[PATCH v2 1/4] psi: add psi_group_flush_stats() function

[Vernon Yang <vernon2gm@gmail.com>]

From: Vernon Yang <yanglincheng@kylinos.cn>

Add psi_group_flush_stats() function to prepare for the subsequent
mthp_ext ebpf program.

no function changes.

Signed-off-by: Vernon Yang <yanglincheng@kylinos.cn>
---
 include/linux/psi.h |  1 +
 kernel/sched/psi.c  | 34 ++++++++++++++++++++++++++--------
 2 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/include/linux/psi.h b/include/linux/psi.h
index e0745873e3f2..7b4fd8190810 100644
--- a/include/linux/psi.h
+++ b/include/linux/psi.h
@@ -22,6 +22,7 @@ void psi_init(void);
 void psi_memstall_enter(unsigned long *flags);
 void psi_memstall_leave(unsigned long *flags);
 
+void psi_group_flush_stats(struct psi_group *group);
 int psi_show(struct seq_file *s, struct psi_group *group, enum psi_res res);
 struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf,
 				       enum psi_res res, struct file *file,
diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index d9c9d9480a45..76ffad90b0b5 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -1242,11 +1242,35 @@ void psi_cgroup_restart(struct psi_group *group)
 }
 #endif /* CONFIG_CGROUPS */
 
+/*
+ * __psi_group_flush_stats - flush the total stall time of a psi group
+ * @group: psi group to flush
+ */
+static void __psi_group_flush_stats(struct psi_group *group)
+{
+	u64 now;
+
+	/* Update averages before reporting them */
+	mutex_lock(&group->avgs_lock);
+	now = sched_clock();
+	collect_percpu_times(group, PSI_AVGS, NULL);
+	if (now >= group->avg_next_update)
+		group->avg_next_update = update_averages(group, now);
+	mutex_unlock(&group->avgs_lock);
+}
+
+void psi_group_flush_stats(struct psi_group *group)
+{
+	if (static_branch_likely(&psi_disabled))
+		return;
+
+	__psi_group_flush_stats(group);
+}
+
 int psi_show(struct seq_file *m, struct psi_group *group, enum psi_res res)
 {
 	bool only_full = false;
 	int full;
-	u64 now;
 
 	if (static_branch_likely(&psi_disabled))
 		return -EOPNOTSUPP;
@@ -1256,13 +1280,7 @@ int psi_show(struct seq_file *m, struct psi_group *group, enum psi_res res)
 		return -EOPNOTSUPP;
 #endif
 
-	/* Update averages before reporting them */
-	mutex_lock(&group->avgs_lock);
-	now = sched_clock();
-	collect_percpu_times(group, PSI_AVGS, NULL);
-	if (now >= group->avg_next_update)
-		group->avg_next_update = update_averages(group, now);
-	mutex_unlock(&group->avgs_lock);
+	__psi_group_flush_stats(group);
 
 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
 	only_full = res == PSI_IRQ;
-- 
2.53.0