diff options
Diffstat (limited to 'kernel/sched.c')
| -rw-r--r-- | kernel/sched.c | 51 |
1 files changed, 49 insertions, 2 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 62830eaec52f..1b7399dfa361 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -273,6 +273,7 @@ struct task_group { struct list_head list; }; +#ifdef CONFIG_USER_SCHED #ifdef CONFIG_FAIR_GROUP_SCHED /* Default task group's sched entity on each cpu */ static DEFINE_PER_CPU(struct sched_entity, init_sched_entity); @@ -284,6 +285,7 @@ static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp; static DEFINE_PER_CPU(struct sched_rt_entity, init_sched_rt_entity); static DEFINE_PER_CPU(struct rt_rq, init_rt_rq) ____cacheline_aligned_in_smp; #endif +#endif /* task_group_lock serializes add/remove of task groups and also changes to * a task group's cpu shares. @@ -7447,6 +7449,10 @@ static void init_tg_cfs_entry(struct rq *rq, struct task_group *tg, list_add(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list); tg->se[cpu] = se; + /* se could be NULL for init_task_group */ + if (!se) + return; + se->cfs_rq = &rq->cfs; se->my_q = cfs_rq; se->load.weight = tg->shares; @@ -7469,6 +7475,9 @@ static void init_tg_rt_entry(struct rq *rq, struct task_group *tg, list_add(&rt_rq->leaf_rt_rq_list, &rq->leaf_rt_rq_list); tg->rt_se[cpu] = rt_se; + if (!rt_se) + return; + rt_se->rt_rq = &rq->rt; rt_se->my_q = rt_rq; rt_se->parent = NULL; @@ -7539,18 +7548,56 @@ void __init sched_init(void) #ifdef CONFIG_FAIR_GROUP_SCHED init_task_group.shares = init_task_group_load; INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); +#ifdef CONFIG_CGROUP_SCHED + /* + * How much cpu bandwidth does init_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, + * 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 + * 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). + */ + init_tg_cfs_entry(rq, &init_task_group, &rq->cfs, NULL, i, 1); +#elif defined CONFIG_USER_SCHED + /* + * In case of task-groups formed thr' the user id of tasks, + * init_task_group represents tasks belonging to root user. + * Hence it forms a sibling of all subsequent groups formed. + * In this case, init_task_group gets only a fraction of overall + * system cpu resource, based on the weight assigned to root + * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished + * by letting tasks of init_task_group sit in a separate cfs_rq + * (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, &per_cpu(init_cfs_rq, i), &per_cpu(init_sched_entity, i), i, 1); #endif +#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); +#ifdef CONFIG_CGROUP_SCHED + init_tg_rt_entry(rq, &init_task_group, &rq->rt, NULL, i, 1); +#elif defined CONFIG_USER_SCHED init_tg_rt_entry(rq, &init_task_group, &per_cpu(init_rt_rq, i), &per_cpu(init_sched_rt_entity, i), i, 1); -#else - rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime; +#endif #endif for (j = 0; j < CPU_LOAD_IDX_MAX; j++) |