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authorvenkatesh.pallipadi@intel.com <venkatesh.pallipadi@intel.com>2009-07-02 20:08:33 -0400
committerDave Jones <davej@redhat.com>2009-07-06 21:38:28 -0400
commitee88415caf736b89500f16e0a545614541a45005 (patch)
treeb54b7d57e0886b042e55580627295677de75072c
parent5a75c82828e7c088ca6e7b4827911dc29cc8e774 (diff)
[CPUFREQ] Cleanup locking in conservative governor
Redesign the locking inside conservative driver. Make dbs_mutex handle all the global state changes inside the driver and invent a new percpu mutex to serialize percpu timer and frequency limit change. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
-rw-r--r--drivers/cpufreq/cpufreq_conservative.c34
1 files changed, 13 insertions, 21 deletions
diff --git a/drivers/cpufreq/cpufreq_conservative.c b/drivers/cpufreq/cpufreq_conservative.c
index 58889f26029a..57490502b21c 100644
--- a/drivers/cpufreq/cpufreq_conservative.c
+++ b/drivers/cpufreq/cpufreq_conservative.c
@@ -63,7 +63,12 @@ struct cpu_dbs_info_s {
63 unsigned int down_skip; 63 unsigned int down_skip;
64 unsigned int requested_freq; 64 unsigned int requested_freq;
65 int cpu; 65 int cpu;
66 unsigned int enable:1; 66 /*
67 * percpu mutex that serializes governor limit change with
68 * do_dbs_timer invocation. We do not want do_dbs_timer to run
69 * when user is changing the governor or limits.
70 */
71 struct mutex timer_mutex;
67}; 72};
68static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info); 73static DEFINE_PER_CPU(struct cpu_dbs_info_s, cpu_dbs_info);
69 74
@@ -71,9 +76,7 @@ static unsigned int dbs_enable; /* number of CPUs using this policy */
71 76
72/* 77/*
73 * dbs_mutex protects data in dbs_tuners_ins from concurrent changes on 78 * dbs_mutex protects data in dbs_tuners_ins from concurrent changes on
74 * different CPUs. It protects dbs_enable in governor start/stop. It also 79 * different CPUs. It protects dbs_enable in governor start/stop.
75 * serializes governor limit_change with do_dbs_timer. We do not want
76 * do_dbs_timer to run when user is changing the governor or limits.
77 */ 80 */
78static DEFINE_MUTEX(dbs_mutex); 81static DEFINE_MUTEX(dbs_mutex);
79 82
@@ -138,9 +141,6 @@ dbs_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
138 141
139 struct cpufreq_policy *policy; 142 struct cpufreq_policy *policy;
140 143
141 if (!this_dbs_info->enable)
142 return 0;
143
144 policy = this_dbs_info->cur_policy; 144 policy = this_dbs_info->cur_policy;
145 145
146 /* 146 /*
@@ -483,17 +483,12 @@ static void do_dbs_timer(struct work_struct *work)
483 483
484 delay -= jiffies % delay; 484 delay -= jiffies % delay;
485 485
486 mutex_lock(&dbs_mutex); 486 mutex_lock(&dbs_info->timer_mutex);
487
488 if (!dbs_info->enable) {
489 mutex_unlock(&dbs_mutex);
490 return;
491 }
492 487
493 dbs_check_cpu(dbs_info); 488 dbs_check_cpu(dbs_info);
494 489
495 queue_delayed_work_on(cpu, kconservative_wq, &dbs_info->work, delay); 490 queue_delayed_work_on(cpu, kconservative_wq, &dbs_info->work, delay);
496 mutex_unlock(&dbs_mutex); 491 mutex_unlock(&dbs_info->timer_mutex);
497} 492}
498 493
499static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info) 494static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info)
@@ -502,7 +497,6 @@ static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info)
502 int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate); 497 int delay = usecs_to_jiffies(dbs_tuners_ins.sampling_rate);
503 delay -= jiffies % delay; 498 delay -= jiffies % delay;
504 499
505 dbs_info->enable = 1;
506 INIT_DELAYED_WORK_DEFERRABLE(&dbs_info->work, do_dbs_timer); 500 INIT_DELAYED_WORK_DEFERRABLE(&dbs_info->work, do_dbs_timer);
507 queue_delayed_work_on(dbs_info->cpu, kconservative_wq, &dbs_info->work, 501 queue_delayed_work_on(dbs_info->cpu, kconservative_wq, &dbs_info->work,
508 delay); 502 delay);
@@ -510,7 +504,6 @@ static inline void dbs_timer_init(struct cpu_dbs_info_s *dbs_info)
510 504
511static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info) 505static inline void dbs_timer_exit(struct cpu_dbs_info_s *dbs_info)
512{ 506{
513 dbs_info->enable = 0;
514 cancel_delayed_work_sync(&dbs_info->work); 507 cancel_delayed_work_sync(&dbs_info->work);
515} 508}
516 509
@@ -529,9 +522,6 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
529 if ((!cpu_online(cpu)) || (!policy->cur)) 522 if ((!cpu_online(cpu)) || (!policy->cur))
530 return -EINVAL; 523 return -EINVAL;
531 524
532 if (this_dbs_info->enable) /* Already enabled */
533 break;
534
535 mutex_lock(&dbs_mutex); 525 mutex_lock(&dbs_mutex);
536 526
537 rc = sysfs_create_group(&policy->kobj, &dbs_attr_group); 527 rc = sysfs_create_group(&policy->kobj, &dbs_attr_group);
@@ -555,6 +545,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
555 this_dbs_info->down_skip = 0; 545 this_dbs_info->down_skip = 0;
556 this_dbs_info->requested_freq = policy->cur; 546 this_dbs_info->requested_freq = policy->cur;
557 547
548 mutex_init(&this_dbs_info->timer_mutex);
558 dbs_enable++; 549 dbs_enable++;
559 /* 550 /*
560 * Start the timerschedule work, when this governor 551 * Start the timerschedule work, when this governor
@@ -596,6 +587,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
596 mutex_lock(&dbs_mutex); 587 mutex_lock(&dbs_mutex);
597 sysfs_remove_group(&policy->kobj, &dbs_attr_group); 588 sysfs_remove_group(&policy->kobj, &dbs_attr_group);
598 dbs_enable--; 589 dbs_enable--;
590 mutex_destroy(&this_dbs_info->timer_mutex);
599 591
600 /* 592 /*
601 * Stop the timerschedule work, when this governor 593 * Stop the timerschedule work, when this governor
@@ -611,7 +603,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
611 break; 603 break;
612 604
613 case CPUFREQ_GOV_LIMITS: 605 case CPUFREQ_GOV_LIMITS:
614 mutex_lock(&dbs_mutex); 606 mutex_lock(&this_dbs_info->timer_mutex);
615 if (policy->max < this_dbs_info->cur_policy->cur) 607 if (policy->max < this_dbs_info->cur_policy->cur)
616 __cpufreq_driver_target( 608 __cpufreq_driver_target(
617 this_dbs_info->cur_policy, 609 this_dbs_info->cur_policy,
@@ -620,7 +612,7 @@ static int cpufreq_governor_dbs(struct cpufreq_policy *policy,
620 __cpufreq_driver_target( 612 __cpufreq_driver_target(
621 this_dbs_info->cur_policy, 613 this_dbs_info->cur_policy,
622 policy->min, CPUFREQ_RELATION_L); 614 policy->min, CPUFREQ_RELATION_L);
623 mutex_unlock(&dbs_mutex); 615 mutex_unlock(&this_dbs_info->timer_mutex);
624 616
625 break; 617 break;
626 } 618 }