Initial import

1 files changed, 549 insertions, 0 deletions

diff --git a/include/linux/swap.h b/include/linux/swap.h
new file mode 100644
index 000000000..1f710a1f8
--- /dev/null
+++ b/include/linux/swap.h
@@ -0,0 +1,549 @@
+#ifndef _LINUX_SWAP_H
+#define _LINUX_SWAP_H
+
+#include <linux/spinlock.h>
+#include <linux/linkage.h>
+#include <linux/mmzone.h>
+#include <linux/list.h>
+#include <linux/memcontrol.h>
+#include <linux/sched.h>
+#include <linux/node.h>
+#include <linux/fs.h>
+#include <linux/atomic.h>
+#include <linux/page-flags.h>
+#include <asm/page.h>
+
+struct notifier_block;
+
+struct bio;
+
+#define SWAP_FLAG_PREFER	0x8000	/* set if swap priority specified */
+#define SWAP_FLAG_PRIO_MASK	0x7fff
+#define SWAP_FLAG_PRIO_SHIFT	0
+#define SWAP_FLAG_DISCARD	0x10000 /* enable discard for swap */
+#define SWAP_FLAG_DISCARD_ONCE	0x20000 /* discard swap area at swapon-time */
+#define SWAP_FLAG_DISCARD_PAGES 0x40000 /* discard page-clusters after use */
+
+#define SWAP_FLAGS_VALID	(SWAP_FLAG_PRIO_MASK | SWAP_FLAG_PREFER | \
+				 SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE | \
+				 SWAP_FLAG_DISCARD_PAGES)
+
+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
+
+/*
+ * Use some of the swap files numbers for other purposes. This
+ * is a convenient way to hook into the VM to trigger special
+ * actions on faults.
+ */
+
+/*
+ * NUMA node memory migration support
+ */
+#ifdef CONFIG_MIGRATION
+#define SWP_MIGRATION_NUM 2
+#define SWP_MIGRATION_READ	(MAX_SWAPFILES + SWP_HWPOISON_NUM)
+#define SWP_MIGRATION_WRITE	(MAX_SWAPFILES + SWP_HWPOISON_NUM + 1)
+#else
+#define SWP_MIGRATION_NUM 0
+#endif
+
+/*
+ * Handling of hardware poisoned pages with memory corruption.
+ */
+#ifdef CONFIG_MEMORY_FAILURE
+#define SWP_HWPOISON_NUM 1
+#define SWP_HWPOISON		MAX_SWAPFILES
+#else
+#define SWP_HWPOISON_NUM 0
+#endif
+
+#define MAX_SWAPFILES \
+	((1 << MAX_SWAPFILES_SHIFT) - SWP_MIGRATION_NUM - SWP_HWPOISON_NUM)
+
+/*
+ * 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. */
+		__u32		version;
+		__u32		last_page;
+		__u32		nr_badpages;
+		unsigned char	sws_uuid[16];
+		unsigned char	sws_volume[16];
+		__u32		padding[117];
+		__u32		badpages[1];
+	} info;
+};
+
+/*
+ * 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_DISCARDABLE = (1 << 2),	/* blkdev support discard */
+	SWP_DISCARDING	= (1 << 3),	/* now discarding a free cluster */
+	SWP_SOLIDSTATE	= (1 << 4),	/* blkdev seeks are cheap */
+	SWP_CONTINUED	= (1 << 5),	/* swap_map has count continuation */
+	SWP_BLKDEV	= (1 << 6),	/* its a block device */
+	SWP_FILE	= (1 << 7),	/* set after swap_activate success */
+	SWP_AREA_DISCARD = (1 << 8),	/* single-time swap area discards */
+	SWP_PAGE_DISCARD = (1 << 9),	/* freed swap page-cluster discards */
+					/* add others here before... */
+	SWP_SCANNING	= (1 << 10),	/* refcount in scan_swap_map */
+};
+
+#define SWAP_CLUSTER_MAX 32UL
+#define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX
+
+/*
+ * Ratio between zone->managed_pages and the "gap" that above the per-zone
+ * "high_wmark". While balancing nodes, We allow kswapd to shrink zones that
+ * do not meet the (high_wmark + gap) watermark, even which already met the
+ * high_wmark, in order to provide better per-zone lru behavior. We are ok to
+ * spend not more than 1% of the memory for this zone balancing "gap".
