[PATCHv2 1/2] drm/amd/amdgpu embed hw_fence into amdgpu_job

Christian König ckoenig.leichtzumerken at gmail.com
Fri Aug 6 09:48:04 UTC 2021



Am 06.08.21 um 07:52 schrieb Jingwen Chen:
> On Thu Aug 05, 2021 at 05:13:22PM -0400, Andrey Grodzovsky wrote:
>> On 2021-08-05 4:31 a.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.
>>>
>>> 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_fence.c   | 63 ++++++++++++++++-----
>>>    drivers/gpu/drm/amd/amdgpu/amdgpu_ib.c      |  2 +-
>>>    drivers/gpu/drm/amd/amdgpu/amdgpu_job.c     | 35 ++++++++----
>>>    drivers/gpu/drm/amd/amdgpu/amdgpu_job.h     |  4 +-
>>>    drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h    |  5 +-
>>>    drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c      |  2 +-
>>>    8 files changed, 84 insertions(+), 30 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_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
>>> index 7495911516c2..5e29d797a265 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
>>> @@ -129,30 +129,46 @@ 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;
>>> +		job->ring = ring;
>>
>> If you would make hw_fence of type amdgpu_fence
>> you could probably avoid the special job->ring = ring
>> See more in related comment at the bottom
>>
> Hi Andry,
>
> I'm only make the amdgpu_fence for the fence without job parameter
> provided to amdgpu_fence_emit. For embeded fence which is the hw_fence
> in amdgpu_job, it will be allocated along with amdgpu_job as dma_fence.

When you have the job and need the ring you can just do 
conatiner_of(job->sched, struct amdgpu_ring, sched).

No need for an extra ring pointer here.

Regards,
Christian.

>
> Regards,
> Jingwen Chen
>>> +	}
>>>    	seq = ++ring->fence_drv.sync_seq;
>>> -	fence->ring = ring;
>>> -	dma_fence_init(&fence->base, &amdgpu_fence_ops,
>>> +	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 +191,9 @@ 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 +637,16 @@ 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 = job->ring;
>>> +	} else {
>>> +		ring = to_amdgpu_fence(f)->ring;
>>> +	}
>>
>> Same as above
>>
>>
>>> +	return (const char *)ring->name;
>>>    }
>>>    /**
>>> @@ -656,8 +680,20 @@ 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 +716,7 @@ 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..65a395060de2 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 +261,8 @@ 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);
>>> +	dma_fence_get(fence);
>>>    	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..92324c978534 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_job.h
>>> @@ -46,7 +46,9 @@ 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 amdgpu_ring *ring;
>> Why not instead of 2 fields above just embed   struct amdgpu_fence as
>> hw_fence  and by this save the extra 'ring' field handling ?
>>
>> Andrey
>>
>>
>>> +	struct dma_fence	*external_hw_fence;
>>>    	uint32_t		preamble_status;
>>>    	uint32_t                preemption_status;
>>>    	uint32_t		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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