1 #ifndef _LINUX_MMZONE_H
2 #define _LINUX_MMZONE_H
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>
19 /* Free memory management - zoned buddy allocator. */
20 #ifndef CONFIG_FORCE_MAX_ZONEORDER
23 #define MAX_ORDER CONFIG_FORCE_MAX_ZONEORDER
25 #define MAX_ORDER_NR_PAGES (1 << (MAX_ORDER - 1))
28 struct list_head free_list;
29 unsigned long nr_free;
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.
40 #if defined(CONFIG_SMP)
43 } ____cacheline_internodealigned_in_smp;
44 #define ZONE_PADDING(name) struct zone_padding name;
46 #define ZONE_PADDING(name)
50 NR_ANON_PAGES, /* Mapped anonymous pages */
51 NR_FILE_MAPPED, /* pagecache pages mapped into pagetables.
52 only modified from process context */
55 NR_SLAB_UNRECLAIMABLE,
56 NR_PAGETABLE, /* used for pagetables */
59 NR_UNSTABLE_NFS, /* NFS unstable pages */
62 NUMA_HIT, /* allocated in intended node */
63 NUMA_MISS, /* allocated in non intended node */
64 NUMA_FOREIGN, /* was intended here, hit elsewhere */
65 NUMA_INTERLEAVE_HIT, /* interleaver preferred this zone */
66 NUMA_LOCAL, /* allocation from local node */
67 NUMA_OTHER, /* allocation from other node */
69 NR_VM_ZONE_STAT_ITEMS };
71 struct per_cpu_pages {
72 int count; /* number of pages in the list */
73 int high; /* high watermark, emptying needed */
74 int batch; /* chunk size for buddy add/remove */
75 struct list_head list; /* the list of pages */
78 struct per_cpu_pageset {
79 struct per_cpu_pages pcp[2]; /* 0: hot. 1: cold */
82 s8 vm_stat_diff[NR_VM_ZONE_STAT_ITEMS];
84 } ____cacheline_aligned_in_smp;
87 #define zone_pcp(__z, __cpu) ((__z)->pageset[(__cpu)])
89 #define zone_pcp(__z, __cpu) (&(__z)->pageset[(__cpu)])
94 * ZONE_DMA is used when there are devices that are not able
95 * to do DMA to all of addressable memory (ZONE_NORMAL). Then we
96 * carve out the portion of memory that is needed for these devices.
97 * The range is arch specific.
102 * ---------------------------
103 * parisc, ia64, sparc <4G
107 * alpha Unlimited or 0-16MB.
109 * i386, x86_64 and multiple other arches
113 #ifdef CONFIG_ZONE_DMA32
115 * x86_64 needs two ZONE_DMAs because it supports devices that are
116 * only able to do DMA to the lower 16M but also 32 bit devices that
117 * can only do DMA areas below 4G.
122 * Normal addressable memory is in ZONE_NORMAL. DMA operations can be
123 * performed on pages in ZONE_NORMAL if the DMA devices support
124 * transfers to all addressable memory.
127 #ifdef CONFIG_HIGHMEM
129 * A memory area that is only addressable by the kernel through
130 * mapping portions into its own address space. This is for example
131 * used by i386 to allow the kernel to address the memory beyond
132 * 900MB. The kernel will set up special mappings (page
133 * table entries on i386) for each page that the kernel needs to
142 * When a memory allocation must conform to specific limitations (such
143 * as being suitable for DMA) the caller will pass in hints to the
144 * allocator in the gfp_mask, in the zone modifier bits. These bits
145 * are used to select a priority ordered list of memory zones which
146 * match the requested limits. See gfp_zone() in include/linux/gfp.h
149 #if !defined(CONFIG_ZONE_DMA32) && !defined(CONFIG_HIGHMEM)
150 #define ZONES_SHIFT 1
152 #define ZONES_SHIFT 2
156 /* Fields commonly accessed by the page allocator */
157 unsigned long free_pages;
158 unsigned long pages_min, pages_low, pages_high;
160 * We don't know if the memory that we're going to allocate will be freeable
161 * or/and it will be released eventually, so to avoid totally wasting several
162 * GB of ram we must reserve some of the lower zone memory (otherwise we risk
163 * to run OOM on the lower zones despite there's tons of freeable ram
164 * on the higher zones). This array is recalculated at runtime if the
165 * sysctl_lowmem_reserve_ratio sysctl changes.
