From: Linus Torvalds Date: Sun, 23 Jul 2006 19:05:00 +0000 (-0700) Subject: [cpufreq] ondemand: make shutdown sequence more robust X-Git-Tag: v2.6.18-rc3~58 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=2cd7cbdf4bd0d0fe58e4dc903e8b413412595504;p=linux-2.6-omap-h63xx.git [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 --- diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c index 87299924e73..178f0c547eb 100644 --- a/drivers/cpufreq/cpufreq_ondemand.c +++ b/drivers/cpufreq/cpufreq_ondemand.c @@ -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)