1 files changed, 426 insertions, 0 deletions

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
new file mode 100644
index 000000000000..e530c6c092f1
--- /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 */