The patch makes number of task_group's tasks in iowait state be tracked separately. This may be useful for containers to check nr_iowait state of a single one.
Signed-off-by: Kirill Tkhai <[email protected]> --- kernel/sched/core.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ kernel/sched/sched.h | 5 +++++ 2 files changed, 50 insertions(+) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 712ee54edaa1..86d1ad5f49bd 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -796,12 +796,32 @@ void deactivate_task(struct rq *rq, struct task_struct *p, int flags) static void task_iowait_start(struct rq *rq, struct task_struct *p) { +#ifdef CONFIG_CGROUP_SCHED + struct task_group *tg = task_group(p); + + /* Task's sched_task_group is changed under both of the below locks */ + BUG_ON(!raw_spin_is_locked(&p->pi_lock) && !raw_spin_is_locked(&rq->lock)); + while (task_group_is_autogroup(tg)) + tg = tg->parent; + atomic_inc(&tg->stat[rq->cpu].nr_iowait); +#endif + atomic_inc(&rq->nr_iowait); delayacct_blkio_start(); } static void task_iowait_end(struct rq *rq, struct task_struct *p) { +#ifdef CONFIG_CGROUP_SCHED + struct task_group *tg = task_group(p); + + /* Task's sched_task_group is changed under both of the below locks */ + BUG_ON(!raw_spin_is_locked(&p->pi_lock) && !raw_spin_is_locked(&rq->lock)); + while (task_group_is_autogroup(tg)) + tg = tg->parent; + atomic_dec(&tg->stat[rq->cpu].nr_iowait); +#endif + delayacct_blkio_end(); atomic_dec(&rq->nr_iowait); } @@ -5805,6 +5825,9 @@ void __init sched_init(void) sched_clock_init(); wait_bit_init(); +#ifdef CONFIG_CGROUP_SCHED + alloc_size += nr_cpu_ids * sizeof(struct tg_stat); +#endif #ifdef CONFIG_FAIR_GROUP_SCHED alloc_size += 2 * nr_cpu_ids * sizeof(void **); #endif @@ -5814,6 +5837,10 @@ void __init sched_init(void) if (alloc_size) { ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT); +#ifdef CONFIG_CGROUP_SCHED + root_task_group.stat = (struct tg_stat *)ptr; + ptr += nr_cpu_ids * sizeof(struct tg_stat); +#endif #ifdef CONFIG_FAIR_GROUP_SCHED root_task_group.se = (struct sched_entity **)ptr; ptr += nr_cpu_ids * sizeof(void **); @@ -6133,6 +6160,8 @@ static DEFINE_SPINLOCK(task_group_lock); static void sched_free_group(struct task_group *tg) { + if (tg->stat) + kfree(tg->stat); free_fair_sched_group(tg); free_rt_sched_group(tg); autogroup_free(tg); @@ -6154,6 +6183,10 @@ struct task_group *sched_create_group(struct task_group *parent) if (!alloc_rt_sched_group(tg, parent)) goto err; + tg->stat = kzalloc(sizeof(struct tg_stat) * nr_cpu_ids, 0); + if (!tg->stat) + goto err; + return tg; err: @@ -6207,8 +6240,16 @@ void sched_offline_group(struct task_group *tg) static void sched_change_group(struct task_struct *tsk, int type) { + int cpu = 0, queued = task_on_rq_queued(tsk); struct task_group *tg; + if (!queued && tsk->in_iowait && type == TASK_MOVE_GROUP) { + cpu = task_cpu(tsk); + tg = task_group(tsk); + while (task_group_is_autogroup(tg)) + tg = tg->parent; + atomic_dec(&tg->stat[cpu].nr_iowait); + } /* * All callers are synchronized by task_rq_lock(); we do not use RCU * which is pointless here. Thus, we pass "true" to task_css_check() @@ -6216,6 +6257,10 @@ static void sched_change_group(struct task_struct *tsk, int type) */ tg = container_of(task_css_check(tsk, cpu_cgrp_id, true), struct task_group, css); + + if (!queued && tsk->in_iowait && type == TASK_MOVE_GROUP) + atomic_inc(&tg->stat[cpu].nr_iowait); + tg = autogroup_task_group(tsk, tg); tsk->sched_task_group = tg; diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 58787e3631c7..5e7cb18e1340 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -290,6 +290,10 @@ struct cfs_bandwidth { #endif }; +struct tg_stat { + atomic_t nr_iowait; +}; + /* task group related information */ struct task_group { struct cgroup_subsys_state css; @@ -330,6 +334,7 @@ struct task_group { #endif struct cfs_bandwidth cfs_bandwidth; + struct tg_stat *stat; }; #ifdef CONFIG_FAIR_GROUP_SCHED
