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/wait.h>
11#include <linux/bitops.h>
12#include <linux/cache.h>
13#include <linux/threads.h>
14#include <linux/numa.h>
15#include <linux/init.h>
16#include <linux/seqlock.h>
17#include <linux/nodemask.h>
18#include <linux/pageblock-flags.h>
19#include <linux/page-flags-layout.h>
20#include <linux/atomic.h>
21#include <asm/page.h>
22
23/* Free memory management - zoned buddy allocator. */
24#ifndef CONFIG_FORCE_MAX_ZONEORDER
25#define MAX_ORDER 11
26#else
27#define MAX_ORDER CONFIG_FORCE_MAX_ZONEORDER
28#endif
29#define MAX_ORDER_NR_PAGES (1 << (MAX_ORDER - 1))
30
31/*
32 * PAGE_ALLOC_COSTLY_ORDER is the order at which allocations are deemed
33 * costly to service. That is between allocation orders which should
34 * coalesce naturally under reasonable reclaim pressure and those which
35 * will not.
36 */
37#define PAGE_ALLOC_COSTLY_ORDER 3
38
39enum migratetype {
40 MIGRATE_UNMOVABLE,
41 MIGRATE_MOVABLE,
42 MIGRATE_RECLAIMABLE,
43 MIGRATE_PCPTYPES, /* the number of types on the pcp lists */
44 MIGRATE_HIGHATOMIC = MIGRATE_PCPTYPES,
45#ifdef CONFIG_CMA
46 /*
47 * MIGRATE_CMA migration type is designed to mimic the way
48 * ZONE_MOVABLE works. Only movable pages can be allocated
49 * from MIGRATE_CMA pageblocks and page allocator never
50 * implicitly change migration type of MIGRATE_CMA pageblock.
51 *
52 * The way to use it is to change migratetype of a range of
53 * pageblocks to MIGRATE_CMA which can be done by
54 * __free_pageblock_cma() function. What is important though
55 * is that a range of pageblocks must be aligned to
56 * MAX_ORDER_NR_PAGES should biggest page be bigger then
57 * a single pageblock.
58 */
59 MIGRATE_CMA,
60#endif
61#ifdef CONFIG_MEMORY_ISOLATION
62 MIGRATE_ISOLATE, /* can't allocate from here */
63#endif
64 MIGRATE_TYPES
65};
66
67/* In mm/page_alloc.c; keep in sync also with show_migration_types() there */
68extern char * const migratetype_names[MIGRATE_TYPES];
69
70#ifdef CONFIG_CMA
71# define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA)
72# define is_migrate_cma_page(_page) (get_pageblock_migratetype(_page) == MIGRATE_CMA)
73#else
74# define is_migrate_cma(migratetype) false
75# define is_migrate_cma_page(_page) false
76#endif
77
78static inline bool is_migrate_movable(int mt)
79{
80 return is_migrate_cma(mt) || mt == MIGRATE_MOVABLE;
81}
82
83#define for_each_migratetype_order(order, type) \
84 for (order = 0; order < MAX_ORDER; order++) \
85 for (type = 0; type < MIGRATE_TYPES; type++)
86
87extern int page_group_by_mobility_disabled;
88
89#define NR_MIGRATETYPE_BITS (PB_migrate_end - PB_migrate + 1)
90#define MIGRATETYPE_MASK ((1UL << NR_MIGRATETYPE_BITS) - 1)
91
92#define get_pageblock_migratetype(page) \
93 get_pfnblock_flags_mask(page, page_to_pfn(page), \
94 PB_migrate_end, MIGRATETYPE_MASK)
95
96struct free_area {
97 struct list_head free_list[MIGRATE_TYPES];
98 unsigned long nr_free;
99};
100
101struct pglist_data;
102
103/*
104 * zone->lock and the zone lru_lock are two of the hottest locks in the kernel.
105 * So add a wild amount of padding here to ensure that they fall into separate
106 * cachelines. There are very few zone structures in the machine, so space
107 * consumption is not a concern here.
108 */
109#if defined(CONFIG_SMP)
110struct zone_padding {
111 char x[0];
112} ____cacheline_internodealigned_in_smp;
113#define ZONE_PADDING(name) struct zone_padding name;
114#else
115#define ZONE_PADDING(name)
116#endif
117
118#ifdef CONFIG_NUMA
119enum numa_stat_item {
120 NUMA_HIT, /* allocated in intended node */
121 NUMA_MISS, /* allocated in non intended node */
122 NUMA_FOREIGN, /* was intended here, hit elsewhere */
123 NUMA_INTERLEAVE_HIT, /* interleaver preferred this zone */
124 NUMA_LOCAL, /* allocation from local node */
125 NUMA_OTHER, /* allocation from other node */
126 NR_VM_NUMA_STAT_ITEMS
127};
128#else
129#define NR_VM_NUMA_STAT_ITEMS 0
130#endif
131
132enum zone_stat_item {
133 /* First 128 byte cacheline (assuming 64 bit words) */
134 NR_FREE_PAGES,
135 NR_ZONE_LRU_BASE, /* Used only for compaction and reclaim retry */
136 NR_ZONE_INACTIVE_ANON = NR_ZONE_LRU_BASE,
137 NR_ZONE_ACTIVE_ANON,
138 NR_ZONE_INACTIVE_FILE,
139 NR_ZONE_ACTIVE_FILE,
140 NR_ZONE_UNEVICTABLE,
141 NR_ZONE_WRITE_PENDING, /* Count of dirty, writeback and unstable pages */
142 NR_MLOCK, /* mlock()ed pages found and moved off LRU */
143 NR_PAGETABLE, /* used for pagetables */
144 NR_KERNEL_STACK_KB, /* measured in KiB */
145 /* Second 128 byte cacheline */
146 NR_BOUNCE,
147#if IS_ENABLED(CONFIG_ZSMALLOC)
