Re: [PATCH] drm/i915: Pull seqno started checks together

[Mika Kuoppala <mika.kuoppala@linux.intel.com>]

Chris Wilson <chris@chris-wilson.co.uk> writes:

> We have a few instances of checking seqno-1 to see if the HW has started
> the request. Pull those together under a helper.
>

Could you elaborate why you want both completed and signaled?
Otherwise it looks good.
-Mika

> Suggested-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_request.c      |  9 +++---
>  drivers/gpu/drm/i915/i915_request.h      | 39 +++++++++++++++---------
>  drivers/gpu/drm/i915/intel_breadcrumbs.c |  6 ++--
>  drivers/gpu/drm/i915/intel_engine_cs.c   |  3 +-
>  drivers/gpu/drm/i915/intel_hangcheck.c   |  2 +-
>  drivers/gpu/drm/i915/intel_ringbuffer.h  | 32 +++++++++++++++----
>  6 files changed, 59 insertions(+), 32 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
> index 5c2c93cbab12..09ed48833b54 100644
> --- a/drivers/gpu/drm/i915/i915_request.c
> +++ b/drivers/gpu/drm/i915/i915_request.c
> @@ -527,7 +527,7 @@ void __i915_request_submit(struct i915_request *request)
>  
>  	seqno = timeline_get_seqno(&engine->timeline);
>  	GEM_BUG_ON(!seqno);
> -	GEM_BUG_ON(i915_seqno_passed(intel_engine_get_seqno(engine), seqno));
> +	GEM_BUG_ON(intel_engine_signaled(engine, seqno));
>  
>  	/* We may be recursing from the signal callback of another i915 fence */
>  	spin_lock_nested(&request->lock, SINGLE_DEPTH_NESTING);
> @@ -579,8 +579,7 @@ void __i915_request_unsubmit(struct i915_request *request)
>  	 */
>  	GEM_BUG_ON(!request->global_seqno);
>  	GEM_BUG_ON(request->global_seqno != engine->timeline.seqno);
> -	GEM_BUG_ON(i915_seqno_passed(intel_engine_get_seqno(engine),
> -				     request->global_seqno));
> +	GEM_BUG_ON(intel_engine_has_completed(engine, request->global_seqno));
>  	engine->timeline.seqno--;
>  
>  	/* We may be recursing from the signal callback of another i915 fence */
> @@ -1205,7 +1204,7 @@ static bool __i915_spin_request(const struct i915_request *rq,
>  	 * it is a fair assumption that it will not complete within our
>  	 * relatively short timeout.
>  	 */
> -	if (!i915_seqno_passed(intel_engine_get_seqno(engine), seqno - 1))
> +	if (!intel_engine_has_started(engine, seqno))
>  		return false;
>  
>  	/*
> @@ -1222,7 +1221,7 @@ static bool __i915_spin_request(const struct i915_request *rq,
>  	irq = READ_ONCE(engine->breadcrumbs.irq_count);
>  	timeout_us += local_clock_us(&cpu);
>  	do {
> -		if (i915_seqno_passed(intel_engine_get_seqno(engine), seqno))
> +		if (intel_engine_has_completed(engine, seqno))
>  			return seqno == i915_request_global_seqno(rq);
>  
>  		/*
> diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h
> index e1c9365dfefb..05888de2e045 100644
> --- a/drivers/gpu/drm/i915/i915_request.h
> +++ b/drivers/gpu/drm/i915/i915_request.h
> @@ -272,7 +272,10 @@ long i915_request_wait(struct i915_request *rq,
>  #define I915_WAIT_ALL		BIT(2) /* used by i915_gem_object_wait() */
>  #define I915_WAIT_FOR_IDLE_BOOST BIT(3)
>  
> -static inline u32 intel_engine_get_seqno(struct intel_engine_cs *engine);
> +static inline bool intel_engine_has_started(struct intel_engine_cs *engine,
> +					    u32 seqno);
> +static inline bool intel_engine_has_completed(struct intel_engine_cs *engine,
> +					    u32 seqno);
>  
>  /**
>   * Returns true if seq1 is later than seq2.
> @@ -282,11 +285,31 @@ static inline bool i915_seqno_passed(u32 seq1, u32 seq2)
>  	return (s32)(seq1 - seq2) >= 0;
>  }
>  
> +/**
> + * i915_request_started - check if the request has begun being executed
> + * @rq: the request
> + *
> + * Returns true if the request has been submitted to hardware, and the hardware
> + * has advanced passed the end of the previous request and so should be either
> + * currently processing the request (though it may be preempted and so
> + * not necessarily the next request to complete) or have completed the request.
> + */
> +static inline bool i915_request_started(const struct i915_request *rq)
> +{
> +	u32 seqno;
> +
> +	seqno = i915_request_global_seqno(rq);
> +	if (!seqno) /* not yet submitted to HW */
> +		return false;
> +
> +	return intel_engine_has_started(rq->engine, seqno);
> +}
> +
>  static inline bool
>  __i915_request_completed(const struct i915_request *rq, u32 seqno)
>  {
>  	GEM_BUG_ON(!seqno);
> -	return i915_seqno_passed(intel_engine_get_seqno(rq->engine), seqno) &&
> +	return intel_engine_has_completed(rq->engine, seqno) &&
>  		seqno == i915_request_global_seqno(rq);
>  }
>  
> @@ -301,18 +324,6 @@ static inline bool i915_request_completed(const struct i915_request *rq)
>  	return __i915_request_completed(rq, seqno);
>  }
>  
