[PATCH v2 1/2] drm/i915/gvt: Factor out scan and shadow from workload dispatch

Dong, Chuanxiao chuanxiao.dong at intel.com
Thu Jun 8 06:46:54 UTC 2017


> -----Original Message-----
> From: intel-gvt-dev [mailto:intel-gvt-dev-bounces at lists.freedesktop.org] On
> Behalf Of Ping Gao
> Sent: Thursday, June 8, 2017 10:31 AM
> To: intel-gvt-dev at lists.freedesktop.org
> Cc: Gao, Ping A <ping.a.gao at intel.com>
> Subject: [PATCH v2 1/2] drm/i915/gvt: Factor out scan and shadow from
> workload dispatch
> 
> To perform the workload scan and shadow in ELSP writing stage for
> performance consideration, the workload scan and shadow stuffs should be
> factored out from dispatch_workload().
> 
> v2:Put context pin before i915_add_request;
>    Refine the comments;
>    Rename some APIs;
> 
> Signed-off-by: Ping Gao <ping.a.gao at intel.com>
> ---
>  drivers/gpu/drm/i915/gvt/cmd_parser.c |  2 +-
> drivers/gpu/drm/i915/gvt/cmd_parser.h |  2 +-
>  drivers/gpu/drm/i915/gvt/gvt.h        |  2 +
>  drivers/gpu/drm/i915/gvt/scheduler.c  | 82 ++++++++++++++++++++----------
> -----
>  4 files changed, 52 insertions(+), 36 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/cmd_parser.c
> b/drivers/gpu/drm/i915/gvt/cmd_parser.c
> index 5634eb1..e68fda2 100644
> --- a/drivers/gpu/drm/i915/gvt/cmd_parser.c
> +++ b/drivers/gpu/drm/i915/gvt/cmd_parser.c
> @@ -2643,7 +2643,7 @@ static int shadow_workload_ring_buffer(struct
> intel_vgpu_workload *workload)
>  	return 0;
>  }
> 
> -int intel_gvt_scan_and_shadow_workload(struct intel_vgpu_workload
> *workload)
> +int intel_gvt_scan_and_shadow_ringbuffer(struct intel_vgpu_workload
> +*workload)
>  {
>  	int ret;
>  	struct intel_vgpu *vgpu = workload->vgpu; diff --git
> a/drivers/gpu/drm/i915/gvt/cmd_parser.h
> b/drivers/gpu/drm/i915/gvt/cmd_parser.h
> index bed3351..2867036 100644
> --- a/drivers/gpu/drm/i915/gvt/cmd_parser.h
> +++ b/drivers/gpu/drm/i915/gvt/cmd_parser.h
> @@ -42,7 +42,7 @@ void intel_gvt_clean_cmd_parser(struct intel_gvt *gvt);
> 
>  int intel_gvt_init_cmd_parser(struct intel_gvt *gvt);
> 
> -int intel_gvt_scan_and_shadow_workload(struct intel_vgpu_workload
> *workload);
> +int intel_gvt_scan_and_shadow_ringbuffer(struct intel_vgpu_workload
> +*workload);
> 
>  int intel_gvt_scan_and_shadow_wa_ctx(struct intel_shadow_wa_ctx
> *wa_ctx);
> 
> diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
> index 930732e..ae6e7a4 100644
> --- a/drivers/gpu/drm/i915/gvt/gvt.h
> +++ b/drivers/gpu/drm/i915/gvt/gvt.h
> @@ -450,6 +450,8 @@ int intel_vgpu_init_opregion(struct intel_vgpu *vgpu,
> u32 gpa);  int intel_vgpu_emulate_opregion_request(struct intel_vgpu *vgpu,
> u32 swsci);  void populate_pvinfo_page(struct intel_vgpu *vgpu);
> 
> +int intel_gvt_scan_and_shadow_workload(struct intel_vgpu_workload
> +*workload);
> +
>  struct intel_gvt_ops {
>  	int (*emulate_cfg_read)(struct intel_vgpu *, unsigned int, void *,
>  				unsigned int);
> diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c
> b/drivers/gpu/drm/i915/gvt/scheduler.c
> index 6ae286c..3a78e7e 100644
> --- a/drivers/gpu/drm/i915/gvt/scheduler.c
> +++ b/drivers/gpu/drm/i915/gvt/scheduler.c
> @@ -172,42 +172,27 @@ static int shadow_context_status_change(struct
> notifier_block *nb,
>  	return NOTIFY_OK;
>  }
> 
> -static int dispatch_workload(struct intel_vgpu_workload *workload)
> +/**
> + * intel_gvt_scan_and_shadow_workload - audit the workload by scanning
> +and
> + * shadow it as well, include ringbuffer,wa_ctx and ctx.
> + * @workload: an abstract entity for each execlist submission.
> + *
> + * This function is called before the workload submitting to i915, to
> +make
> + * sure the content of the workload is valid.
> + */
> +int intel_gvt_scan_and_shadow_workload(struct intel_vgpu_workload
> +*workload)
>  {
>  	int ring_id = workload->ring_id;
>  	struct i915_gem_context *shadow_ctx = workload->vgpu-
> >shadow_ctx;
>  	struct drm_i915_private *dev_priv = workload->vgpu->gvt->dev_priv;
> -	struct intel_engine_cs *engine = dev_priv->engine[ring_id];
>  	struct drm_i915_gem_request *rq;
>  	struct intel_vgpu *vgpu = workload->vgpu;
> -	struct intel_ring *ring;
>  	int ret;
> 
> -	gvt_dbg_sched("ring id %d prepare to dispatch workload %p\n",
> -		ring_id, workload);
> -
>  	shadow_ctx->desc_template &= ~(0x3 <<
