[Intel-gfx] [PATCH v2 06/14] drm/i915/guc: Add a second client, to be used for preemption

Michal Wajdeczko michal.wajdeczko at intel.com
Thu Oct 19 19:36:39 UTC 2017


On Thu, 19 Oct 2017 20:36:11 +0200, Michał Winiarski  
<michal.winiarski at intel.com> wrote:

> From: Dave Gordon <david.s.gordon at intel.com>
>
> This second client is created with priority KMD_HIGH, and marked
> as preemptive. This will allow us to request preemption using GuC  
> actions.
>
> v2: Extract clients creation into a helper, debugfs fixups. (Michał)
> Recreate doorbell on init. (Daniele)
> Move clients into an array.
>
> Signed-off-by: Dave Gordon <david.s.gordon at intel.com>
> Signed-off-by: Michał Winiarski <michal.winiarski at intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> Cc: Jeff McGee <jeff.mcgee at intel.com>
> Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
> Cc: Oscar Mateo <oscar.mateo at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_debugfs.c        |  11 +--
>  drivers/gpu/drm/i915/i915_guc_submission.c | 107  
> ++++++++++++++++++++---------
>  drivers/gpu/drm/i915/intel_guc.h           |   9 ++-
>  drivers/gpu/drm/i915/intel_uncore.c        |   2 +-
>  4 files changed, 91 insertions(+), 38 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c  
> b/drivers/gpu/drm/i915/i915_debugfs.c
> index c65e381b85f3..daf7a16a4ee2 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -2459,7 +2459,7 @@ static bool check_guc_submission(struct seq_file  
> *m)
>  	struct drm_i915_private *dev_priv = node_to_i915(m->private);
>  	const struct intel_guc *guc = &dev_priv->guc;
> -	if (!guc->execbuf_client) {
> +	if (!guc->client[SUBMIT]) {
>  		seq_printf(m, "GuC submission %s\n",
>  			   HAS_GUC_SCHED(dev_priv) ?
>  			   "disabled" :
> @@ -2474,6 +2474,7 @@ static int i915_guc_info(struct seq_file *m, void  
> *data)
>  {
>  	struct drm_i915_private *dev_priv = node_to_i915(m->private);
>  	const struct intel_guc *guc = &dev_priv->guc;
> +	u32 i;
> 	if (!check_guc_submission(m))
>  		return 0;
> @@ -2482,8 +2483,10 @@ static int i915_guc_info(struct seq_file *m, void  
> *data)
>  	seq_printf(m, "\t%*pb\n", GUC_NUM_DOORBELLS, guc->doorbell_bitmap);
>  	seq_printf(m, "Doorbell next cacheline: 0x%x\n\n", guc->db_cacheline);
> -	seq_printf(m, "\nGuC execbuf client @ %p:\n", guc->execbuf_client);
> -	i915_guc_client_info(m, dev_priv, guc->execbuf_client);
> +	for (i = 0; i < I915_GUC_NUM_CLIENTS; i++) {
> +		seq_printf(m, "\nGuC client @ %p:\n", guc->client[i]);
> +		i915_guc_client_info(m, dev_priv, guc->client[i]);
> +	}
> 	i915_guc_log_info(m, dev_priv);
> @@ -2497,7 +2500,7 @@ static int i915_guc_stage_pool(struct seq_file *m,  
> void *data)
>  	struct drm_i915_private *dev_priv = node_to_i915(m->private);
>  	const struct intel_guc *guc = &dev_priv->guc;
>  	struct guc_stage_desc *desc = guc->stage_desc_pool_vaddr;
> -	struct i915_guc_client *client = guc->execbuf_client;
> +	struct i915_guc_client *client = guc->client[SUBMIT];
>  	unsigned int tmp;
>  	int index;
> diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c  
> b/drivers/gpu/drm/i915/i915_guc_submission.c
> index 0bd1fcffa78d..d8b8125aa4cc 100644
> --- a/drivers/gpu/drm/i915/i915_guc_submission.c
> +++ b/drivers/gpu/drm/i915/i915_guc_submission.c
> @@ -33,10 +33,11 @@
>   *
>   * GuC client:
>   * A i915_guc_client refers to a submission path through GuC.  
> Currently, there
> - * is only one of these (the execbuf_client) and this one is charged  
> with all
> - * submissions to the GuC. This struct is the owner of a doorbell, a  
> process
> - * descriptor and a workqueue (all of them inside a single gem object  
> that
> - * contains all required pages for these elements).
> + * are two clients. One of them (SUBMIT) is charged with all  
> submissions to the
> + * GuC, the other one (PREEMPT) is responsible for preempting the  
> SUBMIT one.
> + * This struct is the owner of a doorbell, a process descriptor and a  
> workqueue
> + * (all of them inside a single gem object that contains all required  
> pages for
> + * these elements).

