[PATCH v4] drm/amd/amdgpu embed hw_fence into amdgpu_job

Andrey Grodzovsky andrey.grodzovsky at amd.com
Tue Aug 10 16:40:50 UTC 2021


Reviewed-by: Andrey Grodzovsky <andrey.grodzovsky at amd.com>

Andrey

On 2021-08-09 11:22 p.m., Jingwen Chen wrote:
> From: Jack Zhang <Jack.Zhang1 at amd.com>
>
> Why: Previously hw fence is alloced separately with job.
> It caused historical lifetime issues and corner cases.
> The ideal situation is to take fence to manage both job
> and fence's lifetime, and simplify the design of gpu-scheduler.
>
> How:
> We propose to embed hw_fence into amdgpu_job.
> 1. We cover the normal job submission by this method.
> 2. For ib_test, and submit without a parent job keep the
> legacy way to create a hw fence separately.
> v2:
> use AMDGPU_FENCE_FLAG_EMBED_IN_JOB_BIT to show that the fence is
> embeded in a job.
> v3:
> remove redundant variable ring in amdgpu_job
> v4:
> add tdr sequence support for this feature. Add a job_run_counter to
> indicate whether this job is a resubmit job.
>
> Signed-off-by: Jingwen Chen <Jingwen.Chen2 at amd.com>
> Signed-off-by: Jack Zhang <Jack.Zhang7 at hotmail.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c  |  1 -
>   drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c |  2 +-
>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c  | 12 +++-
>   drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c   | 73 ++++++++++++++++-----
>   drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c      |  2 +-
>   drivers/gpu/drm/amd/amdgpu/amdgpu_job.c     | 39 +++++++----
>   drivers/gpu/drm/amd/amdgpu/amdgpu_job.h     |  6 +-
>   drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h    |  5 +-
>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c      |  2 +-
>   9 files changed, 108 insertions(+), 34 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
> index 7b46ba551cb2..3003ee1c9487 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
> @@ -714,7 +714,6 @@ int amdgpu_amdkfd_submit_ib(struct kgd_dev *kgd, enum kgd_engine_type engine,
>   	ret = dma_fence_wait(f, false);
>   
>   err_ib_sched:
> -	dma_fence_put(f);
>   	amdgpu_job_free(job);
>   err:
>   	return ret;
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
> index 536005bff24a..277128846dd1 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.c
> @@ -1414,7 +1414,7 @@ static void amdgpu_ib_preempt_mark_partial_job(struct amdgpu_ring *ring)
>   			continue;
>   		}
>   		job = to_amdgpu_job(s_job);
> -		if (preempted && job->fence == fence)
> +		if (preempted && (&job->hw_fence) == fence)
>   			/* mark the job as preempted */
>   			job->preemption_status |= AMDGPU_IB_PREEMPTED;
>   	}
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index 9e53ff851496..ade2fa07a50a 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -4447,7 +4447,7 @@ int amdgpu_device_mode1_reset(struct amdgpu_device *adev)
>   int amdgpu_device_pre_asic_reset(struct amdgpu_device *adev,
>   				 struct amdgpu_reset_context *reset_context)
>   {
> -	int i, r = 0;
> +	int i, j, r = 0;
>   	struct amdgpu_job *job = NULL;
>   	bool need_full_reset =
>   		test_bit(AMDGPU_NEED_FULL_RESET, &reset_context->flags);
> @@ -4471,6 +4471,16 @@ int amdgpu_device_pre_asic_reset(struct amdgpu_device *adev,
>   		if (!ring || !ring->sched.thread)
>   			continue;
>   
> +		/*clear job fence from fence drv to avoid force_completion
> +		 *leave NULL and vm flush fence in fence drv */
> +		for (j = 0; j <= ring->fence_drv.num_fences_mask; j ++) {
> +			struct dma_fence *old,**ptr;
> +			ptr = &ring->fence_drv.fences[j];
> +			old = rcu_dereference_protected(*ptr, 1);
> +			if (old && test_bit(AMDGPU_FENCE_FLAG_EMBED_IN_JOB_BIT, &old->flags)) {
> +				RCU_INIT_POINTER(*ptr, NULL);
> +			}
> +		}
>   		/* after all hw jobs are reset, hw fence is meaningless, so force_completion */
>   		amdgpu_fence_driver_force_completion(ring);
>   	}
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> index 7495911516c2..a8302e324110 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
> @@ -129,30 +129,50 @@ static u32 amdgpu_fence_read(struct amdgpu_ring *ring)
>    *
>    * @ring: ring the fence is associated with
>    * @f: resulting fence object
> + * @job: job the fence is embeded in
>    * @flags: flags to pass into the subordinate .emit_fence() call
>    *
>    * Emits a fence command on the requested ring (all asics).
