1 #ifndef _LINUX_MMZONE_H 2 #define _LINUX_MMZONE_H 3 4 #ifndef __ASSEMBLY__ 5 #ifndef __GENERATING_BOUNDS_H 6 7 #include <linux/spinlock.h> 8 #include <linux/list.h> 9 #include <linux/wait.h> 10 #include <linux/bitops.h> 11 #include <linux/cache.h> 12 #include <linux/threads.h> 13 #include <linux/numa.h> 14 #include <linux/init.h> 15 #include <linux/seqlock.h> 16 #include <linux/nodemask.h> 17 #include <linux/pageblock-flags.h> 18 #include <linux/page-flags-layout.h> 19 #include <linux/atomic.h> 20 #include <asm/page.h> 21 22 /* Free memory management - zoned buddy allocator. */ 23 #ifndef CONFIG_FORCE_MAX_ZONEORDER 24 #define MAX_ORDER 11 25 #else 26 #define MAX_ORDER CONFIG_FORCE_MAX_ZONEORDER 27 #endif 28 #define MAX_ORDER_NR_PAGES (1 << (MAX_ORDER - 1)) 29 30 /* 31 * PAGE_ALLOC_COSTLY_ORDER is the order at which allocations are deemed 32 * costly to service. That is between allocation orders which should 33 * coalesce naturally under reasonable reclaim pressure and those which 34 * will not. 35 */ 36 #define PAGE_ALLOC_COSTLY_ORDER 3 37 38 enum { 39 MIGRATE_UNMOVABLE, 40 MIGRATE_MOVABLE, 41 MIGRATE_RECLAIMABLE, 42 MIGRATE_PCPTYPES, /* the number of types on the pcp lists */ 43 MIGRATE_HIGHATOMIC = MIGRATE_PCPTYPES, 44 #ifdef CONFIG_CMA 45 /* 46 * MIGRATE_CMA migration type is designed to mimic the way 47 * ZONE_MOVABLE works. Only movable pages can be allocated 48 * from MIGRATE_CMA pageblocks and page allocator never 49 * implicitly change migration type of MIGRATE_CMA pageblock. 50 * 51 * The way to use it is to change migratetype of a range of 52 * pageblocks to MIGRATE_CMA which can be done by 53 * __free_pageblock_cma() function. What is important though 54 * is that a range of pageblocks must be aligned to 55 * MAX_ORDER_NR_PAGES should biggest page be bigger then 56 * a single pageblock. 57 */ 58 MIGRATE_CMA, 59 #endif 60 #ifdef CONFIG_MEMORY_ISOLATION 61 MIGRATE_ISOLATE, /* can't allocate from here */ 62 #endif 63 MIGRATE_TYPES 64 }; 65 66 /* In mm/page_alloc.c; keep in sync also with show_migration_types() there */ 67 extern char * const migratetype_names[MIGRATE_TYPES]; 68 69 #ifdef CONFIG_CMA 70 # define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA) 71 # define is_migrate_cma_page(_page) (get_pageblock_migratetype(_page) == MIGRATE_CMA) 72 #else 73 # define is_migrate_cma(migratetype) false 74 # define is_migrate_cma_page(_page) false 75 #endif 76 77 #define for_each_migratetype_order(order, type) \ 78 for (order = 0; order < MAX_ORDER; order++) \ 79 for (type = 0; type < MIGRATE_TYPES; type++) 80 81 extern int page_group_by_mobility_disabled; 82 83 #define NR_MIGRATETYPE_BITS (PB_migrate_end - PB_migrate + 1) 84 #define MIGRATETYPE_MASK ((1UL << NR_MIGRATETYPE_BITS) - 1) 85 86 #define get_pageblock_migratetype(page) \ 87 get_pfnblock_flags_mask(page, page_to_pfn(page), \ 88 PB_migrate_end, MIGRATETYPE_MASK) 89 90 struct free_area { 91 struct list_head free_list[MIGRATE_TYPES]; 92 unsigned long nr_free; 93 }; 94 95 struct pglist_data; 96 97 /* 98 * zone->lock and the zone lru_lock are two of the hottest locks in the kernel. 99 * So add a wild amount of padding here to ensure that they fall into separate 100 * cachelines. There are very few zone structures in the machine, so space 101 * consumption is not a concern here. 102 */ 103 #if defined(CONFIG_SMP) 104 struct zone_padding { 105 char x[0]; 106 } ____cacheline_internodealigned_in_smp; 107 #define ZONE_PADDING(name) struct zone_padding name; 108 #else 109 #define ZONE_PADDING(name) 110 #endif 111 112 enum zone_stat_item { 113 /* First 128 byte cacheline (assuming 64 bit words) */ 114 NR_FREE_PAGES, 115 NR_ZONE_LRU_BASE, /* Used only for compaction and reclaim retry */ 116 NR_ZONE_INACTIVE_ANON = NR_ZONE_LRU_BASE, 117 NR_ZONE_ACTIVE_ANON, 118 NR_ZONE_INACTIVE_FILE, 119 NR_ZONE_ACTIVE_FILE, 120 NR_ZONE_UNEVICTABLE, 121 NR_ZONE_WRITE_PENDING, /* Count of dirty, writeback and unstable pages */ 122 NR_MLOCK, /* mlock()ed pages found and moved off LRU */ 123 NR_SLAB_RECLAIMABLE, 124 NR_SLAB_UNRECLAIMABLE, 125 NR_PAGETABLE, /* used for pagetables */ 126 NR_KERNEL_STACK_KB, /* measured in KiB */ 127 /* Second 128 byte cacheline */ 128 NR_BOUNCE, 129 #if IS_ENABLED(CONFIG_ZSMALLOC) 130 NR_ZSPAGES, /* allocated in zsmalloc */ 131 #endif 132 #ifdef CONFIG_NUMA 133 NUMA_HIT, /* allocated in intended node */ 134 NUMA_MISS, /* allocated in non intended node */ 135 NUMA_FOREIGN, /* was intended here, hit elsewhere */ 136 NUMA_INTERLEAVE_HIT, /* interleaver preferred this zone */ 137 NUMA_LOCAL, /* allocation from local node */ 138 NUMA_OTHER, /* allocation from other node */ 139 #endif 140 NR_FREE_CMA_PAGES, 141 NR_VM_ZONE_STAT_ITEMS }; 142 143 enum node_stat_item { 144 NR_LRU_BASE, 145 NR_INACTIVE_ANON = NR_LRU_BASE, /* must match order of LRU_[IN]ACTIVE */ 146 NR_ACTIVE_ANON, /* " " " " " */ 147 NR_INACTIVE_FILE, /* " " " " " */ 148 NR_ACTIVE_FILE, /* " " " " " */ 149 NR_UNEVICTABLE, /* " " " " " */ 150 NR_ISOLATED_ANON, /* Temporary isolated pages from anon lru */ 151 NR_ISOLATED_FILE, /* Temporary isolated pages from file lru */ 152 NR_PAGES_SCANNED, /* pages scanned since last reclaim */ 153 WORKINGSET_REFAULT, 154 WORKINGSET_ACTIVATE, 155 WORKINGSET_NODERECLAIM, 156 NR_ANON_MAPPED, /* Mapped anonymous pages */ 157 NR_FILE_MAPPED, /* pagecache pages mapped into pagetables. 