1 #ifndef _LINUX_MMZONE_H 2 #define _LINUX_MMZONE_H 3 4 #ifdef __KERNEL__ 5 #ifndef __ASSEMBLY__ 6 7 #include <linux/spinlock.h> 8 #include <linux/list.h> 9 #include <linux/wait.h> 10 #include <linux/cache.h> 11 #include <linux/threads.h> 12 #include <linux/numa.h> 13 #include <linux/init.h> 14 #include <linux/seqlock.h> 15 #include <linux/nodemask.h> 16 #include <asm/atomic.h> 17 #include <asm/page.h> 18 19 /* Free memory management - zoned buddy allocator. */ 20 #ifndef CONFIG_FORCE_MAX_ZONEORDER 21 #define MAX_ORDER 11 22 #else 23 #define MAX_ORDER CONFIG_FORCE_MAX_ZONEORDER 24 #endif 25 #define MAX_ORDER_NR_PAGES (1 << (MAX_ORDER - 1)) 26 27 struct free_area { 28 struct list_head free_list; 29 unsigned long nr_free; 30 }; 31 32 struct pglist_data; 33 34 /* 35 * zone->lock and zone->lru_lock are two of the hottest locks in the kernel. 36 * So add a wild amount of padding here to ensure that they fall into separate 37 * cachelines. There are very few zone structures in the machine, so space 38 * consumption is not a concern here. 39 */ 40 #if defined(CONFIG_SMP) 41 struct zone_padding { 42 char x[0]; 43 } ____cacheline_internodealigned_in_smp; 44 #define ZONE_PADDING(name) struct zone_padding name; 45 #else 46 #define ZONE_PADDING(name) 47 #endif 48 49 enum zone_stat_item { 50 NR_ANON_PAGES, /* Mapped anonymous pages */ 51 NR_FILE_MAPPED, /* pagecache pages mapped into pagetables. 52 only modified from process context */ 53 NR_FILE_PAGES, 54 NR_SLAB_RECLAIMABLE, 55 NR_SLAB_UNRECLAIMABLE, 56 NR_PAGETABLE, /* used for pagetables */ 57 NR_FILE_DIRTY, 58 NR_WRITEBACK, 59 NR_UNSTABLE_NFS, /* NFS unstable pages */ 60 NR_BOUNCE, 61 NR_VMSCAN_WRITE, 62 #ifdef CONFIG_NUMA 63 NUMA_HIT, /* allocated in intended node */ 64 NUMA_MISS, /* allocated in non intended node */ 65 NUMA_FOREIGN, /* was intended here, hit elsewhere */ 66 NUMA_INTERLEAVE_HIT, /* interleaver preferred this zone */ 67 NUMA_LOCAL, /* allocation from local node */ 68 NUMA_OTHER, /* allocation from other node */ 69 #endif 70 NR_VM_ZONE_STAT_ITEMS }; 71 72 struct per_cpu_pages { 73 int count; /* number of pages in the list */ 74 int high; /* high watermark, emptying needed */ 75 int batch; /* chunk size for buddy add/remove */ 76 struct list_head list; /* the list of pages */ 77 }; 78 79 struct per_cpu_pageset { 80 struct per_cpu_pages pcp[2]; /* 0: hot. 1: cold */ 81 #ifdef CONFIG_SMP 82 s8 stat_threshold; 83 s8 vm_stat_diff[NR_VM_ZONE_STAT_ITEMS]; 84 #endif 85 } ____cacheline_aligned_in_smp; 86 87 #ifdef CONFIG_NUMA 88 #define zone_pcp(__z, __cpu) ((__z)->pageset[(__cpu)]) 89 #else 90 #define zone_pcp(__z, __cpu) (&(__z)->pageset[(__cpu)]) 91 #endif 92 93 enum zone_type { 94 /* 95 * ZONE_DMA is used when there are devices that are not able 96 * to do DMA to all of addressable memory (ZONE_NORMAL). Then we 97 * carve out the portion of memory that is needed for these devices. 98 * The range is arch specific. 99 * 100 * Some examples 101 * 102 * Architecture Limit 103 * --------------------------- 104 * parisc, ia64, sparc <4G 105 * s390 <2G 106 * arm26 <48M 107 * arm Various 108 * alpha Unlimited or 0-16MB. 109 * 110 * i386, x86_64 and multiple other arches 111 * <16M. 112 */ 113 ZONE_DMA, 114 #ifdef CONFIG_ZONE_DMA32 115 /* 116 * x86_64 needs two ZONE_DMAs because it supports devices that are 117 * only able to do DMA to the lower 16M but also 32 bit devices that 118 * can only do DMA areas below 4G. 119 */ 120 ZONE_DMA32, 121 #endif 122 /* 123 * Normal addressable memory is in ZONE_NORMAL. DMA operations can be 124 * performed on pages in ZONE_NORMAL if the DMA devices support 125 * transfers to all addressable memory. 