mm/workingset.c: avoid unnecessary max_nodes estimation in count_shad…

…ow_nodes() If list_lru_shrink_count is 0, we always return SHRINK_EMPTY regardless of the value of max_nodes. So we can return early if nodes == 0 to save some cpu cycles of approximating a reasonable limit for the nodes. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Miaohe Lin <[email protected]> Reviewed-by: Andrew Morton <[email protected]> Acked-by: Vlastimil Babka <[email protected]> Cc: Johannes Weiner <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
majek · Feb 24, 2021 · 725cac1 · 725cac1
1 parent c2135f7
commit 725cac1
Showing 1 changed file with 2 additions and 3 deletions.
diff --git a/mm/workingset.c b/mm/workingset.c
@@ -461,6 +461,8 @@ static unsigned long count_shadow_nodes(struct shrinker *shrinker,
 	unsigned long pages;
 
 	nodes = list_lru_shrink_count(&shadow_nodes, sc);
+	if (!nodes)
+		return SHRINK_EMPTY;
 
 	/*
 	 * Approximate a reasonable limit for the nodes
@@ -503,9 +505,6 @@ static unsigned long count_shadow_nodes(struct shrinker *shrinker,
 
 	max_nodes = pages >> (XA_CHUNK_SHIFT - 3);
 
-	if (!nodes)
-		return SHRINK_EMPTY;
-
 	if (nodes <= max_nodes)
 		return 0;
 	return nodes - max_nodes;