> -static inline bool i915_request_started(const struct i915_request *rq)
> -{
> -	u32 seqno;
> -
> -	seqno = i915_request_global_seqno(rq);
> -	if (!seqno)
> -		return false;
> -
> -	return i915_seqno_passed(intel_engine_get_seqno(rq->engine),
> -				 seqno - 1);
> -}
> -
>  static inline bool i915_sched_node_signaled(const struct i915_sched_node *node)
>  {
>  	const struct i915_request *rq =
> diff --git a/drivers/gpu/drm/i915/intel_breadcrumbs.c b/drivers/gpu/drm/i915/intel_breadcrumbs.c
> index 1db6ba7d926e..84bf8d827136 100644
> --- a/drivers/gpu/drm/i915/intel_breadcrumbs.c
> +++ b/drivers/gpu/drm/i915/intel_breadcrumbs.c
> @@ -256,8 +256,7 @@ void intel_engine_disarm_breadcrumbs(struct intel_engine_cs *engine)
>  	spin_unlock(&b->irq_lock);
>  
>  	rbtree_postorder_for_each_entry_safe(wait, n, &b->waiters, node) {
> -		GEM_BUG_ON(!i915_seqno_passed(intel_engine_get_seqno(engine),
> -					      wait->seqno));
> +		GEM_BUG_ON(!intel_engine_signaled(engine, wait->seqno));
>  		RB_CLEAR_NODE(&wait->node);
>  		wake_up_process(wait->tsk);
>  	}
> @@ -508,8 +507,7 @@ bool intel_engine_add_wait(struct intel_engine_cs *engine,
>  		return armed;
>  
>  	/* Make the caller recheck if its request has already started. */
> -	return i915_seqno_passed(intel_engine_get_seqno(engine),
> -				 wait->seqno - 1);
> +	return intel_engine_has_started(engine, wait->seqno);
>  }
>  
>  static inline bool chain_wakeup(struct rb_node *rb, int priority)
> diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
> index 67c4fc5d737c..99d5a24219c1 100644
> --- a/drivers/gpu/drm/i915/intel_engine_cs.c
> +++ b/drivers/gpu/drm/i915/intel_engine_cs.c
> @@ -968,8 +968,7 @@ bool intel_engine_is_idle(struct intel_engine_cs *engine)
>  		return true;
>  
>  	/* Any inflight/incomplete requests? */
> -	if (!i915_seqno_passed(intel_engine_get_seqno(engine),
> -			       intel_engine_last_submit(engine)))
> +	if (!intel_engine_signaled(engine, intel_engine_last_submit(engine)))
>  		return false;
>  
>  	if (I915_SELFTEST_ONLY(engine->breadcrumbs.mock))
> diff --git a/drivers/gpu/drm/i915/intel_hangcheck.c b/drivers/gpu/drm/i915/intel_hangcheck.c
> index 2fc7a0dd0df9..e26d05a46451 100644
> --- a/drivers/gpu/drm/i915/intel_hangcheck.c
> +++ b/drivers/gpu/drm/i915/intel_hangcheck.c
> @@ -142,7 +142,7 @@ static int semaphore_passed(struct intel_engine_cs *engine)
>  	if (signaller->hangcheck.deadlock >= I915_NUM_ENGINES)
>  		return -1;
>  
> -	if (i915_seqno_passed(intel_engine_get_seqno(signaller), seqno))
> +	if (intel_engine_signaled(signaller, seqno))
>  		return 1;
>  
>  	/* cursory check for an unkickable deadlock */
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
> index 57f3787ed6ec..057b88c149f7 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.h
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
> @@ -911,14 +911,10 @@ int intel_engine_stop_cs(struct intel_engine_cs *engine);
>  u64 intel_engine_get_active_head(const struct intel_engine_cs *engine);
>  u64 intel_engine_get_last_batch_head(const struct intel_engine_cs *engine);
>  
> -static inline u32 intel_engine_get_seqno(struct intel_engine_cs *engine)
> -{
> -	return intel_read_status_page(engine, I915_GEM_HWS_INDEX);
> -}
> -
>  static inline u32 intel_engine_last_submit(struct intel_engine_cs *engine)
>  {
> -	/* We are only peeking at the tail of the submit queue (and not the
> +	/*
> +	 * We are only peeking at the tail of the submit queue (and not the
>  	 * queue itself) in order to gain a hint as to the current active
>  	 * state of the engine. Callers are not expected to be taking
>  	 * engine->timeline->lock, nor are they expected to be concerned
> @@ -928,6 +924,30 @@ static inline u32 intel_engine_last_submit(struct intel_engine_cs *engine)
>  	return READ_ONCE(engine->timeline.seqno);
>  }
>  
> +static inline u32 intel_engine_get_seqno(struct intel_engine_cs *engine)
> +{
> +	return intel_read_status_page(engine, I915_GEM_HWS_INDEX);
> +}
> +
> +static inline bool intel_engine_signaled(struct intel_engine_cs *engine,
> +					 u32 seqno)
> +{
> +	GEM_BUG_ON(!seqno);
> +	return i915_seqno_passed(intel_engine_get_seqno(engine), seqno);
> +}
> +
> +static inline bool intel_engine_has_completed(struct intel_engine_cs *engine,
> +					      u32 seqno)
> +{
> +	return intel_engine_signaled(engine, seqno);
> +}
> +
> +static inline bool intel_engine_has_started(struct intel_engine_cs *engine,
> +					    u32 seqno)
> +{
> +	return intel_engine_signaled(engine, seqno - 1);
> +}
> +
>  void intel_engine_get_instdone(struct intel_engine_cs *engine,
>  			       struct intel_instdone *instdone);
>  
> -- 
> 2.18.0
>
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