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 38enum { 39 MIGRATE_UNMOVABLE, 40 MIGRATE_RECLAIMABLE, 41 MIGRATE_MOVABLE, 42 MIGRATE_PCPTYPES, /* the number of types on the pcp lists */ 43 MIGRATE_RESERVE = 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#ifdef CONFIG_CMA 67# define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA) 68#else 69# define is_migrate_cma(migratetype) false 70#endif 71 72#define for_each_migratetype_order(order, type) \ 73 for (order = 0; order < MAX_ORDER; order++) \ 74 for (type = 0; type < MIGRATE_TYPES; type++) 75 76extern int page_group_by_mobility_disabled; 77 78#define NR_MIGRATETYPE_BITS (PB_migrate_end - PB_migrate + 1) 79#define MIGRATETYPE_MASK ((1UL << NR_MIGRATETYPE_BITS) - 1) 80 81#define get_pageblock_migratetype(page) \ 82 get_pfnblock_flags_mask(page, page_to_pfn(page), \ 83 PB_migrate_end, MIGRATETYPE_MASK) 84 85static inline int get_pfnblock_migratetype(struct page *page, unsigned long pfn) 86{ 87 BUILD_BUG_ON(PB_migrate_end - PB_migrate != 2); 88 return get_pfnblock_flags_mask(page, pfn, PB_migrate_end, 89 MIGRATETYPE_MASK); 90} 91 92struct free_area { 93 struct list_head free_list[MIGRATE_TYPES]; 94 unsigned long nr_free; 95}; 96 97struct pglist_data; 98 99/* 100 * zone->lock and zone->lru_lock are two of the hottest locks in the kernel. 101 * So add a wild amount of padding here to ensure that they fall into separate 102 * cachelines. There are very few zone structures in the machine, so space 103 * consumption is not a concern here. 104 */ 105#if defined(CONFIG_SMP) 106struct zone_padding { 107 char x[0]; 108} ____cacheline_internodealigned_in_smp; 109#define ZONE_PADDING(name) struct zone_padding name; 110#else 111#define ZONE_PADDING(name) 112#endif 113 114enum zone_stat_item { 115 /* First 128 byte cacheline (assuming 64 bit words) */ 116 NR_FREE_PAGES, 117 NR_ALLOC_BATCH, 118 NR_LRU_BASE, 119 NR_INACTIVE_ANON = NR_LRU_BASE, /* must match order of LRU_[IN]ACTIVE */ 120 NR_ACTIVE_ANON, /* " " " " " */ 121 NR_INACTIVE_FILE, /* " " " " " */ 122 NR_ACTIVE_FILE, /* " " " " " */ 123 NR_UNEVICTABLE, /* " " " " " */ 124 NR_MLOCK, /* mlock()ed pages found and moved off LRU */ 125 NR_ANON_PAGES, /* Mapped anonymous pages */ 126 NR_FILE_MAPPED, /* pagecache pages mapped into pagetables. 127 only modified from process context */ 128 NR_FILE_PAGES, 129 NR_FILE_DIRTY, 130 NR_WRITEBACK, 131 NR_SLAB_RECLAIMABLE, 132 NR_SLAB_UNRECLAIMABLE, 133 NR_PAGETABLE, /* used for pagetables */ 134 NR_KERNEL_STACK, 135 /* Second 128 byte cacheline */ 136 NR_UNSTABLE_NFS, /* NFS unstable pages */ 137 NR_BOUNCE, 138 NR_VMSCAN_WRITE, 139 NR_VMSCAN_IMMEDIATE, /* Prioritise for reclaim when writeback ends */ 140 NR_WRITEBACK_TEMP, /* Writeback using temporary buffers */ 141 NR_ISOLATED_ANON, /* Temporary isolated pages from anon lru */ 142 NR_ISOLATED_FILE, /* Temporary isolated pages from file lru */ 143 NR_SHMEM, /* shmem pages (included tmpfs/GEM pages) */ 144 NR_DIRTIED, /* page dirtyings since bootup */ 145 NR_WRITTEN, /* page writings since bootup */ 146 NR_PAGES_SCANNED, /* pages scanned since last reclaim */ 147#ifdef CONFIG_NUMA 148 NUMA_HIT, /* allocated in intended node */ 149 NUMA_MISS, /* allocated in non intended node */ 150 NUMA_FOREIGN, /* was intended here, hit elsewhere */ 151 NUMA_INTERLEAVE_HIT, /* interleaver preferred this zone */ 152 NUMA_LOCAL, /* allocation from local node */ 153 NUMA_OTHER, /* allocation from other node */ 154#endif 155 WORKINGSET_REFAULT, 156 WORKINGSET_ACTIVATE, 157 WORKINGSET_NODERECLAIM, 158 NR_ANON_TRANSPARENT_HUGEPAGES, 159 NR_FREE_CMA_PAGES, 160 NR_VM_ZONE_STAT_ITEMS }; 161 162/* 163 * We do arithmetic on the LRU lists in various places in the code, 164 * so it is important to keep the active lists LRU_ACTIVE higher in 165 * the array than the corresponding inactive lists, and to keep 166 * the *_FILE lists LRU_FILE higher than the corresponding _ANON lists. 167 * 168 * This has to be kept in sync with the statistics in zone_stat_item 169 * above and the descriptions in vmstat_text in mm/vmstat.c 170 */ 171#define LRU_BASE 0 172#define LRU_ACTIVE 1 173#define LRU_FILE 2 174 175enum lru_list { 176 LRU_INACTIVE_ANON = LRU_BASE, 177 LRU_ACTIVE_ANON = LRU_BASE + LRU_ACTIVE, 178 LRU_INACTIVE_FILE = LRU_BASE + LRU_FILE, 179 LRU_ACTIVE_FILE = LRU_BASE + LRU_FILE + LRU_ACTIVE, 180 LRU_UNEVICTABLE, 181 NR_LRU_LISTS 182}; 183 184#define for_each_lru(lru) for (lru = 0; lru < NR_LRU_LISTS; lru++) 185 186#define for_each_evictable_lru(lru) for (lru = 0; lru <= LRU_ACTIVE_FILE; lru++) 187 188static inline int is_file_lru(enum lru_list lru) 189{ 190 return (lru == LRU_INACTIVE_FILE || lru == LRU_ACTIVE_FILE); 191} 192 193static inline int is_active_lru(enum lru_list lru) 194{ 195 return (lru == LRU_ACTIVE_ANON || lru == LRU_ACTIVE_FILE); 196} 197 198static inline int is_unevictable_lru(enum lru_list lru) 199{ 200 return (lru == LRU_UNEVICTABLE); 201} 202 203struct zone_reclaim_stat { 204 /* 205 * The pageout code in vmscan.c keeps track of how many of the 206 * mem/swap backed and file backed pages are referenced. 