Hmm, it's little unfortunate that SUBMIT and PREEMPT enums are defined
in intel_guc.h while mostly used in guc_submission.c

>   *
>   * GuC stage descriptor:
>   * During initialization, the driver allocates a static pool of 1024  
> such
> @@ -363,6 +364,8 @@ static void guc_stage_desc_init(struct intel_guc  
> *guc,
>  	memset(desc, 0, sizeof(*desc));
> 	desc->attribute = GUC_STAGE_DESC_ATTR_ACTIVE |  
> GUC_STAGE_DESC_ATTR_KERNEL;
> +	if (client->priority <= GUC_CLIENT_PRIORITY_HIGH)
> +		desc->attribute |= GUC_STAGE_DESC_ATTR_PREEMPT;
>  	desc->stage_id = client->stage_id;
>  	desc->priority = client->priority;
>  	desc->db_id = client->doorbell_id;
> @@ -553,7 +556,7 @@ static void i915_guc_submit(struct intel_engine_cs  
> *engine)
>  {
>  	struct drm_i915_private *dev_priv = engine->i915;
>  	struct intel_guc *guc = &dev_priv->guc;
> -	struct i915_guc_client *client = guc->execbuf_client;
> +	struct i915_guc_client *client = guc->client[SUBMIT];

what about using helpers like:

static inline
struct i915_guc_client *guc_exec_client(struct intel_guc *guc)
{
	return guc->client[SUBMIT];
}

> +	struct i915_guc_client *client = guc->client[SUBMIT];

