[PATCH v6] drm/amdgpu: handle IH ring1 overflow

Felix Kuehling felix.kuehling at amd.com
Thu Nov 25 01:56:03 UTC 2021


Am 2021-11-24 um 5:58 p.m. schrieb Philip Yang:
> IH ring1 is used to process GPU retry fault, overflow is enabled to
> drain retry fault because we want receive other interrupts while
> handling retry fault to recover range. There is no overflow flag set
> when wptr pass rptr. Use timestamp of rptr and wptr to handle overflow
> and drain retry fault.
>
> Add amdgpu_ih_function interface decode_iv_ts for different chips to get
> timestamp from IV entry with different iv size and timestamp offset.
> amdgpu_ih_decode_iv_ts_helper is used for vega10, vega20, navi10.
>
> Drain retry fault is done if processed_timestamp is equal to or larger
> than checkpoint timestamp. Page fault handler skips retry fault entry if
> entry timestamp goes backward.
>
> Signed-off-by: Philip Yang <Philip.Yang at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_ih.c | 58 +++++++++++++-------------
>  drivers/gpu/drm/amd/amdgpu/amdgpu_ih.h | 16 ++++++-
>  drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c |  5 +++
>  drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c  |  5 +++
>  drivers/gpu/drm/amd/amdgpu/navi10_ih.c |  1 +
>  drivers/gpu/drm/amd/amdgpu/vega10_ih.c |  1 +
>  drivers/gpu/drm/amd/amdgpu/vega20_ih.c |  1 +
>  drivers/gpu/drm/amd/amdkfd/kfd_svm.c   |  2 +-
>  8 files changed, 56 insertions(+), 33 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ih.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ih.c
> index 0c7963dfacad..3e043acaab82 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ih.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ih.c
> @@ -164,52 +164,32 @@ void amdgpu_ih_ring_write(struct amdgpu_ih_ring *ih, const uint32_t *iv,
>  	}
>  }
>  
> -/* Waiter helper that checks current rptr matches or passes checkpoint wptr */
> -static bool amdgpu_ih_has_checkpoint_processed(struct amdgpu_device *adev,
> -					struct amdgpu_ih_ring *ih,
> -					uint32_t checkpoint_wptr,
> -					uint32_t *prev_rptr)
> -{
> -	uint32_t cur_rptr = ih->rptr | (*prev_rptr & ~ih->ptr_mask);
> -
> -	/* rptr has wrapped. */
> -	if (cur_rptr < *prev_rptr)
> -		cur_rptr += ih->ptr_mask + 1;
> -	*prev_rptr = cur_rptr;
> -
> -	/* check ring is empty to workaround missing wptr overflow flag */
> -	return cur_rptr >= checkpoint_wptr ||
> -	       (cur_rptr & ih->ptr_mask) == amdgpu_ih_get_wptr(adev, ih);
> -}
> -
>  /**
> - * amdgpu_ih_wait_on_checkpoint_process - wait to process IVs up to checkpoint
> + * amdgpu_ih_wait_on_checkpoint_process_ts - wait to process IVs up to checkpoint
>   *
>   * @adev: amdgpu_device pointer
>   * @ih: ih ring to process
>   *
>   * Used to ensure ring has processed IVs up to the checkpoint write pointer.
>   */
> -int amdgpu_ih_wait_on_checkpoint_process(struct amdgpu_device *adev,
> +int amdgpu_ih_wait_on_checkpoint_process_ts(struct amdgpu_device *adev,
>  					struct amdgpu_ih_ring *ih)
>  {
> -	uint32_t checkpoint_wptr, rptr;
> +	uint32_t checkpoint_wptr;
> +	uint64_t checkpoint_ts;
> +	long timeout = HZ;
>  
>  	if (!ih->enabled || adev->shutdown)
>  		return -ENODEV;
>  
>  	checkpoint_wptr = amdgpu_ih_get_wptr(adev, ih);
> -	/* Order wptr with rptr. */
> +	/* Order wptr with ring data. */
>  	rmb();
> -	rptr = READ_ONCE(ih->rptr);
> -
> -	/* wptr has wrapped. */
> -	if (rptr > checkpoint_wptr)
> -		checkpoint_wptr += ih->ptr_mask + 1;
> +	checkpoint_ts = amdgpu_ih_decode_iv_ts(adev, ih, checkpoint_wptr, -1);
>  
> -	return wait_event_interruptible(ih->wait_process,
> -				amdgpu_ih_has_checkpoint_processed(adev, ih,
> -						checkpoint_wptr, &rptr));
> +	return wait_event_interruptible_timeout(ih->wait_process,
> +		    !amdgpu_ih_ts_after(ih->processed_timestamp, checkpoint_ts),
> +		    timeout);
>  }
>  
>  /**
> @@ -298,4 +278,22 @@ void amdgpu_ih_decode_iv_helper(struct amdgpu_device *adev,
>  
>  	/* wptr/rptr are in bytes! */
>  	ih->rptr += 32;
> +	if (ih == &adev->irq.ih1 &&
> +	    amdgpu_ih_ts_after(ih->processed_timestamp, entry->timestamp))
> +		ih->processed_timestamp = entry->timestamp;

I'd call this "latest_decoded_timestamp". At this point it hasn't been
processed yet.

