The patch titled
Subject: swap: check mapping_empty() for swap cache before being freed
has been added to the -mm tree. Its filename is
swap-check-mapping_empty-for-swap-cache-before-being-freed.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/swap-check-mapping_empty-for-swap-cache-before-being-freed.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/swap-check-mapping_empty-for-swap-cache-before-being-freed.patch
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------------------------------------------------------
From: Huang Ying <ying.huang@xxxxxxxxx>
Subject: swap: check mapping_empty() for swap cache before being freed
To check whether all pages and shadow entries in swap cache has been
removed before swap cache is freed.
Link: https://lkml.kernel.org/r/20210608005121.511140-1-ying.huang@xxxxxxxxx
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>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/swap_state.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- a/mm/swap_state.c~swap-check-mapping_empty-for-swap-cache-before-being-freed
+++ a/mm/swap_state.c
@@ -693,7 +693,12 @@ int init_swap_address_space(unsigned int
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;
}
_
Patches currently in -mm which might be from ying.huang@xxxxxxxxx are
mm-swap-remove-unnecessary-smp_rmb-in-swap_type_to_swap_info.patch
mm-free-idle-swap-cache-page-after-cow.patch
swap-check-mapping_empty-for-swap-cache-before-being-freed.patch
