1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_MMZONE_H
3 #define _LINUX_MMZONE_H
6 #ifndef __GENERATING_BOUNDS_H
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 <linux/mm_types.h>
22 #include <linux/page-flags.h>
25 /* Free memory management - zoned buddy allocator. */
26 #ifndef CONFIG_FORCE_MAX_ZONEORDER
29 #define MAX_ORDER CONFIG_FORCE_MAX_ZONEORDER
31 #define MAX_ORDER_NR_PAGES (1 << (MAX_ORDER - 1))
34 * PAGE_ALLOC_COSTLY_ORDER is the order at which allocations are deemed
35 * costly to service. That is between allocation orders which should
36 * coalesce naturally under reasonable reclaim pressure and those which
39 #define PAGE_ALLOC_COSTLY_ORDER 3
45 MIGRATE_PCPTYPES, /* the number of types on the pcp lists */
46 MIGRATE_HIGHATOMIC = MIGRATE_PCPTYPES,
49 * MIGRATE_CMA migration type is designed to mimic the way
50 * ZONE_MOVABLE works. Only movable pages can be allocated
51 * from MIGRATE_CMA pageblocks and page allocator never
52 * implicitly change migration type of MIGRATE_CMA pageblock.
54 * The way to use it is to change migratetype of a range of
55 * pageblocks to MIGRATE_CMA which can be done by
56 * __free_pageblock_cma() function. What is important though
57 * is that a range of pageblocks must be aligned to
58 * MAX_ORDER_NR_PAGES should biggest page be bigger then
63 #ifdef CONFIG_MEMORY_ISOLATION
64 MIGRATE_ISOLATE, /* can't allocate from here */
69 /* In mm/page_alloc.c; keep in sync also with show_migration_types() there */
70 extern const char * const migratetype_names[MIGRATE_TYPES];
73 # define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA)
74 # define is_migrate_cma_page(_page) (get_pageblock_migratetype(_page) == MIGRATE_CMA)
76 # define is_migrate_cma(migratetype) false
77 # define is_migrate_cma_page(_page) false
80 static inline bool is_migrate_movable(int mt)
82 return is_migrate_cma(mt) || mt == MIGRATE_MOVABLE;
85 #define for_each_migratetype_order(order, type) \
86 for (order = 0; order < MAX_ORDER; order++) \
87 for (type = 0; type < MIGRATE_TYPES; type++)
89 extern int page_group_by_mobility_disabled;
91 #define NR_MIGRATETYPE_BITS (PB_migrate_end - PB_migrate + 1)
92 #define MIGRATETYPE_MASK ((1UL << NR_MIGRATETYPE_BITS) - 1)
94 #define get_pageblock_migratetype(page) \
95 get_pfnblock_flags_mask(page, page_to_pfn(page), \
96 PB_migrate_end, MIGRATETYPE_MASK)
99 struct list_head free_list[MIGRATE_TYPES];
100 unsigned long nr_free;
103 /* Used for pages not on another list */
104 static inline void add_to_free_area(struct page *page, struct free_area *area,
107 list_add(&page->lru, &area->free_list[migratetype]);
111 /* Used for pages not on another list */
112 static inline void add_to_free_area_tail(struct page *page, struct free_area *area,
115 list_add_tail(&page->lru, &area->free_list[migratetype]);
119 #ifdef CONFIG_SHUFFLE_PAGE_ALLOCATOR
120 /* Used to preserve page allocation order entropy */
121 void add_to_free_area_random(struct page *page, struct free_area *area,
124 static inline void add_to_free_area_random(struct page *page,
125 struct free_area *area, int migratetype)
127 add_to_free_area(page, area, migratetype);
131 /* Used for pages which are on another list */
132 static inline void move_to_free_area(struct page *page, struct free_area *area,
135 list_move(&page->lru, &area->free_list[migratetype]);
138 static inline struct page *get_page_from_free_area(struct free_area *area,
141 return list_first_entry_or_null(&area->free_list[migratetype],
145 static inline void del_page_from_free_area(struct page *page,
146 struct free_area *area)
148 list_del(&page->lru);
149 __ClearPageBuddy(page);
150 set_page_private(page, 0);
154 static inline bool free_area_empty(struct free_area *area, int migratetype)
156 return list_empty(&area->free_list[migratetype]);
162 * zone->lock and the zone lru_lock are two of the hottest locks in the kernel.
163 * So add a wild amount of padding here to ensure that they fall into separate
164 * cachelines. There are very few zone structures in the machine, so space
165 * consumption is not a concern here.
167 #if defined(CONFIG_SMP)
168 struct zone_padding {
170 } ____cacheline_internodealigned_in_smp;
171 #define ZONE_PADDING(name) struct zone_padding name;
173 #define ZONE_PADDING(name)
177 enum numa_stat_item {
178 NUMA_HIT, /* allocated in intended node */
179 NUMA_MISS, /* allocated in non intended node */
180 NUMA_FOREIGN, /* was intended here, hit elsewhere */
181 NUMA_INTERLEAVE_HIT, /* interleaver preferred this zone */
182 NUMA_LOCAL, /* allocation from local node */
183 NUMA_OTHER, /* allocation from other node */
184 NR_VM_NUMA_STAT_ITEMS
187 #define NR_VM_NUMA_STAT_ITEMS 0
190 enum zone_stat_item {
191 /* First 128 byte cacheline (assuming 64 bit words) */
193 NR_ZONE_LRU_BASE, /* Used only for compaction and reclaim retry */
194 NR_ZONE_INACTIVE_ANON = NR_ZONE_LRU_BASE,
196 NR_ZONE_INACTIVE_FILE,
199 NR_ZONE_WRITE_PENDING, /* Count of dirty, writeback and unstable pages */
200 NR_MLOCK, /* mlock()ed pages found and moved off LRU */
201 NR_PAGETABLE, /* used for pagetables */
202 NR_KERNEL_STACK_KB, /* measured in KiB */
203 /* Second 128 byte cacheline */
205 #if IS_ENABLED(CONFIG_ZSMALLOC)