207 * The higher the rotated/scanned ratio, the more valuable 208 * that cache is. 209 * 210 * The anon LRU stats live in [0], file LRU stats in [1] 211 */ 212 unsigned long recent_rotated[2]; 213 unsigned long recent_scanned[2]; 214}; 215 216struct lruvec { 217 struct list_head lists[NR_LRU_LISTS]; 218 struct zone_reclaim_stat reclaim_stat; 219#ifdef CONFIG_MEMCG 220 struct zone *zone; 221#endif 222}; 223 224/* Mask used at gathering information at once (see memcontrol.c) */ 225#define LRU_ALL_FILE (BIT(LRU_INACTIVE_FILE) | BIT(LRU_ACTIVE_FILE)) 226#define LRU_ALL_ANON (BIT(LRU_INACTIVE_ANON) | BIT(LRU_ACTIVE_ANON)) 227#define LRU_ALL ((1 << NR_LRU_LISTS) - 1) 228 229/* Isolate clean file */ 230#define ISOLATE_CLEAN ((__force isolate_mode_t)0x1) 231/* Isolate unmapped file */ 232#define ISOLATE_UNMAPPED ((__force isolate_mode_t)0x2) 233/* Isolate for asynchronous migration */ 234#define ISOLATE_ASYNC_MIGRATE ((__force isolate_mode_t)0x4) 235/* Isolate unevictable pages */ 236#define ISOLATE_UNEVICTABLE ((__force isolate_mode_t)0x8) 237 238/* LRU Isolation modes. */ 239typedef unsigned __bitwise__ isolate_mode_t; 240 241enum zone_watermarks { 242 WMARK_MIN, 243 WMARK_LOW, 244 WMARK_HIGH, 245 NR_WMARK 246}; 247 248#define min_wmark_pages(z) (z->watermark[WMARK_MIN]) 249#define low_wmark_pages(z) (z->watermark[WMARK_LOW]) 250#define high_wmark_pages(z) (z->watermark[WMARK_HIGH]) 251 252struct per_cpu_pages { 253 int count; /* number of pages in the list */ 254 int high; /* high watermark, emptying needed */ 255 int batch; /* chunk size for buddy add/remove */ 256 257 /* Lists of pages, one per migrate type stored on the pcp-lists */ 258 struct list_head lists[MIGRATE_PCPTYPES]; 259}; 260 261struct per_cpu_pageset { 262 struct per_cpu_pages pcp; 263#ifdef CONFIG_NUMA 264 s8 expire; 265#endif 266#ifdef CONFIG_SMP 267 s8 stat_threshold; 268 s8 vm_stat_diff[NR_VM_ZONE_STAT_ITEMS]; 269#endif 270}; 271 272#endif /* !__GENERATING_BOUNDS.H */ 273 274enum zone_type { 275#ifdef CONFIG_ZONE_DMA 276 /* 277 * ZONE_DMA is used when there are devices that are not able 278 * to do DMA to all of addressable memory (ZONE_NORMAL). Then we 279 * carve out the portion of memory that is needed for these devices. 280 * The range is arch specific. 281 * 282 * Some examples 283 * 284 * Architecture Limit 285 * --------------------------- 286 * parisc, ia64, sparc <4G 287 * s390 <2G 288 * arm Various 289 * alpha Unlimited or 0-16MB. 290 * 291 * i386, x86_64 and multiple other arches 292 * <16M. 293 */ 294 ZONE_DMA, 295#endif 296#ifdef CONFIG_ZONE_DMA32 297 /* 298 * x86_64 needs two ZONE_DMAs because it supports devices that are 299 * only able to do DMA to the lower 16M but also 32 bit devices that 300 * can only do DMA areas below 4G. 301 */ 302 ZONE_DMA32, 303#endif 304 /* 305 * Normal addressable memory is in ZONE_NORMAL. DMA operations can be 306 * performed on pages in ZONE_NORMAL if the DMA devices support 307 * transfers to all addressable memory. 308 */ 309 ZONE_NORMAL, 310#ifdef CONFIG_HIGHMEM 311 /* 312 * A memory area that is only addressable by the kernel through 313 * mapping portions into its own address space. This is for example 314 * used by i386 to allow the kernel to address the memory beyond 315 * 900MB. The kernel will set up special mappings (page 316 * table entries on i386) for each page that the kernel needs to 317 * access. 318 */ 319 ZONE_HIGHMEM, 320#endif 321 ZONE_MOVABLE, 322 __MAX_NR_ZONES 323}; 324 325#ifndef __GENERATING_BOUNDS_H 326 327struct zone { 328 /* Read-mostly fields */ 329 330 /* zone watermarks, access with *_wmark_pages(zone) macros */ 331 unsigned long watermark[NR_WMARK]; 332 333 /* 334 * We don't know if the memory that we're going to allocate will be freeable 335 * or/and it will be released eventually, so to avoid totally wasting several 336 * GB of ram we must reserve some of the lower zone memory (otherwise we risk 337 * to run OOM on the lower zones despite there's tons of freeable ram 338 * on the higher zones). This array is recalculated at runtime if the 339 * sysctl_lowmem_reserve_ratio sysctl changes. 340 */ 341 long lowmem_reserve[MAX_NR_ZONES]; 342 343#ifdef CONFIG_NUMA 344 int node; 345#endif 346 347 /* 348 * The target ratio of ACTIVE_ANON to INACTIVE_ANON pages on 349 * this zone's LRU. Maintained by the pageout code. 350 */ 351 unsigned int inactive_ratio; 352 353 struct pglist_data *zone_pgdat; 354 struct per_cpu_pageset __percpu *pageset; 355 356 /* 357 * This is a per-zone reserve of pages that should not be 358 * considered dirtyable memory. 359 */ 360 unsigned long dirty_balance_reserve; 361 362#ifndef CONFIG_SPARSEMEM 363 /* 364 * Flags for a pageblock_nr_pages block. See pageblock-flags.h. 365 * In SPARSEMEM, this map is stored in struct mem_section 366 */ 367 unsigned long *pageblock_flags; 368#endif /* CONFIG_SPARSEMEM */ 369 370#ifdef CONFIG_NUMA 371 /* 372 * zone reclaim becomes active if more unmapped pages exist. 