126 */ 127 ZONE_NORMAL, 128 #ifdef CONFIG_HIGHMEM 129 /* 130 * A memory area that is only addressable by the kernel through 131 * mapping portions into its own address space. This is for example 132 * used by i386 to allow the kernel to address the memory beyond 133 * 900MB. The kernel will set up special mappings (page 134 * table entries on i386) for each page that the kernel needs to 135 * access. 136 */ 137 ZONE_HIGHMEM, 138 #endif 139 MAX_NR_ZONES 140 }; 141 142 /* 143 * When a memory allocation must conform to specific limitations (such 144 * as being suitable for DMA) the caller will pass in hints to the 145 * allocator in the gfp_mask, in the zone modifier bits. These bits 146 * are used to select a priority ordered list of memory zones which 147 * match the requested limits. See gfp_zone() in include/linux/gfp.h 148 */ 149 150 #if !defined(CONFIG_ZONE_DMA32) && !defined(CONFIG_HIGHMEM) 151 #define ZONES_SHIFT 1 152 #else 153 #define ZONES_SHIFT 2 154 #endif 155 156 struct zone { 157 /* Fields commonly accessed by the page allocator */ 158 unsigned long free_pages; 159 unsigned long pages_min, pages_low, pages_high; 160 /* 161 * We don't know if the memory that we're going to allocate will be freeable 162 * or/and it will be released eventually, so to avoid totally wasting several 163 * GB of ram we must reserve some of the lower zone memory (otherwise we risk 164 * to run OOM on the lower zones despite there's tons of freeable ram 165 * on the higher zones). This array is recalculated at runtime if the 166 * sysctl_lowmem_reserve_ratio sysctl changes. 167 */ 168 unsigned long lowmem_reserve[MAX_NR_ZONES]; 169 170 #ifdef CONFIG_NUMA 171 int node; 172 /* 173 * zone reclaim becomes active if more unmapped pages exist. 174 */ 175 unsigned long min_unmapped_pages; 176 unsigned long min_slab_pages; 177 struct per_cpu_pageset *pageset[NR_CPUS]; 178 #else 179 struct per_cpu_pageset pageset[NR_CPUS]; 180 #endif 181 /* 182 * free areas of different sizes 183 */ 184 spinlock_t lock; 185 #ifdef CONFIG_MEMORY_HOTPLUG 186 /* see spanned/present_pages for more description */ 187 seqlock_t span_seqlock; 188 #endif 189 struct free_area free_area[MAX_ORDER]; 190 191 192 ZONE_PADDING(_pad1_) 193 194 /* Fields commonly accessed by the page reclaim scanner */ 195 spinlock_t lru_lock; 196 struct list_head active_list; 197 struct list_head inactive_list; 198 unsigned long nr_scan_active; 199 unsigned long nr_scan_inactive; 200 unsigned long nr_active; 201 unsigned long nr_inactive; 202 unsigned long pages_scanned; /* since last reclaim */ 203 int all_unreclaimable; /* All pages pinned */ 204 205 /* A count of how many reclaimers are scanning this zone */ 206 atomic_t reclaim_in_progress; 207 208 /* Zone statistics */ 209 atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS]; 210 211 /* 212 * prev_priority holds the scanning priority for this zone. It is 213 * defined as the scanning priority at which we achieved our reclaim 214 * target at the previous try_to_free_pages() or balance_pgdat() 215 * invokation. 216 * 217 * We use prev_priority as a measure of how much stress page reclaim is 218 * under - it drives the swappiness decision: whether to unmap mapped 219 * pages. 220 * 221 * Access to both this field is quite racy even on uniprocessor. But 222 * it is expected to average out OK. 223 */ 224 int prev_priority; 225 226 227 ZONE_PADDING(_pad2_) 228 /* Rarely used or read-mostly fields */ 229 230 /* 231 * wait_table -- the array holding the hash table 232 * wait_table_hash_nr_entries -- the size of the hash table array 233 * wait_table_bits -- wait_table_size == (1 << wait_table_bits) 234 * 235 * The purpose of all these is to keep track of the people 236 * waiting for a page to become available and make them 237 * runnable again when possible. The trouble is that this 238 * consumes a lot of space, especially when so few things 239 * wait on pages at a given time. So instead of using 240 * per-page waitqueues, we use a waitqueue hash table. 