In sched_init(), there is no need to initialize 'root_task_group.shares' and
'root_task_group.cfs_bandwidth' repeatedly.
CC: Ingo Molnar <mi...@kernel.org>
CC: Peter Zijlstra <pet...@infradead.org>
Signed-off-by: Michael Wang <wang...@linux.vnet.ibm.com>
---
kernel/sched/core.c | 46 +++++++++++++++++++++++++---------------------
1 files changed, 25 insertions(+), 21 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 58453b8..c0c3716 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6955,6 +6955,31 @@ void __init sched_init(void)
#endif /* CONFIG_CGROUP_SCHED */
+#ifdef CONFIG_FAIR_GROUP_SCHED
+ root_task_group.shares = ROOT_TASK_GROUP_LOAD;
+
+ /*
+ * 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
+ * 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 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 root_task_group's tasks sit
+ * directly in rq->cfs (i.e root_task_group->se[] = NULL).
+ */
+ init_cfs_bandwidth(&root_task_group.cfs_bandwidth);
+#endif
+
for_each_possible_cpu(i) {
struct rq *rq;
@@ -6966,28 +6991,7 @@ void __init sched_init(void)
init_cfs_rq(&rq->cfs);
init_rt_rq(&rq->rt, rq);
#ifdef CONFIG_FAIR_GROUP_SCHED
- root_task_group.shares = ROOT_TASK_GROUP_LOAD;
INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
- /*
- * 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
- * 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 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 root_task_group's tasks sit
- * directly in rq->cfs (i.e root_task_group->se[] = NULL).
- */
- init_cfs_bandwidth(&root_task_group.cfs_bandwidth);
init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL);
#endif /* CONFIG_FAIR_GROUP_SCHED */
--
1.7.4.1
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