diff options
Diffstat (limited to 'mm/swapfile.c')
| -rw-r--r-- | mm/swapfile.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c index e74112e8e5f4..6c0585b16418 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -22,6 +22,7 @@ #include <linux/seq_file.h> #include <linux/init.h> #include <linux/module.h> +#include <linux/ksm.h> #include <linux/rmap.h> #include <linux/security.h> #include <linux/backing-dev.h> @@ -650,6 +651,8 @@ int reuse_swap_page(struct page *page) int count; VM_BUG_ON(!PageLocked(page)); + if (unlikely(PageKsm(page))) + return 0; count = page_mapcount(page); if (count <= 1 && PageSwapCache(page)) { count += page_swapcount(page); @@ -658,7 +661,7 @@ int reuse_swap_page(struct page *page) SetPageDirty(page); } } - return count == 1; + return count <= 1; } /* @@ -1185,6 +1188,12 @@ static int try_to_unuse(unsigned int type) * read from disk into another page. Splitting into two * pages would be incorrect if swap supported "shared * private" pages, but they are handled by tmpfs files. + * + * Given how unuse_vma() targets one particular offset + * in an anon_vma, once the anon_vma has been determined, + * this splitting happens to be just what is needed to + * handle where KSM pages have been swapped out: re-reading + * is unnecessarily slow, but we can fix that later on. */ if (swap_count(*swap_map) && PageDirty(page) && PageSwapCache(page)) { |