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sched/psi: Fix psi_seq initialization

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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: 570c8efd5e ("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: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Peter Zijlstra 2025-07-15 15:11:14 -04:00 • committed by Linus Torvalds
parent d632ab86af
commit 99b773d720
1 changed files with 1 additions and 5 deletions
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6
kernel/sched/psi.c
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@ -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);