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mm/swapfile.c: use swap_count() in swap_page_trans_huge_swapped() 

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.

Link: http://lkml.kernel.org/r/20180720071845.17920-4-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Suggested-and-reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Huang Ying 2018-08-21 21:52:09 -07:00 committed by Linus Torvalds
parent fe5266d5d5
commit afa4711ef1
1 changed files with 2 additions and 2 deletions
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4
mm/swapfile.c
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@ -1429,12 +1429,12 @@ 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;
}