373 */ 374 unsigned long min_unmapped_pages; 375 unsigned long min_slab_pages; 376#endif /* CONFIG_NUMA */ 377 378 /* zone_start_pfn == zone_start_paddr >> PAGE_SHIFT */ 379 unsigned long zone_start_pfn; 380 381 /* 382 * spanned_pages is the total pages spanned by the zone, including 383 * holes, which is calculated as: 384 * spanned_pages = zone_end_pfn - zone_start_pfn; 385 * 386 * present_pages is physical pages existing within the zone, which 387 * is calculated as: 388 * present_pages = spanned_pages - absent_pages(pages in holes); 389 * 390 * managed_pages is present pages managed by the buddy system, which 391 * is calculated as (reserved_pages includes pages allocated by the 392 * bootmem allocator): 393 * managed_pages = present_pages - reserved_pages; 394 * 395 * So present_pages may be used by memory hotplug or memory power 396 * management logic to figure out unmanaged pages by checking 397 * (present_pages - managed_pages). And managed_pages should be used 398 * by page allocator and vm scanner to calculate all kinds of watermarks 399 * and thresholds. 400 * 401 * Locking rules: 402 * 403 * zone_start_pfn and spanned_pages are protected by span_seqlock. 404 * It is a seqlock because it has to be read outside of zone->lock, 405 * and it is done in the main allocator path. But, it is written 406 * quite infrequently. 407 * 408 * The span_seq lock is declared along with zone->lock because it is 409 * frequently read in proximity to zone->lock. It's good to 410 * give them a chance of being in the same cacheline. 411 * 412 * Write access to present_pages at runtime should be protected by 413 * mem_hotplug_begin/end(). Any reader who can't tolerant drift of 414 * present_pages should get_online_mems() to get a stable value. 415 * 416 * Read access to managed_pages should be safe because it's unsigned 417 * long. Write access to zone->managed_pages and totalram_pages are 418 * protected by managed_page_count_lock at runtime. Idealy only 419 * adjust_managed_page_count() should be used instead of directly 420 * touching zone->managed_pages and totalram_pages. 421 */ 422 unsigned long managed_pages; 423 unsigned long spanned_pages; 424 unsigned long present_pages; 425 426 const char *name; 427 428 /* 429 * Number of MIGRATE_RESERVE page block. To maintain for just 430 * optimization. Protected by zone->lock. 431 */ 432 int nr_migrate_reserve_block; 433 434#ifdef CONFIG_MEMORY_ISOLATION 435 /* 436 * Number of isolated pageblock. It is used to solve incorrect 437 * freepage counting problem due to racy retrieving migratetype 438 * of pageblock. Protected by zone->lock. 439 */ 440 unsigned long nr_isolate_pageblock; 441#endif 442 443#ifdef CONFIG_MEMORY_HOTPLUG 444 /* see spanned/present_pages for more description */ 445 seqlock_t span_seqlock; 446#endif 447 448 /* 449 * wait_table -- the array holding the hash table 450 * wait_table_hash_nr_entries -- the size of the hash table array 451 * wait_table_bits -- wait_table_size == (1 << wait_table_bits) 452 * 453 * The purpose of all these is to keep track of the people 454 * waiting for a page to become available and make them 455 * runnable again when possible. The trouble is that this 456 * consumes a lot of space, especially when so few things 457 * wait on pages at a given time. So instead of using 458 * per-page waitqueues, we use a waitqueue hash table. 459 * 460 * The bucket discipline is to sleep on the same queue when 461 * colliding and wake all in that wait queue when removing. 462 * When something wakes, it must check to be sure its page is 463 * truly available, a la thundering herd. The cost of a 464 * collision is great, but given the expected load of the 465 * table, they should be so rare as to be outweighed by the 466 * benefits from the saved space. 467 * 468 * __wait_on_page_locked() and unlock_page() in mm/filemap.c, are the 469 * primary users of these fields, and in mm/page_alloc.c 470 * free_area_init_core() performs the initialization of them. 471 */ 472 wait_queue_head_t *wait_table; 473 unsigned long wait_table_hash_nr_entries; 474 unsigned long wait_table_bits; 475 476 ZONE_PADDING(_pad1_) 477 /* free areas of different sizes */ 478 struct free_area free_area[MAX_ORDER]; 479 480 /* zone flags, see below */ 481 unsigned long flags; 482 483 /* Write-intensive fields used from the page allocator */ 484 spinlock_t lock; 485 486 ZONE_PADDING(_pad2_) 487 488 /* Write-intensive fields used by page reclaim */ 489 490 /* Fields commonly accessed by the page reclaim scanner */ 491 spinlock_t lru_lock; 492 struct lruvec lruvec; 493 494 /* Evictions & activations on the inactive file list */ 495 atomic_long_t inactive_age; 496 497 /* 498 * When free pages are below this point, additional steps are taken 499 * when reading the number of free pages to avoid per-cpu counter 500 * drift allowing watermarks to be breached 501 */ 502 unsigned long percpu_drift_mark; 503 504#if defined CONFIG_COMPACTION || defined CONFIG_CMA 505 /* pfn where compaction free scanner should start */ 506 unsigned long compact_cached_free_pfn; 507 /* pfn where async and sync compaction migration scanner should start */ 508 unsigned long compact_cached_migrate_pfn[2]; 509#endif 510 511#ifdef CONFIG_COMPACTION 512 /* 513 * On compaction failure, 1<<compact_defer_shift compactions 514 * are skipped before trying again. The number attempted since 515 * last failure is tracked with compact_considered. 