From f885dc20eb83c134b559059481d77c724297d236 Mon Sep 17 00:00:00 2001
From: Tim Schlueter <schlueter.tim@linux.com>
Date: Thu, 23 Aug 2018 22:37:31 -0700
Subject: [PATCH] Don't read meminfo if there are no shrinkers

---
 linux/shrinker.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/linux/shrinker.c b/linux/shrinker.c
index b8fc2464..7926be06 100644
--- a/linux/shrinker.c
+++ b/linux/shrinker.c
@@ -69,8 +69,15 @@ static struct meminfo read_meminfo(void)
 void run_shrinkers(void)
 {
 	struct shrinker *shrinker;
-	struct meminfo info = read_meminfo();
-	s64 want_shrink = (info.total >> 2) - info.available;
+	struct meminfo info;
+	s64 want_shrink;
+
+	/* Fast out if there are no shrinkers to run. */
+	if (list_empty(&shrinker_list))
+		return;
+
+	info = read_meminfo();
+	want_shrink = (info.total >> 2) - info.available;
 
 	if (want_shrink <= 0)
 		return;