+ */
+#define KSWAPD_ZONE_BALANCE_GAP_RATIO 100
+
+#define SWAP_MAP_MAX	0x3e	/* Max duplication count, in first swap_map */
+#define SWAP_MAP_BAD	0x3f	/* Note pageblock is bad, in first swap_map */
+#define SWAP_HAS_CACHE	0x40	/* Flag page is cached, in first swap_map */
+#define SWAP_CONT_MAX	0x7f	/* Max count, in each swap_map continuation */
+#define COUNT_CONTINUED	0x80	/* See swap_map continuation for full count */
+#define SWAP_MAP_SHMEM	0xbf	/* Owned by shmem/tmpfs, in first swap_map */
+
+/*
+ * We use this to track usage of a cluster. A cluster is a block of swap disk
+ * space with SWAPFILE_CLUSTER pages long and naturally aligns in disk. All
+ * free clusters are organized into a list. We fetch an entry from the list to
+ * get a free cluster.
+ *
+ * The data field stores next cluster if the cluster is free or cluster usage
+ * counter otherwise. The flags field determines if a cluster is free. This is
+ * protected by swap_info_struct.lock.
+ */
+struct swap_cluster_info {
+	unsigned int data:24;
+	unsigned int flags:8;
+};
+#define CLUSTER_FLAG_FREE 1 /* This cluster is free */
+#define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */
+
+/*
+ * We assign a cluster to each CPU, so each CPU can allocate swap entry from
+ * its own cluster and swapout sequentially. The purpose is to optimize swapout
+ * throughput.
+ */
+struct percpu_cluster {
+	struct swap_cluster_info index; /* Current cluster index */
+	unsigned int next; /* Likely next allocation offset */
+};
+
+/*
+ * The in-memory structure used to track swap areas.
+ */
+struct swap_info_struct {
+	unsigned long	flags;		/* SWP_USED etc: see above */
+	signed short	prio;		/* swap priority of this type */
+	struct plist_node list;		/* entry in swap_active_head */
+	struct plist_node avail_list;	/* entry in swap_avail_head */
+	signed char	type;		/* strange name for an index */
+	unsigned int	max;		/* extent of the swap_map */
+	unsigned char *swap_map;	/* vmalloc'ed array of usage counts */
+	struct swap_cluster_info *cluster_info; /* cluster info. Only for SSD */
+	struct swap_cluster_info free_cluster_head; /* free cluster list head */
+	struct swap_cluster_info free_cluster_tail; /* free cluster list tail */
+	unsigned int lowest_bit;	/* index of first free in swap_map */
+	unsigned int highest_bit;	/* index of last free in swap_map */
+	unsigned int pages;		/* total of usable pages of swap */
+	unsigned int inuse_pages;	/* number of those currently in use */
+	unsigned int cluster_next;	/* likely index for next allocation */
+	unsigned int cluster_nr;	/* countdown to next cluster search */
+	struct percpu_cluster __percpu *percpu_cluster; /* per cpu's swap location */
+	struct swap_extent *curr_swap_extent;
+	struct swap_extent first_swap_extent;
+	struct block_device *bdev;	/* swap device or bdev of swap file */
+	struct file *swap_file;		/* seldom referenced */
+	unsigned int old_block_size;	/* seldom referenced */
+#ifdef CONFIG_FRONTSWAP
+	unsigned long *frontswap_map;	/* frontswap in-use, one bit per page */
+	atomic_t frontswap_pages;	/* frontswap pages in-use counter */
+#endif
+	spinlock_t lock;		/*
+					 * protect map scan related fields like
+					 * swap_map, lowest_bit, highest_bit,
+					 * inuse_pages, cluster_next,
+					 * cluster_nr, lowest_alloc,
+					 * highest_alloc, free/discard cluster
+					 * list. other fields are only changed
+					 * at swapon/swapoff, so are protected
+					 * by swap_lock. changing flags need
+					 * hold this lock and swap_lock. If
+					 * both locks need hold, hold swap_lock
+					 * first.
