linux-imx

/*

 *  linux/mm/swapfile.c

 *

 *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds

 *  Swap reorganised 29.12.95, Stephen Tweedie

 */

​

#include <linux/mm.h>

#include <linux/sched/mm.h>

#include <linux/sched/task.h>

#include <linux/hugetlb.h>

#include <linux/mman.h>

#include <linux/slab.h>

#include <linux/kernel_stat.h>

#include <linux/swap.h>

#include <linux/vmalloc.h>

#include <linux/pagemap.h>

#include <linux/namei.h>

#include <linux/shmem_fs.h>

#include <linux/blkdev.h>

#include <linux/random.h>

#include <linux/writeback.h>

#include <linux/proc_fs.h>

#include <linux/seq_file.h>

#include <linux/init.h>

#include <linux/ksm.h>

#include <linux/rmap.h>

#include <linux/security.h>

#include <linux/backing-dev.h>

#include <linux/mutex.h>

#include <linux/capability.h>

#include <linux/syscalls.h>

#include <linux/memcontrol.h>

#include <linux/poll.h>

#include <linux/oom.h>

#include <linux/frontswap.h>

#include <linux/swapfile.h>

#include <linux/export.h>

#include <linux/swap_slots.h>

#include <linux/sort.h>

​

#include <asm/pgtable.h>

#include <asm/tlbflush.h>

#include <linux/swapops.h>

#include <linux/swap_cgroup.h>

​

static bool swap_count_continued(struct swap_info_struct *, pgoff_t,

                 unsigned char);

static void free_swap_count_continuations(struct swap_info_struct *);

static sector_t map_swap_entry(swp_entry_t, struct block_device**);

​

DEFINE_SPINLOCK(swap_lock);

static unsigned int nr_swapfiles;

atomic_long_t nr_swap_pages;

/*

 * Some modules use swappable objects and may try to swap them out under

 * memory pressure (via the shrinker). Before doing so, they may wish to

 * check to see if any swap space is available.

 */

EXPORT_SYMBOL_GPL(nr_swap_pages);

/* protected with swap_lock. reading in vm_swap_full() doesn't need lock */

long total_swap_pages;

static int least_priority = -1;

​

static const char Bad_file[] = "Bad swap file entry ";

static const char Unused_file[] = "Unused swap file entry ";

static const char Bad_offset[] = "Bad swap offset entry ";

static const char Unused_offset[] = "Unused swap offset entry ";

​

/*

 * all active swap_info_structs

 * protected with swap_lock, and ordered by priority.

 */

PLIST_HEAD(swap_active_head);

​

/*

 * all available (active, not full) swap_info_structs

 * protected with swap_avail_lock, ordered by priority.

 * This is used by get_swap_page() instead of swap_active_head

 * because swap_active_head includes all swap_info_structs,

 * but get_swap_page() doesn't need to look at full ones.

 * This uses its own lock instead of swap_lock because when a

 * swap_info_struct changes between not-full/full, it needs to

 * add/remove itself to/from this list, but the swap_info_struct->lock

 * is held and the locking order requires swap_lock to be taken

 * before any swap_info_struct->lock.

 */

static struct plist_head *swap_avail_heads;

static DEFINE_SPINLOCK(swap_avail_lock);

​

struct swap_info_struct *swap_info[MAX_SWAPFILES];

​