148 NR_ZSPAGES, /* allocated in zsmalloc */
149#endif
150 NR_FREE_CMA_PAGES,
151 NR_VM_ZONE_STAT_ITEMS };
152
153enum node_stat_item {
154 NR_LRU_BASE,
155 NR_INACTIVE_ANON = NR_LRU_BASE, /* must match order of LRU_[IN]ACTIVE */
156 NR_ACTIVE_ANON, /* " " " " " */
157 NR_INACTIVE_FILE, /* " " " " " */
158 NR_ACTIVE_FILE, /* " " " " " */
159 NR_UNEVICTABLE, /* " " " " " */
160 NR_SLAB_RECLAIMABLE,
161 NR_SLAB_UNRECLAIMABLE,
162 NR_ISOLATED_ANON, /* Temporary isolated pages from anon lru */
163 NR_ISOLATED_FILE, /* Temporary isolated pages from file lru */
164 WORKINGSET_REFAULT,
165 WORKINGSET_ACTIVATE,
166 WORKINGSET_NODERECLAIM,
167 NR_ANON_MAPPED, /* Mapped anonymous pages */
168 NR_FILE_MAPPED, /* pagecache pages mapped into pagetables.
169 only modified from process context */
170 NR_FILE_PAGES,
171 NR_FILE_DIRTY,
172 NR_WRITEBACK,
173 NR_WRITEBACK_TEMP, /* Writeback using temporary buffers */
174 NR_SHMEM, /* shmem pages (included tmpfs/GEM pages) */
175 NR_SHMEM_THPS,
176 NR_SHMEM_PMDMAPPED,
177 NR_ANON_THPS,
178 NR_UNSTABLE_NFS, /* NFS unstable pages */
179 NR_VMSCAN_WRITE,
180 NR_VMSCAN_IMMEDIATE, /* Prioritise for reclaim when writeback ends */
181 NR_DIRTIED, /* page dirtyings since bootup */
182 NR_WRITTEN, /* page writings since bootup */
183 NR_INDIRECTLY_RECLAIMABLE_BYTES, /* measured in bytes */
184 NR_VM_NODE_STAT_ITEMS
185};
186
187/*
188 * We do arithmetic on the LRU lists in various places in the code,
189 * so it is important to keep the active lists LRU_ACTIVE higher in
190 * the array than the corresponding inactive lists, and to keep
191 * the *_FILE lists LRU_FILE higher than the corresponding _ANON lists.
192 *
193 * This has to be kept in sync with the statistics in zone_stat_item
194 * above and the descriptions in vmstat_text in mm/vmstat.c
195 */
196#define LRU_BASE 0
197#define LRU_ACTIVE 1
198#define LRU_FILE 2
199
200enum lru_list {
201 LRU_INACTIVE_ANON = LRU_BASE,
202 LRU_ACTIVE_ANON = LRU_BASE + LRU_ACTIVE,
203 LRU_INACTIVE_FILE = LRU_BASE + LRU_FILE,
204 LRU_ACTIVE_FILE = LRU_BASE + LRU_FILE + LRU_ACTIVE,
205 LRU_UNEVICTABLE,
206 NR_LRU_LISTS
207};
208
209#define for_each_lru(lru) for (lru = 0; lru < NR_LRU_LISTS; lru++)
210
211#define for_each_evictable_lru(lru) for (lru = 0; lru <= LRU_ACTIVE_FILE; lru++)
212
213static inline int is_file_lru(enum lru_list lru)
214{
215 return (lru == LRU_INACTIVE_FILE || lru == LRU_ACTIVE_FILE);
216}
217
218static inline int is_active_lru(enum lru_list lru)
219{
220 return (lru == LRU_ACTIVE_ANON || lru == LRU_ACTIVE_FILE);
221}
222
223struct zone_reclaim_stat {
224 /*
225 * The pageout code in vmscan.c keeps track of how many of the
226 * mem/swap backed and file backed pages are referenced.
227 * The higher the rotated/scanned ratio, the more valuable
228 * that cache is.
229 *
230 * The anon LRU stats live in [0], file LRU stats in [1]
231 */
232 unsigned long recent_rotated[2];
233 unsigned long recent_scanned[2];
234};
235
236struct lruvec {
237 struct list_head lists[NR_LRU_LISTS];
238 struct zone_reclaim_stat reclaim_stat;
239 /* Evictions & activations on the inactive file list */
240 atomic_long_t inactive_age;
241 /* Refaults at the time of last reclaim cycle */
242 unsigned long refaults;
243#ifdef CONFIG_MEMCG
244 struct pglist_data *pgdat;
245#endif
246};
247
248/* Mask used at gathering information at once (see memcontrol.c) */
249#define LRU_ALL_FILE (BIT(LRU_INACTIVE_FILE) | BIT(LRU_ACTIVE_FILE))
250#define LRU_ALL_ANON (BIT(LRU_INACTIVE_ANON) | BIT(LRU_ACTIVE_ANON))
251#define LRU_ALL ((1 << NR_LRU_LISTS) - 1)
252
253/* Isolate unmapped file */
254#define ISOLATE_UNMAPPED ((__force isolate_mode_t)0x2)
255/* Isolate for asynchronous migration */
256#define ISOLATE_ASYNC_MIGRATE ((__force isolate_mode_t)0x4)
257/* Isolate unevictable pages */
258#define ISOLATE_UNEVICTABLE ((__force isolate_mode_t)0x8)
259
260/* LRU Isolation modes. */
261typedef unsigned __bitwise isolate_mode_t;
262
263enum zone_watermarks {
264 WMARK_MIN,
265 WMARK_LOW,
266 WMARK_HIGH,
267 NR_WMARK
268};
269
270#define min_wmark_pages(z) (z->watermark[WMARK_MIN])
271#define low_wmark_pages(z) (z->watermark[WMARK_LOW])
272#define high_wmark_pages(z) (z->watermark[WMARK_HIGH])
273
274struct per_cpu_pages {
275 int count; /* number of pages in the list */
276 int high; /* high watermark, emptying needed */
277 int batch; /* chunk size for buddy add/remove */
278
279 /* Lists of pages, one per migrate type stored on the pcp-lists */
280 struct list_head lists[MIGRATE_PCPTYPES];
281};
282
283struct per_cpu_pageset {
284 struct per_cpu_pages pcp;
285#ifdef CONFIG_NUMA
286 s8 expire;
287 u16 vm_numa_stat_diff[NR_VM_NUMA_STAT_ITEMS];
288#endif
289#ifdef CONFIG_SMP
290 s8 stat_threshold;
291 s8 vm_stat_diff[NR_VM_ZONE_STAT_ITEMS];
292#endif
293};
294
295struct per_cpu_nodestat {
296 s8 stat_threshold;
297 s8 vm_node_stat_diff[NR_VM_NODE_STAT_ITEMS];
298};
299
300#endif /* !__GENERATING_BOUNDS.H */
301
302enum zone_type {
303#ifdef CONFIG_ZONE_DMA
304 /*
305 * ZONE_DMA is used when there are devices that are not able
306 * to do DMA to all of addressable memory (ZONE_NORMAL). Then we
307 * carve out the portion of memory that is needed for these devices.