+					 */
+	struct work_struct discard_work; /* discard worker */
+	struct swap_cluster_info discard_cluster_head; /* list head of discard clusters */
+	struct swap_cluster_info discard_cluster_tail; /* list tail of discard clusters */
+};
+
+/* linux/mm/workingset.c */
+void *workingset_eviction(struct address_space *mapping, struct page *page);
+bool workingset_refault(void *shadow);
+void workingset_activation(struct page *page);
+extern struct list_lru workingset_shadow_nodes;
+
+static inline unsigned int workingset_node_pages(struct radix_tree_node *node)
+{
+	return node->count & RADIX_TREE_COUNT_MASK;
+}
+
+static inline void workingset_node_pages_inc(struct radix_tree_node *node)
+{
+	node->count++;
+}
+
+static inline void workingset_node_pages_dec(struct radix_tree_node *node)
+{
+	node->count--;
+}
+
+static inline unsigned int workingset_node_shadows(struct radix_tree_node *node)
+{
+	return node->count >> RADIX_TREE_COUNT_SHIFT;
+}
+
+static inline void workingset_node_shadows_inc(struct radix_tree_node *node)
+{
+	node->count += 1U << RADIX_TREE_COUNT_SHIFT;
+}
+
+static inline void workingset_node_shadows_dec(struct radix_tree_node *node)
+{
+	node->count -= 1U << RADIX_TREE_COUNT_SHIFT;
+}
+
+/* linux/mm/page_alloc.c */
+extern unsigned long totalram_pages;
+extern unsigned long totalreserve_pages;
+extern unsigned long dirty_balance_reserve;
+extern unsigned long nr_free_buffer_pages(void);
+extern unsigned long nr_unallocated_buffer_pages(void);
+extern unsigned long nr_free_pagecache_pages(void);
+
+/* Definition of global_page_state not available yet */
+#define nr_free_pages() global_page_state(NR_FREE_PAGES)
+
+
+/* linux/mm/swap.c */
+extern void lru_cache_add(struct page *);
+extern void lru_cache_add_anon(struct page *page);
+extern void lru_cache_add_file(struct page *page);
+extern void lru_add_page_tail(struct page *page, struct page *page_tail,
+			 struct lruvec *lruvec, struct list_head *head);
+extern void activate_page(struct page *);
+extern void mark_page_accessed(struct page *);
+extern void lru_add_drain(void);
+extern void lru_add_drain_cpu(int cpu);
+extern void lru_add_drain_all(void);
+extern void rotate_reclaimable_page(struct page *page);
+extern void deactivate_file_page(struct page *page);
+extern void swap_setup(void);
+
+extern void add_page_to_unevictable_list(struct page *page);
+
+extern void lru_cache_add_active_or_unevictable(struct page *page,
+						struct vm_area_struct *vma);
+
+/* linux/mm/vmscan.c */
+extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
+					gfp_t gfp_mask, nodemask_t *mask);
+extern int __isolate_lru_page(struct page *page, isolate_mode_t mode);
+extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
+						  unsigned long nr_pages,
+						  gfp_t gfp_mask,
+						  bool may_swap);
+extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
+						gfp_t gfp_mask, bool noswap,
+						struct zone *zone,
+						unsigned long *nr_scanned);
+extern unsigned long shrink_all_memory(unsigned long nr_pages);
+extern unsigned long shrink_memory_mask(unsigned long nr_to_reclaim,
+		gfp_t mask);
+extern int vm_swappiness;
+extern int remove_mapping(struct address_space *mapping, struct page *page);
+extern unsigned long vm_total_pages;
+
+#ifdef CONFIG_NUMA
+extern int zone_reclaim_mode;
+extern int sysctl_min_unmapped_ratio;
+extern int sysctl_min_slab_ratio;
+extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
+#else
+#define zone_reclaim_mode 0
+static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
+{
+	return 0;
+}
+#endif
+
+extern int page_evictable(struct page *page);
+extern void check_move_unevictable_pages(struct page **, int nr_pages);
+
+extern int kswapd_run(int nid);
+extern void kswapd_stop(int nid);
+#ifdef CONFIG_MEMCG
+extern int mem_cgroup_swappiness(struct mem_cgroup *mem);
+#else
+static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
+{
+	return vm_swappiness;
+}
+#endif
+#ifdef CONFIG_MEMCG_SWAP
+extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry);
+extern void mem_cgroup_uncharge_swap(swp_entry_t entry);
+#else
+static inline void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
+{
+}
+static inline void mem_cgroup_uncharge_swap(swp_entry_t entry)
+{
+}
+#endif
+#ifdef CONFIG_SWAP
+/* linux/mm/page_io.c */
+extern int swap_readpage(struct page *);
+extern int swap_writepage(struct page *page, struct writeback_control *wbc);
+extern void end_swap_bio_write(struct bio *bio, int err);
+extern int __swap_writepage(struct page *page, struct writeback_control *wbc,
+	void (*end_write_func)(struct bio *, int));
+extern int swap_set_page_dirty(struct page *page);