206 NR_ZSPAGES, /* allocated in zsmalloc */
209 NR_VM_ZONE_STAT_ITEMS };
211 enum node_stat_item {
213 NR_INACTIVE_ANON = NR_LRU_BASE, /* must match order of LRU_[IN]ACTIVE */
214 NR_ACTIVE_ANON, /* " " " " " */
215 NR_INACTIVE_FILE, /* " " " " " */
216 NR_ACTIVE_FILE, /* " " " " " */
217 NR_UNEVICTABLE, /* " " " " " */
219 NR_SLAB_UNRECLAIMABLE,
220 NR_ISOLATED_ANON, /* Temporary isolated pages from anon lru */
221 NR_ISOLATED_FILE, /* Temporary isolated pages from file lru */
226 WORKINGSET_NODERECLAIM,
227 NR_ANON_MAPPED, /* Mapped anonymous pages */
228 NR_FILE_MAPPED, /* pagecache pages mapped into pagetables.
229 only modified from process context */
233 NR_WRITEBACK_TEMP, /* Writeback using temporary buffers */
234 NR_SHMEM, /* shmem pages (included tmpfs/GEM pages) */
240 NR_UNSTABLE_NFS, /* NFS unstable pages */
242 NR_VMSCAN_IMMEDIATE, /* Prioritise for reclaim when writeback ends */
243 NR_DIRTIED, /* page dirtyings since bootup */
244 NR_WRITTEN, /* page writings since bootup */
245 NR_KERNEL_MISC_RECLAIMABLE, /* reclaimable non-slab kernel pages */
246 NR_VM_NODE_STAT_ITEMS
250 * We do arithmetic on the LRU lists in various places in the code,
251 * so it is important to keep the active lists LRU_ACTIVE higher in
252 * the array than the corresponding inactive lists, and to keep
253 * the *_FILE lists LRU_FILE higher than the corresponding _ANON lists.
255 * This has to be kept in sync with the statistics in zone_stat_item
256 * above and the descriptions in vmstat_text in mm/vmstat.c
263 LRU_INACTIVE_ANON = LRU_BASE,
264 LRU_ACTIVE_ANON = LRU_BASE + LRU_ACTIVE,
265 LRU_INACTIVE_FILE = LRU_BASE + LRU_FILE,
266 LRU_ACTIVE_FILE = LRU_BASE + LRU_FILE + LRU_ACTIVE,
271 #define for_each_lru(lru) for (lru = 0; lru < NR_LRU_LISTS; lru++)
273 #define for_each_evictable_lru(lru) for (lru = 0; lru <= LRU_ACTIVE_FILE; lru++)
275 static inline bool is_file_lru(enum lru_list lru)
277 return (lru == LRU_INACTIVE_FILE || lru == LRU_ACTIVE_FILE);
280 static inline bool is_active_lru(enum lru_list lru)
282 return (lru == LRU_ACTIVE_ANON || lru == LRU_ACTIVE_FILE);
285 #define ANON_AND_FILE 2
287 struct zone_reclaim_stat {
289 * The pageout code in vmscan.c keeps track of how many of the
290 * mem/swap backed and file backed pages are referenced.
291 * The higher the rotated/scanned ratio, the more valuable
294 * The anon LRU stats live in [0], file LRU stats in [1]
296 unsigned long recent_rotated[2];
297 unsigned long recent_scanned[2];
301 LRUVEC_CONGESTED, /* lruvec has many dirty pages
302 * backed by a congested BDI
306 #endif /* !__GENERATING_BOUNDS_H */
309 * Evictable pages are divided into multiple generations. The youngest and the
310 * oldest generation numbers, max_seq and min_seq, are monotonically increasing.
311 * They form a sliding window of a variable size [MIN_NR_GENS, MAX_NR_GENS]. An
312 * offset within MAX_NR_GENS, i.e., gen, indexes the LRU list of the
313 * corresponding generation. The gen counter in page->flags stores gen+1 while
314 * a page is on one of lrugen->lists[]. Otherwise it stores 0.
316 * A page is added to the youngest generation on faulting. The aging needs to
317 * check the accessed bit at least twice before handing this page over to the
318 * eviction. The first check takes care of the accessed bit set on the initial
319 * fault; the second check makes sure this page hasn't been used since then.
320 * This process, AKA second chance, requires a minimum of two generations,
321 * hence MIN_NR_GENS. And to maintain ABI compatibility with the active/inactive
322 * LRU, e.g., /proc/vmstat, these two generations are considered active; the
323 * rest of generations, if they exist, are considered inactive. See
324 * lru_gen_is_active().
326 * PG_active is always cleared while a page is on one of lrugen->lists[] so that
327 * the aging needs not to worry about it. And it's set again when a page
328 * considered active is isolated for non-reclaiming purposes, e.g., migration.
329 * See lru_gen_add_page() and lru_gen_del_page().
331 * MAX_NR_GENS is set to 4 so that the multi-gen LRU can support twice the
332 * number of categories of the active/inactive LRU when keeping track of
333 * accesses through page tables. This requires order_base_2(MAX_NR_GENS+1) bits
336 #define MIN_NR_GENS 2U
337 #define MAX_NR_GENS 4U
339 #ifndef __GENERATING_BOUNDS_H
343 #define LRU_GEN_MASK ((BIT(LRU_GEN_WIDTH) - 1) << LRU_GEN_PGOFF)
344 #define LRU_REFS_MASK ((BIT(LRU_REFS_WIDTH) - 1) << LRU_REFS_PGOFF)
346 #ifdef CONFIG_LRU_GEN
354 * The youngest generation number is stored in max_seq for both anon and file
355 * types as they are aged on an equal footing. The oldest generation numbers are
356 * stored in min_seq[] separately for anon and file types as clean file pages
357 * can be evicted regardless of swap constraints.
359 * Normally anon and file min_seq are in sync. But if swapping is constrained,
360 * e.g., out of swap space, file min_seq is allowed to advance and leave anon
363 * The number of pages in each generation is eventually consistent and therefore
364 * can be transiently negative.
