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-rw-r--r--include/linux/swap.h293
1 files changed, 293 insertions, 0 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h
new file mode 100644
index 000000000000..3bbc41be9bd0
--- /dev/null
+++ b/include/linux/swap.h
@@ -0,0 +1,293 @@
+#ifndef _LINUX_SWAP_H
+#define _LINUX_SWAP_H
+
+#include <linux/config.h>
+#include <linux/spinlock.h>
+#include <linux/linkage.h>
+#include <linux/mmzone.h>
+#include <linux/list.h>
+#include <linux/sched.h>
+#include <asm/atomic.h>
+#include <asm/page.h>
+
+#define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */
+#define SWAP_FLAG_PRIO_MASK 0x7fff
+#define SWAP_FLAG_PRIO_SHIFT 0
+
+static inline int current_is_kswapd(void)
+{
+ return current->flags & PF_KSWAPD;
+}
+
+/*
+ * MAX_SWAPFILES defines the maximum number of swaptypes: things which can
+ * be swapped to. The swap type and the offset into that swap type are
+ * encoded into pte's and into pgoff_t's in the swapcache. Using five bits
+ * for the type means that the maximum number of swapcache pages is 27 bits
+ * on 32-bit-pgoff_t architectures. And that assumes that the architecture packs
+ * the type/offset into the pte as 5/27 as well.
+ */
+#define MAX_SWAPFILES_SHIFT 5
+#define MAX_SWAPFILES (1 << MAX_SWAPFILES_SHIFT)
+
+/*
+ * Magic header for a swap area. The first part of the union is
+ * what the swap magic looks like for the old (limited to 128MB)
+ * swap area format, the second part of the union adds - in the
+ * old reserved area - some extra information. Note that the first
+ * kilobyte is reserved for boot loader or disk label stuff...
+ *
+ * Having the magic at the end of the PAGE_SIZE makes detecting swap
+ * areas somewhat tricky on machines that support multiple page sizes.
+ * For 2.5 we'll probably want to move the magic to just beyond the
+ * bootbits...
+ */
+union swap_header {
+ struct {
+ char reserved[PAGE_SIZE - 10];
+ char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
+ } magic;
+ struct {
+ char bootbits[1024]; /* Space for disklabel etc. */
+ unsigned int version;
+ unsigned int last_page;
+ unsigned int nr_badpages;
+ unsigned int padding[125];
+ unsigned int badpages[1];
+ } info;
+};
+
+ /* A swap entry has to fit into a "unsigned long", as
+ * the entry is hidden in the "index" field of the
+ * swapper address space.
+ */
+typedef struct {
+ unsigned long val;
+} swp_entry_t;
+
+/*
+ * current->reclaim_state points to one of these when a task is running
+ * memory reclaim
+ */
+struct reclaim_state {
+ unsigned long reclaimed_slab;
+};
+
+#ifdef __KERNEL__
+
+struct address_space;
+struct sysinfo;
+struct writeback_control;
+struct zone;
+
+/*
+ * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
+ * disk blocks. A list of swap extents maps the entire swapfile. (Where the
+ * term `swapfile' refers to either a blockdevice or an IS_REG file. Apart
+ * from setup, they're handled identically.
+ *
+ * We always assume that blocks are of size PAGE_SIZE.
+ */
+struct swap_extent {
+ struct list_head list;
+ pgoff_t start_page;
+ pgoff_t nr_pages;
+ sector_t start_block;
+};
+
+/*
+ * Max bad pages in the new format..
+ */
+#define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
+#define MAX_SWAP_BADPAGES \
+ ((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))
+
+enum {
+ SWP_USED = (1 << 0), /* is slot in swap_info[] used? */
+ SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */
+ SWP_ACTIVE = (SWP_USED | SWP_WRITEOK),
+};
+
+#define SWAP_CLUSTER_MAX 32
+
+#define SWAP_MAP_MAX 0x7fff
+#define SWAP_MAP_BAD 0x8000
+
+/*
+ * The in-memory structure used to track swap areas.
+ * extent_list.prev points at the lowest-index extent. That list is
+ * sorted.