158 only modified from process context */ 159 NR_FILE_PAGES, 160 NR_FILE_DIRTY, 161 NR_WRITEBACK, 162 NR_WRITEBACK_TEMP, /* Writeback using temporary buffers */ 163 NR_SHMEM, /* shmem pages (included tmpfs/GEM pages) */ 164 NR_SHMEM_THPS, 165 NR_SHMEM_PMDMAPPED, 166 NR_ANON_THPS, 167 NR_UNSTABLE_NFS, /* NFS unstable pages */ 168 NR_VMSCAN_WRITE, 169 NR_VMSCAN_IMMEDIATE, /* Prioritise for reclaim when writeback ends */ 170 NR_DIRTIED, /* page dirtyings since bootup */ 171 NR_WRITTEN, /* page writings since bootup */ 172 NR_VM_NODE_STAT_ITEMS 173 }; 174 175 /* 176 * We do arithmetic on the LRU lists in various places in the code, 177 * so it is important to keep the active lists LRU_ACTIVE higher in 178 * the array than the corresponding inactive lists, and to keep 179 * the *_FILE lists LRU_FILE higher than the corresponding _ANON lists. 180 * 181 * This has to be kept in sync with the statistics in zone_stat_item 182 * above and the descriptions in vmstat_text in mm/vmstat.c 183 */ 184 #define LRU_BASE 0 185 #define LRU_ACTIVE 1 186 #define LRU_FILE 2 187 188 enum lru_list { 189 LRU_INACTIVE_ANON = LRU_BASE, 190 LRU_ACTIVE_ANON = LRU_BASE + LRU_ACTIVE, 191 LRU_INACTIVE_FILE = LRU_BASE + LRU_FILE, 192 LRU_ACTIVE_FILE = LRU_BASE + LRU_FILE + LRU_ACTIVE, 193 LRU_UNEVICTABLE, 194 NR_LRU_LISTS 195 }; 196 197 #define for_each_lru(lru) for (lru = 0; lru < NR_LRU_LISTS; lru++) 198 199 #define for_each_evictable_lru(lru) for (lru = 0; lru <= LRU_ACTIVE_FILE; lru++) 200 201 static inline int is_file_lru(enum lru_list lru) 202 { 203 return (lru == LRU_INACTIVE_FILE || lru == LRU_ACTIVE_FILE); 204 } 205 206 static inline int is_active_lru(enum lru_list lru) 207 { 208 return (lru == LRU_ACTIVE_ANON || lru == LRU_ACTIVE_FILE); 209 } 210 211 struct zone_reclaim_stat { 212 /* 213 * The pageout code in vmscan.c keeps track of how many of the 214 * mem/swap backed and file backed pages are referenced. 215 * The higher the rotated/scanned ratio, the more valuable 216 * that cache is. 217 * 218 * The anon LRU stats live in [0], file LRU stats in [1] 219 */ 220 unsigned long recent_rotated[2]; 221 unsigned long recent_scanned[2]; 222 }; 223 224 struct lruvec { 225 struct list_head lists[NR_LRU_LISTS]; 226 struct zone_reclaim_stat reclaim_stat; 227 /* Evictions & activations on the inactive file list */ 228 atomic_long_t inactive_age; 229 #ifdef CONFIG_MEMCG 230 struct pglist_data *pgdat; 231 #endif 232 }; 233 234 /* Mask used at gathering information at once (see memcontrol.c) */ 235 #define LRU_ALL_FILE (BIT(LRU_INACTIVE_FILE) | BIT(LRU_ACTIVE_FILE)) 236 #define LRU_ALL_ANON (BIT(LRU_INACTIVE_ANON) | BIT(LRU_ACTIVE_ANON)) 237 #define LRU_ALL ((1 << NR_LRU_LISTS) - 1) 238 239 /* Isolate clean file */ 240 #define ISOLATE_CLEAN ((__force isolate_mode_t)0x1) 241 /* Isolate unmapped file */ 242 #define ISOLATE_UNMAPPED ((__force isolate_mode_t)0x2) 243 /* Isolate for asynchronous migration */ 244 #define ISOLATE_ASYNC_MIGRATE ((__force isolate_mode_t)0x4) 245 /* Isolate unevictable pages */ 246 #define ISOLATE_UNEVICTABLE ((__force isolate_mode_t)0x8) 247 248 /* LRU Isolation modes. */ 249 typedef unsigned __bitwise isolate_mode_t; 250 251 enum zone_watermarks { 252 WMARK_MIN, 253 WMARK_LOW, 254 WMARK_HIGH, 255 NR_WMARK 256 }; 257 258 #define min_wmark_pages(z) (z->watermark[WMARK_MIN]) 259 #define low_wmark_pages(z) (z->watermark[WMARK_LOW]) 260 #define high_wmark_pages(z) (z->watermark[WMARK_HIGH]) 261 262 struct per_cpu_pages { 263 int count; /* number of pages in the list */ 264 int high; /* high watermark, emptying needed */ 265 int batch; /* chunk size for buddy add/remove */ 266 267 /* Lists of pages, one per migrate type stored on the pcp-lists */ 268 struct list_head lists[MIGRATE_PCPTYPES]; 269 }; 270 271 struct per_cpu_pageset { 272 struct per_cpu_pages pcp; 273 #ifdef CONFIG_NUMA 274 s8 expire; 275 #endif 276 #ifdef CONFIG_SMP 277 s8 stat_threshold; 278 s8 vm_stat_diff[NR_VM_ZONE_STAT_ITEMS]; 279 #endif 280 }; 281 282 struct per_cpu_nodestat { 283 s8 stat_threshold; 284 s8 vm_node_stat_diff[NR_VM_NODE_STAT_ITEMS]; 285 }; 286 287 #endif /* !__GENERATING_BOUNDS.H */ 288 289 enum zone_type { 290 #ifdef CONFIG_ZONE_DMA 291 /* 292 * ZONE_DMA is used when there are devices that are not able 293 * to do DMA to all of addressable memory (ZONE_NORMAL). Then we 294 * carve out the portion of memory that is needed for these devices. 295 * The range is arch specific. 296 * 297 * Some examples 298 * 299 * Architecture Limit 300 * --------------------------- 301 * parisc, ia64, sparc <4G 302 * s390 <2G 303 * arm Various 304 * alpha Unlimited or 0-16MB. 305 * 306 * i386, x86_64 and multiple other arches 307 * <16M. 308 */ 309 ZONE_DMA, 310 #endif 311 #ifdef CONFIG_ZONE_DMA32 312 /* 313 * x86_64 needs two ZONE_DMAs because it supports devices that are 314 * only able to do DMA to the lower 16M but also 32 bit devices that 315 * can only do DMA areas below 4G. 316 */ 317 ZONE_DMA32, 318 #endif 319 /* 320 * Normal addressable memory is in ZONE_NORMAL. DMA operations can be 321 * performed on pages in ZONE_NORMAL if the DMA devices support 322 * transfers to all addressable memory. 