>    * Returns 0 on success, -ENOMEM on failure.
>    */
> -int amdgpu_fence_emit(struct amdgpu_ring *ring, struct dma_fence **f,
> +int amdgpu_fence_emit(struct amdgpu_ring *ring, struct dma_fence **f, struct amdgpu_job *job,
>   		      unsigned flags)
>   {
>   	struct amdgpu_device *adev = ring->adev;
> -	struct amdgpu_fence *fence;
> +	struct dma_fence *fence;
> +	struct amdgpu_fence *am_fence;
>   	struct dma_fence __rcu **ptr;
>   	uint32_t seq;
>   	int r;
>   
> -	fence = kmem_cache_alloc(amdgpu_fence_slab, GFP_KERNEL);
> -	if (fence == NULL)
> -		return -ENOMEM;
> +	if (job == NULL) {
> +		/* create a sperate hw fence */
> +		am_fence = kmem_cache_alloc(amdgpu_fence_slab, GFP_ATOMIC);
> +		if (am_fence == NULL)
> +			return -ENOMEM;
> +		fence = &am_fence->base;
> +		am_fence->ring = ring;
> +	} else {
> +		/* take use of job-embedded fence */
> +		fence = &job->hw_fence;
> +	}
>   
>   	seq = ++ring->fence_drv.sync_seq;
> -	fence->ring = ring;
> -	dma_fence_init(&fence->base, &amdgpu_fence_ops,
> -		       &ring->fence_drv.lock,
> -		       adev->fence_context + ring->idx,
> -		       seq);
> +	if (job != NULL && job->job_run_counter) {
> +		/* reinit seq for resubmitted jobs */
> +		fence->seqno = seq;
> +	} else {
> +		dma_fence_init(fence, &amdgpu_fence_ops,
> +				&ring->fence_drv.lock,
> +				adev->fence_context + ring->idx,
> +				seq);
> +	}
> +
> +	if (job != NULL) {
> +		/* mark this fence has a parent job */
> +		set_bit(AMDGPU_FENCE_FLAG_EMBED_IN_JOB_BIT, &fence->flags);
> +	}
> +
>   	amdgpu_ring_emit_fence(ring, ring->fence_drv.gpu_addr,
>   			       seq, flags | AMDGPU_FENCE_FLAG_INT);
>   	pm_runtime_get_noresume(adev_to_drm(adev)->dev);
> @@ -175,9 +195,9 @@ int amdgpu_fence_emit(struct amdgpu_ring *ring, struct dma_fence **f,
>   	/* This function can't be called concurrently anyway, otherwise
>   	 * emitting the fence would mess up the hardware ring buffer.
