controllers: verify that resource application went ok or not

Signed-off-by: Levente Kurusa <lkurusa@acm.org>

src/memory.rs

@@ -121,7 +121,7 @@ impl Controller for MemController {
     fn get_path_mut<'a>(self: &'a mut Self) -> &'a mut PathBuf { &mut self.path }
     fn get_base<'a>(self: &'a Self) -> &'a PathBuf { &self.base }
 
-    fn apply(self: &Self, res: &Resources) {
+    fn apply(self: &Self, res: &Resources) -> Result<(), CgroupError> {
         /* get the resources that apply to this controller */
         let memres: &MemoryResources = &res.memory;
 
@@ -133,6 +133,8 @@ impl Controller for MemController {
             let _ = self.set_tcp_limit(memres.kernel_tcp_memory_limit);
             let _ = self.set_swappiness(memres.swappiness);
         }
+
+        Ok(())
     }
 }