241 * 242 * The bucket discipline is to sleep on the same queue when 243 * colliding and wake all in that wait queue when removing. 244 * When something wakes, it must check to be sure its page is 245 * truly available, a la thundering herd. The cost of a 246 * collision is great, but given the expected load of the 247 * table, they should be so rare as to be outweighed by the 248 * benefits from the saved space. 249 * 250 * __wait_on_page_locked() and unlock_page() in mm/filemap.c, are the 251 * primary users of these fields, and in mm/page_alloc.c 252 * free_area_init_core() performs the initialization of them. 253 */ 254 wait_queue_head_t * wait_table; 255 unsigned long wait_table_hash_nr_entries; 256 unsigned long wait_table_bits; 257 258 /* 259 * Discontig memory support fields. 260 */ 261 struct pglist_data *zone_pgdat; 262 /* zone_start_pfn == zone_start_paddr >> PAGE_SHIFT */ 263 unsigned long zone_start_pfn; 264 265 /* 266 * zone_start_pfn, spanned_pages and present_pages are all 267 * protected by span_seqlock. It is a seqlock because it has 268 * to be read outside of zone->lock, and it is done in the main 269 * allocator path. But, it is written quite infrequently. 270 * 271 * The lock is declared along with zone->lock because it is 272 * frequently read in proximity to zone->lock. It's good to 273 * give them a chance of being in the same cacheline. 274 */ 275 unsigned long spanned_pages; /* total size, including holes */ 276 unsigned long present_pages; /* amount of memory (excluding holes) */ 277 278 /* 279 * rarely used fields: 280 */ 281 const char *name; 282 } ____cacheline_internodealigned_in_smp; 283 284 /* 285 * The "priority" of VM scanning is how much of the queues we will scan in one 286 * go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the 287 * queues ("queue_length >> 12") during an aging round. 288 */ 289 #define DEF_PRIORITY 12 290 291 /* Maximum number of zones on a zonelist */ 292 #define MAX_ZONES_PER_ZONELIST (MAX_NUMNODES * MAX_NR_ZONES) 293 294 #ifdef CONFIG_NUMA 295 /* 296 * We cache key information from each zonelist for smaller cache 297 * footprint when scanning for free pages in get_page_from_freelist(). 298 * 299 * 1) The BITMAP fullzones tracks which zones in a zonelist have come 300 * up short of free memory since the last time (last_fullzone_zap) 301 * we zero'd fullzones. 302 * 2) The array z_to_n[] maps each zone in the zonelist to its node 303 * id, so that we can efficiently evaluate whether that node is 304 * set in the current tasks mems_allowed. 305 * 306 * Both fullzones and z_to_n[] are one-to-one with the zonelist, 307 * indexed by a zones offset in the zonelist zones[] array. 308 * 309 * The get_page_from_freelist() routine does two scans. During the 310 * first scan, we skip zones whose corresponding bit in 'fullzones' 311 * is set or whose corresponding node in current->mems_allowed (which 312 * comes from cpusets) is not set. During the second scan, we bypass 313 * this zonelist_cache, to ensure we look methodically at each zone. 314 * 315 * Once per second, we zero out (zap) fullzones, forcing us to 316 * reconsider nodes that might have regained more free memory. 317 * The field last_full_zap is the time we last zapped fullzones. 