define KASAN_TAG_MASK ((1UL << KASAN_TAG_WIDTH) - 1)
1095	#define ZONEID_MASK ((1UL << ZONEID_SHIFT) - 1)
1096
1097	static inline enum zone_type page_zonenum(const struct page *page)
1098	{
1099	ASSERT_EXCLUSIVE_BITS(page->flags, ZONES_MASK << ZONES_PGSHIFT);
1100	return (page->flags >> ZONES_PGSHIFT) & ZONES_MASK;
1101	}
1102
1103	static inline enum zone_type folio_zonenum(const struct folio *folio)
1104	{
1105	return page_zonenum(page: &folio->page);
1106	}
1107
1108	#ifdef CONFIG_ZONE_DEVICE
1109	static inline bool is_zone_device_page(const struct page *page)
1110	{
1111	return page_zonenum(page) == ZONE_DEVICE;
1112	}
1113
1114	/*
1115	* Consecutive zone device pages should not be merged into the same sgl
1116	* or bvec segment with other types of pages or if they belong to different
1117	* pgmaps. Otherwise getting the pgmap of a given segment is not possible
1118	* without scanning the entire segment. This helper returns true either if
1119	* both pages are not zone device pages or both pages are zone device pages
1120	* with the same pgmap.
1121	*/
1122	static inline bool zone_device_pages_have_same_pgmap(const struct page *a,
1123	const struct page *b)
1124	{
1125	if (is_zone_device_page(page: a) != is_zone_device_page(page: b))
1126	return false;
1127	if (!is_zone_device_page(page: a))
1128	return true;
1129	return a->pgmap == b->pgmap;
1130	}
1131
1132	extern void memmap_init_zone_device(struct zone *, unsigned long,
1133	unsigned long, struct dev_pagemap *);
1134	#else
1135	static inline bool is_zone_device_page(const struct page *page)
1136	{
1137	return false;
1138	}
1139	static inline bool zone_device_pages_have_same_pgmap(const struct page *a,
1140	const struct page *b)
1141	{
1142	return true;
1143	}
1144	#endif
1145
1146	static inline bool folio_is_zone_device(const struct folio *folio)
1147	{
1148	return is_zone_device_page(page: &folio->page);
1149	}
1150
1151	static inline bool is_zone_movable_page(const struct page *page)
1152	{
1153	return page_zonenum(page) == ZONE_MOVABLE;
1154	}
1155
1156	static inline bool folio_is_zone_movable(const struct folio *folio)
1157	{
1158	return folio_zonenum(folio) == ZONE_MOVABLE;
1159	}
1160	#endif
1161
1162	/*
1163	* Return true if [start_pfn, start_pfn + nr_pages) range has a non-empty
1164	* intersection with the given zone
1165	*/
1166	static inline bool zone_intersects(struct zone *zone,
1167	unsigned long start_pfn, unsigned long nr_pages)
1168	{
1169	if (zone_is_empty(zone))
1170	return false;
1171	if (start_pfn >= zone_end_pfn(zone) ||
1172	start_pfn + nr_pages <= zone->zone_start_pfn)
1173	return false;
1174
1175	return true;
1176	}
1177
1178	/*
1179	* The "priority" of VM scanning is how much of the queues we will scan in one
1180	* go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the
1181	* queues ("queue_length >> 12") during an aging round.
1182	*/
1183	#define DEF_PRIORITY 12
1184
1185	/* Maximum number of zones on a zonelist */
1186	#define MAX_ZONES_PER_ZONELIST (MAX_NUMNODES * MAX_NR_ZONES)
1187
1188	enum {
1189	ZONELIST_FALLBACK, /* zonelist with fallback */
1190	#ifdef CONFIG_NUMA
1191	/*
1192	* The NUMA zonelists are doubled because we need zonelists that
1193	* restrict the allocations to a single node for __GFP_THISNODE.
1194	*/
1195	ZONELIST_NOFALLBACK, /* zonelist without fallback (__GFP_THISNODE) */
1196	#endif
1197	MAX_ZONELISTS
1198	};
1199
1200	/*
1201	* This struct contains information about a zone in a zonelist. It is stored
1202	* here to avoid dereferences into large structures and lookups of tables
1203	*/
1204	struct zoneref {
1205	struct zone *zone; /* Pointer to actual zone */
1206	int zone_idx; /* zone_idx(zoneref->zone) */
1207	};
1208
1209	/*
1210	* One allocation request operates on a zonelist. A zonelist
1211	* is a list of zones, the first one is the 'goal' of the
1212	* allocation, the other zones are fallback zones, in decreasing
1213	* priority.
1214	*
1215	* To speed the reading of the zonelist, the zonerefs contain the zone index
1216	* of the entry being read. Helper functions to access information given
1217	* a struct zoneref are
1218	*
1219	* zonelist_zone() - Return the struct zone * for an entry in _zonerefs
1220	* zonelist_zone_idx() - Return the index of the zone for an entry
1221	* zonelist_node_idx() - Return the index of the node for an entry
1222	*/
1223	struct zonelist {
1224	struct zoneref _zonerefs[MAX_ZONES_PER_ZONELIST + 1];
1225	};
1226
1227	/*
1228	* The array of struct pages for flatmem.