167 unsigned long lowmem_reserve[MAX_NR_ZONES];
171 * zone reclaim becomes active if more unmapped pages exist.
173 unsigned long min_unmapped_pages;
174 struct per_cpu_pageset *pageset[NR_CPUS];
176 struct per_cpu_pageset pageset[NR_CPUS];
179 * free areas of different sizes
182 #ifdef CONFIG_MEMORY_HOTPLUG
183 /* see spanned/present_pages for more description */
184 seqlock_t span_seqlock;
186 struct free_area free_area[MAX_ORDER];
191 /* Fields commonly accessed by the page reclaim scanner */
193 struct list_head active_list;
194 struct list_head inactive_list;
195 unsigned long nr_scan_active;
196 unsigned long nr_scan_inactive;
197 unsigned long nr_active;
198 unsigned long nr_inactive;
199 unsigned long pages_scanned; /* since last reclaim */
200 int all_unreclaimable; /* All pages pinned */
202 /* A count of how many reclaimers are scanning this zone */
203 atomic_t reclaim_in_progress;
205 /* Zone statistics */
206 atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
209 * prev_priority holds the scanning priority for this zone. It is
210 * defined as the scanning priority at which we achieved our reclaim
211 * target at the previous try_to_free_pages() or balance_pgdat()
214 * We use prev_priority as a measure of how much stress page reclaim is
215 * under - it drives the swappiness decision: whether to unmap mapped
218 * temp_priority is used to remember the scanning priority at which
219 * this zone was successfully refilled to free_pages == pages_high.
221 * Access to both these fields is quite racy even on uniprocessor. But
222 * it is expected to average out OK.
229 /* Rarely used or read-mostly fields */
232 * wait_table -- the array holding the hash table
233 * wait_table_hash_nr_entries -- the size of the hash table array
234 * wait_table_bits -- wait_table_size == (1 << wait_table_bits)
236 * The purpose of all these is to keep track of the people
237 * waiting for a page to become available and make them
238 * runnable again when possible. The trouble is that this
239 * consumes a lot of space, especially when so few things
240 * wait on pages at a given time. So instead of using
241 * per-page waitqueues, we use a waitqueue hash table.
243 * The bucket discipline is to sleep on the same queue when
244 * colliding and wake all in that wait queue when removing.
245 * When something wakes, it must check to be sure its page is
246 * truly available, a la thundering herd. The cost of a
247 * collision is great, but given the expected load of the
248 * table, they should be so rare as to be outweighed by the
249 * benefits from the saved space.
251 * __wait_on_page_locked() and unlock_page() in mm/filemap.c, are the
252 * primary users of these fields, and in mm/page_alloc.c
253 * free_area_init_core() performs the initialization of them.
255 wait_queue_head_t * wait_table;
256 unsigned long wait_table_hash_nr_entries;
257 unsigned long wait_table_bits;
260 * Discontig memory support fields.
262 struct pglist_data *zone_pgdat;
263 /* zone_start_pfn == zone_start_paddr >> PAGE_SHIFT */
264 unsigned long zone_start_pfn;
267 * zone_start_pfn, spanned_pages and present_pages are all
268 * protected by span_seqlock. It is a seqlock because it has
269 * to be read outside of zone->lock, and it is done in the main
270 * allocator path. But, it is written quite infrequently.
272 * The lock is declared along with zone->lock because it is
273 * frequently read in proximity to zone->lock. It's good to
274 * give them a chance of being in the same cacheline.
276 unsigned long spanned_pages; /* total size, including holes */
277 unsigned long present_pages; /* amount of memory (excluding holes) */
280 * rarely used fields:
283 } ____cacheline_internodealigned_in_smp;
286 * The "priority" of VM scanning is how much of the queues we will scan in one
287 * go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the
288 * queues ("queue_length >> 12") during an aging round.
