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Diffstat (limited to 'include/linux/mmzone.h')
| -rw-r--r-- | include/linux/mmzone.h | 426 |
1 files changed, 426 insertions, 0 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h new file mode 100644 index 00000000000..e530c6c092f --- /dev/null +++ b/include/linux/mmzone.h @@ -0,0 +1,426 @@ +#ifndef _LINUX_MMZONE_H +#define _LINUX_MMZONE_H + +#ifdef __KERNEL__ +#ifndef __ASSEMBLY__ + +#include <linux/config.h> +#include <linux/spinlock.h> +#include <linux/list.h> +#include <linux/wait.h> +#include <linux/cache.h> +#include <linux/threads.h> +#include <linux/numa.h> +#include <linux/init.h> +#include <asm/atomic.h> + +/* Free memory management - zoned buddy allocator. */ +#ifndef CONFIG_FORCE_MAX_ZONEORDER +#define MAX_ORDER 11 +#else +#define MAX_ORDER CONFIG_FORCE_MAX_ZONEORDER +#endif + +struct free_area { + struct list_head free_list; + unsigned long nr_free; +}; + +struct pglist_data; + +/* + * zone->lock and zone->lru_lock are two of the hottest locks in the kernel. + * So add a wild amount of padding here to ensure that they fall into separate + * cachelines. There are very few zone structures in the machine, so space + * consumption is not a concern here. + */ +#if defined(CONFIG_SMP) +struct zone_padding { + char x[0]; +} ____cacheline_maxaligned_in_smp; +#define ZONE_PADDING(name) struct zone_padding name; +#else +#define ZONE_PADDING(name) +#endif + +struct per_cpu_pages { + int count; /* number of pages in the list */ + int low; /* low watermark, refill needed */ + int high; /* high watermark, emptying needed */ + int batch; /* chunk size for buddy add/remove */ + struct list_head list; /* the list of pages */ +}; + +struct per_cpu_pageset { + struct per_cpu_pages pcp[2]; /* 0: hot. 1: cold */ +#ifdef CONFIG_NUMA + unsigned long numa_hit; /* allocated in intended node */ + unsigned long numa_miss; /* allocated in non intended node */ + unsigned long numa_foreign; /* was intended here, hit elsewhere */ + unsigned long interleave_hit; /* interleaver prefered this zone */ + unsigned long local_node; /* allocation from local node */ + unsigned long other_node; /* allocation from other node */ +#endif +} ____cacheline_aligned_in_smp; + +#define ZONE_DMA 0 +#define ZONE_NORMAL 1 +#define ZONE_HIGHMEM 2 + +#define MAX_NR_ZONES 3 /* Sync this with ZONES_SHIFT */ +#define ZONES_SHIFT 2 /* ceil(log2(MAX_NR_ZONES)) */ + + +/* + * When a memory allocation must conform to specific limitations (such + * as being suitable for DMA) the caller will pass in hints to the + * allocator in the gfp_mask, in the zone modifier bits. These bits + * are used to select a priority ordered list of memory zones which + * match the requested limits. GFP_ZONEMASK defines which bits within + * the gfp_mask should be considered as zone modifiers. Each valid + * combination of the zone modifier bits has a corresponding list + * of zones (in node_zonelists). Thus for two zone modifiers there + * will be a maximum of 4 (2 ** 2) zonelists, for 3 modifiers there will + * be 8 (2 ** 3) zonelists. GFP_ZONETYPES defines the number of possible + * combinations of zone modifiers in "zone modifier space". + */ +#define GFP_ZONEMASK 0x03 +/* + * As an optimisation any zone modifier bits which are only valid when + * no other zone modifier bits are set (loners) should be placed in + * the highest order bits of this field. This allows us to reduce the + * extent of the zonelists thus saving space. For example in the case + * of three zone modifier bits, we could require up to eight zonelists. + * If the left most zone modifier is a "loner" then the highest valid + * zonelist would be four allowing us to allocate only five zonelists. + * Use the first form when the left most bit is not a "loner", otherwise + * use the second. + */ +/* #define GFP_ZONETYPES (GFP_ZONEMASK + 1) */ /* Non-loner */ +#define GFP_ZONETYPES ((GFP_ZONEMASK + 1) / 2 + 1) /* Loner */ + +/* + * On machines where it is needed (eg PCs) we divide physical memory + * into multiple physical zones. On a PC we have 3 zones: + * + * ZONE_DMA < 16 MB ISA DMA capable memory + * ZONE_NORMAL 16-896 MB direct mapped by the kernel + * ZONE_HIGHMEM > 896 MB only page cache and user processes + */ + +struct zone { + /* Fields commonly accessed by the page allocator */ + unsigned long free_pages; + unsigned long pages_min, pages_low, pages_high; + /* + * We don't know if the memory that we're going to allocate will be freeable + * or/and it will be released eventually, so to avoid totally wasting several + * GB of ram we must reserve some of the lower zone memory (otherwise we risk + * to run OOM on the lower zones despite there's tons of freeable ram + * on the higher zones). This array is recalculated