1229	* It must be declared for SPARSEMEM as well because there are configurations
1230	* that rely on that.
1231	*/
1232	extern struct page *mem_map;
1233
1234	#ifdef CONFIG_TRANSPARENT_HUGEPAGE
1235	struct deferred_split {
1236	spinlock_t split_queue_lock;
1237	struct list_head split_queue;
1238	unsigned long split_queue_len;
1239	};
1240	#endif
1241
1242	#ifdef CONFIG_MEMORY_FAILURE
1243	/*
1244	* Per NUMA node memory failure handling statistics.
1245	*/
1246	struct memory_failure_stats {
1247	/*
1248	* Number of raw pages poisoned.
1249	* Cases not accounted: memory outside kernel control, offline page,
1250	* arch-specific memory_failure (SGX), hwpoison_filter() filtered
1251	* error events, and unpoison actions from hwpoison_unpoison.
1252	*/
1253	unsigned long total;
1254	/*
1255	* Recovery results of poisoned raw pages handled by memory_failure,
1256	* in sync with mf_result.
1257	* total = ignored + failed + delayed + recovered.
1258	* total * PAGE_SIZE * #nodes = /proc/meminfo/HardwareCorrupted.
1259	*/
1260	unsigned long ignored;
1261	unsigned long failed;
1262	unsigned long delayed;
1263	unsigned long recovered;
1264	};
1265	#endif
1266
1267	/*
1268	* On NUMA machines, each NUMA node would have a pg_data_t to describe
1269	* it's memory layout. On UMA machines there is a single pglist_data which
1270	* describes the whole memory.
1271	*
1272	* Memory statistics and page replacement data structures are maintained on a
1273	* per-zone basis.
1274	*/
1275	typedef struct pglist_data {
1276	/*
1277	* node_zones contains just the zones for THIS node. Not all of the
1278	* zones may be populated, but it is the full list. It is referenced by
1279	* this node's node_zonelists as well as other node's node_zonelists.
1280	*/
1281	struct zone node_zones[MAX_NR_ZONES];
1282
1283	/*
1284	* node_zonelists contains references to all zones in all nodes.
1285	* Generally the first zones will be references to this node's
1286	* node_zones.
1287	*/
1288	struct zonelist node_zonelists[MAX_ZONELISTS];
1289
1290	int nr_zones; /* number of populated zones in this node */
1291	#ifdef CONFIG_FLATMEM /* means !SPARSEMEM */
1292	struct page *node_mem_map;
1293	#ifdef CONFIG_PAGE_EXTENSION
1294	struct page_ext *node_page_ext;
1295	#endif
1296	#endif
1297	#if defined(CONFIG_MEMORY_HOTPLUG) || defined(CONFIG_DEFERRED_STRUCT_PAGE_INIT)
1298	/*
1299	* Must be held any time you expect node_start_pfn,
1300	* node_present_pages, node_spanned_pages or nr_zones to stay constant.
1301	* Also synchronizes pgdat->first_deferred_pfn during deferred page
1302	* init.
1303	*
1304	* pgdat_resize_lock() and pgdat_resize_unlock() are provided to
1305	* manipulate node_size_lock without checking for CONFIG_MEMORY_HOTPLUG
1306	* or CONFIG_DEFERRED_STRUCT_PAGE_INIT.
1307	*
1308	* Nests above zone->lock and zone->span_seqlock
1309	*/
1310	spinlock_t node_size_lock;
1311	#endif
1312	unsigned long node_start_pfn;
1313	unsigned long node_present_pages; /* total number of physical pages */
1314	unsigned long node_spanned_pages; /* total size of physical page
1315	range, including holes */
1316	int node_id;
1317	wait_queue_head_t kswapd_wait;
1318	wait_queue_head_t pfmemalloc_wait;
1319
1320	/* workqueues for throttling reclaim for different reasons. */
1321	wait_queue_head_t reclaim_wait[NR_VMSCAN_THROTTLE];
1322
1323	atomic_t nr_writeback_throttled;/* nr of writeback-throttled tasks */
1324	unsigned long nr_reclaim_start; /* nr pages written while throttled
1325	* when throttling started. */
1326	#ifdef CONFIG_MEMORY_HOTPLUG
1327	struct mutex kswapd_lock;
1328	#endif
1329	struct task_struct *kswapd; /* Protected by kswapd_lock */
1330	int kswapd_order;
1331	enum zone_type kswapd_highest_zoneidx;
1332
1333	int kswapd_failures; /* Number of 'reclaimed == 0' runs */
1334
1335	#ifdef CONFIG_COMPACTION
1336	int kcompactd_max_order;
1337	enum zone_type kcompactd_highest_zoneidx;
1338	wait_queue_head_t kcompactd_wait;
1339	struct task_struct *kcompactd;
1340	bool proactive_compact_trigger;
1341	#endif
1342	/*
1343	* This is a per-node reserve of pages that are not available
1344	* to userspace allocations.
