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-rw-r--r--mm/swap_state.c68
1 files changed, 56 insertions, 12 deletions
diff --git a/mm/swap_state.c b/mm/swap_state.c
index 35d7e0ee1c77..3863acd6189c 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -17,6 +17,7 @@
#include <linux/blkdev.h>
#include <linux/pagevec.h>
#include <linux/migrate.h>
+#include <linux/vmalloc.h>
#include <asm/pgtable.h>
@@ -32,15 +33,8 @@ static const struct address_space_operations swap_aops = {
#endif
};
-struct address_space swapper_spaces[MAX_SWAPFILES] = {
- [0 ... MAX_SWAPFILES - 1] = {
- .page_tree = RADIX_TREE_INIT(GFP_ATOMIC|__GFP_NOWARN),
- .i_mmap_writable = ATOMIC_INIT(0),
- .a_ops = &swap_aops,
- /* swap cache doesn't use writeback related tags */
- .flags = 1 << AS_NO_WRITEBACK_TAGS,
- }
-};
+struct address_space *swapper_spaces[MAX_SWAPFILES];
+static unsigned int nr_swapper_spaces[MAX_SWAPFILES];
#define INC_CACHE_INFO(x) do { swap_cache_info.x++; } while (0)
@@ -53,11 +47,26 @@ static struct {
unsigned long total_swapcache_pages(void)
{
- int i;
+ unsigned int i, j, nr;
unsigned long ret = 0;
+ struct address_space *spaces;
- for (i = 0; i < MAX_SWAPFILES; i++)
- ret += swapper_spaces[i].nrpages;
+ rcu_read_lock();
+ for (i = 0; i < MAX_SWAPFILES; i++) {
+ /*
+ * The corresponding entries in nr_swapper_spaces and
+ * swapper_spaces will be reused only after at least
+ * one grace period. So it is impossible for them
+ * belongs to different usage.
+ */
+ nr = nr_swapper_spaces[i];
+ spaces = rcu_dereference(swapper_spaces[i]);
+ if (!nr || !spaces)
+ continue;
+ for (j = 0; j < nr; j++)
+ ret += spaces[j].nrpages;
+ }
+ rcu_read_unlock();
return ret;
}
@@ -505,3 +514,38 @@ struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask,
skip:
return read_swap_cache_async(entry, gfp_mask, vma, addr);
}
+
+int init_swap_address_space(unsigned int type, unsigned long nr_pages)
+{
+ struct address_space *spaces, *space;
+ unsigned int i, nr;
+
+ nr = DIV_ROUND_UP(nr_pages, SWAP_ADDRESS_SPACE_PAGES);
+ spaces = vzalloc(sizeof(struct address_space) * nr);
+ if (!spaces)
+ return -ENOMEM;
+ for (i = 0; i < nr; i++) {
+ space = spaces + i;
+ INIT_RADIX_TREE(&space->page_tree, GFP_ATOMIC|__GFP_NOWARN);
+ atomic_set(&space->i_mmap_writable, 0);
+ space->a_ops = &swap_aops;
+ /* swap cache doesn't use writeback related tags */
+ mapping_set_no_writeback_tags(space);
+ spin_lock_init(&space->tree_lock);
+ }
+ nr_swapper_spaces[type] = nr;
+ rcu_assign_pointer(swapper_spaces[type], spaces);
+
+ return 0;
+}
+
+void exit_swap_address_space(unsigned int type)
+{
+ struct address_space *spaces;
+
+ spaces = swapper_spaces[type];
+ nr_swapper_spaces[type] = 0;
+ rcu_assign_pointer(swapper_spaces[type], NULL);
+ synchronize_rcu();
+ kvfree(spaces);
+}