366 struct lru_gen_struct {
367 /* the aging increments the youngest generation number */
368 unsigned long max_seq;
369 /* the eviction increments the oldest generation numbers */
370 unsigned long min_seq[ANON_AND_FILE];
371 /* the multi-gen LRU lists, lazily sorted on eviction */
372 struct list_head lists[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES];
373 /* the multi-gen LRU sizes, eventually consistent */
374 long nr_pages[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES];
377 void lru_gen_init_lruvec(struct lruvec *lruvec);
380 void lru_gen_init_memcg(struct mem_cgroup *memcg);
381 void lru_gen_exit_memcg(struct mem_cgroup *memcg);
384 #else /* !CONFIG_LRU_GEN */
386 static inline void lru_gen_init_lruvec(struct lruvec *lruvec)
391 static inline void lru_gen_init_memcg(struct mem_cgroup *memcg)
395 static inline void lru_gen_exit_memcg(struct mem_cgroup *memcg)
400 #endif /* CONFIG_LRU_GEN */
403 struct list_head lists[NR_LRU_LISTS];
404 struct zone_reclaim_stat reclaim_stat;
405 /* Evictions & activations on the inactive file list */
406 atomic_long_t inactive_age;
407 /* Refaults at the time of last reclaim cycle */
408 unsigned long refaults;
409 /* Various lruvec state flags (enum lruvec_flags) */
411 #ifdef CONFIG_LRU_GEN
412 /* evictable pages divided into generations */
413 struct lru_gen_struct lrugen;
416 struct pglist_data *pgdat;
420 /* Isolate unmapped file */
421 #define ISOLATE_UNMAPPED ((__force isolate_mode_t)0x2)
422 /* Isolate for asynchronous migration */
423 #define ISOLATE_ASYNC_MIGRATE ((__force isolate_mode_t)0x4)
424 /* Isolate unevictable pages */
425 #define ISOLATE_UNEVICTABLE ((__force isolate_mode_t)0x8)
427 /* LRU Isolation modes. */
428 typedef unsigned __bitwise isolate_mode_t;
430 enum zone_watermarks {
437 #define min_wmark_pages(z) (z->_watermark[WMARK_MIN] + z->watermark_boost)
438 #define low_wmark_pages(z) (z->_watermark[WMARK_LOW] + z->watermark_boost)
439 #define high_wmark_pages(z) (z->_watermark[WMARK_HIGH] + z->watermark_boost)
440 #define wmark_pages(z, i) (z->_watermark[i] + z->watermark_boost)
442 struct per_cpu_pages {
443 int count; /* number of pages in the list */
444 int high; /* high watermark, emptying needed */
445 int batch; /* chunk size for buddy add/remove */
447 /* Lists of pages, one per migrate type stored on the pcp-lists */
448 struct list_head lists[MIGRATE_PCPTYPES];
451 struct per_cpu_pageset {
452 struct per_cpu_pages pcp;
455 u16 vm_numa_stat_diff[NR_VM_NUMA_STAT_ITEMS];
459 s8 vm_stat_diff[NR_VM_ZONE_STAT_ITEMS];
463 struct per_cpu_nodestat {
465 s8 vm_node_stat_diff[NR_VM_NODE_STAT_ITEMS];
468 #endif /* !__GENERATING_BOUNDS.H */
472 * ZONE_DMA and ZONE_DMA32 are used when there are peripherals not able
473 * to DMA to all of the addressable memory (ZONE_NORMAL).
474 * On architectures where this area covers the whole 32 bit address
475 * space ZONE_DMA32 is used. ZONE_DMA is left for the ones with smaller
476 * DMA addressing constraints. This distinction is important as a 32bit
477 * DMA mask is assumed when ZONE_DMA32 is defined. Some 64-bit
478 * platforms may need both zones as they support peripherals with
479 * different DMA addressing limitations.
483 * - i386 and x86_64 have a fixed 16M ZONE_DMA and ZONE_DMA32 for the
484 * rest of the lower 4G.
486 * - arm only uses ZONE_DMA, the size, up to 4G, may vary depending on
487 * the specific device.
489 * - arm64 has a fixed 1G ZONE_DMA and ZONE_DMA32 for the rest of the
492 * - powerpc only uses ZONE_DMA, the size, up to 2G, may vary
493 * depending on the specific device.
495 * - s390 uses ZONE_DMA fixed to the lower 2G.
497 * - ia64 and riscv only use ZONE_DMA32.
499 * - parisc uses neither.
501 #ifdef CONFIG_ZONE_DMA
504 #ifdef CONFIG_ZONE_DMA32
508 * Normal addressable memory is in ZONE_NORMAL. DMA operations can be
509 * performed on pages in ZONE_NORMAL if the DMA devices support
510 * transfers to all addressable memory.
513 #ifdef CONFIG_HIGHMEM
515 * A memory area that is only addressable by the kernel through
516 * mapping portions into its own address space. This is for example
517 * used by i386 to allow the kernel to address the memory beyond
518 * 900MB. The kernel will set up special mappings (page
519 * table entries on i386) for each page that the kernel needs to
525 #ifdef CONFIG_ZONE_DEVICE
532 #ifndef __GENERATING_BOUNDS_H
534 #define ASYNC_AND_SYNC 2
537 /* Read-mostly fields */
539 /* zone watermarks, access with *_wmark_pages(zone) macros */
540 unsigned long _watermark[NR_WMARK];
541 unsigned long watermark_boost;
543 unsigned long nr_reserved_highatomic;
546 * We don't know if the memory that we're going to allocate will be
547 * freeable or/and it will be released eventually, so to avoid totally
548 * wasting several GB of ram we must reserve some of the lower zone
549 * memory (otherwise we risk to run OOM on the lower zones despite
550 * there being tons of freeable ram on the higher zones). This array is
551 * recalculated at runtime if the sysctl_lowmem_reserve_ratio sysctl
554 long lowmem_reserve[MAX_NR_ZONES];
559 struct pglist_data *zone_pgdat;
560 struct per_cpu_pageset __percpu *pageset;
562 #ifndef CONFIG_SPARSEMEM
564 * Flags for a pageblock_nr_pages block. See pageblock-flags.h.
565 * In SPARSEMEM, this map is stored in struct mem_section
567 unsigned long *pageblock_flags;
568 #endif /* CONFIG_SPARSEMEM */
570 /* zone_start_pfn == zone_start_paddr >> PAGE_SHIFT */
571 unsigned long zone_start_pfn;
574 * spanned_pages is the total pages spanned by the zone, including
575 * holes, which is calculated as:
576 * spanned_pages = zone_end_pfn - zone_start_pfn;
578 * present_pages is physical pages existing within the zone, which
580 * present_pages = spanned_pages - absent_pages(pages in holes);
582 * managed_pages is present pages managed by the buddy system, which
583 * is calculated as (reserved_pages includes pages allocated by the
584 * bootmem allocator):
585 * managed_pages = present_pages - reserved_pages;
587 * So present_pages may be used by memory hotplug or memory power
588 * management logic to figure out unmanaged pages by checking
589 * (present_pages - managed_pages). And managed_pages should be used
590 * by page allocator and vm scanner to calculate all kinds of watermarks
595 * zone_start_pfn and spanned_pages are protected by span_seqlock.
596 * It is a seqlock because it has to be read outside of zone->lock,
597 * and it is done in the main allocator path. But, it is written
598 * quite infrequently.