323 */ 324 ZONE_NORMAL, 325 #ifdef CONFIG_HIGHMEM 326 /* 327 * A memory area that is only addressable by the kernel through 328 * mapping portions into its own address space. This is for example 329 * used by i386 to allow the kernel to address the memory beyond 330 * 900MB. The kernel will set up special mappings (page 331 * table entries on i386) for each page that the kernel needs to 332 * access. 333 */ 334 ZONE_HIGHMEM, 335 #endif 336 ZONE_MOVABLE, 337 #ifdef CONFIG_ZONE_DEVICE 338 ZONE_DEVICE, 339 #endif 340 __MAX_NR_ZONES 341 342 }; 343 344 #ifndef __GENERATING_BOUNDS_H 345 346 struct zone { 347 /* Read-mostly fields */ 348 349 /* zone watermarks, access with *_wmark_pages(zone) macros */ 350 unsigned long watermark[NR_WMARK]; 351 352 unsigned long nr_reserved_highatomic; 353 354 /* 355 * We don't know if the memory that we're going to allocate will be 356 * freeable or/and it will be released eventually, so to avoid totally 357 * wasting several GB of ram we must reserve some of the lower zone 358 * memory (otherwise we risk to run OOM on the lower zones despite 359 * there being tons of freeable ram on the higher zones). This array is 360 * recalculated at runtime if the sysctl_lowmem_reserve_ratio sysctl 361 * changes. 362 */ 363 long lowmem_reserve[MAX_NR_ZONES]; 364 365 #ifdef CONFIG_NUMA 366 int node; 367 #endif 368 struct pglist_data *zone_pgdat; 369 struct per_cpu_pageset __percpu *pageset; 370 371 #ifndef CONFIG_SPARSEMEM 372 /* 373 * Flags for a pageblock_nr_pages block. See pageblock-flags.h. 374 * In SPARSEMEM, this map is stored in struct mem_section 375 */ 376 unsigned long *pageblock_flags; 377 #endif /* CONFIG_SPARSEMEM */ 378 379 /* zone_start_pfn == zone_start_paddr >> PAGE_SHIFT */ 380 unsigned long zone_start_pfn; 381 382 /* 383 * spanned_pages is the total pages spanned by the zone, including 384 * holes, which is calculated as: 385 * spanned_pages = zone_end_pfn - zone_start_pfn; 386 * 387 * present_pages is physical pages existing within the zone, which 388 * is calculated as: 389 * present_pages = spanned_pages - absent_pages(pages in holes); 390 * 391 * managed_pages is present pages managed by the buddy system, which 392 * is calculated as (reserved_pages includes pages allocated by the 393 * bootmem allocator): 394 * managed_pages = present_pages - reserved_pages; 395 * 396 * So present_pages may be used by memory hotplug or memory power 397 * management logic to figure out unmanaged pages by checking 398 * (present_pages - managed_pages). And managed_pages should be used 399 * by page allocator and vm scanner to calculate all kinds of watermarks 400 * and thresholds. 401 * 402 * Locking rules: 403 * 404 * zone_start_pfn and spanned_pages are protected by span_seqlock. 405 * It is a seqlock because it has to be read outside of zone->lock, 406 * and it is done in the main allocator path. But, it is written 407 * quite infrequently. 408 * 409 * The span_seq lock is declared along with zone->lock because it is 410 * frequently read in proximity to zone->lock. It's good to 411 * give them a chance of being in the same cacheline. 412 * 413 * Write access to present_pages at runtime should be protected by 414 * mem_hotplug_begin/end(). Any reader who can't tolerant drift of 415 * present_pages should get_online_mems() to get a stable value. 416 * 417 * Read access to managed_pages should be safe because it's unsigned 418 * long. Write access to zone->managed_pages and totalram_pages are 419 * protected by managed_page_count_lock at runtime. Idealy only 420 * adjust_managed_page_count() should be used instead of directly 421 * touching zone->managed_pages and totalram_pages. 422 */ 423 unsigned long managed_pages; 424 unsigned long spanned_pages; 425 unsigned long present_pages; 426 427 const char *name; 428 429 #ifdef CONFIG_MEMORY_ISOLATION 430 /* 431 * Number of isolated pageblock. It is used to solve incorrect 432 * freepage counting problem due to racy retrieving migratetype 433 * of pageblock. Protected by zone->lock. 434 */ 435 unsigned long nr_isolate_pageblock; 436 #endif 437 438 #ifdef CONFIG_MEMORY_HOTPLUG 439 /* see spanned/present_pages for more description */ 440 seqlock_t span_seqlock; 441 #endif 442 443 int initialized; 444 445 /* Write-intensive fields used from the page allocator */ 446 ZONE_PADDING(_pad1_) 447 448 /* free areas of different sizes */ 449 struct free_area free_area[MAX_ORDER]; 450 451 /* zone flags, see below */ 452 unsigned long flags; 453 454 /* Primarily protects free_area */ 455 spinlock_t lock; 456 457 /* Write-intensive fields used by compaction and vmstats. */ 458 ZONE_PADDING(_pad2_) 459 460 /* 461 * When free pages are below this point, additional steps are taken 462 * when reading the number of free pages to avoid per-cpu counter 463 * drift allowing watermarks to be breached 464 */ 465 unsigned long percpu_drift_mark; 466 467 #if defined CONFIG_COMPACTION || defined CONFIG_CMA 468 /* pfn where compaction free scanner should start */ 469 unsigned long compact_cached_free_pfn; 470 /* pfn where async and sync compaction migration scanner should start */ 471 unsigned long compact_cached_migrate_pfn[2]; 472 #endif 473 474 #ifdef CONFIG_COMPACTION 475 /* 476 * On compaction failure, 1<<compact_defer_shift compactions 477 * are skipped before trying again. The number attempted since 478 * last failure is tracked with compact_considered. 