>  	struct intel_engine_execlists * const execlists = &engine->execlists;
>  	struct execlist_port *port = execlists->port;
>  	const unsigned int engine_id = engine->id;
> @@ -750,10 +753,11 @@ static int __reset_doorbell(struct  
> i915_guc_client* client, u16 db_id)
>   */
>  static int guc_init_doorbell_hw(struct intel_guc *guc)
>  {
> -	struct i915_guc_client *client = guc->execbuf_client;
> +	struct i915_guc_client *client = guc->client[SUBMIT];
>  	bool recreate_first_client = false;
>  	u16 db_id;
>  	int ret;
> +	u32 i;
> 	/* For unused doorbells, make sure they are disabled */
>  	for_each_clear_bit(db_id, guc->doorbell_bitmap, GUC_NUM_DOORBELLS) {
> @@ -761,7 +765,7 @@ static int guc_init_doorbell_hw(struct intel_guc  
> *guc)
>  			continue;
> 		if (has_doorbell(client)) {
> -			/* Borrow execbuf_client (we will recreate it later) */
> +			/* Borrow submit client (we will recreate it later) */
>  			destroy_doorbell(client);
>  			recreate_first_client = true;
>  		}
> @@ -780,14 +784,14 @@ static int guc_init_doorbell_hw(struct intel_guc  
> *guc)
>  		__update_doorbell_desc(client, client->doorbell_id);
>  	}
> -	/* Now for every client (and not only execbuf_client) make sure their
> +	/* Now for every client (not only submission client) make sure their
>  	 * doorbells are known by the GuC */
> -	//for (client = client_list; client != NULL; client = client->next)
> +	for (i = 0; i < I915_GUC_NUM_CLIENTS; i++)
>  	{
> -		ret = __create_doorbell(client);
> +		ret = __create_doorbell(guc->client[i]);
>  		if (ret) {
>  			DRM_ERROR("Couldn't recreate client %u doorbell: %d\n",
> -				client->stage_id, ret);
> +				  guc->client[i]->stage_id, ret);
>  			return ret;
>  		}
>  	}
> @@ -914,6 +918,47 @@ static void guc_client_free(struct i915_guc_client  
> *client)
>  	kfree(client);
>  }
> +static int guc_clients_create(struct intel_guc *guc)
> +{
> +	struct drm_i915_private *dev_priv = guc_to_i915(guc);
> +	struct i915_guc_client *client;
> +
> +	client = guc_client_alloc(dev_priv,
> +				  INTEL_INFO(dev_priv)->ring_mask,
> +				  GUC_CLIENT_PRIORITY_KMD_NORMAL,
> +				  dev_priv->kernel_context);
> +	if (IS_ERR(client)) {
> +		DRM_ERROR("Failed to create GuC client for submission!\n");
> +		return PTR_ERR(client);
> +	}
> +	guc->client[SUBMIT] = client;
> +
> +	client = guc_client_alloc(dev_priv,
> +				  INTEL_INFO(dev_priv)->ring_mask,
> +				  GUC_CLIENT_PRIORITY_KMD_HIGH,
> +				  dev_priv->preempt_context);
> +	if (IS_ERR(client)) {
> +		DRM_ERROR("Failed to create GuC client for preemption!\n");
> +		guc_client_free(guc->client[SUBMIT]);
> +		guc->client[SUBMIT] = NULL;
> +		return PTR_ERR(client);
> +	}
> +	guc->client[PREEMPT] = client;
> +
> +	return 0;
> +}
> +
> +static void guc_clients_destroy(struct intel_guc *guc)
> +{
> +	struct i915_guc_client *client;
> +	u32 i;
> +
> +	for (i = 0; i < I915_GUC_NUM_CLIENTS; i++) {
> +		client = fetch_and_zero(&guc->client[i]);
> +		guc_client_free(client);
> +	}
> +}
> +
>  static void guc_policy_init(struct guc_policy *policy)
>  {
>  	policy->execution_quantum = POLICY_DEFAULT_EXECUTION_QUANTUM_US;
> @@ -1143,7 +1188,6 @@ static void guc_interrupts_release(struct  
> drm_i915_private *dev_priv)
>  int i915_guc_submission_enable(struct drm_i915_private *dev_priv)
>  {
>  	struct intel_guc *guc = &dev_priv->guc;
> -	struct i915_guc_client *client = guc->execbuf_client;
>  	struct intel_engine_cs *engine;
