sched: allow the group scheduler to have multiple levels
This patch makes the group scheduler multi hierarchy aware.
[a.p.zijlstra@chello.nl: rt-parts and assorted fixes]
Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/sched.c b/kernel/sched.c
index 1b7399d..f9c8da7 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -7438,10 +7438,11 @@
}
#ifdef CONFIG_FAIR_GROUP_SCHED
-static void init_tg_cfs_entry(struct rq *rq, struct task_group *tg,
- struct cfs_rq *cfs_rq, struct sched_entity *se,
- int cpu, int add)
+static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
+ struct sched_entity *se, int cpu, int add,
+ struct sched_entity *parent)
{
+ struct rq *rq = cpu_rq(cpu);
tg->cfs_rq[cpu] = cfs_rq;
init_cfs_rq(cfs_rq, rq);
cfs_rq->tg = tg;
@@ -7453,19 +7454,25 @@
if (!se)
return;
- se->cfs_rq = &rq->cfs;
+ if (!parent)
+ se->cfs_rq = &rq->cfs;
+ else
+ se->cfs_rq = parent->my_q;
+
se->my_q = cfs_rq;
se->load.weight = tg->shares;
se->load.inv_weight = div64_64(1ULL<<32, se->load.weight);
- se->parent = NULL;
+ se->parent = parent;
}
#endif
#ifdef CONFIG_RT_GROUP_SCHED
-static void init_tg_rt_entry(struct rq *rq, struct task_group *tg,
- struct rt_rq *rt_rq, struct sched_rt_entity *rt_se,
- int cpu, int add)
+static void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
+ struct sched_rt_entity *rt_se, int cpu, int add,
+ struct sched_rt_entity *parent)
{
+ struct rq *rq = cpu_rq(cpu);
+
tg->rt_rq[cpu] = rt_rq;
init_rt_rq(rt_rq, rq);
rt_rq->tg = tg;
@@ -7478,9 +7485,14 @@
if (!rt_se)
return;
+ if (!parent)
+ rt_se->rt_rq = &rq->rt;
+ else
+ rt_se->rt_rq = parent->my_q;
+
rt_se->rt_rq = &rq->rt;
rt_se->my_q = rt_rq;
- rt_se->parent = NULL;
+ rt_se->parent = parent;
INIT_LIST_HEAD(&rt_se->run_list);
}
#endif
@@ -7568,7 +7580,7 @@
* We achieve this by letting init_task_group's tasks sit
* directly in rq->cfs (i.e init_task_group->se[] = NULL).
*/
- init_tg_cfs_entry(rq, &init_task_group, &rq->cfs, NULL, i, 1);
+ init_tg_cfs_entry(&init_task_group, &rq->cfs, NULL, i, 1, NULL);
#elif defined CONFIG_USER_SCHED
/*
* In case of task-groups formed thr' the user id of tasks,
@@ -7581,9 +7593,9 @@
* (init_cfs_rq) and having one entity represent this group of
* tasks in rq->cfs (i.e init_task_group->se[] != NULL).
*/
- init_tg_cfs_entry(rq, &init_task_group,
+ init_tg_cfs_entry(&init_task_group,
&per_cpu(init_cfs_rq, i),
- &per_cpu(init_sched_entity, i), i, 1);
+ &per_cpu(init_sched_entity, i), i, 1, NULL);
#endif
#endif /* CONFIG_FAIR_GROUP_SCHED */
@@ -7592,11 +7604,11 @@
#ifdef CONFIG_RT_GROUP_SCHED
INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
#ifdef CONFIG_CGROUP_SCHED
- init_tg_rt_entry(rq, &init_task_group, &rq->rt, NULL, i, 1);
+ init_tg_rt_entry(&init_task_group, &rq->rt, NULL, i, 1, NULL);
#elif defined CONFIG_USER_SCHED
- init_tg_rt_entry(rq, &init_task_group,
+ init_tg_rt_entry(&init_task_group,
&per_cpu(init_rt_rq, i),
- &per_cpu(init_sched_rt_entity, i), i, 1);
+ &per_cpu(init_sched_rt_entity, i), i, 1, NULL);
#endif
#endif
@@ -7798,10 +7810,11 @@
kfree(tg->se);
}
-static int alloc_fair_sched_group(struct task_group *tg)
+static
+int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
{
struct cfs_rq *cfs_rq;
- struct sched_entity *se;
+ struct sched_entity *se, *parent_se;
struct rq *rq;
int i;
@@ -7827,7 +7840,8 @@
if (!se)
goto err;
- init_tg_cfs_entry(rq, tg, cfs_rq, se, i, 0);
+ parent_se = parent ? parent->se[i] : NULL;
+ init_tg_cfs_entry(tg, cfs_rq, se, i, 0, parent_se);
}
return 1;
@@ -7851,7 +7865,8 @@
{
}
-static inline int alloc_fair_sched_group(struct task_group *tg)
+static inline
+int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
{
return 1;
}
@@ -7883,10 +7898,11 @@
kfree(tg->rt_se);
}
-static int alloc_rt_sched_group(struct task_group *tg)
+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;
+ struct sched_rt_entity *rt_se, *parent_se;
struct rq *rq;
int i;
@@ -7913,7 +7929,8 @@
if (!rt_se)
goto err;
- init_tg_rt_entry(rq, tg, rt_rq, rt_se, i, 0);
+ parent_se = parent ? parent->rt_se[i] : NULL;
+ init_tg_rt_entry(tg, rt_rq, rt_se, i, 0, parent_se);
}
return 1;
@@ -7937,7 +7954,8 @@
{
}
-static inline int alloc_rt_sched_group(struct task_group *tg)
+static inline
+int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
{
return 1;
}
@@ -7960,7 +7978,7 @@
}
/* allocate runqueue etc for a new task group */
-struct task_group *sched_create_group(void)
+struct task_group *sched_create_group(struct task_group *parent)
{
struct task_group *tg;
unsigned long flags;
@@ -7970,10 +7988,10 @@
if (!tg)
return ERR_PTR(-ENOMEM);
- if (!alloc_fair_sched_group(tg))
+ if (!alloc_fair_sched_group(tg, parent))
goto err;
- if (!alloc_rt_sched_group(tg))
+ if (!alloc_rt_sched_group(tg, parent))
goto err;
spin_lock_irqsave(&task_group_lock, flags);
@@ -8085,6 +8103,12 @@
unsigned long flags;
/*
+ * We can't change the weight of the root cgroup.
+ */
+ if (!tg->se[0])
+ return -EINVAL;
+
+ /*
* A weight of 0 or 1 can cause arithmetics problems.
* (The default weight is 1024 - so there's no practical
* limitation from this.)
@@ -8327,7 +8351,7 @@
static struct cgroup_subsys_state *
cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp)
{
- struct task_group *tg;
+ struct task_group *tg, *parent;
if (!cgrp->parent) {
/* This is early initialization for the top cgroup */
@@ -8335,11 +8359,8 @@
return &init_task_group.css;
}
- /* we support only 1-level deep hierarchical scheduler atm */
- if (cgrp->parent->parent)
- return ERR_PTR(-EINVAL);
-
- tg = sched_create_group();
+ parent = cgroup_tg(cgrp->parent);
+ tg = sched_create_group(parent);
if (IS_ERR(tg))
return ERR_PTR(-ENOMEM);