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Message-ID: <20240226194642.47530-1-ppbuk5246@gmail.com>
Date: Mon, 26 Feb 2024 19:46:42 +0000
From: Levi Yun <ppbuk5246@...il.com>
To: hannes@...xchg.org,
surenb@...gle.com,
peterz@...radead.org,
mingo@...hat.com,
juri.lelli@...hat.com,
vincent.guittot@...aro.org,
dietmar.eggemann@....com,
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bsegall@...gle.com,
mgorman@...e.de,
bristot@...hat.com,
vschneid@...hat.com
Cc: linux-kernel@...r.kernel.org,
Levi Yun <ppbuk5246@...il.com>
Subject: [PATCH] psi: Fix avg trigger being fired unexpectedly.
commit 915a087e4c473("psi: Fix trigger being fired unexpectedly at initial")
fixes unexpected event fired when group->total accumlated for PSI_POLL.
But, for PSI_AVGS, win->value should be initialized with group->total[PSI_AVGS].
Moreover, to get exact initial value for win->value, it should be set
under each trigger lock to synchronize each rtpoll/avgs_works.
Signed-off-by: Levi Yun <ppbuk5246@...il.com>
---
kernel/sched/psi.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index 7b4aa5809c0f..e7f66ab2ad3e 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -1323,9 +1323,6 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf,
t->state = state;
t->threshold = threshold_us * NSEC_PER_USEC;
t->win.size = window_us * NSEC_PER_USEC;
- window_reset(&t->win, sched_clock(),
- group->total[PSI_POLL][t->state], 0);
-
t->event = 0;
t->last_event_time = 0;
t->of = of;
@@ -1336,6 +1333,8 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf,
if (privileged) {
mutex_lock(&group->rtpoll_trigger_lock);
+ window_reset(&t->win, sched_clock(),
+ group->total[PSI_POLL][t->state], 0);
if (!rcu_access_pointer(group->rtpoll_task)) {
struct task_struct *task;
@@ -1361,6 +1360,9 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf,
} else {
mutex_lock(&group->avgs_lock);
+ window_reset(&t->win, sched_clock(),
+ group->total[PSI_AVGS][t->state], 0);
+
list_add(&t->node, &group->avg_triggers);
group->avg_nr_triggers[t->state]++;
--
2.39.2
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