Re: [PATCH 32/47] drm/i915: Reset GPU immediately if submission is disabled

[John Harrison <john.c.harrison@xxxxxxxxx>]

On 6/24/2021 00:05, Matthew Brost wrote:
> If submission is disabled by the backend for any reason, reset the GPU
> immediately in the heartbeat code as the backend can't be reenabled
> until the GPU is reset.
>
> Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx>
Reviewed-by: John Harrison <John.C.Harrison@xxxxxxxxx>

> ---
>   .../gpu/drm/i915/gt/intel_engine_heartbeat.c  | 63 +++++++++++++++----
>   .../gpu/drm/i915/gt/intel_engine_heartbeat.h  |  4 ++
>   .../gpu/drm/i915/gt/uc/intel_guc_submission.c |  9 +++
>   drivers/gpu/drm/i915/i915_scheduler.c         |  6 ++
>   drivers/gpu/drm/i915/i915_scheduler.h         |  6 ++
>   drivers/gpu/drm/i915/i915_scheduler_types.h   |  5 ++
>   6 files changed, 80 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c
> index b6a305e6a974..a8495364d906 100644
> --- a/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c
> +++ b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c
> @@ -70,12 +70,30 @@ static void show_heartbeat(const struct i915_request *rq,
>   {
>   	struct drm_printer p = drm_debug_printer("heartbeat");
>   
> -	intel_engine_dump(engine, &p,
> -			  "%s heartbeat {seqno:%llx:%lld, prio:%d} not ticking\n",
> -			  engine->name,
> -			  rq->fence.context,
> -			  rq->fence.seqno,
> -			  rq->sched.attr.priority);
> +	if (!rq) {
> +		intel_engine_dump(engine, &p,
> +				  "%s heartbeat not ticking\n",
> +				  engine->name);
> +	} else {
> +		intel_engine_dump(engine, &p,
> +				  "%s heartbeat {seqno:%llx:%lld, prio:%d} not ticking\n",
> +				  engine->name,
> +				  rq->fence.context,
> +				  rq->fence.seqno,
> +				  rq->sched.attr.priority);
> +	}
> +}
> +
> +static void
> +reset_engine(struct intel_engine_cs *engine, struct i915_request *rq)
> +{
> +	if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
> +		show_heartbeat(rq, engine);
> +
> +	intel_gt_handle_error(engine->gt, engine->mask,
> +			      I915_ERROR_CAPTURE,
> +			      "stopped heartbeat on %s",
> +			      engine->name);
>   }
>   
>   static void heartbeat(struct work_struct *wrk)
> @@ -102,6 +120,11 @@ static void heartbeat(struct work_struct *wrk)
>   	if (intel_gt_is_wedged(engine->gt))
>   		goto out;
>   
> +	if (i915_sched_engine_disabled(engine->sched_engine)) {
> +		reset_engine(engine, engine->heartbeat.systole);
> +		goto out;
> +	}
> +
>   	if (engine->heartbeat.systole) {
>   		long delay = READ_ONCE(engine->props.heartbeat_interval_ms);
>   
> @@ -139,13 +162,7 @@ static void heartbeat(struct work_struct *wrk)
>   			engine->sched_engine->schedule(rq, &attr);
>   			local_bh_enable();
>   		} else {
> -			if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
> -				show_heartbeat(rq, engine);
> -
> -			intel_gt_handle_error(engine->gt, engine->mask,
> -					      I915_ERROR_CAPTURE,
> -					      "stopped heartbeat on %s",
> -					      engine->name);
> +			reset_engine(engine, rq);
>   		}
>   
>   		rq->emitted_jiffies = jiffies;
> @@ -194,6 +211,26 @@ void intel_engine_park_heartbeat(struct intel_engine_cs *engine)
>   		i915_request_put(fetch_and_zero(&engine->heartbeat.systole));
>   }
>   
> +void intel_gt_unpark_heartbeats(struct intel_gt *gt)
> +{
> +	struct intel_engine_cs *engine;
> +	enum intel_engine_id id;
> +
> +	for_each_engine(engine, gt, id)
> +		if (intel_engine_pm_is_awake(engine))
> +			intel_engine_unpark_heartbeat(engine);
> +
> +}
> +
> +void intel_gt_park_heartbeats(struct intel_gt *gt)
> +{
> +	struct intel_engine_cs *engine;
> +	enum intel_engine_id id;
> +
> +	for_each_engine(engine, gt, id)
> +		intel_engine_park_heartbeat(engine);
> +}
> +
>   void intel_engine_init_heartbeat(struct intel_engine_cs *engine)
>   {
>   	INIT_DELAYED_WORK(&engine->heartbeat.work, heartbeat);
> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.h b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.h
> index a488ea3e84a3..5da6d809a87a 100644
> --- a/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.h
> +++ b/drivers/gpu/drm/i915/gt/intel_engine_heartbeat.h
> @@ -7,6 +7,7 @@
>   #define INTEL_ENGINE_HEARTBEAT_H
>   
>   struct intel_engine_cs;
