psi: Fix trigger being fired unexpectedly at initial

When a trigger being created, its win.start_value and win.start_time are
reset to zero. If group->total[PSI_POLL][t->state] has accumulated before,
this trigger will be fired unexpectedly in the next period, even if its
growth time does not reach its threshold.

So set the window of the new trigger to the current state value.

Signed-off-by: Hailong Liu <liuhailong@linux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Suren Baghdasaryan <surenb@google.com>
Link: https://lore.kernel.org/r/1648789811-3788971-1-git-send-email-liuhailong@linux.alibaba.com

diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index a4fa3aadfcba6f06b04d9958959622caa70ff1e0..5a49a8c8783e08a582efbd13bebd0d2bc4612a12 100644 (file)
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -1117,7 +1117,8 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group,
        t->state = state;
        t->threshold = threshold_us * NSEC_PER_USEC;
        t->win.size = window_us * NSEC_PER_USEC;
-       window_reset(&t->win, 0, 0, 0);
+       window_reset(&t->win, sched_clock(),
+                       group->total[PSI_POLL][t->state], 0);
 
        t->event = 0;
        t->last_event_time = 0;