290 #define DEF_PRIORITY 12
293 * One allocation request operates on a zonelist. A zonelist
294 * is a list of zones, the first one is the 'goal' of the
295 * allocation, the other zones are fallback zones, in decreasing
298 * Right now a zonelist takes up less than a cacheline. We never
299 * modify it apart from boot-up, and only a few indices are used,
300 * so despite the zonelist table being relatively big, the cache
301 * footprint of this construct is very small.
304 struct zone *zones[MAX_NUMNODES * MAX_NR_ZONES + 1]; // NULL delimited
309 * The pg_data_t structure is used in machines with CONFIG_DISCONTIGMEM
310 * (mostly NUMA machines?) to denote a higher-level memory zone than the
313 * On NUMA machines, each NUMA node would have a pg_data_t to describe
314 * it's memory layout.
316 * Memory statistics and page replacement data structures are maintained on a
320 typedef struct pglist_data {
321 struct zone node_zones[MAX_NR_ZONES];
322 struct zonelist node_zonelists[MAX_NR_ZONES];
324 #ifdef CONFIG_FLAT_NODE_MEM_MAP
325 struct page *node_mem_map;
327 struct bootmem_data *bdata;
328 #ifdef CONFIG_MEMORY_HOTPLUG
330 * Must be held any time you expect node_start_pfn, node_present_pages
331 * or node_spanned_pages stay constant. Holding this will also
332 * guarantee that any pfn_valid() stays that way.
334 * Nests above zone->lock and zone->size_seqlock.
336 spinlock_t node_size_lock;
338 unsigned long node_start_pfn;
339 unsigned long node_present_pages; /* total number of physical pages */
340 unsigned long node_spanned_pages; /* total size of physical page
341 range, including holes */
343 wait_queue_head_t kswapd_wait;
344 struct task_struct *kswapd;
345 int kswapd_max_order;
348 #define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages)
349 #define node_spanned_pages(nid) (NODE_DATA(nid)->node_spanned_pages)
350 #ifdef CONFIG_FLAT_NODE_MEM_MAP
351 #define pgdat_page_nr(pgdat, pagenr) ((pgdat)->node_mem_map + (pagenr))
353 #define pgdat_page_nr(pgdat, pagenr) pfn_to_page((pgdat)->node_start_pfn + (pagenr))
355 #define nid_page_nr(nid, pagenr) pgdat_page_nr(NODE_DATA(nid),(pagenr))
357 #include <linux/memory_hotplug.h>
359 void __get_zone_counts(unsigned long *active, unsigned long *inactive,
360 unsigned long *free, struct pglist_data *pgdat);
361 void get_zone_counts(unsigned long *active, unsigned long *inactive,
362 unsigned long *free);
363 void build_all_zonelists(void);
364 void wakeup_kswapd(struct zone *zone, int order);
365 int zone_watermark_ok(struct zone *z, int order, unsigned long mark,
366 int classzone_idx, int alloc_flags);
368 extern int init_currently_empty_zone(struct zone *zone, unsigned long start_pfn,
371 #ifdef CONFIG_HAVE_MEMORY_PRESENT
372 void memory_present(int nid, unsigned long start, unsigned long end);
374 static inline void memory_present(int nid, unsigned long start, unsigned long end) {}
377 #ifdef CONFIG_NEED_NODE_MEMMAP_SIZE
378 unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long);
382 * zone_idx() returns 0 for the ZONE_DMA zone, 1 for the ZONE_NORMAL zone, etc.
384 #define zone_idx(zone) ((zone) - (zone)->zone_pgdat->node_zones)
386 static inline int populated_zone(struct zone *zone)
388 return (!!zone->present_pages);
391 static inline int is_highmem_idx(enum zone_type idx)
393 #ifdef CONFIG_HIGHMEM
394 return (idx == ZONE_HIGHMEM);
400 static inline int is_normal_idx(enum zone_type idx)
402 return (idx == ZONE_NORMAL);
406 * is_highmem - helper function to quickly check if a struct zone is a
407 * highmem zone or not. This is an attempt to keep references
408 * to ZONE_{DMA/NORMAL/HIGHMEM/etc} in general code to a minimum.
