Re: [PATCH 1/9] sched/psi: fix periodic aggregation shut off

Chengming Zhou
2022-07-26T13:29:20Z

On 2022/7/25 23:39, Johannes Weiner wrote:
> On Thu, Jul 21, 2022 at 12:04:31PM +0800, Chengming Zhou wrote:
>> @@ -871,13 +861,23 @@ void psi_task_switch(struct task_struct *prev, struct task_struct *next,
>> clear |= TSK_MEMSTALL_RUNNING;
>> if (prev->in_iowait)
>> set |= TSK_IOWAIT;
>> +
>> + /*
>> + * Periodic aggregation shuts off if there is a period of no
>> + * task changes, so we wake it back up if necessary. However,
>> + * don't do this if the task change is the aggregation worker
>> + * itself going to sleep, or we'll ping-pong forever.
>> + */
>> + if (unlikely((prev->flags & PF_WQ_WORKER) &&
>> + wq_worker_last_func(prev) == psi_avgs_work))
>> + wake_clock = false;
>> }
>>
>> psi_flags_change(prev, clear, set);
>>
>> iter = NULL;
>> while ((group = iterate_groups(prev, &iter)) && group != common)
>> - psi_group_change(group, cpu, clear, set, now, true);
>> + psi_group_change(group, cpu, clear, set, now, wake_clock);
>>
>> /*
>> * TSK_ONCPU is handled up to the common ancestor. If we're tasked
>
> Wait, there is another psi_group_change() below this, which handles
> the clearing of TSK_RUNNING for common ancestors. We don't want to
> wake those either, so it needs s/true/wake_clock/ as well.

Yes, I was wrong, will fix.

Thanks!