diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/cpufreq/cpufreq_governor.c | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c index c9a571fd79ac..064582aa5a0d 100644 --- a/drivers/cpufreq/cpufreq_governor.c +++ b/drivers/cpufreq/cpufreq_governor.c @@ -340,7 +340,7 @@ static void dbs_update_util_handler(struct update_util_data *data, u64 time, { struct cpu_dbs_info *cdbs = container_of(data, struct cpu_dbs_info, update_util); struct policy_dbs_info *policy_dbs = cdbs->policy_dbs; - u64 delta_ns; + u64 delta_ns, lst; /* * The work may not be allowed to be queued up right now. @@ -356,7 +356,8 @@ static void dbs_update_util_handler(struct update_util_data *data, u64 time, * of sample_delay_ns used in the computation may be stale. */ smp_rmb(); - delta_ns = time - policy_dbs->last_sample_time; + lst = READ_ONCE(policy_dbs->last_sample_time); + delta_ns = time - lst; if ((s64)delta_ns < policy_dbs->sample_delay_ns) return; @@ -365,9 +366,19 @@ static void dbs_update_util_handler(struct update_util_data *data, u64 time, * at this point. Otherwise, we need to ensure that only one of the * CPUs sharing the policy will do that. */ - if (policy_dbs->is_shared && - !atomic_add_unless(&policy_dbs->work_count, 1, 1)) - return; + if (policy_dbs->is_shared) { + if (!atomic_add_unless(&policy_dbs->work_count, 1, 1)) + return; + + /* + * If another CPU updated last_sample_time in the meantime, we + * shouldn't be here, so clear the work counter and bail out. + */ + if (unlikely(lst != READ_ONCE(policy_dbs->last_sample_time))) { + atomic_set(&policy_dbs->work_count, 0); + return; + } + } policy_dbs->last_sample_time = time; policy_dbs->work_in_progress = true; |