sched/psi: Fix psi_seq initialization
With the seqcount moved out of the group into a global psi_seq,
re-initializing the seqcount on group creation is causing seqcount
corruption.
Fixes: 570c8efd5eb7 ("sched/psi: Optimize psi_group_change() cpu_clock() usage")
Reported-by: Chris Mason <clm@meta.com>
Suggested-by: Beata Michalska <beata.michalska@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>
(cherry picked from commit c639efabe86c3c24b4474e02bf81224060c40c2b)
diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index 2024c1d..59fdb7e 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -176,7 +176,7 @@ struct psi_group psi_system = {
.pcpu = &system_group_pcpu,
};
-static DEFINE_PER_CPU(seqcount_t, psi_seq);
+static DEFINE_PER_CPU(seqcount_t, psi_seq) = SEQCNT_ZERO(psi_seq);
static inline void psi_write_begin(int cpu)
{
@@ -204,11 +204,7 @@ static void poll_timer_fn(struct timer_list *t);
static void group_init(struct psi_group *group)
{
- int cpu;
-
group->enabled = true;
- for_each_possible_cpu(cpu)
- seqcount_init(per_cpu_ptr(&psi_seq, cpu));
group->avg_last_update = sched_clock();
group->avg_next_update = group->avg_last_update + psi_period;
mutex_init(&group->avgs_lock);