On Fri, Nov 05, 2021 at 06:33:10PM -0700, Ricardo Neri wrote:
> @@ -72,6 +78,9 @@ struct hfi_instance {
> u16 die_id;
> struct cpumask *cpus;
> void *hw_table;
> + struct delayed_work update_work;
> + raw_spinlock_t event_lock;
+ raw_spinlock_t interrupt_lock;
> + u64 timestamp;
> bool initialized;
> };
>
> @@ -114,6 +123,75 @@ static struct hfi_instance *hfi_instances;
> static struct hfi_features hfi_features;
> static DEFINE_MUTEX(hfi_lock);
>
> +#define HFI_UPDATE_INTERVAL HZ
> +
> +static void hfi_update_work_fn(struct work_struct *work)
> +{
> + struct hfi_instance *hfi_instance;
> +
> + hfi_instance = container_of(to_delayed_work(work), struct hfi_instance,
> + update_work);
> + if (!hfi_instance)
> + return;
> +
> + /* TODO: Consume update here. */
// this here uses ->event_lock to serialize against the
// interrupt below changing the data...
> +}
> +
> +void intel_hfi_process_event(__u64 pkg_therm_status_msr_val)
> +{
> + struct hfi_instance *hfi_instance;
> + int cpu = smp_processor_id();
> + struct hfi_cpu_info *info;
> + unsigned long flags;
> + u64 timestamp;
> +
> + if (!pkg_therm_status_msr_val)
> + return;
> +
> + info = &per_cpu(hfi_cpu_info, cpu);
> + if (!info)
> + return;
> +
> + /*
> + * It is possible that we get an HFI thermal interrupt on this CPU
> + * before its HFI instance is initialized. This is not a problem. The
> + * CPU that enabled the interrupt for this package will also get the
> + * interrupt and is fully initialized.
> + */
> + hfi_instance = info->hfi_instance;
> + if (!hfi_instance)
> + return;
> +
/*
* If someone is already handling the interrupt, we shouldn't be
* burning time waiting for them to then do more nothing.
*/
if (!raw_spin_trylock(&hfi_instance->interrupt_lock))
return;
> + raw_spin_lock_irqsave(&hfi_instance->event_lock, flags);
> +
> + /*
> + * On most systems, all CPUs in the package receive a package-level
> + * thermal interrupt when there is an HFI update. Since they all are
> + * dealing with the same update (as indicated by the update timestamp),
> + * it is sufficient to let a single CPU to acknowledge the update and
> + * schedule work to process it.
> + */
> + timestamp = *(u64 *)hfi_instance->hw_table;
> + if (hfi_instance->timestamp >= timestamp)
> + goto unlock_spinlock;
This can go the way of the dodo.
> +
> + hfi_instance->timestamp = timestamp;
> +
> + memcpy(hfi_instance->table_base, hfi_instance->hw_table,
> + hfi_features.nr_table_pages << PAGE_SHIFT);
> + /*
> + * Let hardware and other CPUs know that we are done reading the HFI
> + * table and it is free to update it again.
> + */
> + pkg_therm_status_msr_val &= THERM_STATUS_CLEAR_PKG_MASK &
> + ~PACKAGE_THERM_STATUS_HFI_UPDATED;
> + wrmsrl(MSR_IA32_PACKAGE_THERM_STATUS, pkg_therm_status_msr_val);
> + schedule_delayed_work(&hfi_instance->update_work, HFI_UPDATE_INTERVAL);
> +
> +unlock_spinlock:
> + raw_spin_unlock_irqrestore(&hfi_instance->event_lock, flags);
raw_spin_unlock(&hfi_instance->interrupt_lock);
> +}