at runtime if the + * sysctl_lowmem_reserve_ratio sysctl changes. + */ + unsigned long lowmem_reserve[MAX_NR_ZONES]; + + struct per_cpu_pageset pageset[NR_CPUS]; + + /* + * free areas of different sizes + */ + spinlock_t lock; + struct free_area free_area[MAX_ORDER]; + + + ZONE_PADDING(_pad1_) + + /* Fields commonly accessed by the page reclaim scanner */ + spinlock_t lru_lock; + struct list_head active_list; + struct list_head inactive_list; + unsigned long nr_scan_active; + unsigned long nr_scan_inactive; + unsigned long nr_active; + unsigned long nr_inactive; + unsigned long pages_scanned; /* since last reclaim */ + int all_unreclaimable; /* All pages pinned */ + + /* + * prev_priority holds the scanning priority for this zone. It is + * defined as the scanning priority at which we achieved our reclaim + * target at the previous try_to_free_pages() or balance_pgdat() + * invokation. + * + * We use prev_priority as a measure of how much stress page reclaim is + * under - it drives the swappiness decision: whether to unmap mapped + * pages. + * + * temp_priority is used to remember the scanning priority at which + * this zone was successfully refilled to free_pages == pages_high. + * + * Access to both these fields is quite racy even on uniprocessor. But + * it is expected to average out OK. + */ + int temp_priority; + int prev_priority; + + + ZONE_PADDING(_pad2_) + /* Rarely used or read-mostly fields */ + + /* + * wait_table -- the array holding the hash table + * wait_table_size -- the size of the hash table array + * wait_table_bits -- wait_table_size == (1 << wait_table_bits) + * + * The purpose of all these is to keep track of the people + * waiting for a page to become available and make them + * runnable again when possible. The trouble is that this + * consumes a lot of space, especially when so few things + * wait on pages at a given time. So instead of using + * per-page waitqueues, we use a waitqueue hash table. + * + * The bucket discipline is to sleep on the same queue when + * colliding and wake all in that wait queue when removing. + * When something wakes, it must check to be sure its page is + * truly available, a la thundering herd. The cost of a + * collision is great, but given the expected load of the + * table, they should be so rare as to be outweighed by the + * benefits from the saved space. + * + * __wait_on_page_locked() and unlock_page() in mm/filemap.c, are the + * primary users of these fields, and in mm/page_alloc.c + * free_area_init_core() performs the initialization of them. + */ + wait_queue_head_t * wait_table; + unsigned long wait_table_size; + unsigned long wait_table_bits; + + /* + * Discontig memory support fields. + */ + struct pglist_data *zone_pgdat; + struct page *zone_mem_map; + /* zone_start_pfn == zone_start_paddr >> PAGE_SHIFT */ + unsigned long zone_start_pfn; + + unsigned long spanned_pages; /* total size, including holes */ + unsigned long present_pages; /* amount of memory (excluding holes) */ + + /* + * rarely used fields: + */ + char *name; +} ____cacheline_maxaligned_in_smp; + + +/* + * The "priority" of VM scanning is how much of the queues we will scan in one + * go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the + * queues ("queue_length >> 12") during an aging round. + */ +#define DEF_PRIORITY 12 + +/* + * One allocation request operates on a zonelist. A zonelist + * is a list of zones, the first one is the 'goal' of the + * allocation, the other zones are fallback zones, in decreasing + * priority. + * + * Right now a zonelist takes up less than a cacheline. We never + * modify it apart from boot-up, and only a few indices are used, + * so despite the zonelist table being relatively big, the cache + * footprint of this construct is very small. + */ +struct zonelist { + struct zone *zones[MAX_NUMNODES * MAX_NR_ZONES + 1]; // NULL delimited +}; + + +/* + * The pg_data_t structure is used in machines with CONFIG_DISCONTIGMEM + * (mostly NUMA machines?) to denote a higher-level memory zone than the + * zone denotes. + * + * On NUMA machines, each NUMA node would have a pg_data_t to describe + * it's memory layout. + * + * Memory statistics and page replacement data structures are maintained on a + * per-zone basis. + */ +struct bootmem_data; +typedef struct pglist_data { + struct zone node_zones[MAX_NR_ZONES]; + struct zonelist node_zonelists[GFP_ZONETYPES]; + int nr_zones; + struct page *node_mem_map; + struct bootmem_data *bdata; + unsigned long node_start_pfn; + unsigned long node_present_pages; /* total number of physical pages */ + unsigned long node_spanned_pages; /* total size of physical page + range, including holes */ + int node_id; + struct pglist_data *pgdat_next; + wait_queue_head_t