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author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2008-01-25 20:08:29 (GMT) |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-01-25 20:08:29 (GMT) |
commit | fa85ae2418e6843953107cd6a06f645752829bc0 (patch) | |
tree | 004130ac471247a29d3f6adfbfe61c474e725779 /kernel/sched.c | |
parent | 8f4d37ec073c17e2d4aa8851df5837d798606d6f (diff) | |
download | linux-fa85ae2418e6843953107cd6a06f645752829bc0.tar.xz |
sched: rt time limit
Very simple time limit on the realtime scheduling classes.
Allow the rq's realtime class to consume sched_rt_ratio of every
sched_rt_period slice. If the class exceeds this quota the fair class
will preempt the realtime class.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r-- | kernel/sched.c | 70 |
1 files changed, 50 insertions, 20 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 17f93d3..e9a7bee 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -342,13 +342,14 @@ struct cfs_rq { /* Real-Time classes' related field in a runqueue: */ struct rt_rq { struct rt_prio_array active; - int rt_load_balance_idx; - struct list_head *rt_load_balance_head, *rt_load_balance_curr; unsigned long rt_nr_running; +#ifdef CONFIG_SMP unsigned long rt_nr_migratory; - /* highest queued rt task prio */ - int highest_prio; + int highest_prio; /* highest queued rt task prio */ int overloaded; +#endif + u64 rt_time; + u64 rt_throttled; }; #ifdef CONFIG_SMP @@ -415,6 +416,7 @@ struct rq { struct list_head leaf_cfs_rq_list; #endif struct rt_rq rt; + u64 rt_period_expire; /* * This is part of a global counter where only the total sum @@ -601,6 +603,21 @@ const_debug unsigned int sysctl_sched_features = const_debug unsigned int sysctl_sched_nr_migrate = 32; /* + * period over which we measure -rt task cpu usage in ms. + * default: 1s + */ +const_debug unsigned int sysctl_sched_rt_period = 1000; + +#define SCHED_RT_FRAC_SHIFT 16 +#define SCHED_RT_FRAC (1UL << SCHED_RT_FRAC_SHIFT) + +/* + * ratio of time -rt tasks may consume. + * default: 100% + */ +const_debug unsigned int sysctl_sched_rt_ratio = SCHED_RT_FRAC; + +/* * For kernel-internal use: high-speed (but slightly incorrect) per-cpu * clock constructed from sched_clock(): */ @@ -3674,8 +3691,8 @@ void scheduler_tick(void) rq->clock = next_tick; rq->tick_timestamp = rq->clock; update_cpu_load(rq); - if (curr != rq->idle) /* FIXME: needed? */ - curr->sched_class->task_tick(rq, curr, 0); + curr->sched_class->task_tick(rq, curr, 0); + update_sched_rt_period(rq); spin_unlock(&rq->lock); #ifdef CONFIG_SMP @@ -7041,6 +7058,29 @@ static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq) cfs_rq->min_vruntime = (u64)(-(1LL << 20)); } +static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq) +{ + struct rt_prio_array *array; + int i; + + array = &rt_rq->active; + for (i = 0; i < MAX_RT_PRIO; i++) { + INIT_LIST_HEAD(array->queue + i); + __clear_bit(i, array->bitmap); + } + /* delimiter for bitsearch: */ + __set_bit(MAX_RT_PRIO, array->bitmap); + +#ifdef CONFIG_SMP + rt_rq->rt_nr_migratory = 0; + rt_rq->highest_prio = MAX_RT_PRIO; + rt_rq->overloaded = 0; +#endif + + rt_rq->rt_time = 0; + rt_rq->rt_throttled = 0; +} + void __init sched_init(void) { int highest_cpu = 0; @@ -7051,7 +7091,6 @@ void __init sched_init(void) #endif for_each_possible_cpu(i) { - struct rt_prio_array *array; struct rq *rq; rq = cpu_rq(i); @@ -7083,6 +7122,8 @@ void __init sched_init(void) } init_task_group.shares = init_task_group_load; #endif + init_rt_rq(&rq->rt, rq); + rq->rt_period_expire = 0; for (j = 0; j < CPU_LOAD_IDX_MAX; j++) rq->cpu_load[j] = 0; @@ -7095,22 +7136,11 @@ void __init sched_init(void) rq->cpu = i; rq->migration_thread = NULL; INIT_LIST_HEAD(&rq->migration_queue); - rq->rt.highest_prio = MAX_RT_PRIO; - rq->rt.overloaded = 0; rq_attach_root(rq, &def_root_domain); #endif init_rq_hrtick(rq); - atomic_set(&rq->nr_iowait, 0); - - array = &rq->rt.active; - for (j = 0; j < MAX_RT_PRIO; j++) { - INIT_LIST_HEAD(array->queue + j); - __clear_bit(j, array->bitmap); - } highest_cpu = i; - /* delimiter for bitsearch: */ - __set_bit(MAX_RT_PRIO, array->bitmap); } set_load_weight(&init_task); @@ -7282,7 +7312,7 @@ void set_curr_task(int cpu, struct task_struct *p) #ifdef CONFIG_SMP /* * distribute shares of all task groups among their schedulable entities, - * to reflect load distrbution across cpus. + * to reflect load distribution across cpus. */ static int rebalance_shares(struct sched_domain *sd, int this_cpu) { @@ -7349,7 +7379,7 @@ static int rebalance_shares(struct sched_domain *sd, int this_cpu) * sysctl_sched_max_bal_int_shares represents the maximum interval between * consecutive calls to rebalance_shares() in the same sched domain. * - * These settings allows for the appropriate tradeoff between accuracy of + * These settings allows for the appropriate trade-off between accuracy of * fairness and the associated overhead. * */ |