479 */ 480 unsigned int compact_considered; 481 unsigned int compact_defer_shift; 482 int compact_order_failed; 483 #endif 484 485 #if defined CONFIG_COMPACTION || defined CONFIG_CMA 486 /* Set to true when the PG_migrate_skip bits should be cleared */ 487 bool compact_blockskip_flush; 488 #endif 489 490 bool contiguous; 491 492 ZONE_PADDING(_pad3_) 493 /* Zone statistics */ 494 atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS]; 495 } ____cacheline_internodealigned_in_smp; 496 497 enum pgdat_flags { 498 PGDAT_CONGESTED, /* pgdat has many dirty pages backed by 499 * a congested BDI 500 */ 501 PGDAT_DIRTY, /* reclaim scanning has recently found 502 * many dirty file pages at the tail 503 * of the LRU. 504 */ 505 PGDAT_WRITEBACK, /* reclaim scanning has recently found 506 * many pages under writeback 507 */ 508 PGDAT_RECLAIM_LOCKED, /* prevents concurrent reclaim */ 509 }; 510 511 static inline unsigned long zone_end_pfn(const struct zone *zone) 512 { 513 return zone->zone_start_pfn + zone->spanned_pages; 514 } 515 516 static inline bool zone_spans_pfn(const struct zone *zone, unsigned long pfn) 517 { 518 return zone->zone_start_pfn <= pfn && pfn < zone_end_pfn(zone); 519 } 520 521 static inline bool zone_is_initialized(struct zone *zone) 522 { 523 return zone->initialized; 524 } 525 526 static inline bool zone_is_empty(struct zone *zone) 527 { 528 return zone->spanned_pages == 0; 529 } 530 531 /* 532 * The "priority" of VM scanning is how much of the queues we will scan in one 533 * go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the 534 * queues ("queue_length >> 12") during an aging round. 535 */ 536 #define DEF_PRIORITY 12 537 538 /* Maximum number of zones on a zonelist */ 539 #define MAX_ZONES_PER_ZONELIST (MAX_NUMNODES * MAX_NR_ZONES) 540 541 enum { 542 ZONELIST_FALLBACK, /* zonelist with fallback */ 543 #ifdef CONFIG_NUMA 544 /* 545 * The NUMA zonelists are doubled because we need zonelists that 546 * restrict the allocations to a single node for __GFP_THISNODE. 547 */ 548 ZONELIST_NOFALLBACK, /* zonelist without fallback (__GFP_THISNODE) */ 549 #endif 550 MAX_ZONELISTS 551 }; 552 553 /* 554 * This struct contains information about a zone in a zonelist. It is stored 555 * here to avoid dereferences into large structures and lookups of tables 556 */ 557 struct zoneref { 558 struct zone *zone; /* Pointer to actual zone */ 559 int zone_idx; /* zone_idx(zoneref->zone) */ 560 }; 561 562 /* 563 * One allocation request operates on a zonelist. A zonelist 564 * is a list of zones, the first one is the 'goal' of the 565 * allocation, the other zones are fallback zones, in decreasing 566 * priority. 567 * 568 * To speed the reading of the zonelist, the zonerefs contain the zone index 569 * of the entry being read. Helper functions to access information given 570 * a struct zoneref are 571 * 572 * zonelist_zone() - Return the struct zone * for an entry in _zonerefs 573 * zonelist_zone_idx() - Return the index of the zone for an entry 574 * zonelist_node_idx() - Return the index of the node for an entry 575 */ 576 struct zonelist { 577 struct zoneref _zonerefs[MAX_ZONES_PER_ZONELIST + 1]; 578 }; 579 580 #ifndef CONFIG_DISCONTIGMEM 581 /* The array of struct pages - for discontigmem use pgdat->lmem_map */ 582 extern struct page *mem_map; 583 #endif 584 585 /* 586 * The pg_data_t structure is used in machines with CONFIG_DISCONTIGMEM 587 * (mostly NUMA machines?) to denote a higher-level memory zone than the 588 * zone denotes. 589 * 590 * On NUMA machines, each NUMA node would have a pg_data_t to describe 591 * it's memory layout. 592 * 593 * Memory statistics and page replacement data structures are maintained on a 594 * per-zone basis. 595 */ 596 struct bootmem_data; 597 typedef struct pglist_data { 598 struct zone node_zones[MAX_NR_ZONES]; 599 struct zonelist node_zonelists[MAX_ZONELISTS]; 600 int nr_zones; 601 #ifdef CONFIG_FLAT_NODE_MEM_MAP /* means !SPARSEMEM */ 602 struct page *node_mem_map; 603 #ifdef CONFIG_PAGE_EXTENSION 604 struct page_ext *node_page_ext; 605 #endif 606 #endif 607 #ifndef CONFIG_NO_BOOTMEM 608 struct bootmem_data *bdata; 609 #endif 610 #ifdef CONFIG_MEMORY_HOTPLUG 611 /* 612 * Must be held any time you expect node_start_pfn, node_present_pages 613 * or node_spanned_pages stay constant. Holding this will also 614 * guarantee that any pfn_valid() stays that way. 615 * 616 * pgdat_resize_lock() and pgdat_resize_unlock() are provided to 617 * manipulate node_size_lock without checking for CONFIG_MEMORY_HOTPLUG. 618 * 619 * Nests above zone->lock and zone->span_seqlock 620 */ 621 spinlock_t node_size_lock; 622 #endif 623 unsigned long node_start_pfn; 624 unsigned long node_present_pages; /* total number of physical pages */ 625 unsigned long node_spanned_pages; /* total size of physical page 626 range, including holes */ 627 int node_id; 628 wait_queue_head_t kswapd_wait; 629 wait_queue_head_t pfmemalloc_wait; 630 struct task_struct *kswapd; /* Protected by 631 mem_hotplug_begin/end() */ 632 int kswapd_order; 633 enum zone_type kswapd_classzone_idx; 634 635 #ifdef CONFIG_COMPACTION 636 int kcompactd_max_order; 637 enum zone_type kcompactd_classzone_idx; 638 wait_queue_head_t kcompactd_wait; 639 struct task_struct *kcompactd; 640 #endif 641 #ifdef CONFIG_NUMA_BALANCING 642 /* Lock serializing the migrate rate limiting window */ 643 spinlock_t numabalancing_migrate_lock; 644 645 /* Rate limiting time interval */ 646 unsigned long numabalancing_migrate_next_window; 647 648 /* Number of pages migrated during the rate limiting time interval */ 649 unsigned long numabalancing_migrate_nr_pages; 650 #endif 651 /* 652 * This is a per-node reserve of pages that are not available 653 * to userspace allocations. 