The following commit has been merged into the sched/core branch of tip:
Commit-ID: e2a1f85bf9f509afd09b5d3308e3489b65845c28
Gitweb: https://git.kernel.org/tip/e2a1f85bf9f509afd09b5d3308e3489b65845c28
Author: Yang Yang <yang.yang29@xxxxxxxxxx>
AuthorDate: Sun, 14 May 2023 09:33:38 -07:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Sat, 20 May 2023 12:53:16 +02:00
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 <yang.yang29@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Acked-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20230514163338.834345-1-surenb@xxxxxxxxxx
---
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 b49af59..81fca77 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;
|