1345	*/
1346	unsigned long totalreserve_pages;
1347
1348	#ifdef CONFIG_NUMA
1349	/*
1350	* node reclaim becomes active if more unmapped pages exist.
1351	*/
1352	unsigned long min_unmapped_pages;
1353	unsigned long min_slab_pages;
1354	#endif /* CONFIG_NUMA */
1355
1356	/* Write-intensive fields used by page reclaim */
1357	CACHELINE_PADDING(_pad1_);
1358
1359	#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
1360	/*
1361	* If memory initialisation on large machines is deferred then this
1362	* is the first PFN that needs to be initialised.
1363	*/
1364	unsigned long first_deferred_pfn;
1365	#endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
1366
1367	#ifdef CONFIG_TRANSPARENT_HUGEPAGE
1368	struct deferred_split deferred_split_queue;
1369	#endif
1370
1371	#ifdef CONFIG_NUMA_BALANCING
1372	/* start time in ms of current promote rate limit period */
1373	unsigned int nbp_rl_start;
1374	/* number of promote candidate pages at start time of current rate limit period */
1375	unsigned long nbp_rl_nr_cand;
1376	/* promote threshold in ms */
1377	unsigned int nbp_threshold;
1378	/* start time in ms of current promote threshold adjustment period */
1379	unsigned int nbp_th_start;
1380	/*
1381	* number of promote candidate pages at start time of current promote
1382	* threshold adjustment period
1383	*/
1384	unsigned long nbp_th_nr_cand;
1385	#endif
1386	/* Fields commonly accessed by the page reclaim scanner */
1387
1388	/*
1389	* NOTE: THIS IS UNUSED IF MEMCG IS ENABLED.
1390	*
1391	* Use mem_cgroup_lruvec() to look up lruvecs.
1392	*/
1393	struct lruvec __lruvec;
1394
1395	unsigned long flags;
1396
1397	#ifdef CONFIG_LRU_GEN
1398	/* kswap mm walk data */
1399	struct lru_gen_mm_walk mm_walk;
1400	/* lru_gen_folio list */
1401	struct lru_gen_memcg memcg_lru;
1402	#endif
1403
1404	CACHELINE_PADDING(_pad2_);
1405
1406	/* Per-node vmstats */
1407	struct per_cpu_nodestat __percpu *per_cpu_nodestats;
1408	atomic_long_t vm_stat[NR_VM_NODE_STAT_ITEMS];
1409	#ifdef CONFIG_NUMA
1410	struct memory_tier __rcu *memtier;
1411	#endif
1412	#ifdef CONFIG_MEMORY_FAILURE
1413	struct memory_failure_stats mf_stats;
1414	#endif
1415	} pg_data_t;
1416
1417	#define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages)
1418	#define node_spanned_pages(nid) (NODE_DATA(nid)->node_spanned_pages)
1419
1420	#define node_start_pfn(nid) (NODE_DATA(nid)->node_start_pfn)
1421	#define node_end_pfn(nid) pgdat_end_pfn(NODE_DATA(nid))
1422
1423	static inline unsigned long pgdat_end_pfn(pg_data_t *pgdat)
1424	{
1425	return pgdat->node_start_pfn + pgdat->node_spanned_pages;
1426	}
1427
1428	#include <linux/memory_hotplug.h>
1429
1430	void build_all_zonelists(pg_data_t *pgdat);
1431	void wakeup_kswapd(struct zone *zone, gfp_t gfp_mask, int order,
1432	enum zone_type highest_zoneidx);
1433	bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
1434	int highest_zoneidx, unsigned int alloc_flags,
1435	long free_pages);
1436	bool zone_watermark_ok(struct zone *z, unsigned int order,
1437	unsigned long mark, int highest_zoneidx,
1438	unsigned int alloc_flags);
1439	bool zone_watermark_ok_safe(struct zone *z, unsigned int order,
1440	unsigned long mark, int highest_zoneidx);
1441	/*
1442	* Memory initialization context, use to differentiate memory added by
1443	* the platform statically or via memory hotplug interface.
1444	*/
1445	enum meminit_context {
1446	MEMINIT_EARLY,
1447	MEMINIT_HOTPLUG,
1448	};
1449
1450	extern void init_currently_empty_zone(struct zone *zone, unsigned long start_pfn,
1451	unsigned long size);
1452
1453	extern void lruvec_init(struct lruvec *lruvec);
1454
1455	static inline struct pglist_data *lruvec_pgdat(struct lruvec *lruvec)
1456	{
1457	#ifdef CONFIG_MEMCG
1458	return lruvec->pgdat;
1459	#else
1460	return container_of(lruvec, struct pglist_data, __lruvec);
1461	#endif
1462	}
1463
1464	#ifdef CONFIG_HAVE_MEMORYLESS_NODES
1465	int local_memory_node(int node_id);
1466	#else
1467	static inline int local_memory_node(int node_id) { return node_id; };
1468	#endif
1469
1470	/*
1471	* zone_idx() returns 0 for the ZONE_DMA zone, 1 for the ZONE_NORMAL zone, etc.