654 */ 655 unsigned long totalreserve_pages; 656 657 #ifdef CONFIG_NUMA 658 /* 659 * zone reclaim becomes active if more unmapped pages exist. 660 */ 661 unsigned long min_unmapped_pages; 662 unsigned long min_slab_pages; 663 #endif /* CONFIG_NUMA */ 664 665 /* Write-intensive fields used by page reclaim */ 666 ZONE_PADDING(_pad1_) 667 spinlock_t lru_lock; 668 669 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT 670 /* 671 * If memory initialisation on large machines is deferred then this 672 * is the first PFN that needs to be initialised. 673 */ 674 unsigned long first_deferred_pfn; 675 #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */ 676 677 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 678 spinlock_t split_queue_lock; 679 struct list_head split_queue; 680 unsigned long split_queue_len; 681 #endif 682 683 /* Fields commonly accessed by the page reclaim scanner */ 684 struct lruvec lruvec; 685 686 /* 687 * The target ratio of ACTIVE_ANON to INACTIVE_ANON pages on 688 * this node's LRU. Maintained by the pageout code. 689 */ 690 unsigned int inactive_ratio; 691 692 unsigned long flags; 693 694 ZONE_PADDING(_pad2_) 695 696 /* Per-node vmstats */ 697 struct per_cpu_nodestat __percpu *per_cpu_nodestats; 698 atomic_long_t vm_stat[NR_VM_NODE_STAT_ITEMS]; 699 } pg_data_t; 700 701 #define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages) 702 #define node_spanned_pages(nid) (NODE_DATA(nid)->node_spanned_pages) 703 #ifdef CONFIG_FLAT_NODE_MEM_MAP 704 #define pgdat_page_nr(pgdat, pagenr) ((pgdat)->node_mem_map + (pagenr)) 705 #else 706 #define pgdat_page_nr(pgdat, pagenr) pfn_to_page((pgdat)->node_start_pfn + (pagenr)) 707 #endif 708 #define nid_page_nr(nid, pagenr) pgdat_page_nr(NODE_DATA(nid),(pagenr)) 709 710 #define node_start_pfn(nid) (NODE_DATA(nid)->node_start_pfn) 711 #define node_end_pfn(nid) pgdat_end_pfn(NODE_DATA(nid)) 712 static inline spinlock_t *zone_lru_lock(struct zone *zone) 713 { 714 return &zone->zone_pgdat->lru_lock; 715 } 716 717 static inline struct lruvec *node_lruvec(struct pglist_data *pgdat) 718 { 719 return &pgdat->lruvec; 720 } 721 722 static inline unsigned long pgdat_end_pfn(pg_data_t *pgdat) 723 { 724 return pgdat->node_start_pfn + pgdat->node_spanned_pages; 725 } 726 727 static inline bool pgdat_is_empty(pg_data_t *pgdat) 728 { 729 return !pgdat->node_start_pfn && !pgdat->node_spanned_pages; 730 } 731 732 static inline int zone_id(const struct zone *zone) 733 { 734 struct pglist_data *pgdat = zone->zone_pgdat; 735 736 return zone - pgdat->node_zones; 737 } 738 739 #ifdef CONFIG_ZONE_DEVICE 740 static inline bool is_dev_zone(const struct zone *zone) 741 { 742 return zone_id(zone) == ZONE_DEVICE; 743 } 744 #else 745 static inline bool is_dev_zone(const struct zone *zone) 746 { 747 return false; 748 } 749 #endif 750 751 #include <linux/memory_hotplug.h> 752 753 extern struct mutex zonelists_mutex; 754 void build_all_zonelists(pg_data_t *pgdat, struct zone *zone); 755 void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx); 756 bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark, 757 int classzone_idx, unsigned int alloc_flags, 758 long free_pages); 759 bool zone_watermark_ok(struct zone *z, unsigned int order, 760 unsigned long mark, int classzone_idx, 761 unsigned int alloc_flags); 762 bool zone_watermark_ok_safe(struct zone *z, unsigned int order, 763 unsigned long mark, int classzone_idx); 764 enum memmap_context { 765 MEMMAP_EARLY, 766 MEMMAP_HOTPLUG, 767 }; 768 extern int init_currently_empty_zone(struct zone *zone, unsigned long start_pfn, 769 unsigned long size); 770 771 extern void lruvec_init(struct lruvec *lruvec); 772 773 static inline struct pglist_data *lruvec_pgdat(struct lruvec *lruvec) 774 { 775 #ifdef CONFIG_MEMCG 776 return lruvec->pgdat; 777 #else 778 return container_of(lruvec, struct pglist_data, lruvec); 779 #endif 780 } 781 782 extern unsigned long lruvec_lru_size(struct lruvec *lruvec, enum lru_list lru); 783 784 #ifdef CONFIG_HAVE_MEMORY_PRESENT 785 void memory_present(int nid, unsigned long start, unsigned long end); 786 #else 787 static inline void memory_present(int nid, unsigned long start, unsigned long end) {} 788 #endif 789 790 #ifdef CONFIG_HAVE_MEMORYLESS_NODES 791 int local_memory_node(int node_id); 792 #else 793 static inline int local_memory_node(int node_id) { return node_id; }; 794 #endif 795 796 #ifdef CONFIG_NEED_NODE_MEMMAP_SIZE 797 unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long); 798 #endif 799 800 /* 801 * zone_idx() returns 0 for the ZONE_DMA zone, 1 for the ZONE_NORMAL zone, etc. 802 */ 803 #define zone_idx(zone) ((zone) - (zone)->zone_pgdat->node_zones) 804 805 /* 806 * Returns true if a zone has pages managed by the buddy allocator. 807 * All the reclaim decisions have to use this function rather than 808 * populated_zone(). If the whole zone is reserved then we can easily 809 * end up with populated_zone() && !managed_zone(). 