Also, I think it would be safe and cheap enough to do this on all IH
rings, in case someone finds it useful for something else, e.g. using
amdgpu_ih_wait_on_checkpoint_process_ts on IH ring 0.


> +}
> +
> +uint64_t amdgpu_ih_decode_iv_ts_helper(struct amdgpu_ih_ring *ih, u32 rptr,
> +				       signed int offset)
> +{
> +	uint32_t iv_size = 32;
> +	uint32_t dw1, dw2;
> +	uint32_t index;
> +
> +	rptr += iv_size * offset;
> +	index = (rptr & ih->ptr_mask) >> 2;
> +
> +	dw1 = le32_to_cpu(ih->ring[index + 1]);
> +	dw2 = le32_to_cpu(ih->ring[index + 2]);
> +	return dw1 | ((u64)(dw2 & 0xffff) << 32);
>  }
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ih.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ih.h
> index 0649b59830a5..dd1c2eded6b9 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ih.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ih.h
> @@ -68,20 +68,30 @@ struct amdgpu_ih_ring {
>  
>  	/* For waiting on IH processing at checkpoint. */
>  	wait_queue_head_t wait_process;
> +	uint64_t		processed_timestamp;
>  };
>  
> +/* return true if time stamp t2 is after t1 with 48bit wrap around */
> +#define amdgpu_ih_ts_after(t1, t2) \
> +		(((int64_t)((t2) << 16) - (int64_t)((t1) << 16)) > 0LL)
> +
>  /* provided by the ih block */
>  struct amdgpu_ih_funcs {
>  	/* ring read/write ptr handling, called from interrupt context */
>  	u32 (*get_wptr)(struct amdgpu_device *adev, struct amdgpu_ih_ring *ih);
>  	void (*decode_iv)(struct amdgpu_device *adev, struct amdgpu_ih_ring *ih,
>  			  struct amdgpu_iv_entry *entry);
> +	uint64_t (*decode_iv_ts)(struct amdgpu_ih_ring *ih, u32 rptr,
> +				 signed int offset);
>  	void (*set_rptr)(struct amdgpu_device *adev, struct amdgpu_ih_ring *ih);
>  };
>  
>  #define amdgpu_ih_get_wptr(adev, ih) (adev)->irq.ih_funcs->get_wptr((adev), (ih))
>  #define amdgpu_ih_decode_iv(adev, iv) \
>  	(adev)->irq.ih_funcs->decode_iv((adev), (ih), (iv))
> +#define amdgpu_ih_decode_iv_ts(adev, ih, rptr, offset) \
> +	(WARN_ON_ONCE(!(adev)->irq.ih_funcs->decode_iv_ts) ? 0 : \
> +	(adev)->irq.ih_funcs->decode_iv_ts((ih), (rptr), (offset)))
>  #define amdgpu_ih_set_rptr(adev, ih) (adev)->irq.ih_funcs->set_rptr((adev), (ih))
>  
>  int amdgpu_ih_ring_init(struct amdgpu_device *adev, struct amdgpu_ih_ring *ih,
> @@ -89,10 +99,12 @@ int amdgpu_ih_ring_init(struct amdgpu_device *adev, struct amdgpu_ih_ring *ih,
>  void amdgpu_ih_ring_fini(struct amdgpu_device *adev, struct amdgpu_ih_ring *ih);
>  void amdgpu_ih_ring_write(struct amdgpu_ih_ring *ih, const uint32_t *iv,
>  			  unsigned int num_dw);
> -int amdgpu_ih_wait_on_checkpoint_process(struct amdgpu_device *adev,
> -					struct amdgpu_ih_ring *ih);
> +int amdgpu_ih_wait_on_checkpoint_process_ts(struct amdgpu_device *adev,
> +					    struct amdgpu_ih_ring *ih);
>  int amdgpu_ih_process(struct amdgpu_device *adev, struct amdgpu_ih_ring *ih);
>  void amdgpu_ih_decode_iv_helper(struct amdgpu_device *adev,
>  				struct amdgpu_ih_ring *ih,
>  				struct amdgpu_iv_entry *entry);
> +uint64_t amdgpu_ih_decode_iv_ts_helper(struct amdgpu_ih_ring *ih, u32 rptr,
> +				       signed int offset);
>  #endif
> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c
> index 3ec5ff5a6dbe..b129898db433 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c
> @@ -119,6 +119,11 @@ static int gmc_v10_0_process_interrupt(struct amdgpu_device *adev,
>  			return 1;
>  		}
>  
> +		/* Stale retry fault if timestamp goes backward */
> +		if (entry->ih == &adev->irq.ih1 &&
> +		    amdgpu_ih_ts_after(entry->timestamp, entry->ih->processed_timestamp))
> +			return 1;
> +