600 * The span_seq lock is declared along with zone->lock because it is
601 * frequently read in proximity to zone->lock. It's good to
602 * give them a chance of being in the same cacheline.
604 * Write access to present_pages at runtime should be protected by
605 * mem_hotplug_begin/end(). Any reader who can't tolerant drift of
606 * present_pages should get_online_mems() to get a stable value.
608 atomic_long_t managed_pages;
609 unsigned long spanned_pages;
610 unsigned long present_pages;
614 #ifdef CONFIG_MEMORY_ISOLATION
616 * Number of isolated pageblock. It is used to solve incorrect
617 * freepage counting problem due to racy retrieving migratetype
618 * of pageblock. Protected by zone->lock.
620 unsigned long nr_isolate_pageblock;
623 #ifdef CONFIG_MEMORY_HOTPLUG
624 /* see spanned/present_pages for more description */
625 seqlock_t span_seqlock;
630 /* Write-intensive fields used from the page allocator */
633 /* free areas of different sizes */
634 struct free_area free_area[MAX_ORDER];
636 /* zone flags, see below */
639 /* Primarily protects free_area */
642 /* Write-intensive fields used by compaction and vmstats. */
646 * When free pages are below this point, additional steps are taken
647 * when reading the number of free pages to avoid per-cpu counter
648 * drift allowing watermarks to be breached
650 unsigned long percpu_drift_mark;
652 #if defined CONFIG_COMPACTION || defined CONFIG_CMA
653 /* pfn where compaction free scanner should start */
654 unsigned long compact_cached_free_pfn;
655 /* pfn where compaction migration scanner should start */
656 unsigned long compact_cached_migrate_pfn[ASYNC_AND_SYNC];
657 unsigned long compact_init_migrate_pfn;
658 unsigned long compact_init_free_pfn;
661 #ifdef CONFIG_COMPACTION
663 * On compaction failure, 1<<compact_defer_shift compactions
664 * are skipped before trying again. The number attempted since
665 * last failure is tracked with compact_considered.
667 unsigned int compact_considered;
668 unsigned int compact_defer_shift;
669 int compact_order_failed;
672 #if defined CONFIG_COMPACTION || defined CONFIG_CMA
673 /* Set to true when the PG_migrate_skip bits should be cleared */
674 bool compact_blockskip_flush;
680 /* Zone statistics */
681 atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
682 atomic_long_t vm_numa_stat[NR_VM_NUMA_STAT_ITEMS];
683 } ____cacheline_internodealigned_in_smp;
686 PGDAT_DIRTY, /* reclaim scanning has recently found
687 * many dirty file pages at the tail
690 PGDAT_WRITEBACK, /* reclaim scanning has recently found
691 * many pages under writeback
693 PGDAT_RECLAIM_LOCKED, /* prevents concurrent reclaim */
697 ZONE_BOOSTED_WATERMARK, /* zone recently boosted watermarks.
698 * Cleared when kswapd is woken.
702 static inline unsigned long zone_managed_pages(struct zone *zone)
704 return (unsigned long)atomic_long_read(&zone->managed_pages);
707 static inline unsigned long zone_end_pfn(const struct zone *zone)
709 return zone->zone_start_pfn + zone->spanned_pages;
712 static inline bool zone_spans_pfn(const struct zone *zone, unsigned long pfn)
714 return zone->zone_start_pfn <= pfn && pfn < zone_end_pfn(zone);
717 static inline bool zone_is_initialized(struct zone *zone)
719 return zone->initialized;
722 static inline bool zone_is_empty(struct zone *zone)
724 return zone->spanned_pages == 0;
728 * Return true if [start_pfn, start_pfn + nr_pages) range has a non-empty
729 * intersection with the given zone
731 static inline bool zone_intersects(struct zone *zone,
732 unsigned long start_pfn, unsigned long nr_pages)
734 if (zone_is_empty(zone))
736 if (start_pfn >= zone_end_pfn(zone) ||
737 start_pfn + nr_pages <= zone->zone_start_pfn)
744 * The "priority" of VM scanning is how much of the queues we will scan in one
745 * go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the
746 * queues ("queue_length >> 12") during an aging round.
748 #define DEF_PRIORITY 12
750 /* Maximum number of zones on a zonelist */
751 #define MAX_ZONES_PER_ZONELIST (MAX_NUMNODES * MAX_NR_ZONES)
754 ZONELIST_FALLBACK, /* zonelist with fallback */
757 * The NUMA zonelists are doubled because we need zonelists that
758 * restrict the allocations to a single node for __GFP_THISNODE.
760 ZONELIST_NOFALLBACK, /* zonelist without fallback (__GFP_THISNODE) */
766 * This struct contains information about a zone in a zonelist. It is stored
767 * here to avoid dereferences into large structures and lookups of tables
770 struct zone *zone; /* Pointer to actual zone */
771 int zone_idx; /* zone_idx(zoneref->zone) */
775 * One allocation request operates on a zonelist. A zonelist
776 * is a list of zones, the first one is the 'goal' of the
777 * allocation, the other zones are fallback zones, in decreasing
780 * To speed the reading of the zonelist, the zonerefs contain the zone index
781 * of the entry being read. Helper functions to access information given
782 * a struct zoneref are
784 * zonelist_zone() - Return the struct zone * for an entry in _zonerefs
785 * zonelist_zone_idx() - Return the index of the zone for an entry
786 * zonelist_node_idx() - Return the index of the node for an entry
789 struct zoneref _zonerefs[MAX_ZONES_PER_ZONELIST + 1];
792 #ifndef CONFIG_DISCONTIGMEM
793 /* The array of struct pages - for discontigmem use pgdat->lmem_map */
794 extern struct page *mem_map;
797 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
798 struct deferred_split {
799 spinlock_t split_queue_lock;
800 struct list_head split_queue;
801 unsigned long split_queue_len;
806 * On NUMA machines, each NUMA node would have a pg_data_t to describe
807 * it's memory layout. On UMA machines there is a single pglist_data which
808 * describes the whole memory.
810 * Memory statistics and page replacement data structures are maintained on a
814 typedef struct pglist_data {
815 struct zone node_zones[MAX_NR_ZONES];
816 struct zonelist node_zonelists[MAX_ZONELISTS];
818 #ifdef CONFIG_FLAT_NODE_MEM_MAP /* means !SPARSEMEM */
819 struct page *node_mem_map;
820 #ifdef CONFIG_PAGE_EXTENSION
821 struct page_ext *node_page_ext;
824 #if defined(CONFIG_MEMORY_HOTPLUG) || defined(CONFIG_DEFERRED_STRUCT_PAGE_INIT)
826 * Must be held any time you expect node_start_pfn,
827 * node_present_pages, node_spanned_pages or nr_zones to stay constant.
