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 unmapped file */ 240 #define ISOLATE_UNMAPPED ((__force isolate_mode_t)0x2) 241 /* Isolate for asynchronous migration */ 242 #define ISOLATE_ASYNC_MIGRATE ((__force isolate_mode_t)0x4) 243 /* Isolate unevictable pages */ 244 #define ISOLATE_UNEVICTABLE ((__force isolate_mode_t)0x8) 245 246 /* LRU Isolation modes. */ 247 typedef unsigned __bitwise isolate_mode_t; 248 249 enum zone_watermarks { 250 WMARK_MIN, 251 WMARK_LOW, 252 WMARK_HIGH, 253 NR_WMARK 254 }; 255 256 #define min_wmark_pages(z) (z->watermark[WMARK_MIN]) 257 #define low_wmark_pages(z) (z->watermark[WMARK_LOW]) 258 #define high_wmark_pages(z) (z->watermark[WMARK_HIGH]) 259 260 struct per_cpu_pages { 261 int count; /* number of pages in the list */ 262 int high; /* high watermark, emptying needed */ 263 int batch; /* chunk size for buddy add/remove */ 264 265 /* Lists of pages, one per migrate type stored on the pcp-lists */ 266 struct list_head lists[MIGRATE_PCPTYPES]; 267 }; 268 269 struct per_cpu_pageset { 270 struct per_cpu_pages pcp; 271 #ifdef CONFIG_NUMA 272 s8 expire; 273 #endif 274 #ifdef CONFIG_SMP 275 s8 stat_threshold; 276 s8 vm_stat_diff[NR_VM_ZONE_STAT_ITEMS]; 277 #endif 278 }; 279 280 struct per_cpu_nodestat { 281 s8 stat_threshold; 282 s8 vm_node_stat_diff[NR_VM_NODE_STAT_ITEMS]; 283 }; 284 285 #endif /* !__GENERATING_BOUNDS.H */ 286 287 enum zone_type { 288 #ifdef CONFIG_ZONE_DMA 289 /* 290 * ZONE_DMA is used when there are devices that are not able 291 * to do DMA to all of addressable memory (ZONE_NORMAL). Then we 292 * carve out the portion of memory that is needed for these devices. 293 * The range is arch specific. 294 * 295 * Some examples 296 * 297 * Architecture Limit 298 * --------------------------- 299 * parisc, ia64, sparc <4G 300 * s390 <2G 301 * arm Various 302 * alpha Unlimited or 0-16MB. 303 * 304 * i386, x86_64 and multiple other arches 305 * <16M. 306 */ 307 ZONE_DMA, 308 #endif 309 #ifdef CONFIG_ZONE_DMA32 310 /* 311 * x86_64 needs two ZONE_DMAs because it supports devices that are 312 * only able to do DMA to the lower 16M but also 32 bit devices that 313 * can only do DMA areas below 4G. 314 */ 315 ZONE_DMA32, 316 #endif 317 /* 318 * Normal addressable memory is in ZONE_NORMAL. DMA operations can be 319 * performed on pages in ZONE_NORMAL if the DMA devices support 320 * transfers to all addressable memory. 321 */ 322 ZONE_NORMAL, 323 #ifdef CONFIG_HIGHMEM 324 /* 325 * A memory area that is only addressable by the kernel through 326 * mapping portions into its own address space. This is for example 327 * used by i386 to allow the kernel to address the memory beyond 328 * 900MB. The kernel will set up special mappings (page 329 * table entries on i386) for each page that the kernel needs to 330 * access. 331 */ 332 ZONE_HIGHMEM, 333 #endif 334 ZONE_MOVABLE, 335 #ifdef CONFIG_ZONE_DEVICE 336 ZONE_DEVICE, 337 #endif 338 __MAX_NR_ZONES 339 340 }; 341 342 #ifndef __GENERATING_BOUNDS_H 343 344 struct zone { 345 /* Read-mostly fields */ 346 347 /* zone watermarks, access with *_wmark_pages(zone) macros */ 348 unsigned long watermark[NR_WMARK]; 349 350 unsigned long nr_reserved_highatomic; 351 352 /* 353 * We don't know if the memory that we're going to allocate will be 354 * freeable or/and it will be released eventually, so to avoid totally 355 * wasting several GB of ram we must reserve some of the lower zone 356 * memory (otherwise we risk to run OOM on the lower zones despite 357 * there being tons of freeable ram on the higher zones). This array is 358 * recalculated at runtime if the sysctl_lowmem_reserve_ratio sysctl 359 * changes. 360 */ 361 long lowmem_reserve[MAX_NR_ZONES]; 362 363 #ifdef CONFIG_NUMA 364 int node; 365 #endif 366 struct pglist_data *zone_pgdat; 367 struct per_cpu_pageset __percpu *pageset; 368 369 #ifndef CONFIG_SPARSEMEM 370 /* 371 * Flags for a pageblock_nr_pages block. See pageblock-flags.h. 372 * In SPARSEMEM, this map is stored in struct mem_section 373 */ 374 unsigned long *pageblock_flags; 375 #endif /* CONFIG_SPARSEMEM */ 376 377 /* zone_start_pfn == zone_start_paddr >> PAGE_SHIFT */ 378 unsigned long zone_start_pfn; 379 380 /* 381 * spanned_pages is the total pages spanned by the zone, including 382 * holes, which is calculated as: 383 * spanned_pages = zone_end_pfn - zone_start_pfn; 384 * 385 * present_pages is physical pages existing within the zone, which 386 * is calculated as: 387 * present_pages = spanned_pages - absent_pages(pages in holes); 388 * 389 * managed_pages is present pages managed by the buddy system, which 390 * is calculated as (reserved_pages includes pages allocated by the 391 * bootmem allocator): 392 * managed_pages = present_pages - reserved_pages; 393 * 394 * So present_pages may be used by memory hotplug or memory power 395 * management logic to figure out unmanaged pages by checking 396 * (present_pages - managed_pages). And managed_pages should be used 397 * by page allocator and vm scanner to calculate all kinds of watermarks 398 * and thresholds. 399 * 400 * Locking rules: 401 * 402 * zone_start_pfn and spanned_pages are protected by span_seqlock. 403 * It is a seqlock because it has to be read outside of zone->lock, 404 * and it is done in the main allocator path. But, it is written 405 * quite infrequently. 406 * 407 * The span_seq lock is declared along with zone->lock because it is 408 * frequently read in proximity to zone->lock. It's good to 409 * give them a chance of being in the same cacheline. 410 * 411 * Write access to present_pages at runtime should be protected by 412 * mem_hotplug_begin/end(). Any reader who can't tolerant drift of 413 * present_pages should get_online_mems() to get a stable value. 414 * 415 * Read access to managed_pages should be safe because it's unsigned 416 * long. Write access to zone->managed_pages and totalram_pages are 417 * protected by managed_page_count_lock at runtime. Idealy only 418 * adjust_managed_page_count() should be used instead of directly 419 * touching zone->managed_pages and totalram_pages. 420 */ 421 unsigned long managed_pages; 422 unsigned long spanned_pages; 423 unsigned long present_pages; 424 425 const char *name; 426 427 #ifdef CONFIG_MEMORY_ISOLATION 428 /* 429 * Number of isolated pageblock. It is used to solve incorrect 430 * freepage counting problem due to racy retrieving migratetype 431 * of pageblock. Protected by zone->lock. 432 */ 433 unsigned long nr_isolate_pageblock; 434 #endif 435 436 #ifdef CONFIG_MEMORY_HOTPLUG 437 /* see spanned/present_pages for more description */ 438 seqlock_t span_seqlock; 439 #endif 440 441 int initialized; 442 443 /* Write-intensive fields used from the page allocator */ 444 ZONE_PADDING(_pad1_) 445 446 /* free areas of different sizes */ 447 struct free_area free_area[MAX_ORDER]; 448 449 /* zone flags, see below */ 450 unsigned long flags; 451 452 /* Primarily protects free_area */ 453 spinlock_t lock; 454 455 /* Write-intensive fields used by compaction and vmstats. */ 456 ZONE_PADDING(_pad2_) 457 458 /* 459 * When free pages are below this point, additional steps are taken 460 * when reading the number of free pages to avoid per-cpu counter 461 * drift allowing watermarks to be breached 462 */ 463 unsigned long percpu_drift_mark; 464 465 #if defined CONFIG_COMPACTION || defined CONFIG_CMA 466 /* pfn where compaction free scanner should start */ 467 unsigned long compact_cached_free_pfn; 468 /* pfn where async and sync compaction migration scanner should start */ 469 unsigned long compact_cached_migrate_pfn[2]; 470 #endif 471 472 #ifdef CONFIG_COMPACTION 473 /* 474 * On compaction failure, 1<<compact_defer_shift compactions 475 * are skipped before trying again. The number attempted since 476 * last failure is tracked with compact_considered. 477 */ 478 unsigned int compact_considered; 479 unsigned int compact_defer_shift; 480 int compact_order_failed; 481 #endif 482 483 #if defined CONFIG_COMPACTION || defined CONFIG_CMA 484 /* Set to true when the PG_migrate_skip bits should be cleared */ 485 bool compact_blockskip_flush; 486 #endif 487 488 bool contiguous; 489 490 ZONE_PADDING(_pad3_) 491 /* Zone statistics */ 492 atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS]; 493 } ____cacheline_internodealigned_in_smp; 494 495 enum pgdat_flags { 496 PGDAT_CONGESTED, /* pgdat has many dirty pages backed by 497 * a congested BDI 498 */ 499 PGDAT_DIRTY, /* reclaim scanning has recently found 500 * many dirty file pages at the tail 501 * of the LRU. 502 */ 503 PGDAT_WRITEBACK, /* reclaim scanning has recently found 504 * many pages under writeback 505 */ 506 PGDAT_RECLAIM_LOCKED, /* prevents concurrent reclaim */ 507 }; 508 509 static inline unsigned long zone_end_pfn(const struct zone *zone) 510 { 511 return zone->zone_start_pfn + zone->spanned_pages; 512 } 513 514 static inline bool zone_spans_pfn(const struct zone *zone, unsigned long pfn) 515 { 516 return zone->zone_start_pfn <= pfn && pfn < zone_end_pfn(zone); 517 } 518 519 static inline bool zone_is_initialized(struct zone *zone) 520 { 521 return zone->initialized; 522 } 523 524 static inline bool zone_is_empty(struct zone *zone) 525 { 526 return zone->spanned_pages == 0; 527 } 528 529 /* 530 * The "priority" of VM scanning is how much of the queues we will scan in one 531 * go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the 532 * queues ("queue_length >> 12") during an aging round. 533 */ 534 #define DEF_PRIORITY 12 535 536 /* Maximum number of zones on a zonelist */ 537 #define MAX_ZONES_PER_ZONELIST (MAX_NUMNODES * MAX_NR_ZONES) 538 539 enum { 540 ZONELIST_FALLBACK, /* zonelist with fallback */ 541 #ifdef CONFIG_NUMA 542 /* 543 * The NUMA zonelists are doubled because we need zonelists that 544 * restrict the allocations to a single node for __GFP_THISNODE. 545 */ 546 ZONELIST_NOFALLBACK, /* zonelist without fallback (__GFP_THISNODE) */ 547 #endif 548 MAX_ZONELISTS 549 }; 550 551 /* 552 * This struct contains information about a zone in a zonelist. It is stored 553 * here to avoid dereferences into large structures and lookups of tables 554 */ 555 struct zoneref { 556 struct zone *zone; /* Pointer to actual zone */ 557 int zone_idx; /* zone_idx(zoneref->zone) */ 558 }; 559 560 /* 561 * One allocation request operates on a zonelist. A zonelist 562 * is a list of zones, the first one is the 'goal' of the 563 * allocation, the other zones are fallback zones, in decreasing 564 * priority. 565 * 566 * To speed the reading of the zonelist, the zonerefs contain the zone index 567 * of the entry being read. Helper functions to access information given 568 * a struct zoneref are 569 * 570 * zonelist_zone() - Return the struct zone * for an entry in _zonerefs 571 * zonelist_zone_idx() - Return the index of the zone for an entry 572 * zonelist_node_idx() - Return the index of the node for an entry 573 */ 574 struct zonelist { 575 struct zoneref _zonerefs[MAX_ZONES_PER_ZONELIST + 1]; 576 }; 577 578 #ifndef CONFIG_DISCONTIGMEM 579 /* The array of struct pages - for discontigmem use pgdat->lmem_map */ 580 extern struct page *mem_map; 581 #endif 582 583 /* 584 * The pg_data_t structure is used in machines with CONFIG_DISCONTIGMEM 585 * (mostly NUMA machines?) to denote a higher-level memory zone than the 586 * zone denotes. 587 * 588 * On NUMA machines, each NUMA node would have a pg_data_t to describe 589 * it's memory layout. 590 * 591 * Memory statistics and page replacement data structures are maintained on a 592 * per-zone basis. 593 */ 594 struct bootmem_data; 595 typedef struct pglist_data { 596 struct zone node_zones[MAX_NR_ZONES]; 597 struct zonelist node_zonelists[MAX_ZONELISTS]; 598 int nr_zones; 599 #ifdef CONFIG_FLAT_NODE_MEM_MAP /* means !SPARSEMEM */ 600 struct page *node_mem_map; 601 #ifdef CONFIG_PAGE_EXTENSION 602 struct page_ext *node_page_ext; 603 #endif 604 #endif 605 #ifndef CONFIG_NO_BOOTMEM 606 struct bootmem_data *bdata; 607 #endif 608 #ifdef CONFIG_MEMORY_HOTPLUG 609 /* 610 * Must be held any time you expect node_start_pfn, node_present_pages 611 * or node_spanned_pages stay constant. Holding this will also 612 * guarantee that any pfn_valid() stays that way. 613 * 614 * pgdat_resize_lock() and pgdat_resize_unlock() are provided to 615 * manipulate node_size_lock without checking for CONFIG_MEMORY_HOTPLUG. 