810 */ 811 static inline bool managed_zone(struct zone *zone) 812 { 813 return zone->managed_pages; 814 } 815 816 /* Returns true if a zone has memory */ 817 static inline bool populated_zone(struct zone *zone) 818 { 819 return zone->present_pages; 820 } 821 822 extern int movable_zone; 823 824 #ifdef CONFIG_HIGHMEM 825 static inline int zone_movable_is_highmem(void) 826 { 827 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP 828 return movable_zone == ZONE_HIGHMEM; 829 #else 830 return (ZONE_MOVABLE - 1) == ZONE_HIGHMEM; 831 #endif 832 } 833 #endif 834 835 static inline int is_highmem_idx(enum zone_type idx) 836 { 837 #ifdef CONFIG_HIGHMEM 838 return (idx == ZONE_HIGHMEM || 839 (idx == ZONE_MOVABLE && zone_movable_is_highmem())); 840 #else 841 return 0; 842 #endif 843 } 844 845 /** 846 * is_highmem - helper function to quickly check if a struct zone is a 847 * highmem zone or not. This is an attempt to keep references 848 * to ZONE_{DMA/NORMAL/HIGHMEM/etc} in general code to a minimum. 849 * @zone - pointer to struct zone variable 850 */ 851 static inline int is_highmem(struct zone *zone) 852 { 853 #ifdef CONFIG_HIGHMEM 854 return is_highmem_idx(zone_idx(zone)); 855 #else 856 return 0; 857 #endif 858 } 859 860 /* These two functions are used to setup the per zone pages min values */ 861 struct ctl_table; 862 int min_free_kbytes_sysctl_handler(struct ctl_table *, int, 863 void __user *, size_t *, loff_t *); 864 int watermark_scale_factor_sysctl_handler(struct ctl_table *, int, 865 void __user *, size_t *, loff_t *); 866 extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1]; 867 int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int, 868 void __user *, size_t *, loff_t *); 869 int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *, int, 870 void __user *, size_t *, loff_t *); 871 int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *, int, 872 void __user *, size_t *, loff_t *); 873 int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *, int, 874 void __user *, size_t *, loff_t *); 875 876 extern int numa_zonelist_order_handler(struct ctl_table *, int, 877 void __user *, size_t *, loff_t *); 878 extern char numa_zonelist_order[]; 879 #define NUMA_ZONELIST_ORDER_LEN 16 /* string buffer size */ 880 881 #ifndef CONFIG_NEED_MULTIPLE_NODES 882 883 extern struct pglist_data contig_page_data; 884 #define NODE_DATA(nid) (&contig_page_data) 885 #define NODE_MEM_MAP(nid) mem_map 886 887 #else /* CONFIG_NEED_MULTIPLE_NODES */ 888 889 #include <asm/mmzone.h> 890 891 #endif /* !CONFIG_NEED_MULTIPLE_NODES */ 892 893 extern struct pglist_data *first_online_pgdat(void); 894 extern struct pglist_data *next_online_pgdat(struct pglist_data *pgdat); 895 extern struct zone *next_zone(struct zone *zone); 896 897 /** 898 * for_each_online_pgdat - helper macro to iterate over all online nodes 899 * @pgdat - pointer to a pg_data_t variable 900 */ 901 #define for_each_online_pgdat(pgdat) \ 902 for (pgdat = first_online_pgdat(); \ 903 pgdat; \ 904 pgdat = next_online_pgdat(pgdat)) 905 /** 906 * for_each_zone - helper macro to iterate over all memory zones 907 * @zone - pointer to struct zone variable 908 * 909 * The user only needs to declare the zone variable, for_each_zone 910 * fills it in. 911 */ 912 #define for_each_zone(zone) \ 913 for (zone = (first_online_pgdat())->node_zones; \ 914 zone; \ 915 zone = next_zone(zone)) 916 917 #define for_each_populated_zone(zone) \ 918 for (zone = (first_online_pgdat())->node_zones; \ 919 zone; \ 920 zone = next_zone(zone)) \ 921 if (!populated_zone(zone)) \ 922 ; /* do nothing */ \ 923 else 924 925 static inline struct zone *zonelist_zone(struct zoneref *zoneref) 926 { 927 return zoneref->zone; 928 } 929 930 static inline int zonelist_zone_idx(struct zoneref *zoneref) 931 { 932 return zoneref->zone_idx; 933 } 934 935 static inline int zonelist_node_idx(struct zoneref *zoneref) 936 { 937 #ifdef CONFIG_NUMA 938 /* zone_to_nid not available in this context */ 939 return zoneref->zone->node; 940 #else 941 return 0; 942 #endif /* CONFIG_NUMA */ 943 } 944 945 struct zoneref *__next_zones_zonelist(struct zoneref *z, 946 enum zone_type highest_zoneidx, 947 nodemask_t *nodes); 948 949 /** 950 * 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 951 * @z - The cursor used as a starting point for the search 952 * @highest_zoneidx - The zone index of the highest zone to return 953 * @nodes - An optional nodemask to filter the zonelist with 954 * 955 * This function returns the next zone at or below a given zone index that is 956 * within the allowed nodemask using a cursor as the starting point for the 957 * search. The zoneref returned is a cursor that represents the current zone 958 * being examined. It should be advanced by one before calling 959 * next_zones_zonelist again. 