Messages in this thread Patch in this message | | | From | Hillf Danton <> | Subject | Re: [PATCH v5 2/2] sched/fair: Check a task has a fitting cpu when updating misfit | Date | Tue, 6 Feb 2024 18:55:30 +0800 |
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On Mon, 5 Feb 2024 02:11:23 +0000 Qais Yousef <qyousef@layalina.io> > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -5092,24 +5092,36 @@ static inline int task_fits_cpu(struct task_struct *p, int cpu) > > static inline void update_misfit_status(struct task_struct *p, struct rq *rq) > { > + unsigned long cpu_cap; > + int cpu = cpu_of(rq); > + > if (!sched_asym_cpucap_active()) > return; > > - if (!p || p->nr_cpus_allowed == 1) { > - rq->misfit_task_load = 0; > - return; > - } > + if (!p || p->nr_cpus_allowed == 1) > + goto out; > > - if (task_fits_cpu(p, cpu_of(rq))) { > - rq->misfit_task_load = 0; > - return; > - } > + cpu_cap = arch_scale_cpu_capacity(cpu); > + > + /* If we can't fit the biggest CPU, that's the best we can ever get. */ > + if (cpu_cap == rq->rd->max_cpu_capacity) > + goto out; > + > + /* Affinity allows us to go somewhere higher? */ > + if (cpu_cap == p->max_allowed_capacity) > + goto out;
Looks good. > + > + if (task_fits_cpu(p, cpu)) > + goto out; > > /* > * Make sure that misfit_task_load will not be null even if > * task_h_load() returns 0. > */ > rq->misfit_task_load = max_t(unsigned long, task_h_load(p), 1); > + return; > +out: > + rq->misfit_task_load = 0; > } > > #else /* CONFIG_SMP */ > @@ -8241,6 +8253,36 @@ static void task_dead_fair(struct task_struct *p) > remove_entity_load_avg(&p->se); > } > > +/* > + * Check the max capacity the task is allowed to run at for misfit detection. > + */ > +static void set_task_max_allowed_capacity(struct task_struct *p) > +{ > + struct asym_cap_data *entry; > + > + if (!sched_asym_cpucap_active()) > + return; > + > + rcu_read_lock(); > + list_for_each_entry_rcu(entry, &asym_cap_list, link) { > + cpumask_t *cpumask; > + > + cpumask = cpu_capacity_span(entry); > + if (!cpumask_intersects(p->cpus_ptr, cpumask)) > + continue; > + > + p->max_allowed_capacity = entry->capacity; > + break;
Given what max_allowed_capacity could mean, it is needed to find the max capacity by iterating the asym_cap_list instead of the first capacity determined by the allowed CPU mask. > + } > + rcu_read_unlock(); > +}
BTW is it working in case of systems with a super core?
cpu0-3 cpu4-6 cpu7 little big super core core core
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