From e2a1f85bf9f509afd09b5d3308e3489b65845c28 Mon Sep 17 00:00:00 2001 From: Yang Yang Date: Sun, 14 May 2023 09:33:38 -0700 Subject: [PATCH] sched/psi: Avoid resetting the min update period when it is unnecessary Psi_group's poll_min_period is determined by the minimum window size of psi_trigger when creating new triggers. While destroying a psi_trigger, there is no need to reset poll_min_period if the psi_trigger being destroyed did not have the minimum window size, since in this condition poll_min_period will remain the same as before. Signed-off-by: Yang Yang Signed-off-by: Peter Zijlstra (Intel) Acked-by: Suren Baghdasaryan Link: https://lkml.kernel.org/r/20230514163338.834345-1-surenb@google.com --- kernel/sched/psi.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index b49af594ad28..81fca77397f6 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -1407,11 +1407,16 @@ void psi_trigger_destroy(struct psi_trigger *t) group->rtpoll_nr_triggers[t->state]--; if (!group->rtpoll_nr_triggers[t->state]) group->rtpoll_states &= ~(1 << t->state); - /* reset min update period for the remaining triggers */ - list_for_each_entry(tmp, &group->rtpoll_triggers, node) - period = min(period, div_u64(tmp->win.size, - UPDATES_PER_WINDOW)); - group->rtpoll_min_period = period; + /* + * Reset min update period for the remaining triggers + * iff the destroying trigger had the min window size. + */ + if (group->rtpoll_min_period == div_u64(t->win.size, UPDATES_PER_WINDOW)) { + list_for_each_entry(tmp, &group->rtpoll_triggers, node) + period = min(period, div_u64(tmp->win.size, + UPDATES_PER_WINDOW)); + group->rtpoll_min_period = period; + } /* Destroy rtpoll_task when the last trigger is destroyed */ if (group->rtpoll_states == 0) { group->rtpoll_until = 0;