On 03.04.20 14:30, Qais Yousef wrote:
[...]
> @@ -924,6 +945,14 @@ uclamp_eff_get(struct task_struct *p, enum uclamp_id clamp_id)
> return uc_req;
> }
>
> +static void uclamp_rt_sync_default_util_min(struct task_struct *p)
> +{
> + struct uclamp_se *uc_se = &p->uclamp_req[UCLAMP_MIN];
> +
> + if (!uc_se->user_defined)
> + uclamp_se_set(uc_se, sysctl_sched_rt_default_uclamp_util_min, false);
> +}
> +
> unsigned long uclamp_eff_value(struct task_struct *p, enum uclamp_id clamp_id)
> {
> struct uclamp_se uc_eff;
> @@ -1030,6 +1059,12 @@ static inline void uclamp_rq_inc(struct rq *rq, struct task_struct *p)
> if (unlikely(!p->sched_class->uclamp_enabled))
> return;
>
> + /*
> + * When sysctl_sched_rt_default_uclamp_util_min value is changed by the
> + * user, we apply any new value on the next wakeup, which is here.
> + */
> + uclamp_rt_sync_default_util_min(p);
> +
Does this have to be an extra function? Can we not reuse
uclamp_tg_restrict() by slightly rename it to uclamp_restrict()?
This function will then deal with enforcing restrictions, whether system
and taskgroup hierarchy related or default value (latter only for rt-min
right now since the others are fixed) related.
uclamp_eff_get() -> uclamp_restrict() is called from:
'enqueue_task(), uclamp_update_active() -> uclamp_rq_inc() -> uclamp_rq_inc_id()' and
'task_fits_capacity() -> clamp_task_util(), rt_task_fits_capacity() -> uclamp_eff_value()' and
'schedutil_cpu_util(), find_energy_efficient_cpu() -> uclamp_rq_util_with() -> uclamp_eff_value()'
so there would be more check-points than the one in 'enqueue_task() -> uclamp_rq_inc()' now.
Only lightly tested:
---8<---
From: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
Date: Sun, 19 Apr 2020 01:20:17 +0200
Subject: [PATCH] sched/core: uclamp: Move uclamp_rt_sync_default_util_min()
into uclamp_tg_restrict()
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
---
kernel/sched/core.c | 34 +++++++++++++++-------------------
1 file changed, 15 insertions(+), 19 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 8f4e0d5c7daf..6802113d6d4b 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -899,12 +899,22 @@ unsigned int uclamp_rq_max_value(struct rq *rq, enum uclamp_id clamp_id,
}
static inline struct uclamp_se
-uclamp_tg_restrict(struct task_struct *p, enum uclamp_id clamp_id)
+uclamp_restrict(struct task_struct *p, enum uclamp_id clamp_id)
{
- struct uclamp_se uc_req = p->uclamp_req[clamp_id];
-#ifdef CONFIG_UCLAMP_TASK_GROUP
- struct uclamp_se uc_max;
+ struct uclamp_se uc_req, __maybe_unused uc_max;
+
+ if (unlikely(rt_task(p)) && clamp_id == UCLAMP_MIN &&
+ !uc_req.user_defined) {
+ struct uclamp_se *uc_se = &p->uclamp_req[UCLAMP_MIN];
+ int rt_min = sysctl_sched_rt_default_uclamp_util_min;
+
+ if (uc_se->value != rt_min)
+ uclamp_se_set(uc_se, rt_min, false);
+ }
+ uc_req = p->uclamp_req[clamp_id];
+
+#ifdef CONFIG_UCLAMP_TASK_GROUP
/*
* Tasks in autogroups or root task group will be
* restricted by system defaults.
@@ -933,7 +943,7 @@ uclamp_tg_restrict(struct task_struct *p, enum uclamp_id clamp_id)
static inline struct uclamp_se
uclamp_eff_get(struct task_struct *p, enum uclamp_id clamp_id)
{
- struct uclamp_se uc_req = uclamp_tg_restrict(p, clamp_id);
+ struct uclamp_se uc_req = uclamp_restrict(p, clamp_id);
struct uclamp_se uc_max = uclamp_default[clamp_id];
/* System default restrictions always apply */
@@ -943,14 +953,6 @@ uclamp_eff_get(struct task_struct *p, enum uclamp_id clamp_id)
return uc_req;
}
-static void uclamp_rt_sync_default_util_min(struct task_struct *p)
-{
- struct uclamp_se *uc_se = &p->uclamp_req[UCLAMP_MIN];
-
- if (!uc_se->user_defined)
- uclamp_se_set(uc_se, sysctl_sched_rt_default_uclamp_util_min, false);
-}
-
unsigned long uclamp_eff_value(struct task_struct *p, enum uclamp_id clamp_id)
{
struct uclamp_se uc_eff;
@@ -1057,12 +1059,6 @@ static inline void uclamp_rq_inc(struct rq *rq, struct task_struct *p)
if (unlikely(!p->sched_class->uclamp_enabled))
return;
- /*
- * When sysctl_sched_rt_default_uclamp_util_min value is changed by the
- * user, we apply any new value on the next wakeup, which is here.
- */
- uclamp_rt_sync_default_util_min(p);
-
for_each_clamp_id(clamp_id)
uclamp_rq_inc_id(rq, p, clamp_id);
--
2.17.1