308 * The range is arch specific.
309 *
310 * Some examples
311 *
312 * Architecture Limit
313 * ---------------------------
314 * parisc, ia64, sparc <4G
315 * s390 <2G
316 * arm Various
317 * alpha Unlimited or 0-16MB.
318 *
319 * i386, x86_64 and multiple other arches
320 * <16M.
321 */
322 ZONE_DMA,
323#endif
324#ifdef CONFIG_ZONE_DMA32
325 /*
326 * x86_64 needs two ZONE_DMAs because it supports devices that are
327 * only able to do DMA to the lower 16M but also 32 bit devices that
328 * can only do DMA areas below 4G.
329 */
330 ZONE_DMA32,
331#endif
332 /*
333 * Normal addressable memory is in ZONE_NORMAL. DMA operations can be
334 * performed on pages in ZONE_NORMAL if the DMA devices support
335 * transfers to all addressable memory.
336 */
337 ZONE_NORMAL,
338#ifdef CONFIG_HIGHMEM
339 /*
340 * A memory area that is only addressable by the kernel through
341 * mapping portions into its own address space. This is for example
342 * used by i386 to allow the kernel to address the memory beyond
343 * 900MB. The kernel will set up special mappings (page
344 * table entries on i386) for each page that the kernel needs to
345 * access.
346 */
347 ZONE_HIGHMEM,
348#endif
349 ZONE_MOVABLE,
350#ifdef CONFIG_ZONE_DEVICE
351 ZONE_DEVICE,
352#endif
353 __MAX_NR_ZONES
354
355};
356
357#ifndef __GENERATING_BOUNDS_H
358
359struct zone {
360 /* Read-mostly fields */
361
362 /* zone watermarks, access with *_wmark_pages(zone) macros */
363 unsigned long watermark[NR_WMARK];
364
365 unsigned long nr_reserved_highatomic;
366
367 /*
368 * We don't know if the memory that we're going to allocate will be
369 * freeable or/and it will be released eventually, so to avoid totally
370 * wasting several GB of ram we must reserve some of the lower zone
371 * memory (otherwise we risk to run OOM on the lower zones despite
372 * there being tons of freeable ram on the higher zones). This array is
373 * recalculated at runtime if the sysctl_lowmem_reserve_ratio sysctl
374 * changes.
375 */
376 long lowmem_reserve[MAX_NR_ZONES];
377
378#ifdef CONFIG_NUMA
379 int node;
380#endif
381 struct pglist_data *zone_pgdat;
382 struct per_cpu_pageset __percpu *pageset;
383
384#ifndef CONFIG_SPARSEMEM
385 /*
386 * Flags for a pageblock_nr_pages block. See pageblock-flags.h.
387 * In SPARSEMEM, this map is stored in struct mem_section
388 */
389 unsigned long *pageblock_flags;
390#endif /* CONFIG_SPARSEMEM */
391
392 /* zone_start_pfn == zone_start_paddr >> PAGE_SHIFT */
393 unsigned long zone_start_pfn;
394
395 /*
396 * spanned_pages is the total pages spanned by the zone, including
397 * holes, which is calculated as:
398 * spanned_pages = zone_end_pfn - zone_start_pfn;
399 *
400 * present_pages is physical pages existing within the zone, which
401 * is calculated as:
402 * present_pages = spanned_pages - absent_pages(pages in holes);
403 *
404 * managed_pages is present pages managed by the buddy system, which
405 * is calculated as (reserved_pages includes pages allocated by the
406 * bootmem allocator):
407 * managed_pages = present_pages - reserved_pages;
408 *
409 * So present_pages may be used by memory hotplug or memory power
410 * management logic to figure out unmanaged pages by checking
411 * (present_pages - managed_pages). And managed_pages should be used
412 * by page allocator and vm scanner to calculate all kinds of watermarks
413 * and thresholds.
414 *
415 * Locking rules:
416 *
417 * zone_start_pfn and spanned_pages are protected by span_seqlock.
418 * It is a seqlock because it has to be read outside of zone->lock,
419 * and it is done in the main allocator path. But, it is written
420 * quite infrequently.
421 *
422 * The span_seq lock is declared along with zone->lock because it is
423 * frequently read in proximity to zone->lock. It's good to
424 * give them a chance of being in the same cacheline.
425 *
426 * Write access to present_pages at runtime should be protected by
427 * mem_hotplug_begin/end(). Any reader who can't tolerant drift of
428 * present_pages should get_online_mems() to get a stable value.
429 *
430 * Read access to managed_pages should be safe because it's unsigned
431 * long. Write access to zone->managed_pages and totalram_pages are
432 * protected by managed_page_count_lock at runtime. Idealy only
433 * adjust_managed_page_count() should be used instead of directly
434 * touching zone->managed_pages and totalram_pages.
435 */
436 unsigned long managed_pages;
437 unsigned long spanned_pages;
438 unsigned long present_pages;
439
440 const char *name;
441
442#ifdef CONFIG_MEMORY_ISOLATION
443 /*
444 * Number of isolated pageblock. It is used to solve incorrect
445 * freepage counting problem due to racy retrieving migratetype
446 * of pageblock. Protected by zone->lock.
447 */
448 unsigned long nr_isolate_pageblock;
449#endif
450
451#ifdef CONFIG_MEMORY_HOTPLUG
452 /* see spanned/present_pages for more description */
453 seqlock_t span_seqlock;
454#endif
455
456 int initialized;
457
458 /* Write-intensive fields used from the page allocator */
459 ZONE_PADDING(_pad1_)
460
461 /* free areas of different sizes */
462 struct free_area free_area[MAX_ORDER];
463
464 /* zone flags, see below */
465 unsigned long flags;
466
467 /* Primarily protects free_area */
468 spinlock_t lock;
469
470 /* Write-intensive fields used by compaction and vmstats. */
471 ZONE_PADDING(_pad2_)
472
473 /*
474 * When free pages are below this point, additional steps are taken
475 * when reading the number of free pages to avoid per-cpu counter
476 * drift allowing watermarks to be breached
477 */
478 unsigned long percpu_drift_mark;
479
480#if defined CONFIG_COMPACTION || defined CONFIG_CMA
481 /* pfn where compaction free scanner should start */
482 unsigned long compact_cached_free_pfn;
483 /* pfn where async and sync compaction migration scanner should start */
484 unsigned long compact_cached_migrate_pfn[2];
485#endif
486
487#ifdef CONFIG_COMPACTION
488 /*
489 * On compaction failure, 1<<compact_defer_shift compactions
490 * are skipped before trying again. The number attempted since
491 * last failure is tracked with compact_considered.