828 * Also synchronizes pgdat->first_deferred_pfn during deferred page
831 * pgdat_resize_lock() and pgdat_resize_unlock() are provided to
832 * manipulate node_size_lock without checking for CONFIG_MEMORY_HOTPLUG
833 * or CONFIG_DEFERRED_STRUCT_PAGE_INIT.
835 * Nests above zone->lock and zone->span_seqlock
837 spinlock_t node_size_lock;
839 unsigned long node_start_pfn;
840 unsigned long node_present_pages; /* total number of physical pages */
841 unsigned long node_spanned_pages; /* total size of physical page
842 range, including holes */
844 wait_queue_head_t kswapd_wait;
845 wait_queue_head_t pfmemalloc_wait;
846 struct task_struct *kswapd; /* Protected by
847 mem_hotplug_begin/end() */
849 enum zone_type kswapd_classzone_idx;
851 int kswapd_failures; /* Number of 'reclaimed == 0' runs */
853 #ifdef CONFIG_COMPACTION
854 int kcompactd_max_order;
855 enum zone_type kcompactd_classzone_idx;
856 wait_queue_head_t kcompactd_wait;
857 struct task_struct *kcompactd;
860 * This is a per-node reserve of pages that are not available
861 * to userspace allocations.
863 unsigned long totalreserve_pages;
867 * zone reclaim becomes active if more unmapped pages exist.
869 unsigned long min_unmapped_pages;
870 unsigned long min_slab_pages;
871 #endif /* CONFIG_NUMA */
873 /* Write-intensive fields used by page reclaim */
877 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
879 * If memory initialisation on large machines is deferred then this
880 * is the first PFN that needs to be initialised.
882 unsigned long first_deferred_pfn;
883 #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
885 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
886 struct deferred_split deferred_split_queue;
889 /* Fields commonly accessed by the page reclaim scanner */
892 * NOTE: THIS IS UNUSED IF MEMCG IS ENABLED.
894 * Use mem_cgroup_lruvec() to look up lruvecs.
896 struct lruvec __lruvec;
902 /* Per-node vmstats */
903 struct per_cpu_nodestat __percpu *per_cpu_nodestats;
904 atomic_long_t vm_stat[NR_VM_NODE_STAT_ITEMS];
907 #define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages)
908 #define node_spanned_pages(nid) (NODE_DATA(nid)->node_spanned_pages)
909 #ifdef CONFIG_FLAT_NODE_MEM_MAP
910 #define pgdat_page_nr(pgdat, pagenr) ((pgdat)->node_mem_map + (pagenr))
912 #define pgdat_page_nr(pgdat, pagenr) pfn_to_page((pgdat)->node_start_pfn + (pagenr))
914 #define nid_page_nr(nid, pagenr) pgdat_page_nr(NODE_DATA(nid),(pagenr))
916 #define node_start_pfn(nid) (NODE_DATA(nid)->node_start_pfn)
917 #define node_end_pfn(nid) pgdat_end_pfn(NODE_DATA(nid))
919 static inline unsigned long pgdat_end_pfn(pg_data_t *pgdat)
921 return pgdat->node_start_pfn + pgdat->node_spanned_pages;
924 static inline bool pgdat_is_empty(pg_data_t *pgdat)
926 return !pgdat->node_start_pfn && !pgdat->node_spanned_pages;
929 #include <linux/memory_hotplug.h>
931 void build_all_zonelists(pg_data_t *pgdat);
932 void wakeup_kswapd(struct zone *zone, gfp_t gfp_mask, int order,
933 enum zone_type classzone_idx);
934 bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
935 int classzone_idx, unsigned int alloc_flags,
937 bool zone_watermark_ok(struct zone *z, unsigned int order,
938 unsigned long mark, int classzone_idx,
939 unsigned int alloc_flags);
940 bool zone_watermark_ok_safe(struct zone *z, unsigned int order,
941 unsigned long mark, int classzone_idx);
942 enum memmap_context {
946 extern void init_currently_empty_zone(struct zone *zone, unsigned long start_pfn,
949 extern void lruvec_init(struct lruvec *lruvec);
951 static inline struct pglist_data *lruvec_pgdat(struct lruvec *lruvec)
954 return lruvec->pgdat;
956 return container_of(lruvec, struct pglist_data, __lruvec);
960 extern unsigned long lruvec_lru_size(struct lruvec *lruvec, enum lru_list lru, int zone_idx);
962 #ifdef CONFIG_HAVE_MEMORY_PRESENT
963 void memory_present(int nid, unsigned long start, unsigned long end);
965 static inline void memory_present(int nid, unsigned long start, unsigned long end) {}
968 #if defined(CONFIG_SPARSEMEM)
969 void memblocks_present(void);
971 static inline void memblocks_present(void) {}
974 #ifdef CONFIG_HAVE_MEMORYLESS_NODES
975 int local_memory_node(int node_id);
977 static inline int local_memory_node(int node_id) { return node_id; };
981 * zone_idx() returns 0 for the ZONE_DMA zone, 1 for the ZONE_NORMAL zone, etc.
983 #define zone_idx(zone) ((zone) - (zone)->zone_pgdat->node_zones)
986 * Returns true if a zone has pages managed by the buddy allocator.
987 * All the reclaim decisions have to use this function rather than
988 * populated_zone(). If the whole zone is reserved then we can easily
989 * end up with populated_zone() && !managed_zone().
991 static inline bool managed_zone(struct zone *zone)
993 return zone_managed_pages(zone);
996 /* Returns true if a zone has memory */
997 static inline bool populated_zone(struct zone *zone)
999 return zone->present_pages;
1003 static inline int zone_to_nid(struct zone *zone)
1008 static inline void zone_set_nid(struct zone *zone, int nid)
1013 static inline int zone_to_nid(struct zone *zone)
1018 static inline void zone_set_nid(struct zone *zone, int nid) {}
1021 extern int movable_zone;
1023 #ifdef CONFIG_HIGHMEM
1024 static inline int zone_movable_is_highmem(void)
1026 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
1027 return movable_zone == ZONE_HIGHMEM;
1029 return (ZONE_MOVABLE - 1) == ZONE_HIGHMEM;
1034 static inline int is_highmem_idx(enum zone_type idx)
1036 #ifdef CONFIG_HIGHMEM
1037 return (idx == ZONE_HIGHMEM ||
1038 (idx == ZONE_MOVABLE && zone_movable_is_highmem()));
1045 * is_highmem - helper function to quickly check if a struct zone is a
1046 * highmem zone or not. This is an attempt to keep references
1047 * to ZONE_{DMA/NORMAL/HIGHMEM/etc} in general code to a minimum.