616 * 617 * Nests above zone->lock and zone->span_seqlock 618 */ 619 spinlock_t node_size_lock; 620 #endif 621 unsigned long node_start_pfn; 622 unsigned long node_present_pages; /* total number of physical pages */ 623 unsigned long node_spanned_pages; /* total size of physical page 624 range, including holes */ 625 int node_id; 626 wait_queue_head_t kswapd_wait; 627 wait_queue_head_t pfmemalloc_wait; 628 struct task_struct *kswapd; /* Protected by 629 mem_hotplug_begin/end() */ 630 int kswapd_order; 631 enum zone_type kswapd_classzone_idx; 632 633 #ifdef CONFIG_COMPACTION 634 int kcompactd_max_order; 635 enum zone_type kcompactd_classzone_idx; 636 wait_queue_head_t kcompactd_wait; 637 struct task_struct *kcompactd; 638 #endif 639 #ifdef CONFIG_NUMA_BALANCING 640 /* Lock serializing the migrate rate limiting window */ 641 spinlock_t numabalancing_migrate_lock; 642 643 /* Rate limiting time interval */ 644 unsigned long numabalancing_migrate_next_window; 645 646 /* Number of pages migrated during the rate limiting time interval */ 647 unsigned long numabalancing_migrate_nr_pages; 648 #endif 649 /* 650 * This is a per-node reserve of pages that are not available 651 * to userspace allocations. 652 */ 653 unsigned long totalreserve_pages; 654 655 #ifdef CONFIG_NUMA 656 /* 657 * zone reclaim becomes active if more unmapped pages exist. 658 */ 659 unsigned long min_unmapped_pages; 660 unsigned long min_slab_pages; 661 #endif /* CONFIG_NUMA */ 662 663 /* Write-intensive fields used by page reclaim */ 664 ZONE_PADDING(_pad1_) 665 spinlock_t lru_lock; 666 667 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT 668 /* 669 * If memory initialisation on large machines is deferred then this 670 * is the first PFN that needs to be initialised. 671 */ 672 unsigned long first_deferred_pfn; 673 #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */ 674 675 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 676 spinlock_t split_queue_lock; 677 struct list_head split_queue; 678 unsigned long split_queue_len; 679 #endif 680 681 /* Fields commonly accessed by the page reclaim scanner */ 682 struct lruvec lruvec; 683 684 /* 685 * The target ratio of ACTIVE_ANON to INACTIVE_ANON pages on 686 * this node's LRU. Maintained by the pageout code. 687 */ 688 unsigned int inactive_ratio; 689 690 unsigned long flags; 691 692 ZONE_PADDING(_pad2_) 693 694 /* Per-node vmstats */ 695 struct per_cpu_nodestat __percpu *per_cpu_nodestats; 696 atomic_long_t vm_stat[NR_VM_NODE_STAT_ITEMS]; 697 } pg_data_t; 698 699 #define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages) 700 #define node_spanned_pages(nid) (NODE_DATA(nid)->node_spanned_pages) 701 #ifdef CONFIG_FLAT_NODE_MEM_MAP 702 #define pgdat_page_nr(pgdat, pagenr) ((pgdat)->node_mem_map + (pagenr)) 703 #else 704 #define pgdat_page_nr(pgdat, pagenr) pfn_to_page((pgdat)->node_start_pfn + (pagenr)) 705 #endif 706 #define nid_page_nr(nid, pagenr) pgdat_page_nr(NODE_DATA(nid),(pagenr)) 707 708 #define node_start_pfn(nid) (NODE_DATA(nid)->node_start_pfn) 709 #define node_end_pfn(nid) pgdat_end_pfn(NODE_DATA(nid)) 710 static inline spinlock_t *zone_lru_lock(struct zone *zone) 711 { 712 return &zone->zone_pgdat->lru_lock; 713 } 714 715 static inline struct lruvec *node_lruvec(struct pglist_data *pgdat) 716 { 717 return &pgdat->lruvec; 718 } 719 720 static inline unsigned long pgdat_end_pfn(pg_data_t *pgdat) 721 { 722 return pgdat->node_start_pfn + pgdat->node_spanned_pages; 723 } 724 725 static inline bool pgdat_is_empty(pg_data_t *pgdat) 726 { 727 return !pgdat->node_start_pfn && !pgdat->node_spanned_pages; 728 } 729 730 static inline int zone_id(const struct zone *zone) 731 { 732 struct pglist_data *pgdat = zone->zone_pgdat; 733 734 return zone - pgdat->node_zones; 735 } 736 737 #ifdef CONFIG_ZONE_DEVICE 738 static inline bool is_dev_zone(const struct zone *zone) 739 { 740 return zone_id(zone) == ZONE_DEVICE; 741 } 742 #else 743 static inline bool is_dev_zone(const struct zone *zone) 744 { 745 return false; 746 } 747 #endif 748 749 #include <linux/memory_hotplug.h> 750 751 extern struct mutex zonelists_mutex; 752 void build_all_zonelists(pg_data_t *pgdat, struct zone *zone); 753 void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx); 754 bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark, 755 int classzone_idx, unsigned int alloc_flags, 756 long free_pages); 757 bool zone_watermark_ok(struct zone *z, unsigned int order, 758 unsigned long mark, int classzone_idx, 759 unsigned int alloc_flags); 760 bool zone_watermark_ok_safe(struct zone *z, unsigned int order, 761 unsigned long mark, int classzone_idx); 762 enum memmap_context { 763 MEMMAP_EARLY, 764 MEMMAP_HOTPLUG, 765 }; 766 extern int init_currently_empty_zone(struct zone *zone, unsigned long start_pfn, 767 unsigned long size); 768 769 extern void lruvec_init(struct lruvec *lruvec); 770 771 static inline struct pglist_data *lruvec_pgdat(struct lruvec *lruvec) 772 { 773 #ifdef CONFIG_MEMCG 774 return lruvec->pgdat; 775 #else 776 return container_of(lruvec, struct pglist_data, lruvec); 777 #endif 778 } 779 780 extern unsigned long lruvec_lru_size(struct lruvec *lruvec, enum lru_list lru, int zone_idx); 781 782 #ifdef CONFIG_HAVE_MEMORY_PRESENT 783 void memory_present(int nid, unsigned long start, unsigned long end); 784 #else 785 static inline void memory_present(int nid, unsigned long start, unsigned long end) {} 786 #endif 787 788 #ifdef CONFIG_HAVE_MEMORYLESS_NODES 789 int local_memory_node(int node_id); 790 #else 791 static inline int local_memory_node(int node_id) { return node_id; }; 792 #endif 793 794 #ifdef CONFIG_NEED_NODE_MEMMAP_SIZE 795 unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long); 796 #endif 797 798 /* 799 * zone_idx() returns 0 for the ZONE_DMA zone, 1 for the ZONE_NORMAL zone, etc. 800 */ 801 #define zone_idx(zone) ((zone) - (zone)->zone_pgdat->node_zones) 802 803 /* 804 * Returns true if a zone has pages managed by the buddy allocator. 805 * All the reclaim decisions have to use this function rather than 806 * populated_zone(). If the whole zone is reserved then we can easily 807 * end up with populated_zone() && !managed_zone(). 808 */ 809 static inline bool managed_zone(struct zone *zone) 810 { 811 return zone->managed_pages; 812 } 813 814 /* Returns true if a zone has memory */ 815 static inline bool populated_zone(struct zone *zone) 816 { 817 return zone->present_pages; 818 } 819 820 extern int movable_zone; 821 822 #ifdef CONFIG_HIGHMEM 823 static inline int zone_movable_is_highmem(void) 824 { 825 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP 826 return movable_zone == ZONE_HIGHMEM; 827 #else 828 return (ZONE_MOVABLE - 1) == ZONE_HIGHMEM; 829 #endif 830 } 831 #endif 832 833 static inline int is_highmem_idx(enum zone_type idx) 834 { 835 #ifdef CONFIG_HIGHMEM 836 return (idx == ZONE_HIGHMEM || 837 (idx == ZONE_MOVABLE && zone_movable_is_highmem())); 838 #else 839 return 0; 840 #endif 841 } 842 843 /** 844 * is_highmem - helper function to quickly check if a struct zone is a 845 * highmem zone or not. This is an attempt to keep references 846 * to ZONE_{DMA/NORMAL/HIGHMEM/etc} in general code to a minimum. 847 * @zone - pointer to struct zone variable 848 */ 849 static inline int is_highmem(struct zone *zone) 850 { 851 #ifdef CONFIG_HIGHMEM 852 return is_highmem_idx(zone_idx(zone)); 853 #else 854 return 0; 855 #endif 856 } 857 858 /* These two functions are used to setup the per zone pages min values */ 859 struct ctl_table; 860 int min_free_kbytes_sysctl_handler(struct ctl_table *, int, 861 void __user *, size_t *, loff_t *); 862 int watermark_scale_factor_sysctl_handler(struct ctl_table *, int, 863 void __user *, size_t *, loff_t *); 864 extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1]; 865 int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int, 866 void __user *, size_t *, loff_t *); 867 int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *, int, 868 void __user *, size_t *, loff_t *); 869 int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *, int, 870 void __user *, size_t *, loff_t *); 871 int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *, int, 872 void __user *, size_t *, loff_t *); 873 874 extern int numa_zonelist_order_handler(struct ctl_table *, int, 875 void __user *, size_t *, loff_t *); 876 extern char numa_zonelist_order[]; 877 #define NUMA_ZONELIST_ORDER_LEN 16 /* string buffer size */ 878 879 #ifndef CONFIG_NEED_MULTIPLE_NODES 880 881 extern struct pglist_data contig_page_data; 882 #define NODE_DATA(nid) (&contig_page_data) 883 #define NODE_MEM_MAP(nid) mem_map 884 885 #else /* CONFIG_NEED_MULTIPLE_NODES */ 886 887 #include <asm/mmzone.h> 888 889 #endif /* !CONFIG_NEED_MULTIPLE_NODES */ 890 891 extern struct pglist_data *first_online_pgdat(void); 892 extern struct pglist_data *next_online_pgdat(struct pglist_data *pgdat); 893 extern struct zone *next_zone(struct zone *zone); 894 895 /** 896 * for_each_online_pgdat - helper macro to iterate over all online nodes 897 * @pgdat - pointer to a pg_data_t variable 898 */ 899 #define for_each_online_pgdat(pgdat) \ 900 for (pgdat = first_online_pgdat(); \ 901 