492 */
493 unsigned int compact_considered;
494 unsigned int compact_defer_shift;
495 int compact_order_failed;
496#endif
497
498#if defined CONFIG_COMPACTION || defined CONFIG_CMA
499 /* Set to true when the PG_migrate_skip bits should be cleared */
500 bool compact_blockskip_flush;
501#endif
502
503 bool contiguous;
504
505 ZONE_PADDING(_pad3_)
506 /* Zone statistics */
507 atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
508 atomic_long_t vm_numa_stat[NR_VM_NUMA_STAT_ITEMS];
509} ____cacheline_internodealigned_in_smp;
510
511enum pgdat_flags {
512 PGDAT_CONGESTED, /* pgdat has many dirty pages backed by
513 * a congested BDI
514 */
515 PGDAT_DIRTY, /* reclaim scanning has recently found
516 * many dirty file pages at the tail
517 * of the LRU.
518 */
519 PGDAT_WRITEBACK, /* reclaim scanning has recently found
520 * many pages under writeback
521 */
522 PGDAT_RECLAIM_LOCKED, /* prevents concurrent reclaim */
523};
524
525static inline unsigned long zone_end_pfn(const struct zone *zone)
526{
527 return zone->zone_start_pfn + zone->spanned_pages;
528}
529
530static inline bool zone_spans_pfn(const struct zone *zone, unsigned long pfn)
531{
532 return zone->zone_start_pfn <= pfn && pfn < zone_end_pfn(zone);
533}
534
535static inline bool zone_is_initialized(struct zone *zone)
536{
537 return zone->initialized;
538}
539
540static inline bool zone_is_empty(struct zone *zone)
541{
542 return zone->spanned_pages == 0;
543}
544
545/*
546 * Return true if [start_pfn, start_pfn + nr_pages) range has a non-empty
547 * intersection with the given zone
548 */
549static inline bool zone_intersects(struct zone *zone,
550 unsigned long start_pfn, unsigned long nr_pages)
551{
552 if (zone_is_empty(zone))
553 return false;
554 if (start_pfn >= zone_end_pfn(zone) ||
555 start_pfn + nr_pages <= zone->zone_start_pfn)
556 return false;
557
558 return true;
559}
560
561/*
562 * The "priority" of VM scanning is how much of the queues we will scan in one
563 * go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the
564 * queues ("queue_length >> 12") during an aging round.
565 */
566#define DEF_PRIORITY 12
567
568/* Maximum number of zones on a zonelist */
569#define MAX_ZONES_PER_ZONELIST (MAX_NUMNODES * MAX_NR_ZONES)
570
571enum {
572 ZONELIST_FALLBACK, /* zonelist with fallback */
573#ifdef CONFIG_NUMA
574 /*
575 * The NUMA zonelists are doubled because we need zonelists that
576 * restrict the allocations to a single node for __GFP_THISNODE.
577 */
578 ZONELIST_NOFALLBACK, /* zonelist without fallback (__GFP_THISNODE) */
579#endif
580 MAX_ZONELISTS
581};
582
583/*
584 * This struct contains information about a zone in a zonelist. It is stored
585 * here to avoid dereferences into large structures and lookups of tables
586 */
587struct zoneref {
588 struct zone *zone; /* Pointer to actual zone */
589 int zone_idx; /* zone_idx(zoneref->zone) */
590};
591
592/*
593 * One allocation request operates on a zonelist. A zonelist
594 * is a list of zones, the first one is the 'goal' of the
595 * allocation, the other zones are fallback zones, in decreasing
596 * priority.
597 *
598 * To speed the reading of the zonelist, the zonerefs contain the zone index
599 * of the entry being read. Helper functions to access information given
600 * a struct zoneref are
601 *
602 * zonelist_zone() - Return the struct zone * for an entry in _zonerefs
603 * zonelist_zone_idx() - Return the index of the zone for an entry
604 * zonelist_node_idx() - Return the index of the node for an entry
605 */
606struct zonelist {
607 struct zoneref _zonerefs[MAX_ZONES_PER_ZONELIST + 1];
608};
609
610#ifndef CONFIG_DISCONTIGMEM
611/* The array of struct pages - for discontigmem use pgdat->lmem_map */
612extern struct page *mem_map;
613#endif
614
615/*
616 * On NUMA machines, each NUMA node would have a pg_data_t to describe
617 * it's memory layout. On UMA machines there is a single pglist_data which
618 * describes the whole memory.
619 *
620 * Memory statistics and page replacement data structures are maintained on a
621 * per-zone basis.
622 */
623struct bootmem_data;
624typedef struct pglist_data {
625 struct zone node_zones[MAX_NR_ZONES];
626 struct zonelist node_zonelists[MAX_ZONELISTS];
627 int nr_zones;
628#ifdef CONFIG_FLAT_NODE_MEM_MAP /* means !SPARSEMEM */
629 struct page *node_mem_map;
630#ifdef CONFIG_PAGE_EXTENSION
631 struct page_ext *node_page_ext;
632#endif
633#endif
634#ifndef CONFIG_NO_BOOTMEM
635 struct bootmem_data *bdata;
636#endif
637#if defined(CONFIG_MEMORY_HOTPLUG) || defined(CONFIG_DEFERRED_STRUCT_PAGE_INIT)
638 /*
639 * Must be held any time you expect node_start_pfn, node_present_pages
640 * or node_spanned_pages stay constant. Holding this will also
641 * guarantee that any pfn_valid() stays that way.
642 *
643 * pgdat_resize_lock() and pgdat_resize_unlock() are provided to
644 * manipulate node_size_lock without checking for CONFIG_MEMORY_HOTPLUG
645 * or CONFIG_DEFERRED_STRUCT_PAGE_INIT.