>  	enum intel_engine_id id;
>  	int err;
> @@ -1161,28 +1205,29 @@ int i915_guc_submission_enable(struct  
> drm_i915_private *dev_priv)
>  		     sizeof(struct guc_wq_item) *
>  		     I915_NUM_ENGINES > GUC_WQ_SIZE);
> -	if (!client) {
> -		client = guc_client_alloc(dev_priv,
> -					  INTEL_INFO(dev_priv)->ring_mask,
> -					  GUC_CLIENT_PRIORITY_KMD_NORMAL,
> -					  dev_priv->kernel_context);
> -		if (IS_ERR(client)) {
> -			DRM_ERROR("Failed to create GuC client for execbuf!\n");
> -			return PTR_ERR(client);
> -		}
> -
> -		guc->execbuf_client = client;
> +	/*
> +	 * We're being called on both module initialization and on reset,
> +	 * until this flow is changed, we're using regular client presence to
> +	 * determine which case are we in, and whether we should allocate new
> +	 * clients or just reset their workqueues.
> +	 */
> +	if (!guc->client[SUBMIT]) {
> +		GEM_BUG_ON(guc->client[PREEMPT]);
> +		err = guc_clients_create(guc);
> +		if (err)
> +			return err;
> +	} else {
> +		guc_reset_wq(guc->client[SUBMIT]);
> +		guc_reset_wq(guc->client[PREEMPT]);
>  	}
> 	err = intel_guc_sample_forcewake(guc);
>  	if (err)
> -		goto err_execbuf_client;
> -
> -	guc_reset_wq(client);
> +		goto err_free_clients;
> 	err = guc_init_doorbell_hw(guc);
>  	if (err)
> -		goto err_execbuf_client;
> +		goto err_free_clients;
> 	/* Take over from manual control of ELSP (execlists) */
>  	guc_interrupts_capture(dev_priv);
> @@ -1194,9 +1239,8 @@ int i915_guc_submission_enable(struct  
> drm_i915_private *dev_priv)
> 	return 0;
> -err_execbuf_client:
> -	guc_client_free(guc->execbuf_client);
> -	guc->execbuf_client = NULL;
> +err_free_clients:
> +	guc_clients_destroy(guc);
>  	return err;
>  }
> @@ -1209,6 +1253,5 @@ void i915_guc_submission_disable(struct  
> drm_i915_private *dev_priv)
>  	/* Revert back to manual ELSP submission */
>  	intel_engines_reset_default_submission(dev_priv);
> -	guc_client_free(guc->execbuf_client);
> -	guc->execbuf_client = NULL;
> +	guc_clients_destroy(guc);
>  }
> diff --git a/drivers/gpu/drm/i915/intel_guc.h  
> b/drivers/gpu/drm/i915/intel_guc.h
> index aa1583167b0a..15eadf27b7ae 100644
> --- a/drivers/gpu/drm/i915/intel_guc.h
> +++ b/drivers/gpu/drm/i915/intel_guc.h
> @@ -39,6 +39,13 @@
>   * pool and doorbells. intel_guc owns a i915_guc_client to replace the  
> legacy
>   * ExecList submission.
>   */
> +
> +#define I915_GUC_NUM_CLIENTS 2
> +enum i915_guc_client_id {
> +	SUBMIT = 0,
> +	PREEMPT
> +};
> +
>  struct intel_guc {
>  	struct intel_uc_fw fw;
>  	struct intel_guc_log log;
> @@ -57,7 +64,7 @@ struct intel_guc {
>  	struct i915_vma *shared_data;
>  	void *shared_data_vaddr;
> -	struct i915_guc_client *execbuf_client;
> +	struct i915_guc_client *client[I915_GUC_NUM_CLIENTS];
> 	DECLARE_BITMAP(doorbell_bitmap, GUC_NUM_DOORBELLS);
>  	/* Cyclic counter mod pagesize	*/
> diff --git a/drivers/gpu/drm/i915/intel_uncore.c  
> b/drivers/gpu/drm/i915/intel_uncore.c
> index 20e3c65c0999..3d91d8a28d9f 100644
> --- a/drivers/gpu/drm/i915/intel_uncore.c
> +++ b/drivers/gpu/drm/i915/intel_uncore.c
> @@ -1795,7 +1795,7 @@ bool intel_has_gpu_reset(struct drm_i915_private  
> *dev_priv)
>  bool intel_has_reset_engine(struct drm_i915_private *dev_priv)
>  {
>  	return (dev_priv->info.has_reset_engine &&
> -		!dev_priv->guc.execbuf_client &&
> +		!dev_priv->guc.client[SUBMIT] &&
>  		i915_modparams.reset >= 2);
>  }


More information about the Intel-gfx mailing list