pgdat; \ 902 pgdat = next_online_pgdat(pgdat)) 903 /** 904 * for_each_zone - helper macro to iterate over all memory zones 905 * @zone - pointer to struct zone variable 906 * 907 * The user only needs to declare the zone variable, for_each_zone 908 * fills it in. 909 */ 910 #define for_each_zone(zone) \ 911 for (zone = (first_online_pgdat())->node_zones; \ 912 zone; \ 913 zone = next_zone(zone)) 914 915 #define for_each_populated_zone(zone) \ 916 for (zone = (first_online_pgdat())->node_zones; \ 917 zone; \ 918 zone = next_zone(zone)) \ 919 if (!populated_zone(zone)) \ 920 ; /* do nothing */ \ 921 else 922 923 static inline struct zone *zonelist_zone(struct zoneref *zoneref) 924 { 925 return zoneref->zone; 926 } 927 928 static inline int zonelist_zone_idx(struct zoneref *zoneref) 929 { 930 return zoneref->zone_idx; 931 } 932 933 static inline int zonelist_node_idx(struct zoneref *zoneref) 934 { 935 #ifdef CONFIG_NUMA 936 /* zone_to_nid not available in this context */ 937 return zoneref->zone->node; 938 #else 939 return 0; 940 #endif /* CONFIG_NUMA */ 941 } 942 943 struct zoneref *__next_zones_zonelist(struct zoneref *z, 944 enum zone_type highest_zoneidx, 945 nodemask_t *nodes); 946 947 /** 948 * 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 949 * @z - The cursor used as a starting point for the search 950 * @highest_zoneidx - The zone index of the highest zone to return 951 * @nodes - An optional nodemask to filter the zonelist with 952 * 953 * This function returns the next zone at or below a given zone index that is 954 * within the allowed nodemask using a cursor as the starting point for the 955 * search. The zoneref returned is a cursor that represents the current zone 956 * being examined. It should be advanced by one before calling 957 * next_zones_zonelist again. 958 */ 959 static __always_inline struct zoneref *next_zones_zonelist(struct zoneref *z, 960 enum zone_type highest_zoneidx, 961 nodemask_t *nodes) 962 { 963 if (likely(!nodes && zonelist_zone_idx(z) <= highest_zoneidx)) 964 return z; 965 return __next_zones_zonelist(z, highest_zoneidx, nodes); 966 } 967 968 /** 969 * first_zones_zonelist - Returns the first zone at or below highest_zoneidx within the allowed nodemask in a zonelist 970 * @zonelist - The zonelist to search for a suitable zone 971 * @highest_zoneidx - The zone index of the highest zone to return 972 * @nodes - An optional nodemask to filter the zonelist with 973 * @return - Zoneref pointer for the first suitable zone found (see below) 974 * 975 * This function returns the first zone at or below a given zone index that is 976 * within the allowed nodemask. The zoneref returned is a cursor that can be 977 * used to iterate the zonelist with next_zones_zonelist by advancing it by 978 * one before calling. 979 * 980 * When no eligible zone is found, zoneref->zone is NULL (zoneref itself is 981 * never NULL). This may happen either genuinely, or due to concurrent nodemask 982 * update due to cpuset modification. 983 */ 984 static inline struct zoneref *first_zones_zonelist(struct zonelist *zonelist, 985 enum zone_type highest_zoneidx, 986 nodemask_t *nodes) 987 { 988 return next_zones_zonelist(zonelist->_zonerefs, 989 highest_zoneidx, nodes); 990 } 991 992 /** 993 * 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 994 * @zone - The current zone in the iterator 995 * @z - The current pointer within zonelist->zones being iterated 996 * @zlist - The zonelist being iterated 997 * @highidx - The zone index of the highest zone to return 998 * @nodemask - Nodemask allowed by the allocator 999 * 1000 * This iterator iterates though all zones at or below a given zone index and 1001 * within a given nodemask 1002 */ 1003 #define for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, nodemask) \ 1004 for (z = first_zones_zonelist(zlist, highidx, nodemask), zone = zonelist_zone(z); \ 1005 zone; \ 1006 z = next_zones_zonelist(++z, highidx, nodemask), \ 1007 zone = zonelist_zone(z)) 1008 1009 #define for_next_zone_zonelist_nodemask(zone, z, zlist, highidx, nodemask) \ 1010 for (zone = z->zone; \ 1011 zone; \ 1012 z = next_zones_zonelist(++z, highidx, nodemask), \ 1013 zone = zonelist_zone(z)) 1014 1015 1016 /** 1017 * for_each_zone_zonelist - helper macro to iterate over valid zones in a zonelist at or below a given zone index 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 * 1023 * This iterator iterates though all zones at or below a given zone index. 