Re: [PATCH net v2 2/2] net/sched: taprio: do not replay missed entries in advance_sched()

[Vinicius Costa Gomes]

Hi,

Krystian Kaniewski <krystianmkaniewski@xxxxxxxxx> writes:

> On 10/14/26 22:51, Vinicius Costa Gomes wrote:
>>>>> +	struct sched_entry *entry, *found = NULL;
>>>>> +	ktime_t cycle_start = sched->start_time;
>>>>> +	s64 offset, entry_end = 0, elapsed = 0;
>>>>> +
>>>>> +	if (ktime_after(now, cycle_start)) {
>>>>> +		s64 periods = div64_s64(ktime_sub(now, cycle_start),
>>>>> +					sched->period);
>>>>> +
>>>>> +		cycle_start = ktime_add_ns(cycle_start,
>>>>> +					   periods * sched->period);
>>>>> +	}
>>>>> +	offset = ktime_sub(now, cycle_start);
>>>>> +
>>>>> +	/* The offset is less than one period, so an entry which ends after
>>>>> +	 * @now is found at the latest at the entry which reaches the end of
>>>>> +	 * the cycle, or at the last entry. A schedule has at least one entry,
>>>>> +	 * so the loop always sets found.
>>>>> +	 */
>>>>> +	list_for_each_entry(entry, &sched->entries, list) {
>>>>> +		entry_end = min_t(s64, elapsed + entry->interval,
>>>>> +				  sched->cycle_time);
>>>>> +		if (offset < entry_end ||
>>>>> +		    list_is_last(&entry->list, &sched->entries)) {
>>>>> +			found = entry;
>>>>> +			break;
>>>>> +		}
>>>>> +		elapsed = entry_end;
>>>>> +	}
>>>>> +
>>>>> +	*start = ktime_add_ns(cycle_start, elapsed);
>>>>> +	*end = ktime_add_ns(cycle_start, entry_end);
>>>>> +	sched->cycle_end_time = ktime_add_ns(cycle_start,
>>>>> sched->cycle_time);
>>>>
>>>> Having this side effect here was unexpected. I think this would make
>>>> more sense outside this function.
>>>>
>>>
>>> Agreed. I can make taprio_entry_at() return the cycle end through an
>>> extra output argument and have advance_sched() store it explicitly in
>>> oper->cycle_end_time. The helper could then take the schedule as const.
>>>
>>> I can wait for the rest of your review of this patch before sending v3
>>>
>> 
>> I am going to try and review this by end of this week.
>> 
>> 
>> Cheers,
>
> Hi Vinicius,
>
> Just a gentle ping on patch 2/2. Did you have a chance to continue the
> review?


Sorry for the delay, just another minor/optional nitpick. The series
look good, run a couple of tests on a VM. For the series:

Acked-by: Vinicius Costa Gomes <vinicius.gomes@xxxxxxxxx>


> -- 
> Krystian Kaniewski

-- 
Vinicius