1472	*/
1473	#define zone_idx(zone) ((zone) - (zone)->zone_pgdat->node_zones)
1474
1475	#ifdef CONFIG_ZONE_DEVICE
1476	static inline bool zone_is_zone_device(struct zone *zone)
1477	{
1478	return zone_idx(zone) == ZONE_DEVICE;
1479	}
1480	#else
1481	static inline bool zone_is_zone_device(struct zone *zone)
1482	{
1483	return false;
1484	}
1485	#endif
1486
1487	/*
1488	* Returns true if a zone has pages managed by the buddy allocator.
1489	* All the reclaim decisions have to use this function rather than
1490	* populated_zone(). If the whole zone is reserved then we can easily
1491	* end up with populated_zone() && !managed_zone().
1492	*/
1493	static inline bool managed_zone(struct zone *zone)
1494	{
1495	return zone_managed_pages(zone);
1496	}
1497
1498	/* Returns true if a zone has memory */
1499	static inline bool populated_zone(struct zone *zone)
1500	{
1501	return zone->present_pages;
1502	}
1503
1504	#ifdef CONFIG_NUMA
1505	static inline int zone_to_nid(struct zone *zone)
1506	{
1507	return zone->node;
1508	}
1509
1510	static inline void zone_set_nid(struct zone *zone, int nid)
1511	{
1512	zone->node = nid;
1513	}
1514	#else
1515	static inline int zone_to_nid(struct zone *zone)
1516	{
1517	return 0;
1518	}
1519
1520	static inline void zone_set_nid(struct zone *zone, int nid) {}
1521	#endif
1522
1523	extern int movable_zone;
1524
1525	static inline int is_highmem_idx(enum zone_type idx)
1526	{
1527	#ifdef CONFIG_HIGHMEM
1528	return (idx == ZONE_HIGHMEM ||
1529	(idx == ZONE_MOVABLE && movable_zone == ZONE_HIGHMEM));
1530	#else
1531	return 0;
1532	#endif
1533	}
1534
1535	/**
1536	* is_highmem - helper function to quickly check if a struct zone is a
1537	* highmem zone or not. This is an attempt to keep references
1538	* to ZONE_{DMA/NORMAL/HIGHMEM/etc} in general code to a minimum.
1539	* @zone: pointer to struct zone variable
1540	* Return: 1 for a highmem zone, 0 otherwise
1541	*/
1542	static inline int is_highmem(struct zone *zone)
1543	{
1544	return is_highmem_idx(zone_idx(zone));
1545	}
1546
1547	#ifdef CONFIG_ZONE_DMA
1548	bool has_managed_dma(void);
1549	#else
1550	static inline bool has_managed_dma(void)
1551	{
1552	return false;
1553	}
1554	#endif
1555
1556
1557	#ifndef CONFIG_NUMA
1558
1559	extern struct pglist_data contig_page_data;
1560	static inline struct pglist_data *NODE_DATA(int nid)
1561	{
1562	return &contig_page_data;
1563	}
1564
1565	#else /* CONFIG_NUMA */
1566
1567	#include <asm/mmzone.h>
1568
1569	#endif /* !CONFIG_NUMA */
1570
1571	extern struct pglist_data *first_online_pgdat(void);
1572	extern struct pglist_data *next_online_pgdat(struct pglist_data *pgdat);
1573	extern struct zone *next_zone(struct zone *zone);
1574
1575	/**
1576	* for_each_online_pgdat - helper macro to iterate over all online nodes
1577	* @pgdat: pointer to a pg_data_t variable
1578	*/
1579	#define for_each_online_pgdat(pgdat) \
1580	for (pgdat = first_online_pgdat(); \
1581	pgdat; \
1582	pgdat = next_online_pgdat(pgdat))
1583	/**
1584	* for_each_zone - helper macro to iterate over all memory zones
1585	* @zone: pointer to struct zone variable
1586	*
1587	* The user only needs to declare the zone variable, for_each_zone
1588	* fills it in.
