[GIT PULL] scheduler fixes

Ingo Molnar
2023-10-08T09:33:03Z

Linus,

Please pull the latest sched/urgent git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git sched-urgent-2023-10-08

# HEAD: 9e0bc36ab07c550d791bf17feeb479f1dfc42d89 cpufreq: schedutil: Update next_freq when cpufreq_limits change

Misc fixes:

- Two EEVDF fixes: one to fix sysctl_sched_base_slice propagation,
and to fix an avg_vruntime() corner-case.

- A cpufreq frequency scaling fix

Thanks,

Ingo

------------------>
Peter Zijlstra (2):
sched/eevdf: Also update slice on placement
sched/eevdf: Fix avg_vruntime()

Xuewen Yan (1):
cpufreq: schedutil: Update next_freq when cpufreq_limits change

kernel/sched/cpufreq_schedutil.c | 3 ++-
kernel/sched/fair.c | 16 +++++++++++++---
2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index 4492608b7d7f..458d359f5991 100644
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -350,7 +350,8 @@ static void sugov_update_single_freq(struct update_util_data *hook, u64 time,
* Except when the rq is capped by uclamp_max.
*/
if (!uclamp_rq_is_capped(cpu_rq(sg_cpu->cpu)) &&
- sugov_cpu_is_busy(sg_cpu) && next_f < sg_policy->next_freq) {
+ sugov_cpu_is_busy(sg_cpu) && next_f < sg_policy->next_freq &&
+ !sg_policy->need_freq_update) {
next_f = sg_policy->next_freq;

/* Restore cached freq as next_freq has changed */
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index cb225921bbca..ef7490c4b8b4 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -664,6 +664,10 @@ void avg_vruntime_update(struct cfs_rq *cfs_rq, s64 delta)
cfs_rq->avg_vruntime -= cfs_rq->avg_load * delta;
}

+/*
+ * Specifically: avg_runtime() + 0 must result in entity_eligible() := true
+ * For this to be so, the result of this function must have a left bias.
+ */
u64 avg_vruntime(struct cfs_rq *cfs_rq)
{
struct sched_entity *curr = cfs_rq->curr;
@@ -677,8 +681,12 @@ u64 avg_vruntime(struct cfs_rq *cfs_rq)
load += weight;
}

- if (load)
+ if (load) {
+ /* sign flips effective floor / ceil */
+ if (avg < 0)
+ avg -= (load - 1);
avg = div_s64(avg, load);
+ }

return cfs_rq->min_vruntime + avg;
}
@@ -4919,10 +4927,12 @@ static inline void update_misfit_status(struct task_struct *p, struct rq *rq) {}
static void
place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
{
- u64 vslice = calc_delta_fair(se->slice, se);
- u64 vruntime = avg_vruntime(cfs_rq);
+ u64 vslice, vruntime = avg_vruntime(cfs_rq);
s64 lag = 0;

+ se->slice = sysctl_sched_base_slice;
+ vslice = calc_delta_fair(se->slice, se);
+
/*
* Due to how V is constructed as the weighted average of entities,
* adding tasks with positive lag, or removing tasks with negative lag