sched: group-scheduler core

Add interface to control cpu bandwidth allocation to task-groups.

(not yet configurable, due to missing CONFIG_CONTAINERS)
Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>

init/Kconfig

@@ -281,6 +281,15 @@ config CPUSETS
 
 	  Say N if unsure.
 
+config FAIR_GROUP_SCHED
+	bool "Fair group scheduler"
+	depends on EXPERIMENTAL && CONTAINERS
+	help
+	  This option enables you to group tasks and control CPU resource
+	  allocation to such groups.
+
+	  Say N if unsure.
+
 config SYSFS_DEPRECATED
 	bool "Create deprecated sysfs files"
 	default y

kernel/sched_fair.c

@@ -610,8 +610,7 @@ static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp)
  */
 static inline struct cfs_rq *cpu_cfs_rq(struct cfs_rq *cfs_rq, int this_cpu)
 {
-	/* A later patch will take group into account */
-	return &cpu_rq(this_cpu)->cfs;
+	return cfs_rq->tg->cfs_rq[this_cpu];
 }
 
 /* Iterate thr' all leaf cfs_rq's on a runqueue */

kernel/sched_idletask.c

@@ -50,6 +50,10 @@ static void task_tick_idle(struct rq *rq, struct task_struct *curr)
 {
 }
 
+static void set_curr_task_idle(struct rq *rq)
+{
+}
+
 /*
  * Simple, special scheduling class for the per-CPU idle tasks:
  */
@@ -66,6 +70,7 @@ static struct sched_class idle_sched_class __read_mostly = {
 
 	.load_balance		= load_balance_idle,
 
+	.set_curr_task          = set_curr_task_idle,
 	.task_tick		= task_tick_idle,
 	/* no .task_new for idle tasks */
 };

kernel/sched_rt.c

@@ -218,6 +218,10 @@ static void task_tick_rt(struct rq *rq, struct task_struct *p)
 	}
 }
 
+static void set_curr_task_rt(struct rq *rq)
+{
+}
+
 static struct sched_class rt_sched_class __read_mostly = {
 	.enqueue_task		= enqueue_task_rt,
 	.dequeue_task		= dequeue_task_rt,
@@ -230,5 +234,6 @@ static struct sched_class rt_sched_class __read_mostly = {
 
 	.load_balance		= load_balance_rt,
 
+	.set_curr_task          = set_curr_task_rt,
 	.task_tick		= task_tick_rt,
 };