diff options
| -rw-r--r-- | kernel/sched/fair.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index f0380d4987b3..2b449a762074 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -3503,15 +3503,22 @@ unsigned long __weak arch_scale_smt_power(struct sched_domain *sd, int cpu) unsigned long scale_rt_power(int cpu) { struct rq *rq = cpu_rq(cpu); - u64 total, available; + u64 total, available, age_stamp, avg; - total = sched_avg_period() + (rq->clock - rq->age_stamp); + /* + * Since we're reading these variables without serialization make sure + * we read them once before doing sanity checks on them. + */ + age_stamp = ACCESS_ONCE(rq->age_stamp); + avg = ACCESS_ONCE(rq->rt_avg); + + total = sched_avg_period() + (rq->clock - age_stamp); - if (unlikely(total < rq->rt_avg)) { + if (unlikely(total < avg)) { /* Ensures that power won't end up being negative */ available = 0; } else { - available = total - rq->rt_avg; + available = total - avg; } if (unlikely((s64)total < SCHED_POWER_SCALE)) |