516 */ 517 unsigned int compact_considered; 518 unsigned int compact_defer_shift; 519 int compact_order_failed; 520#endif 521 522#if defined CONFIG_COMPACTION || defined CONFIG_CMA 523 /* Set to true when the PG_migrate_skip bits should be cleared */ 524 bool compact_blockskip_flush; 525#endif 526 527 ZONE_PADDING(_pad3_) 528 /* Zone statistics */ 529 atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS]; 530} ____cacheline_internodealigned_in_smp; 531 532enum zone_flags { 533 ZONE_RECLAIM_LOCKED, /* prevents concurrent reclaim */ 534 ZONE_OOM_LOCKED, /* zone is in OOM killer zonelist */ 535 ZONE_CONGESTED, /* zone has many dirty pages backed by 536 * a congested BDI 537 */ 538 ZONE_DIRTY, /* reclaim scanning has recently found 539 * many dirty file pages at the tail 540 * of the LRU. 541 */ 542 ZONE_WRITEBACK, /* reclaim scanning has recently found 543 * many pages under writeback 544 */ 545 ZONE_FAIR_DEPLETED, /* fair zone policy batch depleted */ 546}; 547 548static inline unsigned long zone_end_pfn(const struct zone *zone) 549{ 550 return zone->zone_start_pfn + zone->spanned_pages; 551} 552 553static inline bool zone_spans_pfn(const struct zone *zone, unsigned long pfn) 554{ 555 return zone->zone_start_pfn <= pfn && pfn < zone_end_pfn(zone); 556} 557 558static inline bool zone_is_initialized(struct zone *zone) 559{ 560 return !!zone->wait_table; 561} 562 563static inline bool zone_is_empty(struct zone *zone) 564{ 565 return zone->spanned_pages == 0; 566} 567 568/* 569 * The "priority" of VM scanning is how much of the queues we will scan in one 570 * go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the 571 * queues ("queue_length >> 12") during an aging round. 572 */ 573#define DEF_PRIORITY 12 574 575/* Maximum number of zones on a zonelist */ 576#define MAX_ZONES_PER_ZONELIST (MAX_NUMNODES * MAX_NR_ZONES) 577 578#ifdef CONFIG_NUMA 579 580/* 581 * The NUMA zonelists are doubled because we need zonelists that restrict the 582 * allocations to a single node for __GFP_THISNODE. 583 * 584 * [0] : Zonelist with fallback 585 * [1] : No fallback (__GFP_THISNODE) 586 */ 587#define MAX_ZONELISTS 2 588 589 590/* 591 * We cache key information from each zonelist for smaller cache 592 * footprint when scanning for free pages in get_page_from_freelist(). 593 * 594 * 1) The BITMAP fullzones tracks which zones in a zonelist have come 595 * up short of free memory since the last time (last_fullzone_zap) 596 * we zero'd fullzones. 597 * 2) The array z_to_n[] maps each zone in the zonelist to its node 598 * id, so that we can efficiently evaluate whether that node is 599 * set in the current tasks mems_allowed. 600 * 601 * Both fullzones and z_to_n[] are one-to-one with the zonelist, 602 * indexed by a zones offset in the zonelist zones[] array. 603 * 604 * The get_page_from_freelist() routine does two scans. During the 605 * first scan, we skip zones whose corresponding bit in 'fullzones' 606 * is set or whose corresponding node in current->mems_allowed (which 607 * comes from cpusets) is not set. During the second scan, we bypass 608 * this zonelist_cache, to ensure we look methodically at each zone. 609 * 610 * Once per second, we zero out (zap) fullzones, forcing us to 611 * reconsider nodes that might have regained more free memory. 612 * The field last_full_zap is the time we last zapped fullzones. 613 * 614 * This mechanism reduces the amount of time we waste repeatedly 615 * reexaming zones for free memory when they just came up low on 616 * memory momentarilly ago. 617 * 618 * The zonelist_cache struct members logically belong in struct 619 * zonelist. However, the mempolicy zonelists constructed for 620 * MPOL_BIND are intentionally variable length (and usually much 621 * shorter). A general purpose mechanism for handling structs with 622 * multiple variable length members is more mechanism than we want 623 * here. We resort to some special case hackery instead. 624 * 625 * The MPOL_BIND zonelists don't need this zonelist_cache (in good 626 * part because they are shorter), so we put the fixed length stuff 627 * at the front of the zonelist struct, ending in a variable length 628 * zones[], as is needed by MPOL_BIND. 629 * 630 * Then we put the optional zonelist cache on the end of the zonelist 631 * struct. This optional stuff is found by a 'zlcache_ptr' pointer in 632 * the fixed length portion at the front of the struct. This pointer 633 * both enables us to find the zonelist cache, and in the case of 634 * MPOL_BIND zonelists, (which will just set the zlcache_ptr to NULL) 635 * to know that the zonelist cache is not there. 636 * 637 * The end result is that struct zonelists come in two flavors: 638 * 1) The full, fixed length version, shown below, and 639 * 2) The custom zonelists for MPOL_BIND. 640 * The custom MPOL_BIND zonelists have a NULL zlcache_ptr and no zlcache. 641 * 642 * Even though there may be multiple CPU cores on a node modifying 643 * fullzones or last_full_zap in the same zonelist_cache at the same 644 * time, we don't lock it. This is just hint data - if it is wrong now 645 * and then, the allocator will still function, perhaps a bit slower. 646 */ 647 648 649struct zonelist_cache { 650 unsigned short z_to_n[MAX_ZONES_PER_ZONELIST]; /* zone->nid */ 651 DECLARE_BITMAP(fullzones, MAX_ZONES_PER_ZONELIST); /* zone full? */ 652 unsigned long last_full_zap; /* when last zap'd (jiffies) */ 653}; 654#else 655#define MAX_ZONELISTS 1 656struct zonelist_cache; 657#endif 658 659/* 660 * This struct contains information about a zone in a zonelist. It is stored 661 * here to avoid dereferences into large structures and lookups of tables 662 */ 663struct zoneref { 664 struct zone *zone; /* Pointer to actual zone */ 665 int zone_idx; /* zone_idx(zoneref->zone) */ 666}; 667 668/* 669 * One allocation request operates on a zonelist. A zonelist 670 * is a list of zones, the first one is the 'goal' of the 671 * allocation, the other zones are fallback zones, in decreasing 672 * priority. 