Hello Shrikanth,
On 9/10/2025 11:12 PM, Shrikanth Hegde wrote:
> @@ -8563,7 +8563,7 @@ select_task_rq_fair(struct task_struct *p, int
> prev_cpu, int wake_flags)
> if (!is_rd_overutilized(this_rq()->rd)) {
> new_cpu = find_energy_efficient_cpu(p, prev_cpu);
> if (new_cpu >= 0)
> - return new_cpu;
> + goto check_new_cpu;
Should this fallback to the overutilized path if the most energy
efficient CPU is found to be paravirtualized or should
find_energy_efficient_cpu() be made aware of it?
> new_cpu = prev_cpu;
> }
>
> @@ -8605,7 +8605,12 @@ select_task_rq_fair(struct task_struct *p, int
> prev_cpu, int wake_flags)
> }
> rcu_read_unlock();
>
> - return new_cpu;
> + /* If newly found or prev_cpu is a paravirt cpu, use current cpu */
> +check_new_cpu:
> + if (is_cpu_paravirt(new_cpu))
> + return cpu;
> + else
nit. redundant else.
> + return new_cpu;
> }
>
> /*
> @@ -11734,6 +11739,12 @@ static int sched_balance_rq(int this_cpu, struct rq
> *this_rq,
>
> cpumask_and(cpus, sched_domain_span(sd), cpu_active_mask);
>
> +#ifdef CONFIG_PARAVIRT
> + /* Don't spread load to paravirt CPUs */
> + if (static_branch_unlikely(&cpu_paravirt_push_tasks))
> + cpumask_andnot(cpus, cpus, cpu_paravirt_mask);
> +#endif
Can something similar be also be done in select_idle_sibling() and
sched_balance_find_dst_cpu() for wakeup path?
> +
> schedstat_inc(sd->lb_count[idle]);
>
> redo:
--
Thanks and Regards,
Prateek