409 * @zone - pointer to struct zone variable
411 static inline int is_highmem(struct zone *zone)
413 #ifdef CONFIG_HIGHMEM
414 return zone == zone->zone_pgdat->node_zones + ZONE_HIGHMEM;
420 static inline int is_normal(struct zone *zone)
422 return zone == zone->zone_pgdat->node_zones + ZONE_NORMAL;
425 static inline int is_dma32(struct zone *zone)
427 #ifdef CONFIG_ZONE_DMA32
428 return zone == zone->zone_pgdat->node_zones + ZONE_DMA32;
434 static inline int is_dma(struct zone *zone)
436 return zone == zone->zone_pgdat->node_zones + ZONE_DMA;
439 /* These two functions are used to setup the per zone pages min values */
442 int min_free_kbytes_sysctl_handler(struct ctl_table *, int, struct file *,
443 void __user *, size_t *, loff_t *);
444 extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1];
445 int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int, struct file *,
446 void __user *, size_t *, loff_t *);
447 int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *, int, struct file *,
448 void __user *, size_t *, loff_t *);
449 int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *, int,
450 struct file *, void __user *, size_t *, loff_t *);
452 #include <linux/topology.h>
453 /* Returns the number of the current Node. */
455 #define numa_node_id() (cpu_to_node(raw_smp_processor_id()))
458 #ifndef CONFIG_NEED_MULTIPLE_NODES
460 extern struct pglist_data contig_page_data;
461 #define NODE_DATA(nid) (&contig_page_data)
462 #define NODE_MEM_MAP(nid) mem_map
463 #define MAX_NODES_SHIFT 1
465 #else /* CONFIG_NEED_MULTIPLE_NODES */
467 #include <asm/mmzone.h>
469 #endif /* !CONFIG_NEED_MULTIPLE_NODES */
471 extern struct pglist_data *first_online_pgdat(void);
472 extern struct pglist_data *next_online_pgdat(struct pglist_data *pgdat);
473 extern struct zone *next_zone(struct zone *zone);
476 * for_each_pgdat - helper macro to iterate over all nodes
477 * @pgdat - pointer to a pg_data_t variable
479 #define for_each_online_pgdat(pgdat) \
480 for (pgdat = first_online_pgdat(); \
482 pgdat = next_online_pgdat(pgdat))
484 * for_each_zone - helper macro to iterate over all memory zones
485 * @zone - pointer to struct zone variable
487 * The user only needs to declare the zone variable, for_each_zone
490 #define for_each_zone(zone) \
491 for (zone = (first_online_pgdat())->node_zones; \
493 zone = next_zone(zone))
495 #ifdef CONFIG_SPARSEMEM
496 #include <asm/sparsemem.h>
499 #if BITS_PER_LONG == 32
501 * with 32 bit page->flags field, we reserve 9 bits for node/zone info.
502 * there are 4 zones (3 bits) and this leaves 9-3=6 bits for nodes.
504 #define FLAGS_RESERVED 9
506 #elif BITS_PER_LONG == 64
508 * with 64 bit flags field, there's plenty of room.
510 #define FLAGS_RESERVED 32
514 #error BITS_PER_LONG not defined
518 #ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
519 #define early_pfn_to_nid(nid) (0UL)
522 #ifdef CONFIG_FLATMEM
523 #define pfn_to_nid(pfn) (0)
526 #define pfn_to_section_nr(pfn) ((pfn) >> PFN_SECTION_SHIFT)
527 #define section_nr_to_pfn(sec) ((sec) << PFN_SECTION_SHIFT)
529 #ifdef CONFIG_SPARSEMEM
532 * SECTION_SHIFT #bits space required to store a section #
534 * PA_SECTION_SHIFT physical address to/from section number
535 * PFN_SECTION_SHIFT pfn to/from section number
537 #define SECTIONS_SHIFT (MAX_PHYSMEM_BITS - SECTION_SIZE_BITS)
539 #define PA_SECTION_SHIFT (SECTION_SIZE_BITS)
540 #define PFN_SECTION_SHIFT (SECTION_SIZE_BITS - PAGE_SHIFT)
542 #define NR_MEM_SECTIONS (1UL << SECTIONS_SHIFT)
544 #define PAGES_PER_SECTION (1UL << PFN_SECTION_SHIFT)
545 #define PAGE_SECTION_MASK (~(PAGES_PER_SECTION-1))
547 #if (MAX_ORDER - 1 + PAGE_SHIFT) > SECTION_SIZE_BITS
548 #error Allocator MAX_ORDER exceeds SECTION_SIZE
554 * This is, logically, a pointer to an array of struct
555 * pages. However, it is stored with some other magic.
