Messages in this thread Patch in this message | | | Date | Fri, 26 Jul 2019 16:54:22 +0200 | From | Peter Zijlstra <> | Subject | [RFC][PATCH 13/13] sched/fair: Add trivial fair server |
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Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- kernel/sched/core.c | 6 +++++- kernel/sched/deadline.c | 2 ++ kernel/sched/fair.c | 29 +++++++++++++++++++++++++++++ kernel/sched/sched.h | 6 +++++- 4 files changed, 41 insertions(+), 2 deletions(-)
--- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6501,6 +6504,7 @@ void __init sched_init(void) #endif /* CONFIG_SMP */ hrtick_rq_init(rq); atomic_set(&rq->nr_iowait, 0); + fair_server_init(rq); } set_load_weight(&init_task, false); --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5239,6 +5239,9 @@ enqueue_task_fair(struct rq *rq, struct */ util_est_enqueue(&rq->cfs, p); + if (!rq->cfs.h_nr_running) + dl_server_start(&rq->fair_server); + /* * If in_iowait is set, the code below may not trigger any cpufreq * utilization updates, so do it here explicitly with the IOWAIT flag @@ -5374,6 +5377,9 @@ static void dequeue_task_fair(struct rq if (!se) sub_nr_running(rq, 1); + if (!rq->cfs.h_nr_running) + dl_server_stop(&rq->fair_server); + util_est_dequeue(&rq->cfs, p, task_sleep); hrtick_update(rq); } @@ -6903,6 +6909,29 @@ done: __maybe_unused; return NULL; } +static bool fair_server_has_tasks(struct sched_dl_entity *dl_se) +{ + return !!dl_se->rq->cfs.nr_running; +} + +static struct task_struct *fair_server_pick(struct sched_dl_entity *dl_se) +{ + return pick_next_task_fair(dl_se->rq, NULL, NULL); +} + +void fair_server_init(struct rq *rq) +{ + struct sched_dl_entity *dl_se = &rq->fair_server; + + init_dl_entity(dl_se); + + dl_se->dl_runtime = TICK_NSEC; + dl_se->dl_deadline = 20 * TICK_NSEC; + dl_se->dl_period = 20 * TICK_NSEC; + + dl_server_init(dl_se, rq, fair_server_has_tasks, fair_server_pick); +} + /* * Account for a descheduled task: */ --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -345,6 +345,8 @@ extern void dl_server_init(struct sched_ dl_server_has_tasks_f has_tasks, dl_server_pick_f pick); +extern void fair_server_init(struct rq *); + #ifdef CONFIG_CGROUP_SCHED #include <linux/cgroup.h> @@ -905,6 +907,8 @@ struct rq { struct rt_rq rt; struct dl_rq dl; + struct sched_dl_entity fair_server; + #ifdef CONFIG_FAIR_GROUP_SCHED /* list of leaf cfs_rq on this CPU: */ struct list_head leaf_cfs_rq_list; @@ -968,7 +972,7 @@ struct rq { /* This is used to determine avg_idle's max value */ u64 max_idle_balance_cost; -#endif +#endif /* CONFIG_SMP */ #ifdef CONFIG_IRQ_TIME_ACCOUNTING u64 prev_irq_time;
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