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> --- kernel/sched/psi.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index 020d58967d4e..49d9c75be0c8 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -1000,7 +1000,8 @@ void psi_account_irqtime(struct rq *rq, struct task_struct *curr, struct task_st u64 now, irq; s64 delta; - if (static_branch_likely(&psi_disabled)) + if (static_branch_likely(&psi_disabled) || + !static_branch_likely(&sched_clock_irqtime)) return; if (!curr->pid) -- 2.43.5