kswapd_wait; + struct task_struct *kswapd; + int kswapd_max_order; +} pg_data_t; + +#define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages) +#define node_spanned_pages(nid) (NODE_DATA(nid)->node_spanned_pages) + +extern struct pglist_data *pgdat_list; + +void __get_zone_counts(unsigned long *active, unsigned long *inactive, + unsigned long *free, struct pglist_data *pgdat); +void get_zone_counts(unsigned long *active, unsigned long *inactive, + unsigned long *free); +void build_all_zonelists(void); +void wakeup_kswapd(struct zone *zone, int order); +int zone_watermark_ok(struct zone *z, int order, unsigned long mark, + int alloc_type, int can_try_harder, int gfp_high); + +#ifdef CONFIG_HAVE_MEMORY_PRESENT +void memory_present(int nid, unsigned long start, unsigned long end); +#else +static inline void memory_present(int nid, unsigned long start, unsigned long end) {} +#endif + +#ifdef CONFIG_NEED_NODE_MEMMAP_SIZE +unsigned long __init node_memmap_size_bytes(int, unsigned long, unsigned long); +#endif + +/* + * zone_idx() returns 0 for the ZONE_DMA zone, 1 for the ZONE_NORMAL zone, etc. + */ +#define zone_idx(zone) ((zone) - (zone)->zone_pgdat->node_zones) + +/** + * for_each_pgdat - helper macro to iterate over all nodes + * @pgdat - pointer to a pg_data_t variable + * + * Meant to help with common loops of the form + * pgdat = pgdat_list; + * while(pgdat) { + * ... + * pgdat = pgdat->pgdat_next; + * } + */ +#define for_each_pgdat(pgdat) \ + for (pgdat = pgdat_list; pgdat; pgdat = pgdat->pgdat_next) + +/* + * next_zone - helper magic for for_each_zone() + * Thanks to William Lee Irwin III for this piece of ingenuity. + */ +static inline struct zone *next_zone(struct zone *zone) +{ + pg_data_t *pgdat = zone->zone_pgdat; + + if (zone < pgdat->node_zones + MAX_NR_ZONES - 1) + zone++; + else if (pgdat->pgdat_next) { + pgdat = pgdat->pgdat_next; + zone = pgdat->node_zones; + } else + zone = NULL; + + return zone; +} + +/** + * for_each_zone - helper macro to iterate over all memory zones + * @zone - pointer to struct zone variable + * + * The user only needs to declare the zone variable, for_each_zone + * fills it in. This basically means for_each_zone() is an + * easier to read version of this piece of code: + * + * for (pgdat = pgdat_list; pgdat; pgdat = pgdat->node_next) + * for (i = 0; i < MAX_NR_ZONES; ++i) { + * struct zone * z = pgdat->node_zones + i; + * ... + * } + * } + */ +#define for_each_zone(zone) \ + for (zone = pgdat_list->node_zones; zone; zone = next_zone(zone)) + +static inline int is_highmem_idx(int idx) +{ + return (idx == ZONE_HIGHMEM); +} + +static inline int is_normal_idx(int idx) +{ + return (idx == ZONE_NORMAL); +} +/** + * is_highmem - helper function to quickly check if a struct zone is a + * highmem zone or not. This is an attempt to keep references + * to ZONE_{DMA/NORMAL/HIGHMEM/etc} in general code to a minimum. + * @zone - pointer to struct zone variable + */ +static inline int is_highmem(struct zone *zone) +{ + return zone == zone->zone_pgdat->node_zones + ZONE_HIGHMEM; +} + +static inline int is_normal(struct zone *zone) +{ + return zone == zone->zone_pgdat->node_zones + ZONE_NORMAL; +} + +/* These two functions are used to setup the per zone pages min values */ +struct ctl_table; +struct file; +int min_free_kbytes_sysctl_handler(struct ctl_table *, int, struct file *, + void __user *, size_t *, loff_t *); +extern int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1]; +int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *, int, struct file *, + void __user *, size_t *, loff_t *); + +#include <linux/topology.h> +/* Returns the number of the current Node. */ +#define numa_node_id() (cpu_to_node(_smp_processor_id())) + +#ifndef CONFIG_DISCONTIGMEM + +extern struct pglist_data contig_page_data; +#define NODE_DATA(nid) (&contig_page_data) +#define NODE_MEM_MAP(nid) mem_map +#define MAX_NODES_SHIFT 1 +#define pfn_to_nid(pfn) (0) + +#else /* CONFIG_DISCONTIGMEM */ + +#include <asm/mmzone.h> + +#if BITS_PER_LONG == 32 || defined(ARCH_HAS_ATOMIC_UNSIGNED) +/* + * with 32 bit page->flags field, we reserve 8 bits for node/zone info. + * there are 3 zones (2 bits) and this leaves 8-2=6 bits for nodes. + */ +#define MAX_NODES_SHIFT 6 +#elif BITS_PER_LONG == 64 +/* + * with 64 bit flags field, there's plenty of room. + */ +#define MAX_NODES_SHIFT 10 +#endif + +#endif /* !CONFIG_DISCONTIGMEM */ + +#if NODES_SHIFT > MAX_NODES_SHIFT +#error NODES_SHIFT > MAX_NODES_SHIFT +#endif + +/* There are currently 3 zones: DMA, Normal & Highmem, thus we need 2 bits */ +#define MAX_ZONES_SHIFT 2 + +#if ZONES_SHIFT > MAX_ZONES_SHIFT +#error ZONES_SHIFT > MAX_ZONES_SHIFT +#endif + +#endif /* !__ASSEMBLY__ */ +#endif /* __KERNEL__ */ +#endif /* _LINUX_MMZONE_H */ |