diff options
| author | Tony Luck <tony.luck@intel.com> | 2006-06-23 13:46:23 -0700 |
|---|---|---|
| committer | Tony Luck <tony.luck@intel.com> | 2006-06-23 13:46:23 -0700 |
| commit | 8cf60e04a131310199d5776e2f9e915f0c468899 (patch) | |
| tree | 373a68e88e6737713a0a5723d552cdeefffff929 /drivers/cpufreq/cpufreq_conservative.c | |
| parent | 1323523f505606cfd24af6122369afddefc3b09d (diff) | |
| parent | 95eaa5fa8eb2c345244acd5f65b200b115ae8c65 (diff) | |
Auto-update from upstream
Diffstat (limited to 'drivers/cpufreq/cpufreq_conservative.c')
| -rw-r--r-- | drivers/cpufreq/cpufreq_conservative.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/cpufreq/cpufreq_conservative.c b/drivers/cpufreq/cpufreq_conservative.c index e07a35487bd..b3ebc8f0197 100644 --- a/drivers/cpufreq/cpufreq_conservative.c +++ b/drivers/cpufreq/cpufreq_conservative.c @@ -22,6 +22,7 @@ #include <linux/types.h> #include <linux/fs.h> #include <linux/sysfs.h> +#include <linux/cpu.h> #include <linux/sched.h> #include <linux/kmod.h> #include <linux/workqueue.h> @@ -72,6 +73,14 @@ static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info); static unsigned int dbs_enable; /* number of CPUs using this policy */ +/* + * DEADLOCK ALERT! There is a ordering requirement between cpu_hotplug + * lock and dbs_mutex. cpu_hotplug lock should always be held before + * dbs_mutex. If any function that can potentially take cpu_hotplug lock + * (like __cpufreq_driver_target()) is being called with dbs_mutex taken, then + * cpu_hotplug lock should be taken before that. Note that cpu_hotplug lock + * is recursive for the same process. -Venki + */ static DEFINE_MUTEX (dbs_mutex); static DECLARE_WORK (dbs_work, do_dbs_timer, NULL); @@ -414,12 +423,14 @@ static void dbs_check_cpu(int cpu) static void do_dbs_timer(void *data) { int i; + lock_cpu_hotplug(); mutex_lock(&dbs_mutex); for_each_online_cpu(i) dbs_check_cpu(i); schedule_delayed_work(&dbs_work, usecs_to_jiffies(dbs_tuners_ins.sampling_rate)); mutex_unlock(&dbs_mutex); + unlock_cpu_hotplug(); } static inline void dbs_timer_init(void) @@ -514,6 +525,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy, break; case CPUFREQ_GOV_LIMITS: + lock_cpu_hotplug(); mutex_lock(&dbs_mutex); if (policy->max < this_dbs_info->cur_policy->cur) __cpufreq_driver_target( @@ -524,6 +536,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy, this_dbs_info->cur_policy, policy->min, CPUFREQ_RELATION_L); mutex_unlock(&dbs_mutex); + unlock_cpu_hotplug(); break; } return 0; |