This is a note to let you know that I've just added the patch titled
sched/uclamp: Make cpu_overutilized() use util_fits_cpu()
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sched-uclamp-make-cpu_overutilized-use-util_fits_cpu.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit e7a2af41dc6690ce8d1e923a4bbb1ffe6e7f51f0
Author: Qais Yousef <qais.yousef@xxxxxxx>
Date: Thu Aug 4 15:36:06 2022 +0100
sched/uclamp: Make cpu_overutilized() use util_fits_cpu()
[ Upstream commit c56ab1b3506ba0e7a872509964b100912bde165d ]
So that it is now uclamp aware.
This fixes a major problem of busy tasks capped with UCLAMP_MAX keeping
the system in overutilized state which disables EAS and leads to wasting
energy in the long run.
Without this patch running a busy background activity like JIT
compilation on Pixel 6 causes the system to be in overutilized state
74.5% of the time.
With this patch this goes down to 9.79%.
It also fixes another problem when long running tasks that have their
UCLAMP_MIN changed while running such that they need to upmigrate to
honour the new UCLAMP_MIN value. The upmigration doesn't get triggered
because overutilized state never gets set in this state, hence misfit
migration never happens at tick in this case until the task wakes up
again.
Fixes: af24bde8df202 ("sched/uclamp: Add uclamp support to energy_compute()")
Signed-off-by: Qais Yousef <qais.yousef@xxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20220804143609.515789-7-qais.yousef@xxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index cabbdac97eaa..a0ee3192e5a7 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5987,7 +5987,10 @@ static inline void hrtick_update(struct rq *rq)
#ifdef CONFIG_SMP
static inline bool cpu_overutilized(int cpu)
{
- return !fits_capacity(cpu_util_cfs(cpu), capacity_of(cpu));
+ unsigned long rq_util_min = uclamp_rq_get(cpu_rq(cpu), UCLAMP_MIN);
+ unsigned long rq_util_max = uclamp_rq_get(cpu_rq(cpu), UCLAMP_MAX);
+
+ return !util_fits_cpu(cpu_util_cfs(cpu), rq_util_min, rq_util_max, cpu);
}
static inline void update_overutilized_status(struct rq *rq)