> +struct intel_gt;
>   
>   void intel_engine_init_heartbeat(struct intel_engine_cs *engine);
>   
> @@ -16,6 +17,9 @@ int intel_engine_set_heartbeat(struct intel_engine_cs *engine,
>   void intel_engine_park_heartbeat(struct intel_engine_cs *engine);
>   void intel_engine_unpark_heartbeat(struct intel_engine_cs *engine);
>   
> +void intel_gt_park_heartbeats(struct intel_gt *gt);
> +void intel_gt_unpark_heartbeats(struct intel_gt *gt);
> +
>   int intel_engine_pulse(struct intel_engine_cs *engine);
>   int intel_engine_flush_barriers(struct intel_engine_cs *engine);
>   
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> index b8c894ad8caf..59fca9748c15 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> @@ -10,6 +10,7 @@
>   #include "gt/intel_breadcrumbs.h"
>   #include "gt/intel_context.h"
>   #include "gt/intel_engine_pm.h"
> +#include "gt/intel_engine_heartbeat.h"
>   #include "gt/intel_gt.h"
>   #include "gt/intel_gt_irq.h"
>   #include "gt/intel_gt_pm.h"
> @@ -605,6 +606,7 @@ void intel_guc_submission_reset_prepare(struct intel_guc *guc)
>   		/* Reset called during driver load? GuC not yet initialised! */
>   		return;
>   
> +	intel_gt_park_heartbeats(guc_to_gt(guc));
>   	disable_submission(guc);
>   	guc->interrupts.disable(guc);
>   
> @@ -890,6 +892,7 @@ void intel_guc_submission_reset_finish(struct intel_guc *guc)
>   	atomic_set(&guc->outstanding_submission_g2h, 0);
>   
>   	enable_submission(guc);
> +	intel_gt_unpark_heartbeats(guc_to_gt(guc));
>   }
>   
>   /*
> @@ -1859,6 +1862,11 @@ static int guc_resume(struct intel_engine_cs *engine)
>   	return 0;
>   }
>   
> +static bool guc_sched_engine_disabled(struct i915_sched_engine *sched_engine)
> +{
> +	return !sched_engine->tasklet.callback;
> +}
> +
>   static void guc_set_default_submission(struct intel_engine_cs *engine)
>   {
>   	engine->submit_request = guc_submit_request;
> @@ -2009,6 +2017,7 @@ int intel_guc_submission_setup(struct intel_engine_cs *engine)
>   			return -ENOMEM;
>   
>   		guc->sched_engine->schedule = i915_schedule;
> +		guc->sched_engine->disabled = guc_sched_engine_disabled;
>   		guc->sched_engine->private_data = guc;
>   		tasklet_setup(&guc->sched_engine->tasklet,
>   			      guc_submission_tasklet);
> diff --git a/drivers/gpu/drm/i915/i915_scheduler.c b/drivers/gpu/drm/i915/i915_scheduler.c
> index 3a58a9130309..3fb009ea2cb2 100644
> --- a/drivers/gpu/drm/i915/i915_scheduler.c
> +++ b/drivers/gpu/drm/i915/i915_scheduler.c
> @@ -440,6 +440,11 @@ void i915_sched_engine_free(struct kref *kref)
>   	kfree(sched_engine);
>   }
>   
> +static bool default_disabled(struct i915_sched_engine *sched_engine)
> +{
> +	return false;
> +}
> +
>   struct i915_sched_engine *
>   i915_sched_engine_create(unsigned int subclass)
>   {
> @@ -453,6 +458,7 @@ i915_sched_engine_create(unsigned int subclass)
>   
>   	sched_engine->queue = RB_ROOT_CACHED;
>   	sched_engine->queue_priority_hint = INT_MIN;
> +	sched_engine->disabled = default_disabled;
>   
>   	INIT_LIST_HEAD(&sched_engine->requests);
>   	INIT_LIST_HEAD(&sched_engine->hold);
> diff --git a/drivers/gpu/drm/i915/i915_scheduler.h b/drivers/gpu/drm/i915/i915_scheduler.h
> index 650ab8e0db9f..72105a53b0e1 100644
> --- a/drivers/gpu/drm/i915/i915_scheduler.h
> +++ b/drivers/gpu/drm/i915/i915_scheduler.h
> @@ -98,4 +98,10 @@ void i915_request_show_with_schedule(struct drm_printer *m,
>   				     const char *prefix,
>   				     int indent);
>   
> +static inline bool
> +i915_sched_engine_disabled(struct i915_sched_engine *sched_engine)
> +{
> +	return sched_engine->disabled(sched_engine);
> +}
> +
>   #endif /* _I915_SCHEDULER_H_ */
> diff --git a/drivers/gpu/drm/i915/i915_scheduler_types.h b/drivers/gpu/drm/i915/i915_scheduler_types.h
> index 5935c3152bdc..cfaf52e528d0 100644
> --- a/drivers/gpu/drm/i915/i915_scheduler_types.h
> +++ b/drivers/gpu/drm/i915/i915_scheduler_types.h
> @@ -163,6 +163,11 @@ struct i915_sched_engine {
>   	 */
>   	void *private_data;
>   
> +	/**
> +	 * @disabled: check if backend has disabled submission
> +	 */
> +	bool	(*disabled)(struct i915_sched_engine *sched_engine);
> +
>   	/**
>   	 * @kick_backend: kick backend after a request's priority has changed
>   	 */