[cpufreq] ondemand: make shutdown sequence more robust
Shutting down the ondemand policy was fraught with potential
problems, causing issues for SMP suspend (which wants to hot-
unplug) all but the last CPU.
This should fix at least the worst problems (divide-by-zero
and infinite wait for the workqueue to shut down).
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
index 8729992..178f0c5 100644
--- a/drivers/cpufreq/cpufreq_ondemand.c
+++ b/drivers/cpufreq/cpufreq_ondemand.c
@@ -239,6 +239,8 @@
total_ticks = (unsigned int) cputime64_sub(cur_jiffies,
this_dbs_info->prev_cpu_wall);
this_dbs_info->prev_cpu_wall = cur_jiffies;
+ if (!total_ticks)
+ return;
/*
* Every sampling_rate, we check, if current idle time is less
* than 20% (default), then we try to increase frequency
@@ -304,6 +306,9 @@
unsigned int cpu = smp_processor_id();
struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu);
+ if (!dbs_info->enable)
+ return;
+
dbs_check_cpu(dbs_info);
queue_delayed_work_on(cpu, kondemand_wq, &dbs_info->work,
usecs_to_jiffies(dbs_tuners_ins.sampling_rate));
@@ -319,11 +324,11 @@
return;
}
-static inline void dbs_timer_exit(unsigned int cpu)
+static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info)
{
- struct cpu_dbs_info_s *dbs_info = &per_cpu(cpu_dbs_info, cpu);
-
- cancel_rearming_delayed_workqueue(kondemand_wq, &dbs_info->work);
+ dbs_info->enable = 0;
+ cancel_delayed_work(&dbs_info->work);
+ flush_workqueue(kondemand_wq);
}
static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
@@ -396,8 +401,7 @@
case CPUFREQ_GOV_STOP:
mutex_lock(&dbs_mutex);
- dbs_timer_exit(policy->cpu);
- this_dbs_info->enable = 0;
+ dbs_timer_exit(this_dbs_info);
sysfs_remove_group(&policy->kobj, &dbs_attr_group);
dbs_enable--;
if (dbs_enable == 0)