556 * (see sparse.c::sparse_init_one_section())
558 * Additionally during early boot we encode node id of
559 * the location of the section here to guide allocation.
560 * (see sparse.c::memory_present())
562 * Making it a UL at least makes someone do a cast
563 * before using it wrong.
565 unsigned long section_mem_map;
568 #ifdef CONFIG_SPARSEMEM_EXTREME
569 #define SECTIONS_PER_ROOT (PAGE_SIZE / sizeof (struct mem_section))
571 #define SECTIONS_PER_ROOT 1
574 #define SECTION_NR_TO_ROOT(sec) ((sec) / SECTIONS_PER_ROOT)
575 #define NR_SECTION_ROOTS (NR_MEM_SECTIONS / SECTIONS_PER_ROOT)
576 #define SECTION_ROOT_MASK (SECTIONS_PER_ROOT - 1)
578 #ifdef CONFIG_SPARSEMEM_EXTREME
579 extern struct mem_section *mem_section[NR_SECTION_ROOTS];
581 extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT];
584 static inline struct mem_section *__nr_to_section(unsigned long nr)
586 if (!mem_section[SECTION_NR_TO_ROOT(nr)])
588 return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK];
590 extern int __section_nr(struct mem_section* ms);
593 * We use the lower bits of the mem_map pointer to store
594 * a little bit of information. There should be at least
595 * 3 bits here due to 32-bit alignment.
597 #define SECTION_MARKED_PRESENT (1UL<<0)
598 #define SECTION_HAS_MEM_MAP (1UL<<1)
599 #define SECTION_MAP_LAST_BIT (1UL<<2)
600 #define SECTION_MAP_MASK (~(SECTION_MAP_LAST_BIT-1))
601 #define SECTION_NID_SHIFT 2
603 static inline struct page *__section_mem_map_addr(struct mem_section *section)
605 unsigned long map = section->section_mem_map;
606 map &= SECTION_MAP_MASK;
607 return (struct page *)map;
610 static inline int valid_section(struct mem_section *section)
612 return (section && (section->section_mem_map & SECTION_MARKED_PRESENT));
615 static inline int section_has_mem_map(struct mem_section *section)
617 return (section && (section->section_mem_map & SECTION_HAS_MEM_MAP));
620 static inline int valid_section_nr(unsigned long nr)
622 return valid_section(__nr_to_section(nr));
625 static inline struct mem_section *__pfn_to_section(unsigned long pfn)
627 return __nr_to_section(pfn_to_section_nr(pfn));
630 static inline int pfn_valid(unsigned long pfn)
632 if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
634 return valid_section(__nr_to_section(pfn_to_section_nr(pfn)));
638 * These are _only_ used during initialisation, therefore they
639 * can use __initdata ... They could have names to indicate
643 #define pfn_to_nid(pfn) \
645 unsigned long __pfn_to_nid_pfn = (pfn); \
646 page_to_nid(pfn_to_page(__pfn_to_nid_pfn)); \
649 #define pfn_to_nid(pfn) (0)
652 #define early_pfn_valid(pfn) pfn_valid(pfn)
653 void sparse_init(void);
655 #define sparse_init() do {} while (0)
656 #define sparse_index_init(_sec, _nid) do {} while (0)
657 #endif /* CONFIG_SPARSEMEM */
659 #ifndef early_pfn_valid
660 #define early_pfn_valid(pfn) (1)
663 void memory_present(int nid, unsigned long start, unsigned long end);
664 unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long);
666 #endif /* !__ASSEMBLY__ */
667 #endif /* __KERNEL__ */
668 #endif /* _LINUX_MMZONE_H */