318 * 319 * This mechanism reduces the amount of time we waste repeatedly 320 * reexaming zones for free memory when they just came up low on 321 * memory momentarilly ago. 322 * 323 * The zonelist_cache struct members logically belong in struct 324 * zonelist. However, the mempolicy zonelists constructed for 325 * MPOL_BIND are intentionally variable length (and usually much 326 * shorter). A general purpose mechanism for handling structs with 327 * multiple variable length members is more mechanism than we want 328 * here. We resort to some special case hackery instead. 329 * 330 * The MPOL_BIND zonelists don't need this zonelist_cache (in good 331 * part because they are shorter), so we put the fixed length stuff 332 * at the front of the zonelist struct, ending in a variable length 333 * zones[], as is needed by MPOL_BIND. 334 * 335 * Then we put the optional zonelist cache on the end of the zonelist 336 * struct. This optional stuff is found by a 'zlcache_ptr' pointer in 337 * the fixed length portion at the front of the struct. This pointer 338 * both enables us to find the zonelist cache, and in the case of 339 * MPOL_BIND zonelists, (which will just set the zlcache_ptr to NULL) 340 * to know that the zonelist cache is not there. 341 * 342 * The end result is that struct zonelists come in two flavors: 343 * 1) The full, fixed length version, shown below, and 344 * 2) The custom zonelists for MPOL_BIND. 345 * The custom MPOL_BIND zonelists have a NULL zlcache_ptr and no zlcache. 346 * 347 * Even though there may be multiple CPU cores on a node modifying 348 * fullzones or last_full_zap in the same zonelist_cache at the same 349 * time, we don't lock it. This is just hint data - if it is wrong now 350 * and then, the allocator will still function, perhaps a bit slower. 351 */ 352 353 354 struct zonelist_cache { 355 unsigned short z_to_n[MAX_ZONES_PER_ZONELIST]; /* zone->nid */ 356 DECLARE_BITMAP(fullzones, MAX_ZONES_PER_ZONELIST); /* zone full? */ 357 unsigned long last_full_zap; /* when last zap'd (jiffies) */ 358 }; 359 #else 360 struct zonelist_cache; 361 #endif 362 363 /* 364 * One allocation request operates on a zonelist. A zonelist 365 * is a list of zones, the first one is the 'goal' of the 366 * allocation, the other zones are fallback zones, in decreasing 367 * priority. 368 * 369 * If zlcache_ptr is not NULL, then it is just the address of zlcache, 370 * as explained above. If zlcache_ptr is NULL, there is no zlcache. 371 */ 372 373 struct zonelist { 374 struct zonelist_cache *zlcache_ptr; // NULL or &zlcache 375 struct zone *zones[MAX_ZONES_PER_ZONELIST + 1]; // NULL delimited 376 #ifdef CONFIG_NUMA 377 struct zonelist_cache zlcache; // optional ... 378 #endif 379 }; 380 381 #ifdef CONFIG_ARCH_POPULATES_NODE_MAP 382 struct node_active_region { 383 unsigned long start_pfn; 384 unsigned long end_pfn; 385 int nid; 386 }; 387 #endif /* CONFIG_ARCH_POPULATES_NODE_MAP */ 388 389 #ifndef CONFIG_DISCONTIGMEM 390 /* The array of struct pages - for discontigmem use pgdat->lmem_map */ 391 extern struct page *mem_map; 392 #endif 393 394 /* 395 * The pg_data_t structure is used in machines with CONFIG_DISCONTIGMEM 396 * (mostly NUMA machines?) to denote a higher-level memory zone than the 397 * zone denotes. 398 * 399 * On NUMA machines, each NUMA node would have a pg_data_t to describe 400 * it's memory layout. 401 * 402 * Memory statistics and page replacement data structures are maintained on a 403 * per-zone basis. 404 */ 405 struct bootmem_data; 406 typedef struct pglist_data { 407 struct zone node_zones[MAX_NR_ZONES]; 408 struct zonelist node_zonelists[MAX_NR_ZONES]; 409 int nr_zones; 410 #ifdef CONFIG_FLAT_NODE_MEM_MAP 411 struct page *node_mem_map; 412 #endif 413 struct bootmem_data *bdata; 414 #ifdef CONFIG_MEMORY_HOTPLUG 415 /* 416 * Must be held any time you expect node_start_pfn, node_present_pages 417 * or node_spanned_pages stay constant. Holding this will also 418 * guarantee that any pfn_valid() stays that way. 419 * 420 * Nests above zone->lock and zone->size_seqlock. 