Commit 99b773d7 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Linus Torvalds
Browse files

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: 570c8efd ("sched/psi: Optimize psi_group_change() cpu_clock() usage")
Reported-by: default avatarChris Mason <clm@meta.com>
Suggested-by: default avatarBeata Michalska <beata.michalska@arm.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d632ab86

kernel/sched/psi.c

+1 −5
Original line number Diff line number Diff line
@@ -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);