1589	*/
1590	#define for_each_zone(zone) \
1591	for (zone = (first_online_pgdat())->node_zones; \
1592	zone; \
1593	zone = next_zone(zone))
1594
1595	#define for_each_populated_zone(zone) \
1596	for (zone = (first_online_pgdat())->node_zones; \
1597	zone; \
1598	zone = next_zone(zone)) \
1599	if (!populated_zone(zone)) \
1600	; /* do nothing */ \
1601	else
1602
1603	static inline struct zone *zonelist_zone(struct zoneref *zoneref)
1604	{
1605	return zoneref->zone;
1606	}
1607
1608	static inline int zonelist_zone_idx(struct zoneref *zoneref)
1609	{
1610	return zoneref->zone_idx;
1611	}
1612
1613	static inline int zonelist_node_idx(struct zoneref *zoneref)
1614	{
1615	return zone_to_nid(zone: zoneref->zone);
1616	}
1617
1618	struct zoneref *__next_zones_zonelist(struct zoneref *z,
1619	enum zone_type highest_zoneidx,
1620	nodemask_t *nodes);
1621
1622	/**
1623	* 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
1624	* @z: The cursor used as a starting point for the search
1625	* @highest_zoneidx: The zone index of the highest zone to return
1626	* @nodes: An optional nodemask to filter the zonelist with
1627	*
1628	* This function returns the next zone at or below a given zone index that is
1629	* within the allowed nodemask using a cursor as the starting point for the
1630	* search. The zoneref returned is a cursor that represents the current zone
1631	* being examined. It should be advanced by one before calling
1632	* next_zones_zonelist again.
1633	*
1634	* Return: the next zone at or below highest_zoneidx within the allowed
1635	* nodemask using a cursor within a zonelist as a starting point
1636	*/
1637	static __always_inline struct zoneref *next_zones_zonelist(struct zoneref *z,
1638	enum zone_type highest_zoneidx,
1639	nodemask_t *nodes)
1640	{
1641	if (likely(!nodes && zonelist_zone_idx(z) <= highest_zoneidx))
1642	return z;
1643	return __next_zones_zonelist(z, highest_zoneidx, nodes);
1644	}
1645
1646	/**
1647	* first_zones_zonelist - Returns the first zone at or below highest_zoneidx within the allowed nodemask in a zonelist
1648	* @zonelist: The zonelist to search for a suitable zone
1649	* @highest_zoneidx: The zone index of the highest zone to return
1650	* @nodes: An optional nodemask to filter the zonelist with
1651	*
1652	* This function returns the first zone at or below a given zone index that is
1653	* within the allowed nodemask. The zoneref returned is a cursor that can be
1654	* used to iterate the zonelist with next_zones_zonelist by advancing it by
1655	* one before calling.
1656	*
1657	* When no eligible zone is found, zoneref->zone is NULL (zoneref itself is
1658	* never NULL). This may happen either genuinely, or due to concurrent nodemask
1659	* update due to cpuset modification.
1660	*
1661	* Return: Zoneref pointer for the first suitable zone found
1662	*/
1663	static inline struct zoneref *first_zones_zonelist(struct zonelist *zonelist,
1664	enum zone_type highest_zoneidx,
1665	nodemask_t *nodes)
1666	{
1667	return next_zones_zonelist(z: zonelist->_zonerefs,
1668	highest_zoneidx, nodes);
1669	}
1670
1671	/**
1672	* 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
1673	* @zone: The current zone in the iterator
1674	* @z: The current pointer within zonelist->_zonerefs being iterated
1675	* @zlist: The zonelist being iterated
1676	* @highidx: The zone index of the highest zone to return
1677	* @nodemask: Nodemask allowed by the allocator
1678	*
1679	* This iterator iterates though all zones at or below a given zone index and
1680	* within a given nodemask
1681	*/
1682	#define for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, nodemask) \
1683	for (z = first_zones_zonelist(zlist, highidx, nodemask), zone = zonelist_zone(z); \
1684	zone; \
1685	z = next_zones_zonelist(++z, highidx, nodemask), \
1686	zone = zonelist_zone(z))
1687
1688	#define for_next_zone_zonelist_nodemask(zone, z, highidx, nodemask) \
1689	for (zone = z->zone; \
1690	zone; \
1691	z = next_zones_zonelist(++z, highidx, nodemask), \
1692	zone = zonelist_zone(z))
1693
1694
1695	/**
1696	* for_each_zone_zonelist - helper macro to iterate over valid zones in a zonelist at or below a given zone index
1697	* @zone: The current zone in the iterator
1698	* @z: The current pointer within zonelist->zones being iterated
1699	* @zlist: The zonelist being iterated
1700	* @highidx: The zone index of the highest zone to return
1701	*
1702	* This iterator iterates though all zones at or below a given zone index.
1703	*/
1704	#define for_each_zone_zonelist(zone, z, zlist, highidx) \
1705	for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, NULL)
1706
1707	/* Whether the 'nodes' are all movable nodes */
1708	static inline bool movable_only_nodes(nodemask_t *nodes)
1709	{
1710	struct zonelist *zonelist;
1711	struct zoneref *z;
1712	int nid;
1713
1714	if (nodes_empty(*nodes))
1715	return false;
1716
1717	/*
1718	* We can chose arbitrary node from the nodemask to get a
1719	* zonelist as they are interlinked. We just need to find
1720	* at least one zone that can satisfy kernel allocations.