+extern void end_swap_bio_read(struct bio *bio, int err);
+
+int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
+		unsigned long nr_pages, sector_t start_block);
+int generic_swapfile_activate(struct swap_info_struct *, struct file *,
+		sector_t *);
+
+/* linux/mm/swap_state.c */
+extern struct address_space swapper_spaces[];
+#define swap_address_space(entry) (&swapper_spaces[swp_type(entry)])
+extern unsigned long total_swapcache_pages(void);
+extern void show_swap_cache_info(void);
+extern int add_to_swap(struct page *, struct list_head *list);
+extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
+extern int __add_to_swap_cache(struct page *page, swp_entry_t entry);
+extern void __delete_from_swap_cache(struct page *);
+extern void delete_from_swap_cache(struct page *);
+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, gfp_t,
+			struct vm_area_struct *vma, unsigned long addr);
+extern struct page *swapin_readahead(swp_entry_t, gfp_t,
+			struct vm_area_struct *vma, unsigned long addr);
+
+/* linux/mm/swapfile.c */
+extern atomic_long_t nr_swap_pages;
+extern long total_swap_pages;
+
+/* Swap 50% full? Release swapcache more aggressively.. */
+static inline bool vm_swap_full(void)
+{
+	return atomic_long_read(&nr_swap_pages) * 2 < total_swap_pages;
+}
+
+static inline long get_nr_swap_pages(void)
+{
+	return atomic_long_read(&nr_swap_pages);
+}
+
+extern void si_swapinfo(struct sysinfo *);
+extern swp_entry_t get_swap_page(void);
+extern swp_entry_t get_swap_page_of_type(int);
+extern int add_swap_count_continuation(swp_entry_t, gfp_t);
+extern void swap_shmem_alloc(swp_entry_t);
+extern int swap_duplicate(swp_entry_t);
+extern int swapcache_prepare(swp_entry_t);
+extern void swap_free(swp_entry_t);
+extern void swapcache_free(swp_entry_t);
+extern int free_swap_and_cache(swp_entry_t);
+extern int swap_type_of(dev_t, sector_t, struct block_device **);
+extern unsigned int count_swap_pages(int, int);
+extern sector_t map_swap_entry(swp_entry_t entry, struct block_device **);
+extern sector_t map_swap_page(struct page *, struct block_device **);
+extern sector_t swapdev_block(int, pgoff_t);
+extern struct swap_info_struct *get_swap_info_struct(unsigned);
+extern int page_swapcount(struct page *);
+extern struct swap_info_struct *page_swap_info(struct page *);
+extern int reuse_swap_page(struct page *);
+extern int try_to_free_swap(struct page *);
+struct backing_dev_info;
+extern void get_swap_range_of_type(int type, swp_entry_t *start,
+		swp_entry_t *end, unsigned int limit);
+
+#else /* CONFIG_SWAP */
+
+#define swap_address_space(entry)		(NULL)
+#define get_nr_swap_pages()			0L
+#define total_swap_pages			0L
+#define total_swapcache_pages()			0UL
+#define vm_swap_full()				0
+
+#define si_swapinfo(val) \
+	do { (val)->freeswap = (val)->totalswap = 0; } while (0)
+/* only sparc can not include linux/pagemap.h in this file
+ * so leave page_cache_release and release_pages undeclared... */
+#define free_page_and_swap_cache(page) \
+	page_cache_release(page)
+#define free_pages_and_swap_cache(pages, nr) \
+	release_pages((pages), (nr), false);
+
+static inline void show_swap_cache_info(void)
+{
+}
+
+#define free_swap_and_cache(swp)	is_migration_entry(swp)
+#define swapcache_prepare(swp)		is_migration_entry(swp)
+
+static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask)
+{
+	return 0;
+}
+
+static inline void swap_shmem_alloc(swp_entry_t swp)
+{
+}
+
+static inline int swap_duplicate(swp_entry_t swp)
+{
+	return 0;
+}
+
+static inline void swap_free(swp_entry_t swp)
+{
+}
+
+static inline void swapcache_free(swp_entry_t swp)
+{
+}
+
+static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
+			struct vm_area_struct *vma, unsigned long addr)
+{
+	return NULL;
+}
+
+static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
+{
+	return 0;
+}
+
+static inline struct page *lookup_swap_cache(swp_entry_t swp)
+{
+	return NULL;
+}
+
+static inline int add_to_swap(struct page *page, struct list_head *list)
+{
+	return 0;
+}
+
+static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
+							gfp_t gfp_mask)
+{
+	return -1;
+}
+
+static inline void __delete_from_swap_cache(struct page *page)
+{
+}
+
+static inline void delete_from_swap_cache(struct page *page)
+{
+}
+
+static inline int page_swapcount(struct page *page)
+{
+	return 0;
+}
+
+#define reuse_swap_page(page)	(page_mapcount(page) == 1)
+
+static inline int try_to_free_swap(struct page *page)
+{
+	return 0;
+}
+
+static inline swp_entry_t get_swap_page(void)
+{
+	swp_entry_t entry;
+	entry.val = 0;
+	return entry;
+}
+
+#endif /* CONFIG_SWAP */
+#endif /* __KERNEL__*/
+#endif /* _LINUX_SWAP_H */