> GEN8_CTX_ADDRESSING_MODE_SHIFT);
>  	shadow_ctx->desc_template |= workload-
> >ctx_desc.addressing_mode <<
>  				    GEN8_CTX_ADDRESSING_MODE_SHIFT;
> 
> -	mutex_lock(&dev_priv->drm.struct_mutex);
> -
> -	/* pin shadow context by gvt even the shadow context will be pinned
> -	 * when i915 alloc request. That is because gvt will update the guest
> -	 * context from shadow context when workload is completed, and at
> that
> -	 * moment, i915 may already unpined the shadow context to make
> the
> -	 * shadow_ctx pages invalid. So gvt need to pin itself. After update
> -	 * the guest context, gvt can unpin the shadow_ctx safely.
> -	 */
> -	ring = engine->context_pin(engine, shadow_ctx);
> -	if (IS_ERR(ring)) {
> -		ret = PTR_ERR(ring);
> -		gvt_vgpu_err("fail to pin shadow context\n");
> -		workload->status = ret;
> -		mutex_unlock(&dev_priv->drm.struct_mutex);
> -		return ret;
> -	}
> -
>  	rq = i915_gem_request_alloc(dev_priv->engine[ring_id],
> shadow_ctx);
>  	if (IS_ERR(rq)) {
>  		gvt_vgpu_err("fail to allocate gem request\n"); @@ -219,7
> +204,7 @@ static int dispatch_workload(struct intel_vgpu_workload
> *workload)
> 
>  	workload->req = i915_gem_request_get(rq);
> 
> -	ret = intel_gvt_scan_and_shadow_workload(workload);
> +	ret = intel_gvt_scan_and_shadow_ringbuffer(workload);
>  	if (ret)
>  		goto out;
> 
> @@ -231,6 +216,27 @@ static int dispatch_workload(struct
> intel_vgpu_workload *workload)
>  	}
> 
>  	ret = populate_shadow_context(workload);
> +
> +out:
> +	return ret;
> +}
> +
> +static int dispatch_workload(struct intel_vgpu_workload *workload) {
> +	int ring_id = workload->ring_id;
> +	struct i915_gem_context *shadow_ctx = workload->vgpu-
> >shadow_ctx;
> +	struct drm_i915_private *dev_priv = workload->vgpu->gvt->dev_priv;
> +	struct intel_engine_cs *engine = dev_priv->engine[ring_id];
> +	struct intel_vgpu *vgpu = workload->vgpu;
> +	struct intel_ring *ring;
> +	int ret = 0;
> +
> +	gvt_dbg_sched("ring id %d prepare to dispatch workload %p\n",
> +		ring_id, workload);
> +
> +	mutex_lock(&dev_priv->drm.struct_mutex);
> +
> +	ret = intel_gvt_scan_and_shadow_workload(workload);
>  	if (ret)
>  		goto out;
> 
> @@ -240,20 +246,28 @@ static int dispatch_workload(struct
> intel_vgpu_workload *workload)
>  			goto out;
>  	}
> 
> +	/* pin shadow context by gvt even the shadow context will be pinned
> +	 * when i915 alloc request. That is because gvt will update the guest
> +	 * context from shadow context when workload is completed, and at
> that
> +	 * moment, i915 may already unpined the shadow context to make
> the
> +	 * shadow_ctx pages invalid. So gvt need to pin itself. After update
> +	 * the guest context, gvt can unpin the shadow_ctx safely.
> +	 */
> +	ring = engine->context_pin(engine, shadow_ctx);
> +	if (IS_ERR(ring)) {
> +		ret = PTR_ERR(ring);
> +		gvt_vgpu_err("fail to pin shadow context\n");
> +		goto out;
> +	}
> +
>  	gvt_dbg_sched("ring id %d submit workload to i915 %p\n",
>  			ring_id, workload->req);
> 
> -	ret = 0;
> +	i915_add_request(workload->req);
>  	workload->dispatched = true;
> -out:
> -	if (ret)
> -		workload->status = ret;
> -
> -	if (!IS_ERR_OR_NULL(rq))
> -		i915_add_request(rq);
> -	else
> -		engine->context_unpin(engine, shadow_ctx);
> 
> +out:
> +	workload->status = ret;

Hi Ping,

If there is no error happened in the above dispatching sequence, workload->status will be set to 0, right? In this case, looks like below part of code in shadow_context_status_change() is useless as workload->status will never be -EINPROGRESS. It is either some error code or 0 during dispatching.

        case INTEL_CONTEXT_SCHEDULE_OUT:
                /* If the status is -EINPROGRESS means this workload
                 * doesn't meet any issue during dispatching so when
                 * get the SCHEDULE_OUT set the status to be zero for
                 * good. If the status is NOT -EINPROGRESS means there
                 * is something wrong happened during dispatching and
                 * the status should not be set to zero
                 */
                if (workload->status == -EINPROGRESS)
                        workload->status = 0; 

Thanks
Chuanxiao
>  	mutex_unlock(&dev_priv->drm.struct_mutex);
>  	return ret;
>  }
> --
> 2.7.4
> 
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