1048 * @zone - pointer to struct zone variable
1050 static inline int is_highmem(struct zone *zone)
1052 #ifdef CONFIG_HIGHMEM
1053 return is_highmem_idx(zone_idx(zone));
1059 /* These two functions are used to setup the per zone pages min values */
1061 int min_free_kbytes_sysctl_handler(struct ctl_table *, int,
1062 void __user *, size_t *, loff_t *);
1063 int watermark_boost_factor_sysctl_handler(struct ctl_table *, int,
1064 void __user *, size_t *, loff_t *);
1065 int watermark_scale_factor_sysctl_handler(struct ctl_table *, int,
1066 void __user *, size_t *, loff_t *);
1067 extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES];
1068 int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int,
1069 void __user *, size_t *, loff_t *);
1070 int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *, int,
1071 void __user *, size_t *, loff_t *);
1072 int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *, int,
1073 void __user *, size_t *, loff_t *);
1074 int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *, int,
1075 void __user *, size_t *, loff_t *);
1077 extern int numa_zonelist_order_handler(struct ctl_table *, int,
1078 void __user *, size_t *, loff_t *);
1079 extern char numa_zonelist_order[];
1080 #define NUMA_ZONELIST_ORDER_LEN 16
1082 #ifndef CONFIG_NEED_MULTIPLE_NODES
1084 extern struct pglist_data contig_page_data;
1085 #define NODE_DATA(nid) (&contig_page_data)
1086 #define NODE_MEM_MAP(nid) mem_map
1088 #else /* CONFIG_NEED_MULTIPLE_NODES */
1090 #include <asm/mmzone.h>
1092 #endif /* !CONFIG_NEED_MULTIPLE_NODES */
1094 extern struct pglist_data *first_online_pgdat(void);
1095 extern struct pglist_data *next_online_pgdat(struct pglist_data *pgdat);
1096 extern struct zone *next_zone(struct zone *zone);
1099 * for_each_online_pgdat - helper macro to iterate over all online nodes
1100 * @pgdat - pointer to a pg_data_t variable
1102 #define for_each_online_pgdat(pgdat) \
1103 for (pgdat = first_online_pgdat(); \
1105 pgdat = next_online_pgdat(pgdat))
1107 * for_each_zone - helper macro to iterate over all memory zones
1108 * @zone - pointer to struct zone variable
1110 * The user only needs to declare the zone variable, for_each_zone
1113 #define for_each_zone(zone) \
1114 for (zone = (first_online_pgdat())->node_zones; \
1116 zone = next_zone(zone))
1118 #define for_each_populated_zone(zone) \
1119 for (zone = (first_online_pgdat())->node_zones; \
1121 zone = next_zone(zone)) \
1122 if (!populated_zone(zone)) \
1123 ; /* do nothing */ \
1126 static inline struct zone *zonelist_zone(struct zoneref *zoneref)
1128 return zoneref->zone;
1131 static inline int zonelist_zone_idx(struct zoneref *zoneref)
1133 return zoneref->zone_idx;
1136 static inline int zonelist_node_idx(struct zoneref *zoneref)
1138 return zone_to_nid(zoneref->zone);
1141 struct zoneref *__next_zones_zonelist(struct zoneref *z,
1142 enum zone_type highest_zoneidx,
1146 * 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
1147 * @z - The cursor used as a starting point for the search
1148 * @highest_zoneidx - The zone index of the highest zone to return
1149 * @nodes - An optional nodemask to filter the zonelist with
1151 * This function returns the next zone at or below a given zone index that is
1152 * within the allowed nodemask using a cursor as the starting point for the
1153 * search. The zoneref returned is a cursor that represents the current zone
1154 * being examined. It should be advanced by one before calling
1155 * next_zones_zonelist again.
1157 static __always_inline struct zoneref *next_zones_zonelist(struct zoneref *z,
1158 enum zone_type highest_zoneidx,
1161 if (likely(!nodes && zonelist_zone_idx(z) <= highest_zoneidx))
1163 return __next_zones_zonelist(z, highest_zoneidx, nodes);
1167 * first_zones_zonelist - Returns the first zone at or below highest_zoneidx within the allowed nodemask in a zonelist
1168 * @zonelist - The zonelist to search for a suitable zone
1169 * @highest_zoneidx - The zone index of the highest zone to return
1170 * @nodes - An optional nodemask to filter the zonelist with
1171 * @return - Zoneref pointer for the first suitable zone found (see below)
1173 * This function returns the first zone at or below a given zone index that is
1174 * within the allowed nodemask. The zoneref returned is a cursor that can be
1175 * used to iterate the zonelist with next_zones_zonelist by advancing it by
1176 * one before calling.
1178 * When no eligible zone is found, zoneref->zone is NULL (zoneref itself is
1179 * never NULL). This may happen either genuinely, or due to concurrent nodemask
1180 * update due to cpuset modification.
1182 static inline struct zoneref *first_zones_zonelist(struct zonelist *zonelist,
1183 enum zone_type highest_zoneidx,
1186 return next_zones_zonelist(zonelist->_zonerefs,
1187 highest_zoneidx, nodes);
1191 * 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
1192 * @zone - The current zone in the iterator
1193 * @z - The current pointer within zonelist->zones being iterated
1194 * @zlist - The zonelist being iterated
1195 * @highidx - The zone index of the highest zone to return
1196 * @nodemask - Nodemask allowed by the allocator
1198 * This iterator iterates though all zones at or below a given zone index and
1199 * within a given nodemask
1201 #define for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, nodemask) \
1202 for (z = first_zones_zonelist(zlist, highidx, nodemask), zone = zonelist_zone(z); \
1204 z = next_zones_zonelist(++z, highidx, nodemask), \
1205 zone = zonelist_zone(z))
1207 #define for_next_zone_zonelist_nodemask(zone, z, zlist, highidx, nodemask) \
1208 for (zone = z->zone; \
1210 z = next_zones_zonelist(++z, highidx, nodemask), \
1211 zone = zonelist_zone(z))
1215 * for_each_zone_zonelist - helper macro to iterate over valid zones in a zonelist at or below a given zone index
1216 * @zone - The current zone in the iterator
1217 * @z - The current pointer within zonelist->zones being iterated
1218 * @zlist - The zonelist being iterated
1219 * @highidx - The zone index of the highest zone to return
1221 * This iterator iterates though all zones at or below a given zone index.
