sched_clock_irqtime may be disabled due to the clock source. When disabled, irq_time_read() won't change over time, so there is nothing to account. We can save iterating the whole hierarchy on every tick and context switch. Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> Reviewed-by: Michal Koutný <mkoutny@xxxxxxxx> Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx> --- kernel/sched/psi.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index 84dad1511d1e..bb56805e3d47 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -998,7 +998,7 @@ void psi_account_irqtime(struct rq *rq, struct task_struct *curr, struct task_st s64 delta; u64 irq; - if (static_branch_likely(&psi_disabled)) + if (static_branch_likely(&psi_disabled) || !irqtime_enabled()) return; if (!curr->pid) @@ -1240,6 +1240,11 @@ int psi_show(struct seq_file *m, struct psi_group *group, enum psi_res res) if (static_branch_likely(&psi_disabled)) return -EOPNOTSUPP; +#ifdef CONFIG_IRQ_TIME_ACCOUNTING + if (!irqtime_enabled() && res == PSI_IRQ) + return -EOPNOTSUPP; +#endif + /* Update averages before reporting them */ mutex_lock(&group->avgs_lock); now = sched_clock(); -- 2.43.5