421 */ 422 spinlock_t node_size_lock; 423 #endif 424 unsigned long node_start_pfn; 425 unsigned long node_present_pages; /* total number of physical pages */ 426 unsigned long node_spanned_pages; /* total size of physical page 427 range, including holes */ 428 int node_id; 429 wait_queue_head_t kswapd_wait; 430 struct task_struct *kswapd; 431 int kswapd_max_order; 432 } pg_data_t; 433 434 #define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages) 435 #define node_spanned_pages(nid) (NODE_DATA(nid)->node_spanned_pages) 436 #ifdef CONFIG_FLAT_NODE_MEM_MAP 437 #define pgdat_page_nr(pgdat, pagenr) ((pgdat)->node_mem_map + (pagenr)) 438 #else 439 #define pgdat_page_nr(pgdat, pagenr) pfn_to_page((pgdat)->node_start_pfn + (pagenr)) 440 #endif 441 #define nid_page_nr(nid, pagenr) pgdat_page_nr(NODE_DATA(nid),(pagenr)) 442 443 #include <linux/memory_hotplug.h> 444 445 void __get_zone_counts(unsigned long *active, unsigned long *inactive, 446 unsigned long *free, struct pglist_data *pgdat); 447 void get_zone_counts(unsigned long *active, unsigned long *inactive, 448 unsigned long *free); 449 void build_all_zonelists(void); 450 void wakeup_kswapd(struct zone *zone, int order); 451 int zone_watermark_ok(struct zone *z, int order, unsigned long mark, 452 int classzone_idx, int alloc_flags); 453 enum memmap_context { 454 MEMMAP_EARLY, 455 MEMMAP_HOTPLUG, 456 }; 457 extern int init_currently_empty_zone(struct zone *zone, unsigned long start_pfn, 458 unsigned long size, 459 enum memmap_context context); 460 461 #ifdef CONFIG_HAVE_MEMORY_PRESENT 462 void memory_present(int nid, unsigned long start, unsigned long end); 463 #else 464 static inline void memory_present(int nid, unsigned long start, unsigned long end) {} 465 #endif 466 467 #ifdef CONFIG_NEED_NODE_MEMMAP_SIZE 468 unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long); 469 #endif 470 471 /* 472 * zone_idx() returns 0 for the ZONE_DMA zone, 1 for the ZONE_NORMAL zone, etc. 473 */ 474 #define zone_idx(zone) ((zone) - (zone)->zone_pgdat->node_zones) 475 476 static inline int populated_zone(struct zone *zone) 477 { 478 return (!!zone->present_pages); 479 } 480 481 static inline int is_highmem_idx(enum zone_type idx) 482 { 483 #ifdef CONFIG_HIGHMEM 484 return (idx == ZONE_HIGHMEM); 485 #else 486 return 0; 487 #endif 488 } 489 490 static inline int is_normal_idx(enum zone_type idx) 491 { 492 return (idx == ZONE_NORMAL); 493 } 494 495 /** 496 * is_highmem - helper function to quickly check if a struct zone is a 497 * highmem zone or not. This is an attempt to keep references 498 * to ZONE_{DMA/NORMAL/HIGHMEM/etc} in general code to a minimum. 499 * @zone - pointer to struct zone variable 500 */ 501 static inline int is_highmem(struct zone *zone) 502 { 503 #ifdef CONFIG_HIGHMEM 504 return zone == zone->zone_pgdat->node_zones + ZONE_HIGHMEM; 505 #else 506 return 0; 507 #endif 508 } 509 510 static inline int is_normal(struct zone *zone) 511 { 512 return zone == zone->zone_pgdat->node_zones + ZONE_NORMAL; 513 } 514 515 static inline int is_dma32(struct zone *zone) 516 { 517 #ifdef CONFIG_ZONE_DMA32 518 return zone == zone->zone_pgdat->node_zones + ZONE_DMA32; 519 #else 520 return 0; 521 #endif 522 } 523 524 static inline int is_dma(struct zone *zone) 525 { 526 return zone == zone->zone_pgdat->node_zones + ZONE_DMA; 527 } 528 529 /* These two functions are used to setup the per zone pages min values */ 530 struct ctl_table; 531 struct file; 532 int min_free_kbytes_sysctl_handler(struct