To check whether all pages and shadow entries in swap cache has been
removed before swap cache is freed.
Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Ilya Dryomov <idryomov@xxxxxxxxx>
---
BTW: The patch reverts the following patch in -mm tree in effect.
mm/swap: remove unused global variable nr_swapper_spaces
---
mm/swap_state.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/mm/swap_state.c b/mm/swap_state.c
index 95e391f46468..c56aa9ac050d 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -37,6 +37,7 @@ static const struct address_space_operations swap_aops = {
};
struct address_space *swapper_spaces[MAX_SWAPFILES] __read_mostly;
+static unsigned int nr_swapper_spaces[MAX_SWAPFILES] __read_mostly;
static bool enable_vma_readahead __read_mostly = true;
#define SWAP_RA_WIN_SHIFT (PAGE_SHIFT / 2)
@@ -684,6 +685,7 @@ int init_swap_address_space(unsigned int type, unsigned long nr_pages)
/* swap cache doesn't use writeback related tags */
mapping_set_no_writeback_tags(space);
}
+ nr_swapper_spaces[type] = nr;
swapper_spaces[type] = spaces;
return 0;
@@ -691,7 +693,13 @@ int init_swap_address_space(unsigned int type, unsigned long nr_pages)
void exit_swap_address_space(unsigned int type)
{
- kvfree(swapper_spaces[type]);
+ int i;
+ struct address_space *spaces = swapper_spaces[type];
+
+ for (i = 0; i < nr_swapper_spaces[type]; i++)
+ VM_WARN_ON_ONCE(!mapping_empty(&spaces[i]));
+ kvfree(spaces);
+ nr_swapper_spaces[type] = 0;
swapper_spaces[type] = NULL;
}
--
2.30.2
