mm/swap.c: trivial mark_page_accessed() cleanup

This avoids duplicated PageReferenced() calls.  No behavior change.

Link: http://lkml.kernel.org/r/20191016225326.GB12497@wfg-t540p.sh.intel.com
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Liu Jingqi <jingqi.liu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/swap.c b/mm/swap.c
index 38c3fa4308e210e4b70bf9b47ab2699d41111e98..66e3c5033688852322864a33df76f57142050d06 100644 (file)
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -373,9 +373,16 @@ static void __lru_cache_activate_page(struct page *page)
 void mark_page_accessed(struct page *page)
 {
        page = compound_head(page);
-       if (!PageActive(page) && !PageUnevictable(page) &&
-                       PageReferenced(page)) {
 
+       if (!PageReferenced(page)) {
+               SetPageReferenced(page);
+       } else if (PageUnevictable(page)) {
+               /*
+                * Unevictable pages are on the "LRU_UNEVICTABLE" list. But,
+                * this list is never rotated or maintained, so marking an
+                * evictable page accessed has no effect.
+                */
+       } else if (!PageActive(page)) {
                /*
                 * If the page is on the LRU, queue it for activation via
                 * activate_page_pvecs. Otherwise, assume the page is on a
@@ -389,8 +396,6 @@ void mark_page_accessed(struct page *page)
                ClearPageReferenced(page);
                if (page_is_file_cache(page))
                        workingset_activation(page);
-       } else if (!PageReferenced(page)) {
-               SetPageReferenced(page);
        }
        if (page_is_idle(page))
                clear_page_idle(page);