646 *
647 * Nests above zone->lock and zone->span_seqlock
648 */
649 spinlock_t node_size_lock;
650#endif
651 unsigned long node_start_pfn;
652 unsigned long node_present_pages; /* total number of physical pages */
653 unsigned long node_spanned_pages; /* total size of physical page
654 range, including holes */
655 int node_id;
656 wait_queue_head_t kswapd_wait;
657 wait_queue_head_t pfmemalloc_wait;
658 struct task_struct *kswapd; /* Protected by
659 mem_hotplug_begin/end() */
660 int kswapd_order;
661 enum zone_type kswapd_classzone_idx;
662
663 int kswapd_failures; /* Number of 'reclaimed == 0' runs */
664
665#ifdef CONFIG_COMPACTION
666 int kcompactd_max_order;
667 enum zone_type kcompactd_classzone_idx;
668 wait_queue_head_t kcompactd_wait;
669 struct task_struct *kcompactd;
670#endif
671#ifdef CONFIG_NUMA_BALANCING
672 /* Lock serializing the migrate rate limiting window */
673 spinlock_t numabalancing_migrate_lock;
674
675 /* Rate limiting time interval */
676 unsigned long numabalancing_migrate_next_window;
677
678 /* Number of pages migrated during the rate limiting time interval */
679 unsigned long numabalancing_migrate_nr_pages;
680#endif
681 /*
682 * This is a per-node reserve of pages that are not available
683 * to userspace allocations.
684 */
685 unsigned long totalreserve_pages;
686
687#ifdef CONFIG_NUMA
688 /*
689 * zone reclaim becomes active if more unmapped pages exist.
690 */
691 unsigned long min_unmapped_pages;
692 unsigned long min_slab_pages;
693#endif /* CONFIG_NUMA */
694
695 /* Write-intensive fields used by page reclaim */
696 ZONE_PADDING(_pad1_)
697 spinlock_t lru_lock;
698
699#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
700 /*
701 * If memory initialisation on large machines is deferred then this
702 * is the first PFN that needs to be initialised.
703 */
704 unsigned long first_deferred_pfn;
705 /* Number of non-deferred pages */
706 unsigned long static_init_pgcnt;
707#endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
708
709#ifdef CONFIG_TRANSPARENT_HUGEPAGE
710 spinlock_t split_queue_lock;
711 struct list_head split_queue;
712 unsigned long split_queue_len;
713#endif
714
715 /* Fields commonly accessed by the page reclaim scanner */
716 struct lruvec lruvec;
717
718 unsigned long flags;
719
720 ZONE_PADDING(_pad2_)
721
722 /* Per-node vmstats */
723 struct per_cpu_nodestat __percpu *per_cpu_nodestats;
724 atomic_long_t vm_stat[NR_VM_NODE_STAT_ITEMS];
725} pg_data_t;
726
727#define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages)
728#define node_spanned_pages(nid) (NODE_DATA(nid)->node_spanned_pages)
729#ifdef CONFIG_FLAT_NODE_MEM_MAP
730#define pgdat_page_nr(pgdat, pagenr) ((pgdat)->node_mem_map + (pagenr))
731#else
732#define pgdat_page_nr(pgdat, pagenr) pfn_to_page((pgdat)->node_start_pfn + (pagenr))
733#endif
734#define nid_page_nr(nid, pagenr) pgdat_page_nr(NODE_DATA(nid),(pagenr))
735
736#define node_start_pfn(nid) (NODE_DATA(nid)->node_start_pfn)
737#define node_end_pfn(nid) pgdat_end_pfn(NODE_DATA(nid))
738static inline spinlock_t *zone_lru_lock(struct zone *zone)
739{
740 return &zone->zone_pgdat->lru_lock;
741}
742
743static inline struct lruvec *node_lruvec(struct pglist_data *pgdat)
744{
745 return &pgdat->lruvec;
746}
747
748static inline unsigned long pgdat_end_pfn(pg_data_t *pgdat)
749{
750 return pgdat->node_start_pfn + pgdat->node_spanned_pages;
751}
752
753static inline bool pgdat_is_empty(pg_data_t *pgdat)
754{
755 return !pgdat->node_start_pfn && !pgdat->node_spanned_pages;
756}
757
758static inline int zone_id(const struct zone *zone)
759{
760 struct pglist_data *pgdat = zone->zone_pgdat;
761
762 return zone - pgdat->node_zones;
763}
764
765#ifdef CONFIG_ZONE_DEVICE
766static inline bool is_dev_zone(const struct zone *zone)
767{
768 return zone_id(zone) == ZONE_DEVICE;
769}
770#else
771static inline bool is_dev_zone(const struct zone *zone)
772{
773 return false;
774}
775#endif
776
777#include <linux/memory_hotplug.h>
778
779void build_all_zonelists(pg_data_t *pgdat);
780void wakeup_kswapd(struct zone *zone, gfp_t gfp_mask, int order,
781 enum zone_type classzone_idx);
782bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
783 int classzone_idx, unsigned int alloc_flags,
784 long free_pages);
785bool zone_watermark_ok(struct zone *z, unsigned int order,
786 unsigned long mark, int classzone_idx,
787 unsigned int alloc_flags);
788bool zone_watermark_ok_safe(struct zone *z, unsigned int order,
789 unsigned long mark, int classzone_idx);
790enum memmap_context {
791 MEMMAP_EARLY,
792 MEMMAP_HOTPLUG,
793};
794extern void init_currently_empty_zone(struct zone *zone, unsigned long start_pfn,
795 unsigned long size);
796
797extern void lruvec_init(struct lruvec *lruvec);
798
799static inline struct pglist_data *lruvec_pgdat(struct lruvec *lruvec)
800{
801#ifdef CONFIG_MEMCG
802 return lruvec->pgdat;
803#else
804 return container_of(lruvec, struct pglist_data, lruvec);
805#endif
806}
807
808extern unsigned long lruvec_lru_size(struct lruvec *lruvec, enum lru_list lru, int zone_idx);
809
810#ifdef CONFIG_HAVE_MEMORY_PRESENT
811void memory_present(int nid, unsigned long start, unsigned long end);
812#else
813static inline void memory_present(int nid, unsigned long start, unsigned long end) {}
814#endif
815
816#ifdef CONFIG_HAVE_MEMORYLESS_NODES
817int local_memory_node(int node_id);
818#else
819static inline int local_memory_node(int node_id) { return node_id; };
820#endif
821
822/*
823 * zone_idx() returns 0 for the ZONE_DMA zone, 1 for the ZONE_NORMAL zone, etc.
824 */
825#define zone_idx(zone) ((zone) - (zone)->zone_pgdat->node_zones)
826
827/*
828 * Returns true if a zone has pages managed by the buddy allocator.
829 * All the reclaim decisions have to use this function rather than
830 * populated_zone(). If the whole zone is reserved then we can easily
831 * end up with populated_zone() && !managed_zone().
