Commit 80cc1d1d authored by Yang Yang's avatar Yang Yang Committed by Ingo Molnar
Browse files

sched/psi: Avoid updating PSI triggers and ->rtpoll_total when there are no state changes 



When psimon wakes up and there are no state changes for ->rtpoll_states,
it's unnecessary to update triggers and ->rtpoll_total because the pressures
being monitored by the user have not changed.

This will help to slightly reduce unnecessary computations of PSI.

[ mingo: Changelog updates ]

Signed-off-by: default avatarYang Yang <yang.yang29@zte.com.cn>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Peter Ziljstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/202310101641075436843@zte.com.cn
parent b19fdb16

kernel/sched/psi.c

+4 −3
Original line number Diff line number Diff line
@@ -704,12 +704,13 @@ static void psi_rtpoll_work(struct psi_group *group) 
	}



	if (now >= group->rtpoll_next_update) {

		if (changed_states & group->rtpoll_states) {

			update_triggers(group, now, &update_total, PSI_POLL);

		group->rtpoll_next_update = now + group->rtpoll_min_period;

		if (update_total)

			memcpy(group->rtpoll_total, group->total[PSI_POLL],

				   sizeof(group->rtpoll_total));

		}

		group->rtpoll_next_update = now + group->rtpoll_min_period;

	}



	psi_schedule_rtpoll_work(group,

		nsecs_to_jiffies(group->rtpoll_next_update - now) + 1,