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sched: allow the group scheduler to have multiple levels
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This patch makes the group scheduler multi hierarchy aware.

[[email protected]: rt-parts and assorted fixes]
Signed-off-by: Dhaval Giani <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
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Dhaval Giani authored and Ingo Molnar committed Apr 19, 2008
1 parent 354d60c commit ec7dc8a
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Showing 3 changed files with 55 additions and 34 deletions.
2 changes: 1 addition & 1 deletion include/linux/sched.h
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Original file line number Diff line number Diff line change
Expand Up @@ -2052,7 +2052,7 @@ extern void normalize_rt_tasks(void);

extern struct task_group init_task_group;

extern struct task_group *sched_create_group(void);
extern struct task_group *sched_create_group(struct task_group *parent);
extern void sched_destroy_group(struct task_group *tg);
extern void sched_move_task(struct task_struct *tsk);
#ifdef CONFIG_FAIR_GROUP_SCHED
Expand Down
85 changes: 53 additions & 32 deletions kernel/sched.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -7438,10 +7438,11 @@ static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
}

#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;
Expand All @@ -7453,19 +7454,25 @@ static void init_tg_cfs_entry(struct rq *rq, struct task_group *tg,
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;
Expand All @@ -7478,9 +7485,14 @@ static void init_tg_rt_entry(struct rq *rq, struct task_group *tg,
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
Expand Down Expand Up @@ -7568,7 +7580,7 @@ void __init sched_init(void)
* 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,
Expand All @@ -7581,9 +7593,9 @@ void __init sched_init(void)
* (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 */
Expand All @@ -7592,11 +7604,11 @@ void __init sched_init(void)
#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

Expand Down Expand Up @@ -7798,10 +7810,11 @@ static void free_fair_sched_group(struct task_group *tg)
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;

Expand All @@ -7827,7 +7840,8 @@ static int alloc_fair_sched_group(struct task_group *tg)
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;
Expand All @@ -7851,7 +7865,8 @@ static inline void free_fair_sched_group(struct task_group *tg)
{
}

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;
}
Expand Down Expand Up @@ -7883,10 +7898,11 @@ static void free_rt_sched_group(struct task_group *tg)
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;

Expand All @@ -7913,7 +7929,8 @@ static int alloc_rt_sched_group(struct task_group *tg)
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;
Expand All @@ -7937,7 +7954,8 @@ static inline void free_rt_sched_group(struct task_group *tg)
{
}

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;
}
Expand All @@ -7960,7 +7978,7 @@ static void free_sched_group(struct task_group *tg)
}

/* 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;
Expand All @@ -7970,10 +7988,10 @@ struct task_group *sched_create_group(void)
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);
Expand Down Expand Up @@ -8084,6 +8102,12 @@ int sched_group_set_shares(struct task_group *tg, unsigned long shares)
int i;
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
Expand Down Expand Up @@ -8327,19 +8351,16 @@ static inline struct task_group *cgroup_tg(struct cgroup *cgrp)
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 */
init_task_group.css.cgroup = cgrp;
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);

Expand Down
2 changes: 1 addition & 1 deletion kernel/user.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -101,7 +101,7 @@ static int sched_create_user(struct user_struct *up)
{
int rc = 0;

up->tg = sched_create_group();
up->tg = sched_create_group(NULL);
if (IS_ERR(up->tg))
rc = -ENOMEM;

Expand Down

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