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Diffstat (limited to 'include/linux/swap.h')
-rw-r--r--include/linux/swap.h32
1 files changed, 27 insertions, 5 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 235c039892ee..a3e22d357e91 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -202,6 +202,18 @@ struct swap_info_struct {
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 and
+ * highest_alloc. 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 swap_list_t {
@@ -209,9 +221,6 @@ struct swap_list_t {
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/page_alloc.c */
extern unsigned long totalram_pages;
extern unsigned long totalreserve_pages;
@@ -347,8 +356,20 @@ extern struct page *swapin_readahead(swp_entry_t, gfp_t,
struct vm_area_struct *vma, unsigned long addr);
/* linux/mm/swapfile.c */
-extern long nr_swap_pages;
+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);
@@ -381,9 +402,10 @@ mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
#else /* CONFIG_SWAP */
-#define nr_swap_pages 0L
+#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)