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    SubjectRe: [PATCH v3 07/10] sched/psi: add PSI_IRQ to track IRQ/SOFTIRQ pressure
    On Wed, Aug 24, 2022 at 04:18:26PM +0800, Chengming Zhou wrote:
    > @@ -903,6 +903,36 @@ void psi_task_switch(struct task_struct *prev, struct task_struct *next,
    > }
    > }
    >
    > +#ifdef CONFIG_IRQ_TIME_ACCOUNTING
    > +void psi_account_irqtime(struct task_struct *task, u32 delta)
    > +{
    > + int cpu = task_cpu(task);
    > + void *iter = NULL;
    > + struct psi_group *group;
    > + struct psi_group_cpu *groupc;
    > + u64 now;
    > +
    > + if (!task->pid)
    > + return;
    > +
    > + now = cpu_clock(cpu);
    > +
    > + while ((group = iterate_groups(task, &iter))) {
    > + groupc = per_cpu_ptr(group->pcpu, cpu);
    > +
    > + write_seqcount_begin(&groupc->seq);
    > +
    > + record_times(groupc, now);
    > + groupc->times[PSI_IRQ_FULL] += delta;
    > +
    > + write_seqcount_end(&groupc->seq);
    > +
    > + if (group->poll_states & (1 << PSI_IRQ_FULL))
    > + psi_schedule_poll_work(group, 1);
    > + }

    Shouldn't this kick avgs_work too? If the CPU is otherwise idle,
    times[PSI_IRQ_FULL] would overflow after two missed averaging runs.

    avgs_work should probably also self-perpetuate when PSI_IRQ_FULL is in
    changed_states. (Looking at that code, I think it can be simplified:
    delete nonidle and do `if (changed_states) schedule_delayed_work()`.)

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