832 */
833static inline bool managed_zone(struct zone *zone)
834{
835 return zone->managed_pages;
836}
837
838/* Returns true if a zone has memory */
839static inline bool populated_zone(struct zone *zone)
840{
841 return zone->present_pages;
842}
843
844extern int movable_zone;
845
846#ifdef CONFIG_HIGHMEM
847static inline int zone_movable_is_highmem(void)
848{
849#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
850 return movable_zone == ZONE_HIGHMEM;
851#else
852 return (ZONE_MOVABLE - 1) == ZONE_HIGHMEM;
853#endif
854}
855#endif
856
857static inline int is_highmem_idx(enum zone_type idx)
858{
859#ifdef CONFIG_HIGHMEM
860 return (idx == ZONE_HIGHMEM ||
861 (idx == ZONE_MOVABLE && zone_movable_is_highmem()));
862#else
863 return 0;
864#endif
865}
866
867/**
868 * is_highmem - helper function to quickly check if a struct zone is a
869 * highmem zone or not. This is an attempt to keep references
870 * to ZONE_{DMA/NORMAL/HIGHMEM/etc} in general code to a minimum.
871 * @zone - pointer to struct zone variable
872 */
873static inline int is_highmem(struct zone *zone)
874{
875#ifdef CONFIG_HIGHMEM
876 return is_highmem_idx(zone_idx(zone));
877#else
878 return 0;
879#endif
880}
881
882/* These two functions are used to setup the per zone pages min values */
883struct ctl_table;
884int min_free_kbytes_sysctl_handler(struct ctl_table *, int,
885 void __user *, size_t *, loff_t *);
886int watermark_scale_factor_sysctl_handler(struct ctl_table *, int,
887 void __user *, size_t *, loff_t *);
888extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES];
889int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int,
890 void __user *, size_t *, loff_t *);
891int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *, int,
892 void __user *, size_t *, loff_t *);
893int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *, int,
894 void __user *, size_t *, loff_t *);
895int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *, int,
896 void __user *, size_t *, loff_t *);
897
898extern int numa_zonelist_order_handler(struct ctl_table *, int,
899 void __user *, size_t *, loff_t *);
900extern char numa_zonelist_order[];
901#define NUMA_ZONELIST_ORDER_LEN 16
902
903#ifndef CONFIG_NEED_MULTIPLE_NODES
904
905extern struct pglist_data contig_page_data;
906#define NODE_DATA(nid) (&contig_page_data)
907#define NODE_MEM_MAP(nid) mem_map
908
909#else /* CONFIG_NEED_MULTIPLE_NODES */
910
911#include <asm/mmzone.h>
912
913#endif /* !CONFIG_NEED_MULTIPLE_NODES */
914
915extern struct pglist_data *first_online_pgdat(void);
916extern struct pglist_data *next_online_pgdat(struct pglist_data *pgdat);
917extern struct zone *next_zone(struct zone *zone);
918
919/**
920 * for_each_online_pgdat - helper macro to iterate over all online nodes
921 * @pgdat - pointer to a pg_data_t variable
922 */
923#define for_each_online_pgdat(pgdat) \
924 for (pgdat = first_online_pgdat(); \
925 pgdat; \
926 pgdat = next_online_pgdat(pgdat))
927/**
928 * for_each_zone - helper macro to iterate over all memory zones
929 * @zone - pointer to struct zone variable
930 *
931 * The user only needs to declare the zone variable, for_each_zone
932 * fills it in.
933 */
934#define for_each_zone(zone) \
935 for (zone = (first_online_pgdat())->node_zones; \
936 zone; \
937 zone = next_zone(zone))
938
939#define for_each_populated_zone(zone) \
940 for (zone = (first_online_pgdat())->node_zones; \
941 zone; \
942 zone = next_zone(zone)) \
943 if (!populated_zone(zone)) \
944 ; /* do nothing */ \
945 else
946
947static inline struct zone *zonelist_zone(struct zoneref *zoneref)
948{
949 return zoneref->zone;
950}
951
952static inline int zonelist_zone_idx(struct zoneref *zoneref)
953{
954 return zoneref->zone_idx;
955}
956
957static inline int zonelist_node_idx(struct zoneref *zoneref)
958{
959#ifdef CONFIG_NUMA
960 /* zone_to_nid not available in this context */
961 return zoneref->zone->node;
962#else
963 return 0;
964#endif /* CONFIG_NUMA */
965}
966
967struct zoneref *__next_zones_zonelist(struct zoneref *z,
968 enum zone_type highest_zoneidx,
969 nodemask_t *nodes);
970
971/**
972 * 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
973 * @z - The cursor used as a starting point for the search
974 * @highest_zoneidx - The zone index of the highest zone to return
975 * @nodes - An optional nodemask to filter the zonelist with
976 *
977 * This function returns the next zone at or below a given zone index that is
978 * within the allowed nodemask using a cursor as the starting point for the
979 * search. The zoneref returned is a cursor that represents the current zone
980 * being examined. It should be advanced by one before calling
981 * next_zones_zonelist again.
982 */
983static __always_inline struct zoneref *next_zones_zonelist(struct zoneref *z,
984 enum zone_type highest_zoneidx,
985 nodemask_t *nodes)
986{
987 if (likely(!nodes && zonelist_zone_idx(z) <= highest_zoneidx))
988 return z;
989 return __next_zones_zonelist(z, highest_zoneidx, nodes);
990}
991
992/**
993 * first_zones_zonelist - Returns the first zone at or below highest_zoneidx within the allowed nodemask in a zonelist
994 * @zonelist - The zonelist to search for a suitable zone
995 * @highest_zoneidx - The zone index of the highest zone to return
996 * @nodes - An optional nodemask to filter the zonelist with
997 * @return - Zoneref pointer for the first suitable zone found (see below)
998 *
999 * This function returns the first zone at or below a given zone index that is
1000 * within the allowed nodemask. The zoneref returned is a cursor that can be
1001 * used to iterate the zonelist with next_zones_zonelist by advancing it by
1002 * one before calling.
1003 *
1004 * When no eligible zone is found, zoneref->zone is NULL (zoneref itself is
1005 * never NULL). This may happen either genuinely, or due to concurrent nodemask
1006 * update due to cpuset modification.