1223 #define for_each_zone_zonelist(zone, z, zlist, highidx) \
1224 for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, NULL)
1226 #ifdef CONFIG_SPARSEMEM
1227 #include <asm/sparsemem.h>
1230 #if !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) && \
1231 !defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP)
1232 static inline unsigned long early_pfn_to_nid(unsigned long pfn)
1234 BUILD_BUG_ON(IS_ENABLED(CONFIG_NUMA));
1239 #ifdef CONFIG_FLATMEM
1240 #define pfn_to_nid(pfn) (0)
1243 #ifdef CONFIG_SPARSEMEM
1246 * SECTION_SHIFT #bits space required to store a section #
1248 * PA_SECTION_SHIFT physical address to/from section number
1249 * PFN_SECTION_SHIFT pfn to/from section number
1251 #define PA_SECTION_SHIFT (SECTION_SIZE_BITS)
1252 #define PFN_SECTION_SHIFT (SECTION_SIZE_BITS - PAGE_SHIFT)
1254 #define NR_MEM_SECTIONS (1UL << SECTIONS_SHIFT)
1256 #define PAGES_PER_SECTION (1UL << PFN_SECTION_SHIFT)
1257 #define PAGE_SECTION_MASK (~(PAGES_PER_SECTION-1))
1259 #define SECTION_BLOCKFLAGS_BITS \
1260 ((1UL << (PFN_SECTION_SHIFT - pageblock_order)) * NR_PAGEBLOCK_BITS)
1262 #if (MAX_ORDER - 1 + PAGE_SHIFT) > SECTION_SIZE_BITS
1263 #error Allocator MAX_ORDER exceeds SECTION_SIZE
1266 static inline unsigned long pfn_to_section_nr(unsigned long pfn)
1268 return pfn >> PFN_SECTION_SHIFT;
1270 static inline unsigned long section_nr_to_pfn(unsigned long sec)
1272 return sec << PFN_SECTION_SHIFT;
1275 #define SECTION_ALIGN_UP(pfn) (((pfn) + PAGES_PER_SECTION - 1) & PAGE_SECTION_MASK)
1276 #define SECTION_ALIGN_DOWN(pfn) ((pfn) & PAGE_SECTION_MASK)
1278 #define SUBSECTION_SHIFT 21
1280 #define PFN_SUBSECTION_SHIFT (SUBSECTION_SHIFT - PAGE_SHIFT)
1281 #define PAGES_PER_SUBSECTION (1UL << PFN_SUBSECTION_SHIFT)
1282 #define PAGE_SUBSECTION_MASK (~(PAGES_PER_SUBSECTION-1))
1284 #if SUBSECTION_SHIFT > SECTION_SIZE_BITS
1285 #error Subsection size exceeds section size
1287 #define SUBSECTIONS_PER_SECTION (1UL << (SECTION_SIZE_BITS - SUBSECTION_SHIFT))
1290 #define SUBSECTION_ALIGN_UP(pfn) ALIGN((pfn), PAGES_PER_SUBSECTION)
1291 #define SUBSECTION_ALIGN_DOWN(pfn) ((pfn) & PAGE_SUBSECTION_MASK)
1293 struct mem_section_usage {
1294 DECLARE_BITMAP(subsection_map, SUBSECTIONS_PER_SECTION);
1295 /* See declaration of similar field in struct zone */
1296 unsigned long pageblock_flags[0];
1299 void subsection_map_init(unsigned long pfn, unsigned long nr_pages);
1303 struct mem_section {
1305 * This is, logically, a pointer to an array of struct
1306 * pages. However, it is stored with some other magic.
1307 * (see sparse.c::sparse_init_one_section())
1309 * Additionally during early boot we encode node id of
1310 * the location of the section here to guide allocation.
1311 * (see sparse.c::memory_present())
1313 * Making it a UL at least makes someone do a cast
1314 * before using it wrong.
1316 unsigned long section_mem_map;
1318 struct mem_section_usage *usage;
1319 #ifdef CONFIG_PAGE_EXTENSION
1321 * If SPARSEMEM, pgdat doesn't have page_ext pointer. We use
1322 * section. (see page_ext.h about this.)
1324 struct page_ext *page_ext;
1328 * WARNING: mem_section must be a power-of-2 in size for the
1329 * calculation and use of SECTION_ROOT_MASK to make sense.
1333 #ifdef CONFIG_SPARSEMEM_EXTREME
1334 #define SECTIONS_PER_ROOT (PAGE_SIZE / sizeof (struct mem_section))
1336 #define SECTIONS_PER_ROOT 1
1339 #define SECTION_NR_TO_ROOT(sec) ((sec) / SECTIONS_PER_ROOT)
1340 #define NR_SECTION_ROOTS DIV_ROUND_UP(NR_MEM_SECTIONS, SECTIONS_PER_ROOT)
1341 #define SECTION_ROOT_MASK (SECTIONS_PER_ROOT - 1)
1343 #ifdef CONFIG_SPARSEMEM_EXTREME
1344 extern struct mem_section **mem_section;
1346 extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT];
1349 static inline unsigned long *section_to_usemap(struct mem_section *ms)
1351 return ms->usage->pageblock_flags;
1354 static inline struct mem_section *__nr_to_section(unsigned long nr)
1356 #ifdef CONFIG_SPARSEMEM_EXTREME
1360 if (!mem_section[SECTION_NR_TO_ROOT(nr)])
1362 return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK];
1364 extern unsigned long __section_nr(struct mem_section *ms);
1365 extern size_t mem_section_usage_size(void);
1368 * We use the lower bits of the mem_map pointer to store
1369 * a little bit of information. The pointer is calculated
1370 * as mem_map - section_nr_to_pfn(pnum). The result is
1371 * aligned to the minimum alignment of the two values:
1372 * 1. All mem_map arrays are page-aligned.
1373 * 2. section_nr_to_pfn() always clears PFN_SECTION_SHIFT
1374 * lowest bits. PFN_SECTION_SHIFT is arch-specific
1375 * (equal SECTION_SIZE_BITS - PAGE_SHIFT), and the
1376 * worst combination is powerpc with 256k pages,
1377 * which results in PFN_SECTION_SHIFT equal 6.
1378 * To sum it up, at least 6 bits are available.