960 */ 961 static __always_inline struct zoneref *next_zones_zonelist(struct zoneref *z, 962 enum zone_type highest_zoneidx, 963 nodemask_t *nodes) 964 { 965 if (likely(!nodes && zonelist_zone_idx(z) <= highest_zoneidx)) 966 return z; 967 return __next_zones_zonelist(z, highest_zoneidx, nodes); 968 } 969 970 /** 971 * first_zones_zonelist - Returns the first zone at or below highest_zoneidx within the allowed nodemask in a zonelist 972 * @zonelist - The zonelist to search for a suitable zone 973 * @highest_zoneidx - The zone index of the highest zone to return 974 * @nodes - An optional nodemask to filter the zonelist with 975 * @zone - The first suitable zone found is returned via this parameter 976 * 977 * This function returns the first zone at or below a given zone index that is 978 * within the allowed nodemask. The zoneref returned is a cursor that can be 979 * used to iterate the zonelist with next_zones_zonelist by advancing it by 980 * one before calling. 981 */ 982 static inline struct zoneref *first_zones_zonelist(struct zonelist *zonelist, 983 enum zone_type highest_zoneidx, 984 nodemask_t *nodes) 985 { 986 return next_zones_zonelist(zonelist->_zonerefs, 987 highest_zoneidx, nodes); 988 } 989 990 /** 991 * 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 992 * @zone - The current zone in the iterator 993 * @z - The current pointer within zonelist->zones being iterated 994 * @zlist - The zonelist being iterated 995 * @highidx - The zone index of the highest zone to return 996 * @nodemask - Nodemask allowed by the allocator 997 * 998 * This iterator iterates though all zones at or below a given zone index and 999 * within a given nodemask 1000 */ 1001 #define for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, nodemask) \ 1002 for (z = first_zones_zonelist(zlist, highidx, nodemask), zone = zonelist_zone(z); \ 1003 zone; \ 1004 z = next_zones_zonelist(++z, highidx, nodemask), \ 1005 zone = zonelist_zone(z)) 1006 1007 #define for_next_zone_zonelist_nodemask(zone, z, zlist, highidx, nodemask) \ 1008 for (zone = z->zone; \ 1009 zone; \ 1010 z = next_zones_zonelist(++z, highidx, nodemask), \ 1011 zone = zonelist_zone(z)) 1012 1013 1014 /** 1015 * for_each_zone_zonelist - helper macro to iterate over valid zones in a zonelist at or below a given zone index 1016 * @zone - The current zone in the iterator 1017 * @z - The current pointer within zonelist->zones being iterated 1018 * @zlist - The zonelist being iterated 1019 * @highidx - The zone index of the highest zone to return 1020 * 1021 * This iterator iterates though all zones at or below a given zone index. 1022 */ 1023 #define for_each_zone_zonelist(zone, z, zlist, highidx) \ 1024 for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, NULL) 1025 1026 #ifdef CONFIG_SPARSEMEM 1027 #include <asm/sparsemem.h> 1028 #endif 1029 1030 #if !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) && \ 1031 !defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) 1032 static inline unsigned long early_pfn_to_nid(unsigned long pfn) 1033 { 1034 return 0; 1035 } 1036 #endif 1037 1038 #ifdef CONFIG_FLATMEM 1039 #define pfn_to_nid(pfn) (0) 1040 #endif 1041 1042 #ifdef CONFIG_SPARSEMEM 1043 1044 /* 1045 * SECTION_SHIFT #bits space required to store a section # 1046 * 1047 * PA_SECTION_SHIFT physical address to/from section number 1048 * PFN_SECTION_SHIFT pfn to/from section number 1049 */ 1050 #define PA_SECTION_SHIFT (SECTION_SIZE_BITS) 1051 #define PFN_SECTION_SHIFT (SECTION_SIZE_BITS - PAGE_SHIFT) 1052 1053 #define NR_MEM_SECTIONS (1UL << SECTIONS_SHIFT) 1054 1055 #define PAGES_PER_SECTION (1UL << PFN_SECTION_SHIFT) 1056 #define PAGE_SECTION_MASK (~(PAGES_PER_SECTION-1)) 1057 1058 #define SECTION_BLOCKFLAGS_BITS \ 1059 ((1UL << (PFN_SECTION_SHIFT - pageblock_order)) * NR_PAGEBLOCK_BITS) 1060 1061 #if (MAX_ORDER - 1 + PAGE_SHIFT) > SECTION_SIZE_BITS 1062 #error Allocator MAX_ORDER exceeds SECTION_SIZE 1063 #endif 1064 1065 #define pfn_to_section_nr(pfn) ((pfn) >> PFN_SECTION_SHIFT) 1066 #define section_nr_to_pfn(sec) ((sec) << PFN_SECTION_SHIFT) 1067 1068 #define SECTION_ALIGN_UP(pfn) (((pfn) + PAGES_PER_SECTION - 1) & PAGE_SECTION_MASK) 1069 #define SECTION_ALIGN_DOWN(pfn) ((pfn) & PAGE_SECTION_MASK) 1070 1071 struct page; 1072 struct page_ext; 1073 struct mem_section { 1074 /* 1075 * This is, logically, a pointer to an array of struct 1076 * pages. However, it is stored with some other magic. 1077 * (see sparse.c::sparse_init_one_section()) 1078 * 1079 * Additionally during early boot we encode node id of 1080 * the location of the section here to guide allocation. 1081 * (see sparse.c::memory_present()) 1082 * 1083 * Making it a UL at least makes someone do a cast 1084 * before using it wrong. 1085 */ 1086 unsigned long section_mem_map; 1087 1088 /* See declaration of similar field in struct zone */ 1089 unsigned long *pageblock_flags; 1090 #ifdef CONFIG_PAGE_EXTENSION 1091 /* 1092 * If SPARSEMEM, pgdat doesn't have page_ext pointer. We use 1093 * section. (see page_ext.h about this.) 1094 */ 1095 struct page_ext *page_ext; 1096 unsigned long pad; 1097 #endif 1098 /* 1099 * WARNING: mem_section must be a power-of-2 in size for the 1100 * calculation and use of SECTION_ROOT_MASK to make sense. 