[Intel-gfx] [RFC] [PATCH 7/7] drm/i915: find guilty batch buffer on ring resets

[Mika Kuoppala]

Ville Syrjälä <ville.syrjala at linux.intel.com> writes:

> On Mon, Feb 04, 2013 at 04:04:43PM +0200, Mika Kuoppala wrote:
>> After hang check timer has declared gpu to be hang,
>> rings are reset. In ring reset, when clearing
>> request list, do post mortem analysis to find out
>> the guilty batch buffer.
>> 
>> Select requests for further analysis by inspecting
>> the completed sequence number which has been updated
>> into the HWS page. If request was completed, it can't
>> be related to the hang.
>> 
>> For completed requests mark the batch as guilty
>       ^^^^^^^^^
>
> That's a typo, right?

It sure is. Will fix.

>> if the ring was not waiting and the ring head was
>> stuck inside the buffer object or in the flush region
>> right after the batch. For everything else, mark
>> them as innocents.
>> 
>> Signed-off-by: Mika Kuoppala <mika.kuoppala at intel.com>
>> ---
>>  drivers/gpu/drm/i915/i915_gem.c |   91 +++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 91 insertions(+)
>> 
>> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
>> index b304b06..db0f3e3 100644
>> --- a/drivers/gpu/drm/i915/i915_gem.c
>> +++ b/drivers/gpu/drm/i915/i915_gem.c
>> @@ -2092,9 +2092,97 @@ i915_gem_request_remove_from_client(struct drm_i915_gem_request *request)
>>  	spin_unlock(&file_priv->mm.lock);
>>  }
>>  
>> +static bool i915_head_inside_object(u32 acthd, struct drm_i915_gem_object *obj)
>> +{
>> +	if (acthd >= obj->gtt_offset &&
>> +	    acthd < obj->gtt_offset + obj->base.size)
>> +		return true;
>> +
>> +	return false;
>> +}
>> +
>> +static bool i915_head_inside_request(u32 acthd, u32 rs, u32 re)
>> +{
>> +	if (rs < re) {
>> +		if (acthd >= rs && acthd < re)
>> +			return true;
>> +	} else if (rs > re) {
>> +		if (acthd >= rs || acthd < re)
>> +			return true;
>> +	}
>> +
>> +	return false;
>> +}
>> +
>> +static bool i915_request_guilty(struct drm_i915_gem_request *request,
>> +				const u32 acthd, bool *inside)
>> +{
>> +	if (request->batch_obj) {
>> +		if (i915_head_inside_object(acthd, request->batch_obj)) {
>> +			*inside = true;
>> +			return true;
>> +		}
>> +	}
>> +
>> +	if (i915_head_inside_request(acthd, request->head, request->tail)) {
>> +		*inside = false;
>> +		return true;
>> +	}
>> +
>> +	return false;
>> +}
>> +
>> +static void i915_set_reset_status(struct intel_ring_buffer *ring,
>> +				  struct drm_i915_gem_request *request,
>> +				  u32 acthd)
>> +{
>> +	bool inside;
>> +	struct i915_reset_stats *rs = NULL;
>> +	bool guilty;
>> +
>> +	/* Innocent until proven guilty */
>> +	guilty = false;
>> +
>> +	if (!ring->hangcheck_waiting &&
>> +	    i915_request_guilty(request, acthd, &inside)) {
>> +		DRM_ERROR("%s hung %s bo (0x%x ctx %d) at 0x%x\n",
>> +			  ring->name,
>> +			  inside ? "inside" : "flushing",
>> +			  request->batch_obj ?
>> +			  request->batch_obj->gtt_offset : 0,
>> +			  request->ctx ? request->ctx->id : 0,
>> +			  acthd);
>> +
>> +		guilty = true;
>> +	}
>> +
>> +	/* If contexts are disabled or this is the default context, use
>> +	 * file_priv->reset_stats
>> +	 */
>> +	if (request->ctx && request->ctx->id != DEFAULT_CONTEXT_ID)
>> +		rs = &request->ctx->reset_stats;
>> +	else if (request->file_priv)
>> +		rs = &request->file_priv->reset_stats;
>> +
>> +	if (rs) {
>> +		rs->total++;
>> +
>> +		if (guilty)
>> +			rs->guilty++;
>> +		else
>> +			rs->innocent++;
>> +	}
>> +}
>> +
>>  static void i915_gem_reset_ring_lists(struct drm_i915_private *dev_priv,
>>  				      struct intel_ring_buffer *ring)
>>  {
>> +	u32 completed_seqno;
>> +	u32 acthd;
>> +
>> +	acthd = intel_ring_get_active_head(ring);
>> +	completed_seqno = ring->get_seqno(ring, false);
>> +
>>  	while (!list_empty(&ring->request_list)) {
>>  		struct drm_i915_gem_request *request;
>>  
>> @@ -2102,6 +2190,9 @@ static void i915_gem_reset_ring_lists(struct drm_i915_private *dev_priv,
>>  					   struct drm_i915_gem_request,
>>  					   list);
>>  
>> +		if (request->seqno > completed_seqno)
>
> i915_seqno_passed()?

For readability or for correctness?

When seqno wraps, the request queue will be cleaned up so
we can't have cross wrap boundary stuff in here.

Or did you have something else in mind that i have missed.

Thanks for review,
-Mika

>
>> +			i915_set_reset_status(ring, request, acthd);
>> +
>>  		list_del(&request->list);
>>  		i915_gem_request_remove_from_client(request);
>>  
>> -- 
>> 1.7.9.5
>> 
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>
> -- 
> Ville Syrjälä
> Intel OTC