1007 */
1008static inline struct zoneref *first_zones_zonelist(struct zonelist *zonelist,
1009 enum zone_type highest_zoneidx,
1010 nodemask_t *nodes)
1011{
1012 return next_zones_zonelist(zonelist->_zonerefs,
1013 highest_zoneidx, nodes);
1014}
1015
1016/**
1017 * 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
1018 * @zone - The current zone in the iterator
1019 * @z - The current pointer within zonelist->zones being iterated
1020 * @zlist - The zonelist being iterated
1021 * @highidx - The zone index of the highest zone to return
1022 * @nodemask - Nodemask allowed by the allocator
1023 *
1024 * This iterator iterates though all zones at or below a given zone index and
1025 * within a given nodemask
1026 */
1027#define for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, nodemask) \
1028 for (z = first_zones_zonelist(zlist, highidx, nodemask), zone = zonelist_zone(z); \
1029 zone; \
1030 z = next_zones_zonelist(++z, highidx, nodemask), \
1031 zone = zonelist_zone(z))
1032
1033#define for_next_zone_zonelist_nodemask(zone, z, zlist, highidx, nodemask) \
1034 for (zone = z->zone; \
1035 zone; \
1036 z = next_zones_zonelist(++z, highidx, nodemask), \
1037 zone = zonelist_zone(z))
1038
1039
1040/**
1041 * for_each_zone_zonelist - helper macro to iterate over valid zones in a zonelist at or below a given zone index
1042 * @zone - The current zone in the iterator
1043 * @z - The current pointer within zonelist->zones being iterated
1044 * @zlist - The zonelist being iterated
1045 * @highidx - The zone index of the highest zone to return
1046 *
1047 * This iterator iterates though all zones at or below a given zone index.
1048 */
1049#define for_each_zone_zonelist(zone, z, zlist, highidx) \
1050 for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, NULL)
1051
1052#ifdef CONFIG_SPARSEMEM
1053#include <asm/sparsemem.h>
1054#endif
1055
1056#if !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) && \
1057 !defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP)
1058static inline unsigned long early_pfn_to_nid(unsigned long pfn)
1059{
1060 BUILD_BUG_ON(IS_ENABLED(CONFIG_NUMA));
1061 return 0;
1062}
1063#endif
1064
1065#ifdef CONFIG_FLATMEM
1066#define pfn_to_nid(pfn) (0)
1067#endif
1068
1069#ifdef CONFIG_SPARSEMEM
1070
1071/*
1072 * SECTION_SHIFT #bits space required to store a section #
1073 *
1074 * PA_SECTION_SHIFT physical address to/from section number
1075 * PFN_SECTION_SHIFT pfn to/from section number
1076 */
1077#define PA_SECTION_SHIFT (SECTION_SIZE_BITS)
1078#define PFN_SECTION_SHIFT (SECTION_SIZE_BITS - PAGE_SHIFT)
1079
1080#define NR_MEM_SECTIONS (1UL << SECTIONS_SHIFT)
1081
1082#define PAGES_PER_SECTION (1UL << PFN_SECTION_SHIFT)
1083#define PAGE_SECTION_MASK (~(PAGES_PER_SECTION-1))
1084
1085#define SECTION_BLOCKFLAGS_BITS \
1086 ((1UL << (PFN_SECTION_SHIFT - pageblock_order)) * NR_PAGEBLOCK_BITS)
1087
1088#if (MAX_ORDER - 1 + PAGE_SHIFT) > SECTION_SIZE_BITS
1089#error Allocator MAX_ORDER exceeds SECTION_SIZE
1090#endif
1091
1092static inline unsigned long pfn_to_section_nr(unsigned long pfn)
1093{
1094 return pfn >> PFN_SECTION_SHIFT;
1095}
1096static inline unsigned long section_nr_to_pfn(unsigned long sec)
1097{
1098 return sec << PFN_SECTION_SHIFT;
1099}
1100
1101#define SECTION_ALIGN_UP(pfn) (((pfn) + PAGES_PER_SECTION - 1) & PAGE_SECTION_MASK)
1102#define SECTION_ALIGN_DOWN(pfn) ((pfn) & PAGE_SECTION_MASK)
1103
1104struct page;
1105struct page_ext;
1106struct mem_section {
1107 /*
1108 * This is, logically, a pointer to an array of struct
1109 * pages. However, it is stored with some other magic.
1110 * (see sparse.c::sparse_init_one_section())
1111 *
1112 * Additionally during early boot we encode node id of
1113 * the location of the section here to guide allocation.
1114 * (see sparse.c::memory_present())
1115 *
1116 * Making it a UL at least makes someone do a cast
1117 * before using it wrong.
1118 */
1119 unsigned long section_mem_map;
1120
1121 /* See declaration of similar field in struct zone */
1122 unsigned long *pageblock_flags;
1123#ifdef CONFIG_PAGE_EXTENSION
1124 /*
1125 * If SPARSEMEM, pgdat doesn't have page_ext pointer. We use
1126 * section. (see page_ext.h about this.)
1127 */
1128 struct page_ext *page_ext;
1129 unsigned long pad;
1130#endif
1131 /*
1132 * WARNING: mem_section must be a power-of-2 in size for the
1133 * calculation and use of SECTION_ROOT_MASK to make sense.
1134 */
1135};
1136
1137#ifdef CONFIG_SPARSEMEM_EXTREME
1138#define SECTIONS_PER_ROOT (PAGE_SIZE / sizeof (struct mem_section))
1139#else
1140#define SECTIONS_PER_ROOT 1
1141#endif
1142
1143#define SECTION_NR_TO_ROOT(sec) ((sec) / SECTIONS_PER_ROOT)
1144#define NR_SECTION_ROOTS DIV_ROUND_UP(NR_MEM_SECTIONS, SECTIONS_PER_ROOT)
1145#define SECTION_ROOT_MASK (SECTIONS_PER_ROOT - 1)
1146
1147#ifdef CONFIG_SPARSEMEM_EXTREME
1148extern struct mem_section **mem_section;
1149#else
1150extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT];
1151#endif
1152
1153static inline struct mem_section *__nr_to_section(unsigned long nr)
1154{
1155#ifdef CONFIG_SPARSEMEM_EXTREME
1156 if (!mem_section)
1157 return NULL;
1158#endif
1159 if (!mem_section[SECTION_NR_TO_ROOT(nr)])
1160 return NULL;
1161 return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK];
1162}
1163extern int __section_nr(struct mem_section* ms);
1164extern unsigned long usemap_size(void);
1165
1166/*
1167 * We use the lower bits of the mem_map pointer to store
1168 * a little bit of information. The pointer is calculated
1169 * as mem_map - section_nr_to_pfn(pnum). The result is
1170 * aligned to the minimum alignment of the two values:
1171 * 1. All mem_map arrays are page-aligned.