>   	 */
> -	rcu_assign_pointer(*ptr, dma_fence_get(&fence->base));
> +	rcu_assign_pointer(*ptr, dma_fence_get(fence));
>   
> -	*f = &fence->base;
> +	*f = fence;
>   
>   	return 0;
>   }
> @@ -621,8 +641,16 @@ static const char *amdgpu_fence_get_driver_name(struct dma_fence *fence)
>   
>   static const char *amdgpu_fence_get_timeline_name(struct dma_fence *f)
>   {
> -	struct amdgpu_fence *fence = to_amdgpu_fence(f);
> -	return (const char *)fence->ring->name;
> +	struct amdgpu_ring *ring;
> +
> +	if (test_bit(AMDGPU_FENCE_FLAG_EMBED_IN_JOB_BIT, &f->flags)) {
> +		struct amdgpu_job *job = container_of(f, struct amdgpu_job, hw_fence);
> +
> +		ring = to_amdgpu_ring(job->base.sched);
> +	} else {
> +		ring = to_amdgpu_fence(f)->ring;
> +	}
> +	return (const char *)ring->name;
>   }
>   
>   /**
> @@ -656,8 +684,20 @@ static bool amdgpu_fence_enable_signaling(struct dma_fence *f)
>   static void amdgpu_fence_free(struct rcu_head *rcu)
>   {
>   	struct dma_fence *f = container_of(rcu, struct dma_fence, rcu);
> -	struct amdgpu_fence *fence = to_amdgpu_fence(f);
> -	kmem_cache_free(amdgpu_fence_slab, fence);
> +
> +	if (test_bit(AMDGPU_FENCE_FLAG_EMBED_IN_JOB_BIT, &f->flags)) {
> +	/* free job if fence has a parent job */
> +		struct amdgpu_job *job;
> +
> +		job = container_of(f, struct amdgpu_job, hw_fence);
> +		kfree(job);
> +	} else {
> +	/* free fence_slab if it's separated fence*/
> +		struct amdgpu_fence *fence;
> +
> +		fence = to_amdgpu_fence(f);
> +		kmem_cache_free(amdgpu_fence_slab, fence);
> +	}
>   }
>   
>   /**
> @@ -680,6 +720,7 @@ static const struct dma_fence_ops amdgpu_fence_ops = {
>   	.release = amdgpu_fence_release,
>   };
>   
> +
>   /*
>    * Fence debugfs
>    */
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
> index ec65ab0ddf89..c076a6b9a5a2 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c
> @@ -262,7 +262,7 @@ int amdgpu_ib_schedule(struct amdgpu_ring *ring, unsigned num_ibs,
>   				       fence_flags | AMDGPU_FENCE_FLAG_64BIT);
>   	}
>   
> -	r = amdgpu_fence_emit(ring, f, fence_flags);
> +	r = amdgpu_fence_emit(ring, f, job, fence_flags);
>   	if (r) {
>   		dev_err(adev->dev, "failed to emit fence (%d)\n", r);
>   		if (job && job->vmid)
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
> index d33e6d97cc89..7da9c1855bd0 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.c
> @@ -127,11 +127,16 @@ void amdgpu_job_free_resources(struct amdgpu_job *job)
>   {
>   	struct amdgpu_ring *ring = to_amdgpu_ring(job->base.sched);
>   	struct dma_fence *f;
> +	struct dma_fence *hw_fence;
>   	unsigned i;
>   
> -	/* use sched fence if available */
> -	f = job->base.s_fence ? &job->base.s_fence->finished : job->fence;
> +	if (job->hw_fence.ops == NULL)
> +		hw_fence = job->external_hw_fence;
> +	else
> +		hw_fence = &job->hw_fence;
>   
> +	/* use sched fence if available */
> +	f = job->base.s_fence ? &job->base.s_fence->finished : hw_fence;
>   	for (i = 0; i < job->num_ibs; ++i)
>   		amdgpu_ib_free(ring->adev, &job->ibs[i], f);
>   }
> @@ -142,20 +147,27 @@ static void amdgpu_job_free_cb(struct drm_sched_job *s_job)
>   
>   	drm_sched_job_cleanup(s_job);
>   
> -	dma_fence_put(job->fence);
>   	amdgpu_sync_free(&job->sync);
>   	amdgpu_sync_free(&job->sched_sync);
> -	kfree(job);
> +
> +    /* only put the hw fence if has embedded fence */
> +	if (job->hw_fence.ops != NULL)
> +		dma_fence_put(&job->hw_fence);
> +	else
> +		kfree(job);
>   }
>   
>   void amdgpu_job_free(struct amdgpu_job *job)
>   {
>   	amdgpu_job_free_resources(job);
> -
> -	dma_fence_put(job->fence);
>   	amdgpu_sync_free(&job->sync);
>   	amdgpu_sync_free(&job->sched_sync);
> -	kfree(job);
> +