1721	*/
1722	nid = first_node(*nodes);
1723	zonelist = &NODE_DATA(nid)->node_zonelists[ZONELIST_FALLBACK];
1724	z = first_zones_zonelist(zonelist, highest_zoneidx: ZONE_NORMAL, nodes);
1725	return (!z->zone) ? true : false;
1726	}
1727
1728
1729	#ifdef CONFIG_SPARSEMEM
1730	#include <asm/sparsemem.h>
1731	#endif
1732
1733	#ifdef CONFIG_FLATMEM
1734	#define pfn_to_nid(pfn) (0)
1735	#endif
1736
1737	#ifdef CONFIG_SPARSEMEM
1738
1739	/*
1740	* PA_SECTION_SHIFT physical address to/from section number
1741	* PFN_SECTION_SHIFT pfn to/from section number
1742	*/
1743	#define PA_SECTION_SHIFT (SECTION_SIZE_BITS)
1744	#define PFN_SECTION_SHIFT (SECTION_SIZE_BITS - PAGE_SHIFT)
1745
1746	#define NR_MEM_SECTIONS (1UL << SECTIONS_SHIFT)
1747
1748	#define PAGES_PER_SECTION (1UL << PFN_SECTION_SHIFT)
1749	#define PAGE_SECTION_MASK (~(PAGES_PER_SECTION-1))
1750
1751	#define SECTION_BLOCKFLAGS_BITS \
1752	((1UL << (PFN_SECTION_SHIFT - pageblock_order)) * NR_PAGEBLOCK_BITS)
1753
1754	#if (MAX_PAGE_ORDER + PAGE_SHIFT) > SECTION_SIZE_BITS
1755	#error Allocator MAX_PAGE_ORDER exceeds SECTION_SIZE
1756	#endif
1757
1758	static inline unsigned long pfn_to_section_nr(unsigned long pfn)
1759	{
1760	return pfn >> PFN_SECTION_SHIFT;
1761	}
1762	static inline unsigned long section_nr_to_pfn(unsigned long sec)
1763	{
1764	return sec << PFN_SECTION_SHIFT;
1765	}
1766
1767	#define SECTION_ALIGN_UP(pfn) (((pfn) + PAGES_PER_SECTION - 1) & PAGE_SECTION_MASK)
1768	#define SECTION_ALIGN_DOWN(pfn) ((pfn) & PAGE_SECTION_MASK)
1769
1770	#define SUBSECTION_SHIFT 21
1771	#define SUBSECTION_SIZE (1UL << SUBSECTION_SHIFT)
1772
1773	#define PFN_SUBSECTION_SHIFT (SUBSECTION_SHIFT - PAGE_SHIFT)
1774	#define PAGES_PER_SUBSECTION (1UL << PFN_SUBSECTION_SHIFT)
1775	#define PAGE_SUBSECTION_MASK (~(PAGES_PER_SUBSECTION-1))
1776
1777	#if SUBSECTION_SHIFT > SECTION_SIZE_BITS
1778	#error Subsection size exceeds section size
1779	#else
1780	#define SUBSECTIONS_PER_SECTION (1UL << (SECTION_SIZE_BITS - SUBSECTION_SHIFT))
1781	#endif
1782
1783	#define SUBSECTION_ALIGN_UP(pfn) ALIGN((pfn), PAGES_PER_SUBSECTION)
1784	#define SUBSECTION_ALIGN_DOWN(pfn) ((pfn) & PAGE_SUBSECTION_MASK)
1785
1786	struct mem_section_usage {
1787	struct rcu_head rcu;
1788	#ifdef CONFIG_SPARSEMEM_VMEMMAP
1789	DECLARE_BITMAP(subsection_map, SUBSECTIONS_PER_SECTION);
1790	#endif
1791	/* See declaration of similar field in struct zone */
1792	unsigned long pageblock_flags[0];
1793	};
1794
1795	void subsection_map_init(unsigned long pfn, unsigned long nr_pages);
1796
1797	struct page;
1798	struct page_ext;
1799	struct mem_section {
1800	/*
1801	* This is, logically, a pointer to an array of struct
1802	* pages. However, it is stored with some other magic.
1803	* (see sparse.c::sparse_init_one_section())
1804	*
1805	* Additionally during early boot we encode node id of
1806	* the location of the section here to guide allocation.
1807	* (see sparse.c::memory_present())
1808	*
1809	* Making it a UL at least makes someone do a cast
1810	* before using it wrong.
1811	*/
1812	unsigned long section_mem_map;
1813
1814	struct mem_section_usage *usage;
1815	#ifdef CONFIG_PAGE_EXTENSION
1816	/*
1817	* If SPARSEMEM, pgdat doesn't have page_ext pointer. We use
1818	* section. (see page_ext.h about this.)
1819	*/
1820	struct page_ext *page_ext;
1821	unsigned long pad;
1822	#endif
1823	/*
1824	* WARNING: mem_section must be a power-of-2 in size for the
1825	* calculation and use of SECTION_ROOT_MASK to make sense.
