diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/cpufreq_schedutil.c | 28 |
1 files changed, 24 insertions, 4 deletions
diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index b713ce0a5702..bcab867575bb 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -81,9 +81,20 @@ static bool sugov_should_update_freq(struct sugov_policy *sg_policy, u64 time) if (!cpufreq_this_cpu_can_update(sg_policy->policy)) return false; - if (unlikely(sg_policy->limits_changed)) { - sg_policy->limits_changed = false; + if (unlikely(READ_ONCE(sg_policy->limits_changed))) { + WRITE_ONCE(sg_policy->limits_changed, false); sg_policy->need_freq_update = true; + + /* + * The above limits_changed update must occur before the reads + * of policy limits in cpufreq_driver_resolve_freq() or a policy + * limits update might be missed, so use a memory barrier to + * ensure it. + * + * This pairs with the write memory barrier in sugov_limits(). + */ + smp_mb(); + return true; } @@ -377,7 +388,7 @@ static inline bool sugov_hold_freq(struct sugov_cpu *sg_cpu) { return false; } static inline void ignore_dl_rate_limit(struct sugov_cpu *sg_cpu) { if (cpu_bw_dl(cpu_rq(sg_cpu->cpu)) > sg_cpu->bw_min) - sg_cpu->sg_policy->limits_changed = true; + WRITE_ONCE(sg_cpu->sg_policy->limits_changed, true); } static inline bool sugov_update_single_common(struct sugov_cpu *sg_cpu, @@ -883,7 +894,16 @@ static void sugov_limits(struct cpufreq_policy *policy) mutex_unlock(&sg_policy->work_lock); } - sg_policy->limits_changed = true; + /* + * The limits_changed update below must take place before the updates + * of policy limits in cpufreq_set_policy() or a policy limits update + * might be missed, so use a memory barrier to ensure it. + * + * This pairs with the memory barrier in sugov_should_update_freq(). + */ + smp_wmb(); + + WRITE_ONCE(sg_policy->limits_changed, true); } struct cpufreq_governor schedutil_gov = { |