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[cpufreq] ondemand: make shutdown sequence more robust

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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>
This commit is contained in:
Linus Torvalds 2006-07-23 12:05:00 -07:00
parent 12157a8d78
commit 2cd7cbdf4b
1 changed files with 10 additions and 6 deletions
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16
drivers/cpufreq/cpufreq_ondemand.c
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@ -239,6 +239,8 @@ static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info)
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 @@ static void do_dbs_timer(void *data)
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 @@ static inline void dbs_timer_init(unsigned int cpu)
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 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
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)