1024 */ 1025 #define for_each_zone_zonelist(zone, z, zlist, highidx) \ 1026 for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, NULL) 1027 1028 #ifdef CONFIG_SPARSEMEM 1029 #include <asm/sparsemem.h> 1030 #endif 1031 1032 #if !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) && \ 1033 !defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) 1034 static inline unsigned long early_pfn_to_nid(unsigned long pfn) 1035 { 1036 return 0; 1037 } 1038 #endif 1039 1040 #ifdef CONFIG_FLATMEM 1041 #define pfn_to_nid(pfn) (0) 1042 #endif 1043 1044 #ifdef CONFIG_SPARSEMEM 1045 1046 /* 1047 * SECTION_SHIFT #bits space required to store a section # 1048 * 1049 * PA_SECTION_SHIFT physical address to/from section number 1050 * PFN_SECTION_SHIFT pfn to/from section number 1051 */ 1052 #define PA_SECTION_SHIFT (SECTION_SIZE_BITS) 1053 #define PFN_SECTION_SHIFT (SECTION_SIZE_BITS - PAGE_SHIFT) 1054 1055 #define NR_MEM_SECTIONS (1UL << SECTIONS_SHIFT) 1056 1057 #define PAGES_PER_SECTION (1UL << PFN_SECTION_SHIFT) 1058 #define PAGE_SECTION_MASK (~(PAGES_PER_SECTION-1)) 1059 1060 #define SECTION_BLOCKFLAGS_BITS \ 1061 ((1UL << (PFN_SECTION_SHIFT - pageblock_order)) * NR_PAGEBLOCK_BITS) 1062 1063 #if (MAX_ORDER - 1 + PAGE_SHIFT) > SECTION_SIZE_BITS 1064 #error Allocator MAX_ORDER exceeds SECTION_SIZE 1065 #endif 1066 1067 #define pfn_to_section_nr(pfn) ((pfn) >> PFN_SECTION_SHIFT) 1068 #define section_nr_to_pfn(sec) ((sec) << PFN_SECTION_SHIFT) 1069 1070 #define SECTION_ALIGN_UP(pfn) (((pfn) + PAGES_PER_SECTION - 1) & PAGE_SECTION_MASK) 1071 #define SECTION_ALIGN_DOWN(pfn) ((pfn) & PAGE_SECTION_MASK) 1072 1073 struct page; 1074 struct page_ext; 1075 struct mem_section { 1076 /* 1077 * This is, logically, a pointer to an array of struct 1078 * pages. However, it is stored with some other magic. 1079 * (see sparse.c::sparse_init_one_section()) 1080 * 1081 * Additionally during early boot we encode node id of 1082 * the location of the section here to guide allocation. 1083 * (see sparse.c::memory_present()) 1084 * 1085 * Making it a UL at least makes someone do a cast 1086 * before using it wrong. 1087 */ 1088 unsigned long section_mem_map; 1089 1090 /* See declaration of similar field in struct zone */ 1091 unsigned long *pageblock_flags; 1092 #ifdef CONFIG_PAGE_EXTENSION 1093 /* 1094 * If SPARSEMEM, pgdat doesn't have page_ext pointer. We use 1095 * section. (see page_ext.h about this.) 1096 */ 1097 struct page_ext *page_ext; 1098 unsigned long pad; 1099 #endif 1100 /* 1101 * WARNING: mem_section must be a power-of-2 in size for the 1102 * calculation and use of SECTION_ROOT_MASK to make sense. 1103 */ 1104 }; 1105 1106 #ifdef CONFIG_SPARSEMEM_EXTREME 1107 #define SECTIONS_PER_ROOT (PAGE_SIZE / sizeof (struct mem_section)) 1108 #else 1109 #define SECTIONS_PER_ROOT 1 1110 #endif 1111 1112 #define SECTION_NR_TO_ROOT(sec) ((sec) / SECTIONS_PER_ROOT) 1113 #define NR_SECTION_ROOTS DIV_ROUND_UP(NR_MEM_SECTIONS, SECTIONS_PER_ROOT) 1114 #define SECTION_ROOT_MASK (SECTIONS_PER_ROOT - 1) 1115 1116 #ifdef CONFIG_SPARSEMEM_EXTREME 1117 extern struct mem_section *mem_section[NR_SECTION_ROOTS]; 1118 #else 1119 extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT]; 1120 #endif 1121 1122 static inline struct mem_section *__nr_to_section(unsigned long nr) 1123 { 1124 if (!mem_section[SECTION_NR_TO_ROOT(nr)]) 1125 return NULL; 1126 return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK]; 1127 } 1128 extern int __section_nr(struct mem_section* ms); 1129 extern unsigned long usemap_size(void); 1130 1131 /* 1132 * We use the lower bits of the mem_map pointer to store 1133 * a little bit of information. There should be at least 1134 * 3 bits here due to 32-bit alignment. 