In swap_page_trans_huge_swapped(), to identify whether there's any page table mapping for a 4k sized swap entry, "si->swap_map[i] != SWAP_HAS_CACHE" is used. This works correctly now, because all users of the function will only call it after checking SWAP_HAS_CACHE. But as pointed out by Daniel, it is better to use "swap_count(map[i])" here, because it works for "map[i] == 0" case too.
And this makes the implementation more consistent between normal and huge swap entry. Signed-off-by: "Huang, Ying" <ying.hu...@intel.com> Suggested-and-reviewed-by: Daniel Jordan <daniel.m.jor...@oracle.com> Acked-by: Dave Hansen <dave.han...@linux.intel.com> Cc: Michal Hocko <mho...@suse.com> Cc: Johannes Weiner <han...@cmpxchg.org> Cc: Shaohua Li <s...@kernel.org> Cc: Hugh Dickins <hu...@google.com> Cc: Minchan Kim <minc...@kernel.org> Cc: Rik van Riel <r...@redhat.com> Cc: Dan Williams <dan.j.willi...@intel.com> --- mm/swapfile.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/swapfile.c b/mm/swapfile.c index 7283104bfafa..833613e59ef7 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1497,12 +1497,12 @@ static bool swap_page_trans_huge_swapped(struct swap_info_struct *si, ci = lock_cluster_or_swap_info(si, offset); if (!ci || !cluster_is_huge(ci)) { - if (map[roffset] != SWAP_HAS_CACHE) + if (swap_count(map[roffset])) ret = true; goto unlock_out; } for (i = 0; i < SWAPFILE_CLUSTER; i++) { - if (map[offset + i] != SWAP_HAS_CACHE) { + if (swap_count(map[offset + i])) { ret = true; break; } -- 2.16.4