1826	*/
1827	};
1828
1829	#ifdef CONFIG_SPARSEMEM_EXTREME
1830	#define SECTIONS_PER_ROOT (PAGE_SIZE / sizeof (struct mem_section))
1831	#else
1832	#define SECTIONS_PER_ROOT 1
1833	#endif
1834
1835	#define SECTION_NR_TO_ROOT(sec) ((sec) / SECTIONS_PER_ROOT)
1836	#define NR_SECTION_ROOTS DIV_ROUND_UP(NR_MEM_SECTIONS, SECTIONS_PER_ROOT)
1837	#define SECTION_ROOT_MASK (SECTIONS_PER_ROOT - 1)
1838
1839	#ifdef CONFIG_SPARSEMEM_EXTREME
1840	extern struct mem_section **mem_section;
1841	#else
1842	extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT];
1843	#endif
1844
1845	static inline unsigned long *section_to_usemap(struct mem_section *ms)
1846	{
1847	return ms->usage->pageblock_flags;
1848	}
1849
1850	static inline struct mem_section *__nr_to_section(unsigned long nr)
1851	{
1852	unsigned long root = SECTION_NR_TO_ROOT(nr);
1853
1854	if (unlikely(root >= NR_SECTION_ROOTS))
1855	return NULL;
1856
1857	#ifdef CONFIG_SPARSEMEM_EXTREME
1858	if (!mem_section || !mem_section[root])
1859	return NULL;
1860	#endif
1861	return &mem_section[root][nr & SECTION_ROOT_MASK];
1862	}
1863	extern size_t mem_section_usage_size(void);
1864
1865	/*
1866	* We use the lower bits of the mem_map pointer to store
1867	* a little bit of information. The pointer is calculated
1868	* as mem_map - section_nr_to_pfn(pnum). The result is
1869	* aligned to the minimum alignment of the two values:
1870	* 1. All mem_map arrays are page-aligned.
1871	* 2. section_nr_to_pfn() always clears PFN_SECTION_SHIFT
1872	* lowest bits. PFN_SECTION_SHIFT is arch-specific
1873	* (equal SECTION_SIZE_BITS - PAGE_SHIFT), and the
1874	* worst combination is powerpc with 256k pages,
1875	* which results in PFN_SECTION_SHIFT equal 6.
1876	* To sum it up, at least 6 bits are available on all architectures.
1877	* However, we can exceed 6 bits on some other architectures except
1878	* powerpc (e.g. 15 bits are available on x86_64, 13 bits are available
1879	* with the worst case of 64K pages on arm64) if we make sure the
1880	* exceeded bit is not applicable to powerpc.
1881	*/
1882	enum {
1883	SECTION_MARKED_PRESENT_BIT,
1884	SECTION_HAS_MEM_MAP_BIT,
1885	SECTION_IS_ONLINE_BIT,
1886	SECTION_IS_EARLY_BIT,
1887	#ifdef CONFIG_ZONE_DEVICE
1888	SECTION_TAINT_ZONE_DEVICE_BIT,
1889	#endif
1890	SECTION_MAP_LAST_BIT,
1891	};
1892
1893	#define SECTION_MARKED_PRESENT BIT(SECTION_MARKED_PRESENT_BIT)
1894	#define SECTION_HAS_MEM_MAP BIT(SECTION_HAS_MEM_MAP_BIT)
1895	#define SECTION_IS_ONLINE BIT(SECTION_IS_ONLINE_BIT)
1896	#define SECTION_IS_EARLY BIT(SECTION_IS_EARLY_BIT)
1897	#ifdef CONFIG_ZONE_DEVICE
1898	#define SECTION_TAINT_ZONE_DEVICE BIT(SECTION_TAINT_ZONE_DEVICE_BIT)
1899	#endif
1900	#define SECTION_MAP_MASK (~(BIT(SECTION_MAP_LAST_BIT) - 1))
1901	#define SECTION_NID_SHIFT SECTION_MAP_LAST_BIT
1902
1903	static inline struct page *__section_mem_map_addr(struct mem_section *section)
1904	{
1905	unsigned long map = section->section_mem_map;
1906	map &= SECTION_MAP_MASK;
1907	return (struct page *)map;
1908	}
1909
1910	static inline int present_section(struct mem_section *section)
1911	{
1912	return (section && (section->section_mem_map & SECTION_MARKED_PRESENT));
1913	}
1914
1915	static inline int present_section_nr(unsigned long nr)
1916	{
1917	return present_section(section: __nr_to_section(nr));
1918	}
1919
1920	static inline int valid_section(struct mem_section *section)
1921	{
1922	return (section && (section->section_mem_map & SECTION_HAS_MEM_MAP));
1923	}
1924
1925	static inline int early_section(struct mem_section *section)
1926	{
1927	return (section && (section->section_mem_map & SECTION_IS_EARLY));
1928	}
1929
1930	static inline int valid_section_nr(unsigned long nr)
1931	{
1932	return valid_section(section: __nr_to_section(nr));
1933	}
1934
1935	static inline int online_section(struct mem_section *section)
1936	{
1937	return (section && (section->section_mem_map & SECTION_IS_ONLINE));
1938	}
1939
1940	#ifdef CONFIG_ZONE_DEVICE
1941	static inline int online_device_section(struct mem_section *section)
1942	{