673 * 674 * If zlcache_ptr is not NULL, then it is just the address of zlcache, 675 * as explained above. If zlcache_ptr is NULL, there is no zlcache. 676 * * 677 * To speed the reading of the zonelist, the zonerefs contain the zone index 678 * of the entry being read. Helper functions to access information given 679 * a struct zoneref are 680 * 681 * zonelist_zone() - Return the struct zone * for an entry in _zonerefs 682 * zonelist_zone_idx() - Return the index of the zone for an entry 683 * zonelist_node_idx() - Return the index of the node for an entry 684 */ 685struct zonelist { 686 struct zonelist_cache *zlcache_ptr; // NULL or &zlcache 687 struct zoneref _zonerefs[MAX_ZONES_PER_ZONELIST + 1]; 688#ifdef CONFIG_NUMA 689 struct zonelist_cache zlcache; // optional ... 690#endif 691}; 692 693#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP 694struct node_active_region { 695 unsigned long start_pfn; 696 unsigned long end_pfn; 697 int nid; 698}; 699#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */ 700 701#ifndef CONFIG_DISCONTIGMEM 702/* The array of struct pages - for discontigmem use pgdat->lmem_map */ 703extern struct page *mem_map; 704#endif 705 706/* 707 * The pg_data_t structure is used in machines with CONFIG_DISCONTIGMEM 708 * (mostly NUMA machines?) to denote a higher-level memory zone than the 709 * zone denotes. 710 * 711 * On NUMA machines, each NUMA node would have a pg_data_t to describe 712 * it's memory layout. 713 * 714 * Memory statistics and page replacement data structures are maintained on a 715 * per-zone basis. 716 */ 717struct bootmem_data; 718typedef struct pglist_data { 719 struct zone node_zones[MAX_NR_ZONES]; 720 struct zonelist node_zonelists[MAX_ZONELISTS]; 721 int nr_zones; 722#ifdef CONFIG_FLAT_NODE_MEM_MAP /* means !SPARSEMEM */ 723 struct page *node_mem_map; 724#ifdef CONFIG_PAGE_EXTENSION 725 struct page_ext *node_page_ext; 726#endif 727#endif 728#ifndef CONFIG_NO_BOOTMEM 729 struct bootmem_data *bdata; 730#endif 731#ifdef CONFIG_MEMORY_HOTPLUG 732 /* 733 * Must be held any time you expect node_start_pfn, node_present_pages 734 * or node_spanned_pages stay constant. Holding this will also 735 * guarantee that any pfn_valid() stays that way. 736 * 737 * pgdat_resize_lock() and pgdat_resize_unlock() are provided to 738 * manipulate node_size_lock without checking for CONFIG_MEMORY_HOTPLUG. 739 * 740 * Nests above zone->lock and zone->span_seqlock 741 */ 742 spinlock_t node_size_lock; 743#endif 744 unsigned long node_start_pfn; 745 unsigned long node_present_pages; /* total number of physical pages */ 746 unsigned long node_spanned_pages; /* total size of physical page 747 range, including holes */ 748 int node_id; 749 wait_queue_head_t kswapd_wait; 750 wait_queue_head_t pfmemalloc_wait; 751 struct task_struct *kswapd; /* Protected by 752 mem_hotplug_begin/end() */ 753 int kswapd_max_order; 754 enum zone_type classzone_idx; 755#ifdef CONFIG_NUMA_BALANCING 756 /* Lock serializing the migrate rate limiting window */ 757 spinlock_t numabalancing_migrate_lock; 758 759 /* Rate limiting time interval */ 760 unsigned long numabalancing_migrate_next_window; 761 762 /* Number of pages migrated during the rate limiting time interval */ 763 unsigned long numabalancing_migrate_nr_pages; 764#endif 765} pg_data_t; 766 767#define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages) 768#define node_spanned_pages(nid) (NODE_DATA(nid)->node_spanned_pages) 769#ifdef CONFIG_FLAT_NODE_MEM_MAP 770#define pgdat_page_nr(pgdat, pagenr) ((pgdat)->node_mem_map + (pagenr)) 771#else 772#define pgdat_page_nr(pgdat, pagenr) pfn_to_page((pgdat)->node_start_pfn + (pagenr)) 773#endif 774#define nid_page_nr(nid, pagenr) pgdat_page_nr(NODE_DATA(nid),(pagenr)) 775 776#define node_start_pfn(nid) (NODE_DATA(nid)->node_start_pfn) 777#define node_end_pfn(nid) pgdat_end_pfn(NODE_DATA(nid)) 778 779static inline unsigned long pgdat_end_pfn(pg_data_t *pgdat) 780{ 781 return pgdat->node_start_pfn + pgdat->node_spanned_pages; 782} 783 784static inline bool pgdat_is_empty(pg_data_t *pgdat) 785{ 786 return !pgdat->node_start_pfn && !pgdat->node_spanned_pages; 787} 788 789#include <linux/memory_hotplug.h> 790 791extern struct mutex zonelists_mutex; 792void build_all_zonelists(pg_data_t *pgdat, struct zone *zone); 793void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx); 794bool zone_watermark_ok(struct zone *z, unsigned int order, 795 unsigned long mark, int classzone_idx, int alloc_flags); 796bool zone_watermark_ok_safe(struct zone *z, unsigned int order, 797 unsigned long mark, int classzone_idx, int alloc_flags); 798enum memmap_context { 799 MEMMAP_EARLY, 800 MEMMAP_HOTPLUG, 801}; 802extern int init_currently_empty_zone(struct zone *zone, unsigned long start_pfn, 803 unsigned long size, 804 enum memmap_context context); 805 806extern void lruvec_init(struct lruvec *lruvec); 