From 4e244108ef8089abcbf9d691f138fa6ddd01d431 Mon Sep 17 00:00:00 2001
From: Qiang Huang <h.huangqiang@huawei.com>
Date: Mon, 13 Jul 2015 18:22:35 +0800
Subject: [PATCH] Fix error when memory cgroup not mounted

Fixes: #57

Normally all cgroup subsystems are optional except device cgroup,
but memory cgroup optional was broken by:
https://github.com/docker/libcontainer/pull/637

This patch fixes this.

Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
---
 libcontainer/cgroups/fs/memory.go | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/libcontainer/cgroups/fs/memory.go b/libcontainer/cgroups/fs/memory.go
index a40e39d8bee..8206b1472b2 100644
--- a/libcontainer/cgroups/fs/memory.go
+++ b/libcontainer/cgroups/fs/memory.go
@@ -19,7 +19,10 @@ type MemoryGroup struct {
 
 func (s *MemoryGroup) Apply(d *data) error {
 	path, err := d.path("memory")
-	if err != nil && !cgroups.IsNotFound(err) {
+	if err != nil {
+		if cgroups.IsNotFound(err) {
+			return nil
+		}
 		return err
 	}
 	if err := os.MkdirAll(path, 0755); err != nil && !os.IsExist(err) {