sched: Consolidate the name of root_task_group and init_task_group

root_task_group is the leftover of USER_SCHED, now it's always
same to init_task_group.
But as Mike suggested, root_task_group is maybe the suitable name
to keep for a tree.
So in this patch:
  init_task_group      --> root_task_group
  init_task_group_load --> root_task_group_load
  INIT_TASK_GROUP_LOAD --> ROOT_TASK_GROUP_LOAD

Suggested-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20110107071736.GA32635@windriver.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 23 insertions, 25 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 04949089e760..54b58ec99fd4 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -278,14 +278,12 @@ struct task_group {
 #endif
 };
 
-#define root_task_group init_task_group
-
 /* task_group_lock serializes the addition/removal of task groups */
 static DEFINE_SPINLOCK(task_group_lock);
 
 #ifdef CONFIG_FAIR_GROUP_SCHED
 
-# define INIT_TASK_GROUP_LOAD   NICE_0_LOAD
+# define ROOT_TASK_GROUP_LOAD   NICE_0_LOAD
 
 /*
  * A weight of 0 or 1 can cause arithmetics problems.
@@ -298,13 +296,13 @@ static DEFINE_SPINLOCK(task_group_lock);
 #define MIN_SHARES      2
 #define MAX_SHARES      (1UL << 18)
 
-static int init_task_group_load = INIT_TASK_GROUP_LOAD;
+static int root_task_group_load = ROOT_TASK_GROUP_LOAD;
 #endif
 
 /* Default task group.
  *      Every task in system belong to this group at bootup.
  */
-struct task_group init_task_group;
+struct task_group root_task_group;
 
 #endif  /* CONFIG_CGROUP_SCHED */
 
@@ -7848,7 +7846,7 @@ static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
         cfs_rq->tg = tg;
 
         tg->se[cpu] = se;
-        /* se could be NULL for init_task_group */
+        /* se could be NULL for root_task_group */
         if (!se)
                 return;
 
@@ -7908,18 +7906,18 @@ void __init sched_init(void)
                 ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT);
 
 #ifdef CONFIG_FAIR_GROUP_SCHED
-                init_task_group.se = (struct sched_entity **)ptr;
+                root_task_group.se = (struct sched_entity **)ptr;
                 ptr += nr_cpu_ids * sizeof(void **);
 
-                init_task_group.cfs_rq = (struct cfs_rq **)ptr;
+                root_task_group.cfs_rq = (struct cfs_rq **)ptr;
                 ptr += nr_cpu_ids * sizeof(void **);
 
 #endif /* CONFIG_FAIR_GROUP_SCHED */
 #ifdef CONFIG_RT_GROUP_SCHED
-                init_task_group.rt_se = (struct sched_rt_entity **)ptr;
+                root_task_group.rt_se = (struct sched_rt_entity **)ptr;
                 ptr += nr_cpu_ids * sizeof(void **);
 
-                init_task_group.rt_rq = (struct rt_rq **)ptr;
+                root_task_group.rt_rq = (struct rt_rq **)ptr;
                 ptr += nr_cpu_ids * sizeof(void **);
 
 #endif /* CONFIG_RT_GROUP_SCHED */
@@ -7939,13 +7937,13 @@ void __init sched_init(void)
                         global_rt_period(), global_rt_runtime());
 
 #ifdef CONFIG_RT_GROUP_SCHED
-        init_rt_bandwidth(&init_task_group.rt_bandwidth,
+        init_rt_bandwidth(&root_task_group.rt_bandwidth,
                         global_rt_period(), global_rt_runtime());
 #endif /* CONFIG_RT_GROUP_SCHED */
 
 #ifdef CONFIG_CGROUP_SCHED
-        list_add(&init_task_group.list, &task_groups);
-        INIT_LIST_HEAD(&init_task_group.children);
+        list_add(&root_task_group.list, &task_groups);
+        INIT_LIST_HEAD(&root_task_group.children);
         autogroup_init(&init_task);
 #endif /* CONFIG_CGROUP_SCHED */
 
@@ -7960,34 +7958,34 @@ void __init sched_init(void)
                 init_cfs_rq(&rq->cfs, rq);
                 init_rt_rq(&rq->rt, rq);
 #ifdef CONFIG_FAIR_GROUP_SCHED
-                init_task_group.shares = init_task_group_load;
+                root_task_group.shares = root_task_group_load;
                 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
                 /*
-                 * How much cpu bandwidth does init_task_group get?
+                 * How much cpu bandwidth does root_task_group get?
                  *
                  * In case of task-groups formed thr' the cgroup filesystem, it
                  * gets 100% of the cpu resources in the system. This overall
                  * system cpu resource is divided among the tasks of
-                 * init_task_group and its child task-groups in a fair manner,
+                 * root_task_group and its child task-groups in a fair manner,
                  * based on each entity's (task or task-group's) weight
                  * (se->load.weight).
                  *
-                 * In other words, if init_task_group has 10 tasks of weight
+                 * In other words, if root_task_group has 10 tasks of weight
                  * 1024) and two child groups A0 and A1 (of weight 1024 each),
                  * then A0's share of the cpu resource is:
                  *
                  *      A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
                  *
-                 * We achieve this by letting init_task_group's tasks sit
-                 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
+                 * We achieve this by letting root_task_group's tasks sit
+                 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
                  */
-                init_tg_cfs_entry(&init_task_group, &rq->cfs, NULL, i, NULL);
+                init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL);
 #endif /* CONFIG_FAIR_GROUP_SCHED */
 
                 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
 #ifdef CONFIG_RT_GROUP_SCHED
                 INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
-                init_tg_rt_entry(&init_task_group, &rq->rt, NULL, i, NULL);
+                init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL);
 #endif
 
                 for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
@@ -8812,7 +8810,7 @@ cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp)
 
         if (!cgrp->parent) {
                 /* This is early initialization for the top cgroup */
-                return &init_task_group.css;
+                return &root_task_group.css;
         }
 
         parent = cgroup_tg(cgrp->parent);
diff --git a/kernel/sched_autogroup.c b/kernel/sched_autogroup.c
index c80fedcd476b..e011e53433a6 100644
--- a/kernel/sched_autogroup.c
+++ b/kernel/sched_autogroup.c
@@ -11,8 +11,8 @@ static atomic_t autogroup_seq_nr;
 
 static void autogroup_init(struct task_struct *init_task)
 {
-        autogroup_default.tg = &init_task_group;
-        init_task_group.autogroup = &autogroup_default;
+        autogroup_default.tg = &root_task_group;
+        root_task_group.autogroup = &autogroup_default;
         kref_init(&autogroup_default.kref);
         init_rwsem(&autogroup_default.lock);
         init_task->signal->autogroup = &autogroup_default;
@@ -63,7 +63,7 @@ static inline struct autogroup *autogroup_create(void)
         if (!ag)
                 goto out_fail;
 
-        tg = sched_create_group(&init_task_group);
+        tg = sched_create_group(&root_task_group);
 
         if (IS_ERR(tg))
                 goto out_free;