ctl_table *, int, struct file *, 533 void __user *, size_t *, loff_t *); 534 extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1]; 535 int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int, struct file *, 536 void __user *, size_t *, loff_t *); 537 int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *, int, struct file *, 538 void __user *, size_t *, loff_t *); 539 int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *, int, 540 struct file *, void __user *, size_t *, loff_t *); 541 int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *, int, 542 struct file *, void __user *, size_t *, loff_t *); 543 544 #include <linux/topology.h> 545 /* Returns the number of the current Node. */ 546 #ifndef numa_node_id 547 #define numa_node_id() (cpu_to_node(raw_smp_processor_id())) 548 #endif 549 550 #ifndef CONFIG_NEED_MULTIPLE_NODES 551 552 extern struct pglist_data contig_page_data; 553 #define NODE_DATA(nid) (&contig_page_data) 554 #define NODE_MEM_MAP(nid) mem_map 555 #define MAX_NODES_SHIFT 1 556 557 #else /* CONFIG_NEED_MULTIPLE_NODES */ 558 559 #include <asm/mmzone.h> 560 561 #endif /* !CONFIG_NEED_MULTIPLE_NODES */ 562 563 extern struct pglist_data *first_online_pgdat(void); 564 extern struct pglist_data *next_online_pgdat(struct pglist_data *pgdat); 565 extern struct zone *next_zone(struct zone *zone); 566 567 /** 568 * for_each_pgdat - helper macro to iterate over all nodes 569 * @pgdat - pointer to a pg_data_t variable 570 */ 571 #define for_each_online_pgdat(pgdat) \ 572 for (pgdat = first_online_pgdat(); \ 573 pgdat; \ 574 pgdat = next_online_pgdat(pgdat)) 575 /** 576 * for_each_zone - helper macro to iterate over all memory zones 577 * @zone - pointer to struct zone variable 578 * 579 * The user only needs to declare the zone variable, for_each_zone 580 * fills it in. 581 */ 582 #define for_each_zone(zone) \ 583 for (zone = (first_online_pgdat())->node_zones; \ 584 zone; \ 585 zone = next_zone(zone)) 586 587 #ifdef CONFIG_SPARSEMEM 588 #include <asm/sparsemem.h> 589 #endif 590 591 #if BITS_PER_LONG == 32 592 /* 593 * with 32 bit page->flags field, we reserve 9 bits for node/zone info. 594 * there are 4 zones (3 bits) and this leaves 9-3=6 bits for nodes. 595 */ 596 #define FLAGS_RESERVED 9 597 598 #elif BITS_PER_LONG == 64 599 /* 600 * with 64 bit flags field, there's plenty of room. 601 */ 602 #define FLAGS_RESERVED 32 603 604 #else 605 606 #error BITS_PER_LONG not defined 607 608 #endif 609 610 #if !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) && \ 611 !defined(CONFIG_ARCH_POPULATES_NODE_MAP) 612 #define early_pfn_to_nid(nid) (0UL) 613 #endif 614 615 #ifdef CONFIG_FLATMEM 616 #define pfn_to_nid(pfn) (0) 617 #endif 618 619 #define pfn_to_section_nr(pfn) ((pfn) >> PFN_SECTION_SHIFT) 620 #define section_nr_to_pfn(sec) ((sec) << PFN_SECTION_SHIFT) 621 622 #ifdef CONFIG_SPARSEMEM 623 624 /* 625 * SECTION_SHIFT #bits space required to store a section # 626 * 627 * PA_SECTION_SHIFT physical address to/from section number 628 * PFN_SECTION_SHIFT pfn to/from section number 629 */ 630 #define SECTIONS_SHIFT (MAX_PHYSMEM_BITS - SECTION_SIZE_BITS) 631 632 #define PA_SECTION_SHIFT (SECTION_SIZE_BITS) 633 #define PFN_SECTION_SHIFT (SECTION_SIZE_BITS - PAGE_SHIFT) 634 635 #define NR_MEM_SECTIONS (1UL << SECTIONS_SHIFT) 636 637 #define PAGES_PER_SECTION (1UL << PFN_SECTION_SHIFT) 638 #define PAGE_SECTION_MASK (~(PAGES_PER_SECTION-1)) 639 640 #if (MAX_ORDER - 1 + PAGE_SHIFT) > SECTION_SIZE_BITS 641 #error Allocator MAX_ORDER exceeds SECTION_SIZE 642 #endif 643 644 struct page; 645 struct mem_section { 646 /* 647 * This is, logically, a pointer to an array of struct 648 * pages. However, it is stored with some other magic. 