1101 */ 1102 }; 1103 1104 #ifdef CONFIG_SPARSEMEM_EXTREME 1105 #define SECTIONS_PER_ROOT (PAGE_SIZE / sizeof (struct mem_section)) 1106 #else 1107 #define SECTIONS_PER_ROOT 1 1108 #endif 1109 1110 #define SECTION_NR_TO_ROOT(sec) ((sec) / SECTIONS_PER_ROOT) 1111 #define NR_SECTION_ROOTS DIV_ROUND_UP(NR_MEM_SECTIONS, SECTIONS_PER_ROOT) 1112 #define SECTION_ROOT_MASK (SECTIONS_PER_ROOT - 1) 1113 1114 #ifdef CONFIG_SPARSEMEM_EXTREME 1115 extern struct mem_section *mem_section[NR_SECTION_ROOTS]; 1116 #else 1117 extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT]; 1118 #endif 1119 1120 static inline struct mem_section *__nr_to_section(unsigned long nr) 1121 { 1122 if (!mem_section[SECTION_NR_TO_ROOT(nr)]) 1123 return NULL; 1124 return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK]; 1125 } 1126 extern int __section_nr(struct mem_section* ms); 1127 extern unsigned long usemap_size(void); 1128 1129 /* 1130 * We use the lower bits of the mem_map pointer to store 1131 * a little bit of information. There should be at least 1132 * 3 bits here due to 32-bit alignment. 1133 */ 1134 #define SECTION_MARKED_PRESENT (1UL<<0) 1135 #define SECTION_HAS_MEM_MAP (1UL<<1) 1136 #define SECTION_MAP_LAST_BIT (1UL<<2) 1137 #define SECTION_MAP_MASK (~(SECTION_MAP_LAST_BIT-1)) 1138 #define SECTION_NID_SHIFT 2 1139 1140 static inline struct page *__section_mem_map_addr(struct mem_section *section) 1141 { 1142 unsigned long map = section->section_mem_map; 1143 map &= SECTION_MAP_MASK; 1144 return (struct page *)map; 1145 } 1146 1147 static inline int present_section(struct mem_section *section) 1148 { 1149 return (section && (section->section_mem_map & SECTION_MARKED_PRESENT)); 1150 } 1151 1152 static inline int present_section_nr(unsigned long nr) 1153 { 1154 return present_section(__nr_to_section(nr)); 1155 } 1156 1157 static inline int valid_section(struct mem_section *section) 1158 { 1159 return (section && (section->section_mem_map & SECTION_HAS_MEM_MAP)); 1160 } 1161 1162 static inline int valid_section_nr(unsigned long nr) 1163 { 1164 return valid_section(__nr_to_section(nr)); 1165 } 1166 1167 static inline struct mem_section *__pfn_to_section(unsigned long pfn) 1168 { 1169 return __nr_to_section(pfn_to_section_nr(pfn)); 1170 } 1171 1172 #ifndef CONFIG_HAVE_ARCH_PFN_VALID 1173 static inline int pfn_valid(unsigned long pfn) 1174 { 1175 if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS) 1176 return 0; 1177 return valid_section(__nr_to_section(pfn_to_section_nr(pfn))); 1178 } 1179 #endif 1180 1181 static inline int pfn_present(unsigned long pfn) 1182 { 1183 if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS) 1184 return 0; 1185 return present_section(__nr_to_section(pfn_to_section_nr(pfn))); 1186 } 1187 1188 /* 1189 * These are _only_ used during initialisation, therefore they 1190 * can use __initdata ... They could have names to indicate 1191 * this restriction. 1192 */ 1193 #ifdef CONFIG_NUMA 1194 #define pfn_to_nid(pfn) \ 1195 ({ \ 1196 unsigned long __pfn_to_nid_pfn = (pfn); \ 1197 page_to_nid(pfn_to_page(__pfn_to_nid_pfn)); \ 1198 }) 1199 #else 1200 #define pfn_to_nid(pfn) (0) 1201 #endif 1202 1203 #define early_pfn_valid(pfn) pfn_valid(pfn) 1204 void sparse_init(void); 1205 #else 1206 #define sparse_init() do {} while (0) 1207 #define sparse_index_init(_sec, _nid) do {} while (0) 1208 #endif /* CONFIG_SPARSEMEM */ 1209 1210 /* 1211 * During memory init memblocks map pfns to nids. The search is expensive and 1212 * this caches recent lookups. The implementation of __early_pfn_to_nid 1213 * may treat start/end as pfns or sections. 1214 */ 1215 struct mminit_pfnnid_cache { 1216 unsigned long last_start; 1217 unsigned long last_end; 1218 int last_nid; 1219 }; 1220 1221 #ifndef early_pfn_valid 1222 #define early_pfn_valid(pfn) (1) 1223 #endif 1224 1225 void memory_present(int nid, unsigned long start, unsigned long end); 1226 unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long); 1227 1228 /* 1229 * If it is possible to have holes within a MAX_ORDER_NR_PAGES, then we 1230 * need to check pfn validility within that MAX_ORDER_NR_PAGES block. 1231 * pfn_valid_within() should be used in this case; we optimise this away 1232 * when we have no holes within a MAX_ORDER_NR_PAGES block. 1233 */ 1234 #ifdef CONFIG_HOLES_IN_ZONE 1235 #define pfn_valid_within(pfn) pfn_valid(pfn) 1236 #else 1237 #define pfn_valid_within(pfn) (1) 1238 #endif 1239 1240 #ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL 1241 /* 1242 * pfn_valid() is meant to be able to tell if a given PFN has valid memmap 1243 * associated with it or not. In FLATMEM, it is expected that holes always 1244 * have valid memmap as long as there is valid PFNs either side of the hole. 1245 * In SPARSEMEM, it is assumed that a valid section has a memmap for the 1246 * entire section. 1247 * 1248 * However, an ARM, and maybe other embedded architectures in the future 1249 * free memmap backing holes to save memory on the assumption the memmap is 1250 * never used. The page_zone linkages are then broken even though pfn_valid() 1251 * returns true. A walker of the full memmap must then do this additional 1252 * check to ensure the memmap they are looking at is sane by making sure 1253 * the zone and PFN linkages are still valid. This is expensive, but walkers 1254 * of the full memmap are extremely rare. 1255 */ 1256 bool memmap_valid_within(unsigned long pfn, 1257 struct page *page, struct zone *zone); 1258 #else 1259 static inline bool memmap_valid_within(unsigned long pfn, 1260 struct page *page, struct zone *zone) 1261 { 1262 return true; 1263 } 1264 #endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */ 1265 1266 #endif /* !__GENERATING_BOUNDS.H */ 1267 #endif /* !__ASSEMBLY__ */ 1268 #endif /* _LINUX_MMZONE_H */ 1269