> +	/* only put the hw fence if has embedded fence */
> +	if (job->hw_fence.ops != NULL)
> +		dma_fence_put(&job->hw_fence);
> +	else
> +		kfree(job);
>   }
>   
>   int amdgpu_job_submit(struct amdgpu_job *job, struct drm_sched_entity *entity,
> @@ -184,11 +196,14 @@ int amdgpu_job_submit_direct(struct amdgpu_job *job, struct amdgpu_ring *ring,
>   
>   	job->base.sched = &ring->sched;
>   	r = amdgpu_ib_schedule(ring, job->num_ibs, job->ibs, NULL, fence);
> -	job->fence = dma_fence_get(*fence);
> +	/* record external_hw_fence for direct submit */
> +	job->external_hw_fence = dma_fence_get(*fence);
>   	if (r)
>   		return r;
>   
>   	amdgpu_job_free(job);
> +	dma_fence_put(*fence);
> +
>   	return 0;
>   }
>   
> @@ -246,10 +261,12 @@ static struct dma_fence *amdgpu_job_run(struct drm_sched_job *sched_job)
>   		if (r)
>   			DRM_ERROR("Error scheduling IBs (%d)\n", r);
>   	}
> -	/* if gpu reset, hw fence will be replaced here */
> -	dma_fence_put(job->fence);
> -	job->fence = dma_fence_get(fence);
>   
> +	if (!job->job_run_counter)
> +		dma_fence_get(fence);
> +	else if (finished->error < 0)
> +		dma_fence_put(&job->hw_fence);
> +	job->job_run_counter ++;
>   	amdgpu_job_free_resources(job);
>   
>   	fence = r ? ERR_PTR(r) : fence;
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h
> index 81caac9b958a..9e65730193b8 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h
> @@ -46,7 +46,8 @@ struct amdgpu_job {
>   	struct amdgpu_sync	sync;
>   	struct amdgpu_sync	sched_sync;
>   	struct amdgpu_ib	*ibs;
> -	struct dma_fence	*fence; /* the hw fence */
> +	struct dma_fence	hw_fence;
> +	struct dma_fence	*external_hw_fence;
>   	uint32_t		preamble_status;
>   	uint32_t                preemption_status;
>   	uint32_t		num_ibs;
> @@ -62,6 +63,9 @@ struct amdgpu_job {
>   	/* user fence handling */
>   	uint64_t		uf_addr;
>   	uint64_t		uf_sequence;
> +
> +	/* job_run_counter >= 1 means a resubmit job */
> +	uint32_t		job_run_counter;
>   };
>   
>   int amdgpu_job_alloc(struct amdgpu_device *adev, unsigned num_ibs,
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
> index 9c11ced4312c..03d4b29a76d6 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
> @@ -48,6 +48,9 @@
>   #define AMDGPU_FENCE_FLAG_INT           (1 << 1)
>   #define AMDGPU_FENCE_FLAG_TC_WB_ONLY    (1 << 2)
>   
> +/* fence flag bit to indicate the face is embeded in job*/
> +#define AMDGPU_FENCE_FLAG_EMBED_IN_JOB_BIT		(DMA_FENCE_FLAG_USER_BITS + 1)
> +
>   #define to_amdgpu_ring(s) container_of((s), struct amdgpu_ring, sched)
>   
>   #define AMDGPU_IB_POOL_SIZE	(1024 * 1024)
> @@ -118,7 +121,7 @@ void amdgpu_fence_driver_hw_init(struct amdgpu_device *adev);
>   void amdgpu_fence_driver_hw_fini(struct amdgpu_device *adev);
>   int amdgpu_fence_driver_sw_init(struct amdgpu_device *adev);
>   void amdgpu_fence_driver_sw_fini(struct amdgpu_device *adev);
> -int amdgpu_fence_emit(struct amdgpu_ring *ring, struct dma_fence **fence,
> +int amdgpu_fence_emit(struct amdgpu_ring *ring, struct dma_fence **fence, struct amdgpu_job *job,
>   		      unsigned flags);
>   int amdgpu_fence_emit_polling(struct amdgpu_ring *ring, uint32_t *s,
>   			      uint32_t timeout);
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index 2a88ed5d983b..2af8860d74cc 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -1218,7 +1218,7 @@ int amdgpu_vm_flush(struct amdgpu_ring *ring, struct amdgpu_job *job,
>   		amdgpu_gmc_emit_pasid_mapping(ring, job->vmid, job->pasid);
>   
>   	if (vm_flush_needed || pasid_mapping_needed) {
> -		r = amdgpu_fence_emit(ring, &fence, 0);
> +		r = amdgpu_fence_emit(ring, &fence, NULL, 0);
>   		if (r)
>   			return r;
>   	}


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