1172 * 2. section_nr_to_pfn() always clears PFN_SECTION_SHIFT
1173 * lowest bits. PFN_SECTION_SHIFT is arch-specific
1174 * (equal SECTION_SIZE_BITS - PAGE_SHIFT), and the
1175 * worst combination is powerpc with 256k pages,
1176 * which results in PFN_SECTION_SHIFT equal 6.
1177 * To sum it up, at least 6 bits are available.
1178 */
1179#define SECTION_MARKED_PRESENT (1UL<<0)
1180#define SECTION_HAS_MEM_MAP (1UL<<1)
1181#define SECTION_IS_ONLINE (1UL<<2)
1182#define SECTION_MAP_LAST_BIT (1UL<<3)
1183#define SECTION_MAP_MASK (~(SECTION_MAP_LAST_BIT-1))
1184#define SECTION_NID_SHIFT 3
1185
1186static inline struct page *__section_mem_map_addr(struct mem_section *section)
1187{
1188 unsigned long map = section->section_mem_map;
1189 map &= SECTION_MAP_MASK;
1190 return (struct page *)map;
1191}
1192
1193static inline int present_section(struct mem_section *section)
1194{
1195 return (section && (section->section_mem_map & SECTION_MARKED_PRESENT));
1196}
1197
1198static inline int present_section_nr(unsigned long nr)
1199{
1200 return present_section(__nr_to_section(nr));
1201}
1202
1203static inline int valid_section(struct mem_section *section)
1204{
1205 return (section && (section->section_mem_map & SECTION_HAS_MEM_MAP));
1206}
1207
1208static inline int valid_section_nr(unsigned long nr)
1209{
1210 return valid_section(__nr_to_section(nr));
1211}
1212
1213static inline int online_section(struct mem_section *section)
1214{
1215 return (section && (section->section_mem_map & SECTION_IS_ONLINE));
1216}
1217
1218static inline int online_section_nr(unsigned long nr)
1219{
1220 return online_section(__nr_to_section(nr));
1221}
1222
1223#ifdef CONFIG_MEMORY_HOTPLUG
1224void online_mem_sections(unsigned long start_pfn, unsigned long end_pfn);
1225#ifdef CONFIG_MEMORY_HOTREMOVE
1226void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn);
1227#endif
1228#endif
1229
1230static inline struct mem_section *__pfn_to_section(unsigned long pfn)
1231{
1232 return __nr_to_section(pfn_to_section_nr(pfn));
1233}
1234
1235extern int __highest_present_section_nr;
1236
1237#ifndef CONFIG_HAVE_ARCH_PFN_VALID
1238static inline int pfn_valid(unsigned long pfn)
1239{
1240 if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
1241 return 0;
1242 return valid_section(__nr_to_section(pfn_to_section_nr(pfn)));
1243}
1244#endif
1245
1246static inline int pfn_present(unsigned long pfn)
1247{
1248 if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
1249 return 0;
1250 return present_section(__nr_to_section(pfn_to_section_nr(pfn)));
1251}
1252
1253/*
1254 * These are _only_ used during initialisation, therefore they
1255 * can use __initdata ... They could have names to indicate
1256 * this restriction.
1257 */
1258#ifdef CONFIG_NUMA
1259#define pfn_to_nid(pfn) \
1260({ \
1261 unsigned long __pfn_to_nid_pfn = (pfn); \
1262 page_to_nid(pfn_to_page(__pfn_to_nid_pfn)); \
1263})
1264#else
1265#define pfn_to_nid(pfn) (0)
1266#endif
1267
1268#define early_pfn_valid(pfn) pfn_valid(pfn)
1269void sparse_init(void);
1270#else
1271#define sparse_init() do {} while (0)
1272#define sparse_index_init(_sec, _nid) do {} while (0)
1273#endif /* CONFIG_SPARSEMEM */
1274
1275/*
1276 * During memory init memblocks map pfns to nids. The search is expensive and
1277 * this caches recent lookups. The implementation of __early_pfn_to_nid
1278 * may treat start/end as pfns or sections.
1279 */
1280struct mminit_pfnnid_cache {
1281 unsigned long last_start;
1282 unsigned long last_end;
1283 int last_nid;
1284};
1285
1286#ifndef early_pfn_valid
1287#define early_pfn_valid(pfn) (1)
1288#endif
1289
1290void memory_present(int nid, unsigned long start, unsigned long end);
1291
1292/*
1293 * If it is possible to have holes within a MAX_ORDER_NR_PAGES, then we
1294 * need to check pfn validility within that MAX_ORDER_NR_PAGES block.
1295 * pfn_valid_within() should be used in this case; we optimise this away
1296 * when we have no holes within a MAX_ORDER_NR_PAGES block.
1297 */
1298#ifdef CONFIG_HOLES_IN_ZONE
1299#define pfn_valid_within(pfn) pfn_valid(pfn)
1300#else
1301#define pfn_valid_within(pfn) (1)
1302#endif
1303
1304#ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL
1305/*
1306 * pfn_valid() is meant to be able to tell if a given PFN has valid memmap
1307 * associated with it or not. This means that a struct page exists for this
1308 * pfn. The caller cannot assume the page is fully initialized in general.
1309 * Hotplugable pages might not have been onlined yet. pfn_to_online_page()
1310 * will ensure the struct page is fully online and initialized. Special pages
1311 * (e.g. ZONE_DEVICE) are never onlined and should be treated accordingly.
1312 *
1313 * In FLATMEM, it is expected that holes always have valid memmap as long as
1314 * there is valid PFNs either side of the hole. In SPARSEMEM, it is assumed
1315 * that a valid section has a memmap for the entire section.
1316 *
1317 * However, an ARM, and maybe other embedded architectures in the future
1318 * free memmap backing holes to save memory on the assumption the memmap is
1319 * never used. The page_zone linkages are then broken even though pfn_valid()
1320 * returns true. A walker of the full memmap must then do this additional
1321 * check to ensure the memmap they are looking at is sane by making sure
1322 * the zone and PFN linkages are still valid. This is expensive, but walkers
1323 * of the full memmap are extremely rare.
1324 */
1325bool memmap_valid_within(unsigned long pfn,
1326 struct page *page, struct zone *zone);
1327#else
1328static inline bool memmap_valid_within(unsigned long pfn,
1329 struct page *page, struct zone *zone)
1330{
1331 return true;
1332}
1333#endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */
1334
1335#endif /* !__GENERATING_BOUNDS.H */
1336#endif /* !__ASSEMBLY__ */
1337#endif /* _LINUX_MMZONE_H */
1338