649 * (see sparse.c::sparse_init_one_section()) 650 * 651 * Additionally during early boot we encode node id of 652 * the location of the section here to guide allocation. 653 * (see sparse.c::memory_present()) 654 * 655 * Making it a UL at least makes someone do a cast 656 * before using it wrong. 657 */ 658 unsigned long section_mem_map; 659 }; 660 661 #ifdef CONFIG_SPARSEMEM_EXTREME 662 #define SECTIONS_PER_ROOT (PAGE_SIZE / sizeof (struct mem_section)) 663 #else 664 #define SECTIONS_PER_ROOT 1 665 #endif 666 667 #define SECTION_NR_TO_ROOT(sec) ((sec) / SECTIONS_PER_ROOT) 668 #define NR_SECTION_ROOTS (NR_MEM_SECTIONS / SECTIONS_PER_ROOT) 669 #define SECTION_ROOT_MASK (SECTIONS_PER_ROOT - 1) 670 671 #ifdef CONFIG_SPARSEMEM_EXTREME 672 extern struct mem_section *mem_section[NR_SECTION_ROOTS]; 673 #else 674 extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT]; 675 #endif 676 677 static inline struct mem_section *__nr_to_section(unsigned long nr) 678 { 679 if (!mem_section[SECTION_NR_TO_ROOT(nr)]) 680 return NULL; 681 return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK]; 682 } 683 extern int __section_nr(struct mem_section* ms); 684 685 /* 686 * We use the lower bits of the mem_map pointer to store 687 * a little bit of information. There should be at least 688 * 3 bits here due to 32-bit alignment. 689 */ 690 #define SECTION_MARKED_PRESENT (1UL<<0) 691 #define SECTION_HAS_MEM_MAP (1UL<<1) 692 #define SECTION_MAP_LAST_BIT (1UL<<2) 693 #define SECTION_MAP_MASK (~(SECTION_MAP_LAST_BIT-1)) 694 #define SECTION_NID_SHIFT 2 695 696 static inline struct page *__section_mem_map_addr(struct mem_section *section) 697 { 698 unsigned long map = section->section_mem_map; 699 map &= SECTION_MAP_MASK; 700 return (struct page *)map; 701 } 702 703 static inline int valid_section(struct mem_section *section) 704 { 705 return (section && (section->section_mem_map & SECTION_MARKED_PRESENT)); 706 } 707 708 static inline int section_has_mem_map(struct mem_section *section) 709 { 710 return (section && (section->section_mem_map & SECTION_HAS_MEM_MAP)); 711 } 712 713 static inline int valid_section_nr(unsigned long nr) 714 { 715 return valid_section(__nr_to_section(nr)); 716 } 717 718 static inline struct mem_section *__pfn_to_section(unsigned long pfn) 719 { 720 return __nr_to_section(pfn_to_section_nr(pfn)); 721 } 722 723 static inline int pfn_valid(unsigned long pfn) 724 { 725 if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS) 726 return 0; 727 return valid_section(__nr_to_section(pfn_to_section_nr(pfn))); 728 } 729 730 /* 731 * These are _only_ used during initialisation, therefore they 732 * can use __initdata ... They could have names to indicate 733 * this restriction. 734 */ 735 #ifdef CONFIG_NUMA 736 #define pfn_to_nid(pfn) \ 737 ({ \ 738 unsigned long __pfn_to_nid_pfn = (pfn); \ 739 page_to_nid(pfn_to_page(__pfn_to_nid_pfn)); \ 740 }) 741 #else 742 #define pfn_to_nid(pfn) (0) 743 #endif 744 745 #define early_pfn_valid(pfn) pfn_valid(pfn) 746 void sparse_init(void); 747 #else 748 #define sparse_init() do {} while (0) 749 #define sparse_index_init(_sec, _nid) do {} while (0) 750 #endif /* CONFIG_SPARSEMEM */ 751 752 #ifdef CONFIG_NODES_SPAN_OTHER_NODES 753 #define early_pfn_in_nid(pfn, nid) (early_pfn_to_nid(pfn) == (nid)) 754 #else 755 #define early_pfn_in_nid(pfn, nid) (1) 756 #endif 757 758 #ifndef early_pfn_valid 759 #define early_pfn_valid(pfn) (1) 760 #endif 761 762 void memory_present(int nid, unsigned long start, unsigned long end); 763 unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long); 764 765 #endif /* !__ASSEMBLY__ */ 766 #endif /* __KERNEL__ */ 767 #endif /* _LINUX_MMZONE_H */ 768