807 808static inline struct zone *lruvec_zone(struct lruvec *lruvec) 809{ 810#ifdef CONFIG_MEMCG 811 return lruvec->zone; 812#else 813 return container_of(lruvec, struct zone, lruvec); 814#endif 815} 816 817#ifdef CONFIG_HAVE_MEMORY_PRESENT 818void memory_present(int nid, unsigned long start, unsigned long end); 819#else 820static inline void memory_present(int nid, unsigned long start, unsigned long end) {} 821#endif 822 823#ifdef CONFIG_HAVE_MEMORYLESS_NODES 824int local_memory_node(int node_id); 825#else 826static inline int local_memory_node(int node_id) { return node_id; }; 827#endif 828 829#ifdef CONFIG_NEED_NODE_MEMMAP_SIZE 830unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long); 831#endif 832 833/* 834 * zone_idx() returns 0 for the ZONE_DMA zone, 1 for the ZONE_NORMAL zone, etc. 835 */ 836#define zone_idx(zone) ((zone) - (zone)->zone_pgdat->node_zones) 837 838static inline int populated_zone(struct zone *zone) 839{ 840 return (!!zone->present_pages); 841} 842 843extern int movable_zone; 844 845#ifdef CONFIG_HIGHMEM 846static inline int zone_movable_is_highmem(void) 847{ 848#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP 849 return movable_zone == ZONE_HIGHMEM; 850#else 851 return (ZONE_MOVABLE - 1) == ZONE_HIGHMEM; 852#endif 853} 854#endif 855 856static inline int is_highmem_idx(enum zone_type idx) 857{ 858#ifdef CONFIG_HIGHMEM 859 return (idx == ZONE_HIGHMEM || 860 (idx == ZONE_MOVABLE && zone_movable_is_highmem())); 861#else 862 return 0; 863#endif 864} 865 866/** 867 * is_highmem - helper function to quickly check if a struct zone is a 868 * highmem zone or not. This is an attempt to keep references 869 * to ZONE_{DMA/NORMAL/HIGHMEM/etc} in general code to a minimum. 870 * @zone - pointer to struct zone variable 871 */ 872static inline int is_highmem(struct zone *zone) 873{ 874#ifdef CONFIG_HIGHMEM 875 int zone_off = (char *)zone - (char *)zone->zone_pgdat->node_zones; 876 return zone_off == ZONE_HIGHMEM * sizeof(*zone) || 877 (zone_off == ZONE_MOVABLE * sizeof(*zone) && 878 zone_movable_is_highmem()); 879#else 880 return 0; 881#endif 882} 883 884/* These two functions are used to setup the per zone pages min values */ 885struct ctl_table; 886int min_free_kbytes_sysctl_handler(struct ctl_table *, int, 887 void __user *, size_t *, loff_t *); 888extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1]; 889int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int, 890 void __user *, size_t *, loff_t *); 891int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *, int, 892 void __user *, size_t *, loff_t *); 893int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *, int, 894 void __user *, size_t *, loff_t *); 895int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *, int, 896 void __user *, size_t *, loff_t *); 897 898extern int numa_zonelist_order_handler(struct ctl_table *, int, 899 void __user *, size_t *, loff_t *); 900extern char numa_zonelist_order[]; 901#define NUMA_ZONELIST_ORDER_LEN 16 /* string buffer size */ 902 903#ifndef CONFIG_NEED_MULTIPLE_NODES 904 905extern struct pglist_data contig_page_data; 906#define NODE_DATA(nid) (&contig_page_data) 907#define NODE_MEM_MAP(nid) mem_map 908 909#else /* CONFIG_NEED_MULTIPLE_NODES */ 910 911#include <asm/mmzone.h> 912 913#endif /* !CONFIG_NEED_MULTIPLE_NODES */ 914 915extern struct pglist_data *first_online_pgdat(void); 916extern struct pglist_data *next_online_pgdat(struct pglist_data *pgdat); 917extern struct zone *next_zone(struct zone *zone); 918 919/** 920 * for_each_online_pgdat - helper macro to iterate over all online nodes 921 * @pgdat - pointer to a pg_data_t variable 922 */ 923#define for_each_online_pgdat(pgdat) \ 924 for (pgdat = first_online_pgdat(); \ 925 pgdat; \ 926 pgdat = next_online_pgdat(pgdat)) 927/** 928 * for_each_zone - helper macro to iterate over all memory zones 929 * @zone - pointer to struct zone variable 930 * 931 * The user only needs to declare the zone variable, for_each_zone 932 * fills it in. 933 */ 934#define for_each_zone(zone) \ 935 for (zone = (first_online_pgdat())->node_zones; \ 936 zone; \ 937 zone = next_zone(zone)) 938 939#define for_each_populated_zone(zone) \ 940 for (zone = (first_online_pgdat())->node_zones; \ 941 zone; \ 942 zone = next_zone(zone)) \ 943 if (!populated_zone(zone)) \ 944 ; /* do nothing */ \ 945 else 946 947static inline struct zone *zonelist_zone(struct zoneref *zoneref) 948{ 949 return zoneref->zone; 950} 951 952static inline int zonelist_zone_idx(struct zoneref *zoneref) 953{ 954 return zoneref->zone_idx; 955} 956 957static inline int zonelist_node_idx(struct zoneref *zoneref) 958{ 959#ifdef CONFIG_NUMA 960 /* zone_to_nid not available in this context */ 961 return zoneref->zone->node; 962#else 963 return 0; 964#endif /* CONFIG_NUMA */ 965} 966 967/** 968 * 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 969 * @z - The cursor used as a starting point for the search 970 * @highest_zoneidx - The zone index of the highest zone to return 971 * @nodes - An optional nodemask to filter the zonelist with 972 * 973 * This function returns the next zone at or below a given zone index that is 974 * within the allowed nodemask using a cursor as the starting point for the 975 * search. The zoneref returned is a cursor that represents the current zone 976 * being examined. It should be advanced by one before calling 977 * next_zones_zonelist again. 