[PATCH v4 2/9] drm/i915/gvt: create an idle vGPU

[Gao, Ping A]

On 2017/3/14 18:15, Tian, Kevin wrote:
>> From: Ping Gao
>> Sent: Wednesday, March 8, 2017 2:24 PM
>>
>> vGPU execution time is given by scheduler, it decide the resource vGPU could
> given->allocated
>
> what's difference between execution time and resource? If same meaning
> just keep the former part.

sure, I will keep use 'vgpu resource' .

>
>> take. Creating an idle vGPU mainly used to help time slice usage calculation
> 'is' mainly
>
>> and worked as a time slice pool to consume the time slice that active vGPU
>> no need. Besides that it also helpful to handle some special case.
> I guess above can be simplified like below:
>
> vGPU execution time is allocated by scheduler. To account for non-allocated
> free cycles, we create an idle vGPU as the placeholder similar to idle task
> concept, which is useful to handle some corner cases in scheduling policy.

OK, thanks!

>
>> Signed-off-by: Ping Gao <ping.a.gao at intel.com>
>> ---
>>  drivers/gpu/drm/i915/gvt/gvt.c  | 11 +++++++++
>> drivers/gpu/drm/i915/gvt/gvt.h  |  3 +++  drivers/gpu/drm/i915/gvt/vgpu.c |
>> 51 +++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 65 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/i915/gvt/gvt.c b/drivers/gpu/drm/i915/gvt/gvt.c
>> index 3e8c30f..996467d 100644
>> --- a/drivers/gpu/drm/i915/gvt/gvt.c
>> +++ b/drivers/gpu/drm/i915/gvt/gvt.c
>> @@ -201,6 +201,8 @@ void intel_gvt_clean_device(struct drm_i915_private
>> *dev_priv)
>>
>>  	idr_destroy(&gvt->vgpu_idr);
>>
>> +	intel_gvt_destroy_idle_vgpu(gvt->idle_vgpu);
> does idle_vgpu also have an idr? If yes, should destroy idle
> vgpu before idr_destroy. 

As you mention later this patch ,I will define a macro of the idr start
to use for active_vgpu .

>
>> +
>>  	kfree(dev_priv->gvt);
>>  	dev_priv->gvt = NULL;
>>  }
>> @@ -219,6 +221,7 @@ void intel_gvt_clean_device(struct drm_i915_private
>> *dev_priv)  int intel_gvt_init_device(struct drm_i915_private *dev_priv)  {
>>  	struct intel_gvt *gvt;
>> +	struct intel_vgpu *vgpu;
>>  	int ret;
>>
>>  	/*
>> @@ -291,6 +294,14 @@ int intel_gvt_init_device(struct drm_i915_private
>> *dev_priv)
>>  		goto out_clean_types;
>>  	}
>>
>> +	vgpu = intel_gvt_create_idle_vgpu(gvt);
>> +	if (IS_ERR(vgpu)) {
>> +		ret = PTR_ERR(vgpu);
>> +		gvt_err("failed to create intel idle vgpu: %d\n", ret);
> "Failed to create idle vGPU"

OK.

>> +		goto out_clean_types;
>> +	}
>> +	gvt->idle_vgpu = vgpu;
>> +
>>  	gvt_dbg_core("gvt device initialization is done\n");
>>  	dev_priv->gvt = gvt;
>>  	return 0;
>> diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
>> index 1839456..f3f5678 100644
>> --- a/drivers/gpu/drm/i915/gvt/gvt.h
>> +++ b/drivers/gpu/drm/i915/gvt/gvt.h
>> @@ -237,6 +237,7 @@ struct intel_gvt {
>>  	struct intel_vgpu_type *types;
>>  	unsigned int num_types;
>>  	atomic_t num_vgpu_sched;
>> +	struct intel_vgpu *idle_vgpu;
>>
>>  	struct task_struct *service_thread;
>>  	wait_queue_head_t service_thread_wq;
>> @@ -378,6 +379,8 @@ static inline void intel_vgpu_write_pci_bar(struct
>> intel_vgpu *vgpu,  int intel_gvt_init_vgpu_types(struct intel_gvt *gvt);  void
>> intel_gvt_clean_vgpu_types(struct intel_gvt *gvt);
>>
>> +struct intel_vgpu *intel_gvt_create_idle_vgpu(struct intel_gvt *gvt);
>> +void intel_gvt_destroy_idle_vgpu(struct intel_vgpu *vgpu);
>>  struct intel_vgpu *intel_gvt_create_vgpu(struct intel_gvt *gvt,
>>  					 struct intel_vgpu_type *type);
>>  void intel_gvt_destroy_vgpu(struct intel_vgpu *vgpu); diff --git
>> a/drivers/gpu/drm/i915/gvt/vgpu.c b/drivers/gpu/drm/i915/gvt/vgpu.c
>> index f3bec5a..945327b 100644
>> --- a/drivers/gpu/drm/i915/gvt/vgpu.c
>> +++ b/drivers/gpu/drm/i915/gvt/vgpu.c
>> @@ -216,6 +216,57 @@ void intel_gvt_destroy_vgpu(struct intel_vgpu
>> *vgpu)
>>  	mutex_unlock(&gvt->lock);
>>  }
>>
>> +/**
>> + * intel_gvt_create_idle_vgpu - create an idle virtual GPU
>> + * @gvt: GVT device
>> + *
>> + * This function is called when user wants to create an idle virtual GPU.
>> + *
>> + * Returns:
>> + * pointer to intel_vgpu, error pointer if failed.
>> + */
>> +struct intel_vgpu *intel_gvt_create_idle_vgpu(struct intel_gvt *gvt) {
>> +	struct intel_vgpu *vgpu;
>> +	enum intel_engine_id i;
>> +	int ret;
>> +
>> +	vgpu = vzalloc(sizeof(*vgpu));
>> +	if (!vgpu)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	vgpu->id = 0;
> please define a macro. Then use that macro as start in idr_alloc
> for other vgpus. 

Sure.

>> +	vgpu->gvt = gvt;
>> +
>> +	for (i = 0; i < I915_NUM_ENGINES; i++)
>> +		INIT_LIST_HEAD(&vgpu->workload_q_head[i]);
>> +
>> +	ret = intel_vgpu_init_sched_policy(vgpu);
>> +	if (ret)
>> +		goto out_free_vgpu;
>> +
>> +	vgpu->active = false;
>> +
>> +	return vgpu;
>> +
>> +out_free_vgpu:
>> +	vfree(vgpu);
>> +	return ERR_PTR(ret);
>> +}
>> +
>> +/**
>> + * intel_gvt_destroy_vgpu - destroy an idle virtual GPU
>> + * @vgpu: virtual GPU
>> + *
>> + * This function is called when user wants to destroy an idle virtual GPU.
>> + *
>> + */
>> +void intel_gvt_destroy_idle_vgpu(struct intel_vgpu *vgpu) {
>> +	intel_vgpu_clean_sched_policy(vgpu);
>> +	vfree(vgpu);
>> +}
>> +
>>  static struct intel_vgpu *__intel_gvt_create_vgpu(struct intel_gvt *gvt,
>>  		struct intel_vgpu_creation_params *param)  {
>> --
>> 2.7.4
>>
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