1135 */ 1136 #define SECTION_MARKED_PRESENT (1UL<<0) 1137 #define SECTION_HAS_MEM_MAP (1UL<<1) 1138 #define SECTION_MAP_LAST_BIT (1UL<<2) 1139 #define SECTION_MAP_MASK (~(SECTION_MAP_LAST_BIT-1)) 1140 #define SECTION_NID_SHIFT 2 1141 1142 static inline struct page *__section_mem_map_addr(struct mem_section *section) 1143 { 1144 unsigned long map = section->section_mem_map; 1145 map &= SECTION_MAP_MASK; 1146 return (struct page *)map; 1147 } 1148 1149 static inline int present_section(struct mem_section *section) 1150 { 1151 return (section && (section->section_mem_map & SECTION_MARKED_PRESENT)); 1152 } 1153 1154 static inline int present_section_nr(unsigned long nr) 1155 { 1156 return present_section(__nr_to_section(nr)); 1157 } 1158 1159 static inline int valid_section(struct mem_section *section) 1160 { 1161 return (section && (section->section_mem_map & SECTION_HAS_MEM_MAP)); 1162 } 1163 1164 static inline int valid_section_nr(unsigned long nr) 1165 { 1166 return valid_section(__nr_to_section(nr)); 1167 } 1168 1169 static inline struct mem_section *__pfn_to_section(unsigned long pfn) 1170 { 1171 return __nr_to_section(pfn_to_section_nr(pfn)); 1172 } 1173 1174 #ifndef CONFIG_HAVE_ARCH_PFN_VALID 1175 static inline int pfn_valid(unsigned long pfn) 1176 { 1177 if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS) 1178 return 0; 1179 return valid_section(__nr_to_section(pfn_to_section_nr(pfn))); 1180 } 1181 #endif 1182 1183 static inline int pfn_present(unsigned long pfn) 1184 { 1185 if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS) 1186 return 0; 1187 return present_section(__nr_to_section(pfn_to_section_nr(pfn))); 1188 } 1189 1190 /* 1191 * These are _only_ used during initialisation, therefore they 1192 * can use __initdata ... They could have names to indicate 1193 * this restriction. 1194 */ 1195 #ifdef CONFIG_NUMA 1196 #define pfn_to_nid(pfn) \ 1197 ({ \ 1198 unsigned long __pfn_to_nid_pfn = (pfn); \ 1199 page_to_nid(pfn_to_page(__pfn_to_nid_pfn)); \ 1200 }) 1201 #else 1202 #define pfn_to_nid(pfn) (0) 1203 #endif 1204 1205 #define early_pfn_valid(pfn) pfn_valid(pfn) 1206 void sparse_init(void); 1207 #else 1208 #define sparse_init() do {} while (0) 1209 #define sparse_index_init(_sec, _nid) do {} while (0) 1210 #endif /* CONFIG_SPARSEMEM */ 1211 1212 /* 1213 * During memory init memblocks map pfns to nids. The search is expensive and 1214 * this caches recent lookups. The implementation of __early_pfn_to_nid 1215 * may treat start/end as pfns or sections. 1216 */ 1217 struct mminit_pfnnid_cache { 1218 unsigned long last_start; 1219 unsigned long last_end; 1220 int last_nid; 1221 }; 1222 1223 #ifndef early_pfn_valid 1224 #define early_pfn_valid(pfn) (1) 1225 #endif 1226 1227 void memory_present(int nid, unsigned long start, unsigned long end); 1228 unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long); 1229 1230 /* 1231 * If it is possible to have holes within a MAX_ORDER_NR_PAGES, then we 1232 * need to check pfn validility within that MAX_ORDER_NR_PAGES block. 1233 * pfn_valid_within() should be used in this case; we optimise this away 1234 * when we have no holes within a MAX_ORDER_NR_PAGES block. 1235 */ 1236 #ifdef CONFIG_HOLES_IN_ZONE 1237 #define pfn_valid_within(pfn) pfn_valid(pfn) 1238 #else 1239 #define pfn_valid_within(pfn) (1) 1240 #endif 1241 1242 #ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL 1243 /* 1244 * pfn_valid() is meant to be able to tell if a given PFN has valid memmap 1245 * associated with it or not. In FLATMEM, it is expected that holes always 1246 * have valid memmap as long as there is valid PFNs either side of the hole. 1247 * In SPARSEMEM, it is assumed that a valid section has a memmap for the 1248 * entire section. 1249 * 1250 * However, an ARM, and maybe other embedded architectures in the future 1251 * free memmap backing holes to save memory on the assumption the memmap is 1252 * never used. The page_zone linkages are then broken even though pfn_valid() 1253 * returns true. A walker of the full memmap must then do this additional 1254 * check to ensure the memmap they are looking at is sane by making sure 1255 * the zone and PFN linkages are still valid. This is expensive, but walkers 1256 * of the full memmap are extremely rare. 1257 */ 1258 bool memmap_valid_within(unsigned long pfn, 1259 struct page *page, struct zone *zone); 1260 #else 1261 static inline bool memmap_valid_within(unsigned long pfn, 1262 struct page *page, struct zone *zone) 1263 { 1264 return true; 1265 } 1266 #endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */ 1267 1268 #endif /* !__GENERATING_BOUNDS.H */ 1269 #endif /* !__ASSEMBLY__ */ 1270 #endif /* _LINUX_MMZONE_H */ 1271