1380 #define SECTION_MARKED_PRESENT (1UL<<0)
1381 #define SECTION_HAS_MEM_MAP (1UL<<1)
1382 #define SECTION_IS_ONLINE (1UL<<2)
1383 #define SECTION_IS_EARLY (1UL<<3)
1384 #define SECTION_MAP_LAST_BIT (1UL<<4)
1385 #define SECTION_MAP_MASK (~(SECTION_MAP_LAST_BIT-1))
1386 #define SECTION_NID_SHIFT 3
1388 static inline struct page *__section_mem_map_addr(struct mem_section *section)
1390 unsigned long map = section->section_mem_map;
1391 map &= SECTION_MAP_MASK;
1392 return (struct page *)map;
1395 static inline int present_section(struct mem_section *section)
1397 return (section && (section->section_mem_map & SECTION_MARKED_PRESENT));
1400 static inline int present_section_nr(unsigned long nr)
1402 return present_section(__nr_to_section(nr));
1405 static inline int valid_section(struct mem_section *section)
1407 return (section && (section->section_mem_map & SECTION_HAS_MEM_MAP));
1410 static inline int early_section(struct mem_section *section)
1412 return (section && (section->section_mem_map & SECTION_IS_EARLY));
1415 static inline int valid_section_nr(unsigned long nr)
1417 return valid_section(__nr_to_section(nr));
1420 static inline int online_section(struct mem_section *section)
1422 return (section && (section->section_mem_map & SECTION_IS_ONLINE));
1425 static inline int online_section_nr(unsigned long nr)
1427 return online_section(__nr_to_section(nr));
1430 #ifdef CONFIG_MEMORY_HOTPLUG
1431 void online_mem_sections(unsigned long start_pfn, unsigned long end_pfn);
1432 #ifdef CONFIG_MEMORY_HOTREMOVE
1433 void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn);
1437 static inline struct mem_section *__pfn_to_section(unsigned long pfn)
1439 return __nr_to_section(pfn_to_section_nr(pfn));
1442 extern unsigned long __highest_present_section_nr;
1444 static inline int subsection_map_index(unsigned long pfn)
1446 return (pfn & ~(PAGE_SECTION_MASK)) / PAGES_PER_SUBSECTION;
1449 #ifdef CONFIG_SPARSEMEM_VMEMMAP
1450 static inline int pfn_section_valid(struct mem_section *ms, unsigned long pfn)
1452 int idx = subsection_map_index(pfn);
1454 return test_bit(idx, ms->usage->subsection_map);
1457 static inline int pfn_section_valid(struct mem_section *ms, unsigned long pfn)
1463 #ifndef CONFIG_HAVE_ARCH_PFN_VALID
1464 static inline int pfn_valid(unsigned long pfn)
1466 struct mem_section *ms;
1468 if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
1470 ms = __nr_to_section(pfn_to_section_nr(pfn));
1471 if (!valid_section(ms))
1474 * Traditionally early sections always returned pfn_valid() for
1475 * the entire section-sized span.
1477 return early_section(ms) || pfn_section_valid(ms, pfn);
1481 static inline int pfn_present(unsigned long pfn)
1483 if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
1485 return present_section(__nr_to_section(pfn_to_section_nr(pfn)));
1489 * These are _only_ used during initialisation, therefore they
1490 * can use __initdata ... They could have names to indicate
1494 #define pfn_to_nid(pfn) \
1496 unsigned long __pfn_to_nid_pfn = (pfn); \
1497 page_to_nid(pfn_to_page(__pfn_to_nid_pfn)); \
1500 #define pfn_to_nid(pfn) (0)
1503 #define early_pfn_valid(pfn) pfn_valid(pfn)
1504 void sparse_init(void);
1506 #define sparse_init() do {} while (0)
1507 #define sparse_index_init(_sec, _nid) do {} while (0)
1508 #define pfn_present pfn_valid
1509 #define subsection_map_init(_pfn, _nr_pages) do {} while (0)
1510 #endif /* CONFIG_SPARSEMEM */
1513 * During memory init memblocks map pfns to nids. The search is expensive and
1514 * this caches recent lookups. The implementation of __early_pfn_to_nid
1515 * may treat start/end as pfns or sections.
1517 struct mminit_pfnnid_cache {
1518 unsigned long last_start;
1519 unsigned long last_end;
1523 #ifndef early_pfn_valid
1524 #define early_pfn_valid(pfn) (1)
1527 void memory_present(int nid, unsigned long start, unsigned long end);
1530 * If it is possible to have holes within a MAX_ORDER_NR_PAGES, then we
1531 * need to check pfn validity within that MAX_ORDER_NR_PAGES block.
1532 * pfn_valid_within() should be used in this case; we optimise this away
1533 * when we have no holes within a MAX_ORDER_NR_PAGES block.
1535 #ifdef CONFIG_HOLES_IN_ZONE
1536 #define pfn_valid_within(pfn) pfn_valid(pfn)
1538 #define pfn_valid_within(pfn) (1)
1541 #ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL
1543 * pfn_valid() is meant to be able to tell if a given PFN has valid memmap
1544 * associated with it or not. This means that a struct page exists for this
1545 * pfn. The caller cannot assume the page is fully initialized in general.
1546 * Hotplugable pages might not have been onlined yet. pfn_to_online_page()
1547 * will ensure the struct page is fully online and initialized. Special pages
1548 * (e.g. ZONE_DEVICE) are never onlined and should be treated accordingly.
1550 * In FLATMEM, it is expected that holes always have valid memmap as long as
1551 * there is valid PFNs either side of the hole. In SPARSEMEM, it is assumed
1552 * that a valid section has a memmap for the entire section.
1554 * However, an ARM, and maybe other embedded architectures in the future
1555 * free memmap backing holes to save memory on the assumption the memmap is
1556 * never used. The page_zone linkages are then broken even though pfn_valid()
1557 * returns true. A walker of the full memmap must then do this additional
1558 * check to ensure the memmap they are looking at is sane by making sure
1559 * the zone and PFN linkages are still valid. This is expensive, but walkers
1560 * of the full memmap are extremely rare.
1562 bool memmap_valid_within(unsigned long pfn,
1563 struct page *page, struct zone *zone);
1565 static inline bool memmap_valid_within(unsigned long pfn,
1566 struct page *page, struct zone *zone)
1570 #endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */
1572 #endif /* !__GENERATING_BOUNDS.H */
1573 #endif /* !__ASSEMBLY__ */
1574 #endif /* _LINUX_MMZONE_H */