This check should go before amdgpu_gmc_filter_faults. Otherwise
amdgpu_gmc_filter_faults may later drop a real fault because it added a
stale fault in its hash table.


>  		/* Try to handle the recoverable page faults by filling page
>  		 * tables
>  		 */
> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> index cb82404df534..c0d9b254bbb5 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> @@ -535,6 +535,11 @@ static int gmc_v9_0_process_interrupt(struct amdgpu_device *adev,
>  			return 1;
>  		}
>  
> +		/* Stale retry fault if timestamp goes backward */
> +		if (entry->ih == &adev->irq.ih1 &&
> +		    amdgpu_ih_ts_after(entry->timestamp, entry->ih->processed_timestamp))
> +			return 1;
> +

Same as above.

Regards,
  Felix


>  		/* Try to handle the recoverable page faults by filling page
>  		 * tables
>  		 */
> diff --git a/drivers/gpu/drm/amd/amdgpu/navi10_ih.c b/drivers/gpu/drm/amd/amdgpu/navi10_ih.c
> index 38241cf0e1f1..8ce5b8ca1fd7 100644
> --- a/drivers/gpu/drm/amd/amdgpu/navi10_ih.c
> +++ b/drivers/gpu/drm/amd/amdgpu/navi10_ih.c
> @@ -716,6 +716,7 @@ static const struct amd_ip_funcs navi10_ih_ip_funcs = {
>  static const struct amdgpu_ih_funcs navi10_ih_funcs = {
>  	.get_wptr = navi10_ih_get_wptr,
>  	.decode_iv = amdgpu_ih_decode_iv_helper,
> +	.decode_iv_ts = amdgpu_ih_decode_iv_ts_helper,
>  	.set_rptr = navi10_ih_set_rptr
>  };
>  
> diff --git a/drivers/gpu/drm/amd/amdgpu/vega10_ih.c b/drivers/gpu/drm/amd/amdgpu/vega10_ih.c
> index a9ca6988009e..3070466f54e1 100644
> --- a/drivers/gpu/drm/amd/amdgpu/vega10_ih.c
> +++ b/drivers/gpu/drm/amd/amdgpu/vega10_ih.c
> @@ -640,6 +640,7 @@ const struct amd_ip_funcs vega10_ih_ip_funcs = {
>  static const struct amdgpu_ih_funcs vega10_ih_funcs = {
>  	.get_wptr = vega10_ih_get_wptr,
>  	.decode_iv = amdgpu_ih_decode_iv_helper,
> +	.decode_iv_ts = amdgpu_ih_decode_iv_ts_helper,
>  	.set_rptr = vega10_ih_set_rptr
>  };
>  
> diff --git a/drivers/gpu/drm/amd/amdgpu/vega20_ih.c b/drivers/gpu/drm/amd/amdgpu/vega20_ih.c
> index f51dfc38ac65..3b4eb8285943 100644
> --- a/drivers/gpu/drm/amd/amdgpu/vega20_ih.c
> +++ b/drivers/gpu/drm/amd/amdgpu/vega20_ih.c
> @@ -688,6 +688,7 @@ const struct amd_ip_funcs vega20_ih_ip_funcs = {
>  static const struct amdgpu_ih_funcs vega20_ih_funcs = {
>  	.get_wptr = vega20_ih_get_wptr,
>  	.decode_iv = amdgpu_ih_decode_iv_helper,
> +	.decode_iv_ts = amdgpu_ih_decode_iv_ts_helper,
>  	.set_rptr = vega20_ih_set_rptr
>  };
>  
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> index 10868d5b549f..663489ae56d7 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> @@ -1974,7 +1974,7 @@ static void svm_range_drain_retry_fault(struct svm_range_list *svms)
>  
>  		pr_debug("drain retry fault gpu %d svms %p\n", i, svms);
>  
> -		amdgpu_ih_wait_on_checkpoint_process(pdd->dev->adev,
> +		amdgpu_ih_wait_on_checkpoint_process_ts(pdd->dev->adev,
>  						     &pdd->dev->adev->irq.ih1);
>  		pr_debug("drain retry fault gpu %d svms 0x%p done\n", i, svms);
>  	}


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