Messages in this thread | | | Subject | Re: [RFCv6 PATCH 03/10] sched: scheduler-driven cpu frequency selection | From | Steve Muckle <> | Date | Wed, 10 Feb 2016 20:44:47 -0800 |
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Hi Ricky,
On 02/01/2016 09:10 AM, Ricky Liang wrote: >> +static int cpufreq_sched_policy_init(struct cpufreq_policy *policy) >> > +{ >> > + struct gov_data *gd; >> > + int cpu; >> > + >> > + for_each_cpu(cpu, policy->cpus) >> > + memset(&per_cpu(cpu_sched_capacity_reqs, cpu), 0, >> > + sizeof(struct sched_capacity_reqs)); >> > + >> > + gd = kzalloc(sizeof(*gd), GFP_KERNEL); >> > + if (!gd) >> > + return -ENOMEM; >> > + >> > + gd->throttle_nsec = policy->cpuinfo.transition_latency ? >> > + policy->cpuinfo.transition_latency : >> > + THROTTLE_NSEC; >> > + pr_debug("%s: throttle threshold = %u [ns]\n", >> > + __func__, gd->throttle_nsec); >> > + >> > + if (cpufreq_driver_is_slow()) { >> > + cpufreq_driver_slow = true; >> > + gd->task = kthread_create(cpufreq_sched_thread, policy, >> > + "kschedfreq:%d", >> > + cpumask_first(policy->related_cpus)); >> > + if (IS_ERR_OR_NULL(gd->task)) { >> > + pr_err("%s: failed to create kschedfreq thread\n", >> > + __func__); >> > + goto err; >> > + } >> > + get_task_struct(gd->task); >> > + kthread_bind_mask(gd->task, policy->related_cpus); >> > + wake_up_process(gd->task); >> > + init_irq_work(&gd->irq_work, cpufreq_sched_irq_work); >> > + } >> > + >> > + policy->governor_data = gd; > > This should be moved before if(cpufreq_driver_is_slow()) {...}. I've > seen NULL pointer deference at boot in cpufreq_sched_thread() when it > tried to run sched_setscheduler_nocheck(gd->task, SCHED_FIFO, ¶m).
Agreed, this has been addressed during various cleanups and reorganization since the last posting.
> >> > + set_sched_freq(); >> > + >> > + return 0; >> > + >> > +err: > And probably also set policy->governor_data to NULL here.
Changed. Thanks for the comments.
thanks, Steve
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