+ */
+struct swap_info_struct {
+ unsigned int flags;
+ spinlock_t sdev_lock;
+ struct file *swap_file;
+ struct block_device *bdev;
+ struct list_head extent_list;
+ int nr_extents;
+ struct swap_extent *curr_swap_extent;
+ unsigned old_block_size;
+ unsigned short * swap_map;
+ unsigned int lowest_bit;
+ unsigned int highest_bit;
+ unsigned int cluster_next;
+ unsigned int cluster_nr;
+ int prio; /* swap priority */
+ int pages;
+ unsigned long max;
+ unsigned long inuse_pages;
+ int next; /* next entry on swap list */
+};
+
+struct swap_list_t {
+ int head; /* head of priority-ordered swapfile list */
+ int next; /* swapfile to be used next */
+};
+
+/* Swap 50% full? Release swapcache more aggressively.. */
+#define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
+
+/* linux/mm/oom_kill.c */
+extern void out_of_memory(unsigned int __nocast gfp_mask);
+
+/* linux/mm/memory.c */
+extern void swapin_readahead(swp_entry_t, unsigned long, struct vm_area_struct *);
+
+/* linux/mm/page_alloc.c */
+extern unsigned long totalram_pages;
+extern unsigned long totalhigh_pages;
+extern long nr_swap_pages;
+extern unsigned int nr_free_pages(void);
+extern unsigned int nr_free_pages_pgdat(pg_data_t *pgdat);
+extern unsigned int nr_free_buffer_pages(void);
+extern unsigned int nr_free_pagecache_pages(void);
+
+/* linux/mm/swap.c */
+extern void FASTCALL(lru_cache_add(struct page *));
+extern void FASTCALL(lru_cache_add_active(struct page *));
+extern void FASTCALL(activate_page(struct page *));
+extern void FASTCALL(mark_page_accessed(struct page *));
+extern void lru_add_drain(void);
+extern int rotate_reclaimable_page(struct page *page);
+extern void swap_setup(void);
+
+/* linux/mm/vmscan.c */
+extern int try_to_free_pages(struct zone **, unsigned int, unsigned int);
+extern int shrink_all_memory(int);
+extern int vm_swappiness;
+
+#ifdef CONFIG_MMU
+/* linux/mm/shmem.c */
+extern int shmem_unuse(swp_entry_t entry, struct page *page);
+#endif /* CONFIG_MMU */
+
+extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *);
+
+#ifdef CONFIG_SWAP
+/* linux/mm/page_io.c */
+extern int swap_readpage(struct file *, struct page *);
+extern int swap_writepage(struct page *page, struct writeback_control *wbc);
+extern int rw_swap_page_sync(int, swp_entry_t, struct page *);
+
+/* linux/mm/swap_state.c */
+extern struct address_space swapper_space;
+#define total_swapcache_pages swapper_space.nrpages
+extern void show_swap_cache_info(void);
+extern int add_to_swap(struct page *);
+extern void __delete_from_swap_cache(struct page *);
+extern void delete_from_swap_cache(struct page *);
+extern int move_to_swap_cache(struct page *, swp_entry_t);
+extern int move_from_swap_cache(struct page *, unsigned long,
+ struct address_space *);
+extern void free_page_and_swap_cache(struct page *);
+extern void free_pages_and_swap_cache(struct page **, int);
+extern struct page * lookup_swap_cache(swp_entry_t);
+extern struct page * read_swap_cache_async(swp_entry_t, struct vm_area_struct *vma,
+ unsigned long addr);
+/* linux/mm/swapfile.c */
+extern long total_swap_pages;
+extern unsigned int nr_swapfiles;
+extern struct swap_info_struct swap_info[];
+extern void si_swapinfo(struct sysinfo *);
+extern swp_entry_t get_swap_page(void);
+extern int swap_duplicate(swp_entry_t);
+extern int valid_swaphandles(swp_entry_t, unsigned long *);
+extern void swap_free(swp_entry_t);
+extern void free_swap_and_cache(swp_entry_t);
+extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
+extern struct swap_info_struct *get_swap_info_struct(unsigned);
+extern int can_share_swap_page(struct page *);
+extern int remove_exclusive_swap_page(struct page *);
+struct backing_dev_info;
+
+extern struct swap_list_t swap_list;
+extern spinlock_t swaplock;
+
+#define swap_list_lock() spin_lock(&swaplock)
+#define swap_list_unlock() spin_unlock(&swaplock)
+#define swap_device_lock(p) spin_lock(&p->sdev_lock)
+#define swap_device_unlock(p) spin_unlock(&p->sdev_lock)
+
+/* linux/mm/thrash.c */
+extern struct mm_struct * swap_token_mm;
+extern unsigned long swap_token_default_timeout;
+extern void grab_swap_token(void);
+extern void __put_swap_token(struct mm_struct *);
+
+static inline int has_swap_token(struct mm_struct *mm)
+{
+ return (mm == swap_token_mm);
+}
+
+static inline void put_swap_token(struct mm_struct *mm)
+{
+ if (has_swap_token(mm))
+ __put_swap_token(mm);
+}
+
+#else /* CONFIG_SWAP */
+
+#define total_swap_pages 0
+#define total_swapcache_pages 0UL
+
+#define si_swapinfo(val) \
+ do { (val)->freeswap = (val)->totalswap = 0; } while (0)
+#define free_page_and_swap_cache(page) \
+ page_cache_release(page)
+#define free_pages_and_swap_cache(pages, nr) \
+ release_pages((pages), (nr), 0);
+
+#define show_swap_cache_info() /*NOTHING*/
+#define free_swap_and_cache(swp) /*NOTHING*/
+#define swap_duplicate(swp) /*NOTHING*/
+#define swap_free(swp) /*NOTHING*/
+#define read_swap_cache_async(swp,vma,addr) NULL
+#define lookup_swap_cache(swp) NULL
+#define valid_swaphandles(swp, off) 0
+#define can_share_swap_page(p) 0
+#define move_to_swap_cache(p, swp) 1
+#define move_from_swap_cache(p, i, m) 1
+#define __delete_from_swap_cache(p) /*NOTHING*/
+#define delete_from_swap_cache(p) /*NOTHING*/
+#define swap_token_default_timeout 0
+
+static inline int remove_exclusive_swap_page(struct page *p)
+{
+ return 0;
+}
+
+static inline swp_entry_t get_swap_page(void)
+{
+ swp_entry_t entry;
+ entry.val = 0;
+ return entry;
+}
+
+/* linux/mm/thrash.c */
+#define put_swap_token(x) do { } while(0)
+#define grab_swap_token() do { } while(0)
+#define has_swap_token(x) 0
+
+#endif /* CONFIG_SWAP */
+#endif /* __KERNEL__*/
+#endif /* _LINUX_SWAP_H */