sched: cleanup for alloc_rt/fair_sched_group()

Impact: cleanup

Remove checking parent == NULL. It won't be NULLL, because we dynamically
create sub task_group only, and sub task_group always has its parent.
(root task_group is statically defined)

Also replace kmalloc_node(GFP_ZERO) with kzalloc_node().

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/sched.c

@@ -8472,7 +8472,7 @@ static
 int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
 {
 	struct cfs_rq *cfs_rq;
-	struct sched_entity *se, *parent_se;
+	struct sched_entity *se;
 	struct rq *rq;
 	int i;
 
@@ -8488,18 +8488,17 @@ int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
 	for_each_possible_cpu(i) {
 		rq = cpu_rq(i);
 
-		cfs_rq = kmalloc_node(sizeof(struct cfs_rq),
-				GFP_KERNEL|__GFP_ZERO, cpu_to_node(i));
+		cfs_rq = kzalloc_node(sizeof(struct cfs_rq),
+				      GFP_KERNEL, cpu_to_node(i));
 		if (!cfs_rq)
 			goto err;
 
-		se = kmalloc_node(sizeof(struct sched_entity),
-				GFP_KERNEL|__GFP_ZERO, cpu_to_node(i));
+		se = kzalloc_node(sizeof(struct sched_entity),
+				  GFP_KERNEL, cpu_to_node(i));
 		if (!se)
 			goto err;
 
-		parent_se = parent ? parent->se[i] : NULL;
-		init_tg_cfs_entry(tg, cfs_rq, se, i, 0, parent_se);
+		init_tg_cfs_entry(tg, cfs_rq, se, i, 0, parent->se[i]);
 	}
 
 	return 1;
@@ -8560,7 +8559,7 @@ static
 int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
 {
 	struct rt_rq *rt_rq;
-	struct sched_rt_entity *rt_se, *parent_se;
+	struct sched_rt_entity *rt_se;
 	struct rq *rq;
 	int i;
 
@@ -8577,18 +8576,17 @@ int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
 	for_each_possible_cpu(i) {
 		rq = cpu_rq(i);
 
-		rt_rq = kmalloc_node(sizeof(struct rt_rq),
-				GFP_KERNEL|__GFP_ZERO, cpu_to_node(i));
+		rt_rq = kzalloc_node(sizeof(struct rt_rq),
+				     GFP_KERNEL, cpu_to_node(i));
 		if (!rt_rq)
 			goto err;
 
-		rt_se = kmalloc_node(sizeof(struct sched_rt_entity),
-				GFP_KERNEL|__GFP_ZERO, cpu_to_node(i));
+		rt_se = kzalloc_node(sizeof(struct sched_rt_entity),
+				     GFP_KERNEL, cpu_to_node(i));
 		if (!rt_se)
 			goto err;
 
-		parent_se = parent ? parent->rt_se[i] : NULL;
-		init_tg_rt_entry(tg, rt_rq, rt_se, i, 0, parent_se);
+		init_tg_rt_entry(tg, rt_rq, rt_se, i, 0, parent->rt_se[i]);
 	}
 
 	return 1;