1943	unsigned long flags = SECTION_IS_ONLINE | SECTION_TAINT_ZONE_DEVICE;
1944
1945	return section && ((section->section_mem_map & flags) == flags);
1946	}
1947	#else
1948	static inline int online_device_section(struct mem_section *section)
1949	{
1950	return 0;
1951	}
1952	#endif
1953
1954	static inline int online_section_nr(unsigned long nr)
1955	{
1956	return online_section(section: __nr_to_section(nr));
1957	}
1958
1959	#ifdef CONFIG_MEMORY_HOTPLUG
1960	void online_mem_sections(unsigned long start_pfn, unsigned long end_pfn);
1961	void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn);
1962	#endif
1963
1964	static inline struct mem_section *__pfn_to_section(unsigned long pfn)
1965	{
1966	return __nr_to_section(nr: pfn_to_section_nr(pfn));
1967	}
1968
1969	extern unsigned long __highest_present_section_nr;
1970
1971	static inline int subsection_map_index(unsigned long pfn)
1972	{
1973	return (pfn & ~(PAGE_SECTION_MASK)) / PAGES_PER_SUBSECTION;
1974	}
1975
1976	#ifdef CONFIG_SPARSEMEM_VMEMMAP
1977	static inline int pfn_section_valid(struct mem_section *ms, unsigned long pfn)
1978	{
1979	int idx = subsection_map_index(pfn);
1980
1981	return test_bit(idx, READ_ONCE(ms->usage)->subsection_map);
1982	}
1983	#else
1984	static inline int pfn_section_valid(struct mem_section *ms, unsigned long pfn)
1985	{
1986	return 1;
1987	}
1988	#endif
1989
1990	#ifndef CONFIG_HAVE_ARCH_PFN_VALID
1991	/**
1992	* pfn_valid - check if there is a valid memory map entry for a PFN
1993	* @pfn: the page frame number to check
1994	*
1995	* Check if there is a valid memory map entry aka struct page for the @pfn.
1996	* Note, that availability of the memory map entry does not imply that
1997	* there is actual usable memory at that @pfn. The struct page may
1998	* represent a hole or an unusable page frame.
1999	*
2000	* Return: 1 for PFNs that have memory map entries and 0 otherwise
2001	*/
2002	static inline int pfn_valid(unsigned long pfn)
2003	{
2004	struct mem_section *ms;
2005	int ret;
2006
2007	/*
2008	* Ensure the upper PAGE_SHIFT bits are clear in the
2009	* pfn. Else it might lead to false positives when
2010	* some of the upper bits are set, but the lower bits
2011	* match a valid pfn.
2012	*/
2013	if (PHYS_PFN(PFN_PHYS(pfn)) != pfn)
2014	return 0;
2015
2016	if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
2017	return 0;
2018	ms = __pfn_to_section(pfn);
2019	rcu_read_lock_sched();
2020	if (!valid_section(section: ms)) {
2021	rcu_read_unlock_sched();
2022	return 0;
2023	}
2024	/*
2025	* Traditionally early sections always returned pfn_valid() for
2026	* the entire section-sized span.
2027	*/
2028	ret = early_section(section: ms) || pfn_section_valid(ms, pfn);
2029	rcu_read_unlock_sched();
2030
2031	return ret;
2032	}
2033	#endif
2034
2035	static inline int pfn_in_present_section(unsigned long pfn)
2036	{
2037	if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
2038	return 0;
2039	return present_section(section: __pfn_to_section(pfn));
2040	}
2041
2042	static inline unsigned long next_present_section_nr(unsigned long section_nr)
2043	{
2044	while (++section_nr <= __highest_present_section_nr) {
2045	if (present_section_nr(nr: section_nr))
2046	return section_nr;
2047	}
2048
2049	return -1;
2050	}
2051
2052	/*
2053	* These are _only_ used during initialisation, therefore they
2054	* can use __initdata ... They could have names to indicate
2055	* this restriction.
2056	*/
2057	#ifdef CONFIG_NUMA
2058	#define pfn_to_nid(pfn) \
2059	({ \
2060	unsigned long __pfn_to_nid_pfn = (pfn); \
2061	page_to_nid(pfn_to_page(__pfn_to_nid_pfn)); \
2062	})
2063	#else
2064	#define pfn_to_nid(pfn) (0)
2065	#endif
2066
2067	void sparse_init(void);
2068	#else
2069	#define sparse_init() do {} while (0)
2070	#define sparse_index_init(_sec, _nid) do {} while (0)
2071	#define pfn_in_present_section pfn_valid
2072	#define subsection_map_init(_pfn, _nr_pages) do {} while (0)
2073	#endif /* CONFIG_SPARSEMEM */
2074
2075	#endif /* !__GENERATING_BOUNDS.H */
2076	#endif /* !__ASSEMBLY__ */
2077	#endif /* _LINUX_MMZONE_H */
2078