Re: [RFC 09/21] drm/i915: Make 'i915_gem_check_olr' actually check by request not seqno

[Daniel Vetter <daniel@ffwll.ch>]

On Mon, Oct 06, 2014 at 03:15:13PM +0100, John.C.Harrison@Intel.com wrote:
> From: John Harrison <John.C.Harrison@Intel.com>

To thin commit message.

Also I wonder whethere we should track the olr state more explicitly in
the request structure instead of jumping through all these hoops. And
explicit olr state for a request might also help to clarify control flow
and checks in a bunch of places.

> For: VIZ-4377
> Signed-off-by: John.C.Harrison@Intel.com
> ---
>  drivers/gpu/drm/i915/i915_drv.h      |   17 ++++++++++++++++-
>  drivers/gpu/drm/i915/i915_gem.c      |   25 ++++++++++---------------
>  drivers/gpu/drm/i915/intel_display.c |    2 +-
>  3 files changed, 27 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 1401266..9504206 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -2483,7 +2483,7 @@ bool i915_gem_retire_requests(struct drm_device *dev);
>  void i915_gem_retire_requests_ring(struct intel_engine_cs *ring);
>  int __must_check i915_gem_check_wedge(struct i915_gpu_error *error,
>  				      bool interruptible);
> -int __must_check i915_gem_check_olr(struct intel_engine_cs *ring, u32 seqno);
> +int __must_check i915_gem_check_olr(struct drm_i915_gem_request *req);
>  
>  static inline bool i915_reset_in_progress(struct i915_gpu_error *error)
>  {
> @@ -3020,4 +3020,19 @@ wait_remaining_ms_from_jiffies(unsigned long timestamp_jiffies, int to_wait_ms)
>  	}
>  }
>  
> +/************************* Deprecated *************************/

There's a gcc flag for functions if you want to mark this as depracated,
otherwise I'd just go with a "XXX: This temporary function will disappear
at the end of the patch series" somewhere.

> +static inline int __must_check i915_gem_check_ols(struct intel_engine_cs *ring, u32 seqno)
> +{
> +	int ret;
> +
> +	BUG_ON(!mutex_is_locked(&ring->dev->struct_mutex));

WARN_ON instead of BUG_ON for locking checks.

> +
> +	ret = 0;
> +	if (seqno == i915_gem_request_get_seqno(ring->outstanding_lazy_request))
> +		ret = i915_add_request(ring, NULL);
> +
> +	return ret;
> +}
> +/************************* Deprecated *************************/
> +
>  #endif
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 0d0eb26..2c7deca 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -1097,19 +1097,18 @@ i915_gem_check_wedge(struct i915_gpu_error *error,
>  }
>  
>  /*
> - * Compare seqno against outstanding lazy request. Emit a request if they are
> - * equal.
> + * Compare arbitrary request against outstanding lazy request. Emit on match.
>   */
>  int
> -i915_gem_check_olr(struct intel_engine_cs *ring, u32 seqno)
> +i915_gem_check_olr(struct drm_i915_gem_request *req)
>  {
>  	int ret;
>  
> -	BUG_ON(!mutex_is_locked(&ring->dev->struct_mutex));
> +	BUG_ON(!mutex_is_locked(&req->ring->dev->struct_mutex));

Same here. Plus please a stern warning in the commit message and cc: to
whomever who managed to sneak this in (and failed to catch it in review).
>  
>  	ret = 0;
> -	if (seqno == i915_gem_request_get_seqno(ring->outstanding_lazy_request))
> -		ret = i915_add_request(ring, NULL);
> +	if (req == req->ring->outstanding_lazy_request)
> +		ret = i915_add_request(req->ring, NULL);
>  
>  	return ret;
>  }
> @@ -1271,7 +1270,7 @@ i915_wait_seqno(struct intel_engine_cs *ring, uint32_t seqno)
>  	if (ret)
>  		return ret;
>  
> -	ret = i915_gem_check_olr(ring, seqno);
> +	ret = i915_gem_check_ols(ring, seqno);
>  	if (ret)
>  		return ret;
>  
> @@ -1338,7 +1337,6 @@ i915_gem_object_wait_rendering__nonblocking(struct drm_i915_gem_object *obj,
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  	struct intel_engine_cs *ring = obj->ring;
>  	unsigned reset_counter;
> -	u32 seqno;
>  	int ret;
>  
>  	BUG_ON(!mutex_is_locked(&dev->struct_mutex));
> @@ -1348,21 +1346,18 @@ i915_gem_object_wait_rendering__nonblocking(struct drm_i915_gem_object *obj,
>  	if (!req)
>  		return 0;
>  
> -	seqno = i915_gem_request_get_seqno(req);
> -	BUG_ON(seqno == 0);
> -
>  	ret = i915_gem_check_wedge(&dev_priv->gpu_error, true);
>  	if (ret)
>  		return ret;
>  
> -	ret = i915_gem_check_olr(ring, seqno);
> +	ret = i915_gem_check_olr(req);
>  	if (ret)
>  		return ret;
>  
>  	reset_counter = atomic_read(&dev_priv->gpu_error.reset_counter);
>  	i915_gem_request_reference(req);
>  	mutex_unlock(&dev->struct_mutex);
> -	ret = __wait_seqno(ring, seqno, reset_counter, true, NULL, file_priv);
> +	ret = __wait_seqno(ring, i915_gem_request_get_seqno(req), reset_counter, true, NULL, file_priv);
>  	mutex_lock(&dev->struct_mutex);
>  	i915_gem_request_unreference(req);
>  	if (ret)
> @@ -2786,7 +2781,7 @@ i915_gem_object_flush_active(struct drm_i915_gem_object *obj)
>  	int ret;
>  
>  	if (obj->active) {
> -		ret = i915_gem_check_olr(obj->ring, i915_gem_request_get_seqno(obj->last_read_req));
> +		ret = i915_gem_check_olr(obj->last_read_req);
>  		if (ret)
>  			return ret;
>  
> @@ -2913,7 +2908,7 @@ i915_gem_object_sync(struct drm_i915_gem_object *obj,
>  	if (seqno <= from->semaphore.sync_seqno[idx]) /* <--- broken?! needs to use i915_seqno_passed()??? */
>  		return 0;
>  
> -	ret = i915_gem_check_olr(obj->ring, seqno);
> +	ret = i915_gem_check_olr(obj->last_read_req);
>  	if (ret)
>  		return ret;
>  
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 6da18c5..2af421e 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -9775,7 +9775,7 @@ static int intel_postpone_flip(struct drm_i915_gem_object *obj)
>  			      i915_gem_request_get_seqno(obj->last_write_req)))
>  		return 0;
>  
> -	ret = i915_gem_check_olr(ring, i915_gem_request_get_seqno(obj->last_write_req));
> +	ret = i915_gem_check_olr(obj->last_write_req);
>  	if (ret)
>  		return ret;
>  
> -- 
> 1.7.9.5
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch