[RFC,6/6] sched/uclamp: Simplify uclamp_eff_value()
Commit Message
From: Hongyan Xia <hongyan.xia2@arm.com>
The commit
sched: Remove all uclamp bucket logic
removes uclamp_{inc/dec}() functions, so now p->uclamp contains the
correct values all the time after a update_uclamp_active() call, and
there's no need to toggle the boolean `active` after an update. As a
result, this function is fairly simple now and can live as a static
inline function.
Signed-off-by: Hongyan Xia <hongyan.xia2@arm.com>
---
kernel/sched/core.c | 13 ++++---------
kernel/sched/sched.h | 14 ++++++++++++--
2 files changed, 16 insertions(+), 11 deletions(-)
Comments
On 04/10/2023 11:04, Hongyan Xia wrote:
> From: Hongyan Xia <hongyan.xia2@arm.com>
>
> The commit
>
> sched: Remove all uclamp bucket logic
>
> removes uclamp_{inc/dec}() functions, so now p->uclamp contains the
s/uclamp_{inc/dec}/uclamp_rq_{inc/dec}
> correct values all the time after a update_uclamp_active() call, and
s/update_uclamp_active()/uclamp_update_active()
> there's no need to toggle the boolean `active` after an update. As a
> result, this function is fairly simple now and can live as a static
> inline function.
[...]
> -unsigned long uclamp_eff_value(struct task_struct *p, enum uclamp_id clamp_id)
> -{
> - if (!uclamp_is_used() || !p->uclamp[clamp_id].active)
> - return uclamp_none(clamp_id);
> -
> - return p->uclamp[clamp_id].value;
> -}
> -
Is there still a need for p->uclamp[clamp_id].active ? Does
uclamp_eff_value() ever get called with !active ?
And why do we have to set uclamp default values in case (!used ||
!active)? Shouldn't they be set already in this situation?
[...]
@@ -1483,21 +1483,15 @@ uclamp_eff_get(struct task_struct *p, enum uclamp_id clamp_id)
return uc_req;
}
-unsigned long uclamp_eff_value(struct task_struct *p, enum uclamp_id clamp_id)
-{
- if (!uclamp_is_used() || !p->uclamp[clamp_id].active)
- return uclamp_none(clamp_id);
-
- return p->uclamp[clamp_id].value;
-}
-
static inline void
uclamp_update_active_nolock(struct task_struct *p)
{
enum uclamp_id clamp_id;
- for_each_clamp_id(clamp_id)
+ for_each_clamp_id(clamp_id) {
p->uclamp[clamp_id] = uclamp_eff_get(p, clamp_id);
+ p->uclamp[clamp_id].active = 1;
+ }
}
static inline void
@@ -1759,6 +1753,7 @@ static void uclamp_fork(struct task_struct *p)
for_each_clamp_id(clamp_id) {
uclamp_se_set(&p->uclamp_req[clamp_id],
uclamp_none(clamp_id), false);
+ p->uclamp[clamp_id].active = 0;
}
}
@@ -2986,8 +2986,6 @@ static inline unsigned long cpu_util_rt(struct rq *rq)
#endif
#ifdef CONFIG_UCLAMP_TASK
-unsigned long uclamp_eff_value(struct task_struct *p, enum uclamp_id clamp_id);
-
/*
* When uclamp is compiled in, the aggregation at rq level is 'turned off'
* by default in the fast path and only gets turned on once userspace performs
@@ -3001,6 +2999,18 @@ static inline bool uclamp_is_used(void)
return static_branch_likely(&sched_uclamp_used);
}
+static inline unsigned long uclamp_eff_value(struct task_struct *p,
+ enum uclamp_id clamp_id)
+{
+ if (uclamp_is_used() && p->uclamp[clamp_id].active)
+ return p->uclamp[clamp_id].value;
+
+ if (clamp_id == UCLAMP_MIN)
+ return 0;
+
+ return SCHED_CAPACITY_SCALE;
+}
+
static inline unsigned long root_cfs_util(struct rq *rq)
{
return READ_ONCE(rq->root_cfs_util_uclamp);