diff options
Diffstat (limited to 'mm/swapfile.c')
| -rw-r--r-- | mm/swapfile.c | 64 |
1 files changed, 62 insertions, 2 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c index d2c37365e..98d348347 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -9,6 +9,7 @@ #include <linux/hugetlb.h> #include <linux/mman.h> #include <linux/slab.h> +#include <linux/export.h> #include <linux/kernel_stat.h> #include <linux/swap.h> #include <linux/vmalloc.h> @@ -43,7 +44,6 @@ 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; @@ -719,6 +719,60 @@ swp_entry_t get_swap_page_of_type(int type) return (swp_entry_t) {0}; } +static unsigned int find_next_to_unuse(struct swap_info_struct *si, + unsigned int prev, bool frontswap); + +void get_swap_range_of_type(int type, swp_entry_t *start, swp_entry_t *end, + unsigned int limit) +{ + struct swap_info_struct *si; + pgoff_t start_at; + unsigned int i; + + *start = swp_entry(0, 0); + *end = swp_entry(0, 0); + si = swap_info[type]; + spin_lock(&si->lock); + if (si && (si->flags & SWP_WRITEOK)) { + atomic_long_dec(&nr_swap_pages); + /* This is called for allocating swap entry, not cache */ + start_at = scan_swap_map(si, 1); + if (start_at) { + unsigned long stop_at = find_next_to_unuse(si, start_at, 0); + if (stop_at > start_at) + stop_at--; + else + stop_at = si->max - 1; + if (stop_at - start_at + 1 > limit) + stop_at = min_t(unsigned int, + start_at + limit - 1, + si->max - 1); + /* Mark them used */ + for (i = start_at; i <= stop_at; i++) + si->swap_map[i] = 1; + /* first page already done above */ + si->inuse_pages += stop_at - start_at; + + atomic_long_sub(stop_at - start_at, &nr_swap_pages); + if (start_at == si->lowest_bit) + si->lowest_bit = stop_at + 1; + if (stop_at == si->highest_bit) + si->highest_bit = start_at - 1; + if (si->inuse_pages == si->pages) { + si->lowest_bit = si->max; + si->highest_bit = 0; + } + for (i = start_at + 1; i <= stop_at; i++) + inc_cluster_info_page(si, si->cluster_info, i); + si->cluster_next = stop_at + 1; + *start = swp_entry(type, start_at); + *end = swp_entry(type, stop_at); + } else + atomic_long_inc(&nr_swap_pages); + } + spin_unlock(&si->lock); +} + static struct swap_info_struct *swap_info_get(swp_entry_t entry) { struct swap_info_struct *p; @@ -1607,7 +1661,7 @@ static void drain_mmlist(void) * Note that the type of this function is sector_t, but it returns page offset * into the bdev, not sector offset. */ -static sector_t map_swap_entry(swp_entry_t entry, struct block_device **bdev) +sector_t map_swap_entry(swp_entry_t entry, struct block_device **bdev) { struct swap_info_struct *sis; struct swap_extent *start_se; @@ -2738,8 +2792,14 @@ pgoff_t __page_file_index(struct page *page) VM_BUG_ON_PAGE(!PageSwapCache(page), page); return swp_offset(swap); } + EXPORT_SYMBOL_GPL(__page_file_index); +struct swap_info_struct *get_swap_info_struct(unsigned type) +{ + return swap_info[type]; +} + /* * add_swap_count_continuation - called when a swap count is duplicated * beyond SWAP_MAP_MAX, it allocates a new page and links that to the entry's |