978 */ 979struct zoneref *next_zones_zonelist(struct zoneref *z, 980 enum zone_type highest_zoneidx, 981 nodemask_t *nodes); 982 983/** 984 * first_zones_zonelist - Returns the first zone at or below highest_zoneidx within the allowed nodemask in a zonelist 985 * @zonelist - The zonelist to search for a suitable zone 986 * @highest_zoneidx - The zone index of the highest zone to return 987 * @nodes - An optional nodemask to filter the zonelist with 988 * @zone - The first suitable zone found is returned via this parameter 989 * 990 * This function returns the first zone at or below a given zone index that is 991 * within the allowed nodemask. The zoneref returned is a cursor that can be 992 * used to iterate the zonelist with next_zones_zonelist by advancing it by 993 * one before calling. 994 */ 995static inline struct zoneref *first_zones_zonelist(struct zonelist *zonelist, 996 enum zone_type highest_zoneidx, 997 nodemask_t *nodes, 998 struct zone **zone) 999{ 1000 struct zoneref *z = next_zones_zonelist(zonelist->_zonerefs, 1001 highest_zoneidx, nodes); 1002 *zone = zonelist_zone(z); 1003 return z; 1004} 1005 1006/** 1007 * 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 1008 * @zone - The current zone in the iterator 1009 * @z - The current pointer within zonelist->zones being iterated 1010 * @zlist - The zonelist being iterated 1011 * @highidx - The zone index of the highest zone to return 1012 * @nodemask - Nodemask allowed by the allocator 1013 * 1014 * This iterator iterates though all zones at or below a given zone index and 1015 * within a given nodemask 1016 */ 1017#define for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, nodemask) \ 1018 for (z = first_zones_zonelist(zlist, highidx, nodemask, &zone); \ 1019 zone; \ 1020 z = next_zones_zonelist(++z, highidx, nodemask), \ 1021 zone = zonelist_zone(z)) \ 1022 1023/** 1024 * for_each_zone_zonelist - helper macro to iterate over valid zones in a zonelist at or below a given zone index 1025 * @zone - The current zone in the iterator 1026 * @z - The current pointer within zonelist->zones being iterated 1027 * @zlist - The zonelist being iterated 1028 * @highidx - The zone index of the highest zone to return 1029 * 1030 * This iterator iterates though all zones at or below a given zone index. 1031 */ 1032#define for_each_zone_zonelist(zone, z, zlist, highidx) \ 1033 for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, NULL) 1034 1035#ifdef CONFIG_SPARSEMEM 1036#include <asm/sparsemem.h> 1037#endif 1038 1039#if !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) && \ 1040 !defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) 1041static inline unsigned long early_pfn_to_nid(unsigned long pfn) 1042{ 1043 return 0; 1044} 1045#endif 1046 1047#ifdef CONFIG_FLATMEM 1048#define pfn_to_nid(pfn) (0) 1049#endif 1050 1051#ifdef CONFIG_SPARSEMEM 1052 1053/* 1054 * SECTION_SHIFT #bits space required to store a section # 1055 * 1056 * PA_SECTION_SHIFT physical address to/from section number 1057 * PFN_SECTION_SHIFT pfn to/from section number 1058 */ 1059#define PA_SECTION_SHIFT (SECTION_SIZE_BITS) 1060#define PFN_SECTION_SHIFT (SECTION_SIZE_BITS - PAGE_SHIFT) 1061 1062#define NR_MEM_SECTIONS (1UL << SECTIONS_SHIFT) 1063 1064#define PAGES_PER_SECTION (1UL << PFN_SECTION_SHIFT) 1065#define PAGE_SECTION_MASK (~(PAGES_PER_SECTION-1)) 1066 1067#define SECTION_BLOCKFLAGS_BITS \ 1068 ((1UL << (PFN_SECTION_SHIFT - pageblock_order)) * NR_PAGEBLOCK_BITS) 1069 1070#if (MAX_ORDER - 1 + PAGE_SHIFT) > SECTION_SIZE_BITS 1071#error Allocator MAX_ORDER exceeds SECTION_SIZE 1072#endif 1073 1074#define pfn_to_section_nr(pfn) ((pfn) >> PFN_SECTION_SHIFT) 1075#define section_nr_to_pfn(sec) ((sec) << PFN_SECTION_SHIFT) 1076 1077#define SECTION_ALIGN_UP(pfn) (((pfn) + PAGES_PER_SECTION - 1) & PAGE_SECTION_MASK) 1078#define SECTION_ALIGN_DOWN(pfn) ((pfn) & PAGE_SECTION_MASK) 1079 1080struct page; 1081struct page_ext; 1082struct mem_section { 1083 /* 1084 * This is, logically, a pointer to an array of struct 1085 * pages. However, it is stored with some other magic. 1086 * (see sparse.c::sparse_init_one_section()) 1087 * 1088 * Additionally during early boot we encode node id of 1089 * the location of the section here to guide allocation. 1090 * (see sparse.c::memory_present()) 1091 * 1092 * Making it a UL at least makes someone do a cast 1093 * before using it wrong. 1094 */ 1095 unsigned long section_mem_map; 1096 1097 /* See declaration of similar field in struct zone */ 1098 unsigned long *pageblock_flags; 1099#ifdef CONFIG_PAGE_EXTENSION 1100 /* 1101 * If !SPARSEMEM, pgdat doesn't have page_ext pointer. We use 1102 * section. (see page_ext.h about this.) 1103 */ 1104 struct page_ext *page_ext; 1105 unsigned long pad; 1106#endif 1107 /* 1108 * WARNING: mem_section must be a power-of-2 in size for the 1109 * calculation and use of SECTION_ROOT_MASK to make sense. 1110 */ 1111}; 1112 1113#ifdef CONFIG_SPARSEMEM_EXTREME 1114#define SECTIONS_PER_ROOT (PAGE_SIZE / sizeof (struct mem_section)) 1115#else 1116#define SECTIONS_PER_ROOT 1 1117#endif 1118 1119#define SECTION_NR_TO_ROOT(sec) ((sec) / SECTIONS_PER_ROOT) 1120#define NR_SECTION_ROOTS DIV_ROUND_UP(NR_MEM_SECTIONS, SECTIONS_PER_ROOT) 1121#define SECTION_ROOT_MASK (SECTIONS_PER_ROOT - 1) 1122 1123#ifdef CONFIG_SPARSEMEM_EXTREME 1124extern struct mem_section *mem_section[NR_SECTION_ROOTS]; 1125#else 1126extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT]; 1127#endif 1128 1129static inline struct mem_section *__nr_to_section(unsigned long nr) 1130{ 1131 if (!mem_section[SECTION_NR_TO_ROOT(nr)]) 1132 return NULL; 1133 return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK]; 1134} 1135extern int __section_nr(struct mem_section* ms); 1136extern unsigned long usemap_size(void); 1137 1138/* 1139 * We use the lower bits of the mem_map pointer to store 1140 * a little bit of information. There should be at least 1141 * 3 bits here due to 32-bit alignment. 1142 */ 1143#define SECTION_MARKED_PRESENT (1UL<<0) 1144#define SECTION_HAS_MEM_MAP (1UL<<1) 1145#define SECTION_MAP_LAST_BIT (1UL<<2) 1146#define SECTION_MAP_MASK (~(SECTION_MAP_LAST_BIT-1)) 1147#define SECTION_NID_SHIFT 2 1148 1149static inline struct page *__section_mem_map_addr(struct mem_section *section) 1150{ 1151 unsigned long map = section->section_mem_map; 1152 map &= SECTION_MAP_MASK; 1153 return (struct page *)map; 1154} 1155 1156static inline int present_section(struct mem_section *section) 1157{ 1158 return (section && (section->section_mem_map & SECTION_MARKED_PRESENT)); 1159} 1160 1161static inline int present_section_nr(unsigned long nr) 1162{ 1163 return present_section(__nr_to_section(nr)); 1164} 1165 1166static inline int valid_section(struct mem_section *section) 1167{ 1168 return (section && (section->section_mem_map & SECTION_HAS_MEM_MAP)); 1169} 1170 1171static inline int valid_section_nr(unsigned long nr) 1172{ 1173 return valid_section(__nr_to_section(nr)); 1174} 1175 1176static inline struct mem_section *__pfn_to_section(unsigned long pfn) 1177{ 1178 return __nr_to_section(pfn_to_section_nr(pfn)); 1179} 1180 1181#ifndef CONFIG_HAVE_ARCH_PFN_VALID 1182static inline int pfn_valid(unsigned long pfn) 1183{ 1184 if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS) 1185 return 0; 1186 return valid_section(__nr_to_section(pfn_to_section_nr(pfn))); 1187} 1188#endif 1189 1190static inline int pfn_present(unsigned long pfn) 1191{ 1192 if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS) 1193 return 0; 1194 return present_section(__nr_to_section(pfn_to_section_nr(pfn))); 1195} 1196 1197/* 1198 * These are _only_ used during initialisation, therefore they 1199 * can use __initdata ... They could have names to indicate 1200 * this restriction. 1201 */ 1202#ifdef CONFIG_NUMA 1203#define pfn_to_nid(pfn) \ 1204({ \ 1205 unsigned long __pfn_to_nid_pfn = (pfn); \ 1206 page_to_nid(pfn_to_page(__pfn_to_nid_pfn)); \ 1207}) 1208#else 1209#define pfn_to_nid(pfn) (0) 1210#endif 1211 1212#define early_pfn_valid(pfn) pfn_valid(pfn) 1213void sparse_init(void); 1214#else 1215#define sparse_init() do {} while (0) 1216#define sparse_index_init(_sec, _nid) do {} while (0) 1217#endif /* CONFIG_SPARSEMEM */ 1218 1219#ifdef CONFIG_NODES_SPAN_OTHER_NODES 1220bool early_pfn_in_nid(unsigned long pfn, int nid); 1221#else 1222#define early_pfn_in_nid(pfn, nid) (1) 1223#endif 1224 1225#ifndef early_pfn_valid 1226#define early_pfn_valid(pfn) (1) 1227#endif 1228 1229void memory_present(int nid, unsigned long start, unsigned long end); 1230unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long); 1231 1232/* 1233 * If it is possible to have holes within a MAX_ORDER_NR_PAGES, then we 1234 * need to check pfn validility within that MAX_ORDER_NR_PAGES block. 1235 * pfn_valid_within() should be used in this case; we optimise this away 1236 * when we have no holes within a MAX_ORDER_NR_PAGES block. 1237 */ 1238#ifdef CONFIG_HOLES_IN_ZONE 1239#define pfn_valid_within(pfn) pfn_valid(pfn) 1240#else 1241#define pfn_valid_within(pfn) (1) 1242#endif 1243 1244#ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL 1245/* 1246 * pfn_valid() is meant to be able to tell if a given PFN has valid memmap 1247 * associated with it or not. In FLATMEM, it is expected that holes always 1248 * have valid memmap as long as there is valid PFNs either side of the hole. 1249 * In SPARSEMEM, it is assumed that a valid section has a memmap for the 1250 * entire section. 1251 * 1252 * However, an ARM, and maybe other embedded architectures in the future 1253 * free memmap backing holes to save memory on the assumption the memmap is 1254 * never used. The page_zone linkages are then broken even though pfn_valid() 1255 * returns true. A walker of the full memmap must then do this additional 1256 * check to ensure the memmap they are looking at is sane by making sure 1257 * the zone and PFN linkages are still valid. This is expensive, but walkers 1258 * of the full memmap are extremely rare. 1259 */ 1260int memmap_valid_within(unsigned long pfn, 1261 struct page *page, struct zone *zone); 1262#else 1263static inline int memmap_valid_within(unsigned long pfn, 1264 struct page *page, struct zone *zone) 1265{ 1266 return 1; 1267} 1268#endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */ 1269 1270#endif /* !__GENERATING_BOUNDS.H */ 1271#endif /* !__ASSEMBLY__ */ 1272#endif /* _LINUX_MMZONE_H */ 1273