Re: [PATCH] drm/amdgpu/mes: fix mes ring buffer overflow

["Christian König" <ckoenig.leichtzumerken@gmail.com>]

Am 19.07.24 um 11:16 schrieb Jack Xiao:
> wait memory room until enough before writing mes packets
> to avoid ring buffer overflow.
>
> Signed-off-by: Jack Xiao <Jack.Xiao@amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/mes_v11_0.c | 18 ++++++++++++++----
>   drivers/gpu/drm/amd/amdgpu/mes_v12_0.c | 18 ++++++++++++++----
>   2 files changed, 28 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/mes_v11_0.c b/drivers/gpu/drm/amd/amdgpu/mes_v11_0.c
> index 8ce51b9236c1..68c74adf79f1 100644
> --- a/drivers/gpu/drm/amd/amdgpu/mes_v11_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/mes_v11_0.c
> @@ -168,7 +168,7 @@ static int mes_v11_0_submit_pkt_and_poll_completion(struct amdgpu_mes *mes,
>   	const char *op_str, *misc_op_str;
>   	unsigned long flags;
>   	u64 status_gpu_addr;
> -	u32 status_offset;
> +	u32 seq, status_offset;
>   	u64 *status_ptr;
>   	signed long r;
>   	int ret;
> @@ -196,6 +196,13 @@ static int mes_v11_0_submit_pkt_and_poll_completion(struct amdgpu_mes *mes,
>   	if (r)
>   		goto error_unlock_free;
>   
> +	seq = ++ring->fence_drv.sync_seq;
> +	r = amdgpu_fence_wait_polling(ring,
> +				      seq - ring->fence_drv.num_fences_mask,
> +				      timeout);
> +	if (r < 1)
> +		goto error_undo;
> +
>   	api_status = (struct MES_API_STATUS *)((char *)pkt + api_status_off);
>   	api_status->api_completion_fence_addr = status_gpu_addr;
>   	api_status->api_completion_fence_value = 1;
> @@ -208,8 +215,7 @@ static int mes_v11_0_submit_pkt_and_poll_completion(struct amdgpu_mes *mes,
>   	mes_status_pkt.header.dwsize = API_FRAME_SIZE_IN_DWORDS;
>   	mes_status_pkt.api_status.api_completion_fence_addr =
>   		ring->fence_drv.gpu_addr;
> -	mes_status_pkt.api_status.api_completion_fence_value =
> -		++ring->fence_drv.sync_seq;
> +	mes_status_pkt.api_status.api_completion_fence_value = seq;
>   
>   	amdgpu_ring_write_multiple(ring, &mes_status_pkt,
>   				   sizeof(mes_status_pkt) / 4);
> @@ -229,7 +235,7 @@ static int mes_v11_0_submit_pkt_and_poll_completion(struct amdgpu_mes *mes,
>   		dev_dbg(adev->dev, "MES msg=%d was emitted\n",
>   			x_pkt->header.opcode);
>   
> -	r = amdgpu_fence_wait_polling(ring, ring->fence_drv.sync_seq, timeout);
> +	r = amdgpu_fence_wait_polling(ring, seq, timeout);
>   	if (r < 1 || !*status_ptr) {
>   
>   		if (misc_op_str)
> @@ -252,6 +258,10 @@ static int mes_v11_0_submit_pkt_and_poll_completion(struct amdgpu_mes *mes,
>   	amdgpu_device_wb_free(adev, status_offset);
>   	return 0;
>   
> +error_undo:
> +	dev_err(adev->dev, "MES ring buffer is full.\n");
> +	amdgpu_ring_undo(ring);
> +
>   error_unlock_free:
>   	spin_unlock_irqrestore(&mes->ring_lock, flags);
>   
> diff --git a/drivers/gpu/drm/amd/amdgpu/mes_v12_0.c b/drivers/gpu/drm/amd/amdgpu/mes_v12_0.c
> index c9f74231ad59..48e01206bcc4 100644
> --- a/drivers/gpu/drm/amd/amdgpu/mes_v12_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/mes_v12_0.c
> @@ -154,7 +154,7 @@ static int mes_v12_0_submit_pkt_and_poll_completion(struct amdgpu_mes *mes,
>   	const char *op_str, *misc_op_str;
>   	unsigned long flags;
>   	u64 status_gpu_addr;
> -	u32 status_offset;
> +	u32 seq, status_offset;
>   	u64 *status_ptr;
>   	signed long r;
>   	int ret;
> @@ -182,6 +182,13 @@ static int mes_v12_0_submit_pkt_and_poll_completion(struct amdgpu_mes *mes,
>   	if (r)
>   		goto error_unlock_free;
>   
> +	seq = ++ring->fence_drv.sync_seq;
> +	r = amdgpu_fence_wait_polling(ring,
> +				      seq - ring->fence_drv.num_fences_mask,

That's what's amdgpu_fence_emit_polling() does anyway.

So this here just moves the polling a bit earlier.

I think we rather need to increase the MES ring size instead.

Regards,
Christian.


> +				      timeout);
> +	if (r < 1)
> +		goto error_undo;
> +
>   	api_status = (struct MES_API_STATUS *)((char *)pkt + api_status_off);
>   	api_status->api_completion_fence_addr = status_gpu_addr;
>   	api_status->api_completion_fence_value = 1;
> @@ -194,8 +201,7 @@ static int mes_v12_0_submit_pkt_and_poll_completion(struct amdgpu_mes *mes,
>   	mes_status_pkt.header.dwsize = API_FRAME_SIZE_IN_DWORDS;
>   	mes_status_pkt.api_status.api_completion_fence_addr =
>   		ring->fence_drv.gpu_addr;
> -	mes_status_pkt.api_status.api_completion_fence_value =
> -		++ring->fence_drv.sync_seq;
> +	mes_status_pkt.api_status.api_completion_fence_value = seq;
>   
>   	amdgpu_ring_write_multiple(ring, &mes_status_pkt,
>   				   sizeof(mes_status_pkt) / 4);
> @@ -215,7 +221,7 @@ static int mes_v12_0_submit_pkt_and_poll_completion(struct amdgpu_mes *mes,
>   		dev_dbg(adev->dev, "MES msg=%d was emitted\n",
>   			x_pkt->header.opcode);
>   
> -	r = amdgpu_fence_wait_polling(ring, ring->fence_drv.sync_seq, timeout);
> +	r = amdgpu_fence_wait_polling(ring, seq, timeout);
>   	if (r < 1 || !*status_ptr) {
>   
>   		if (misc_op_str)
> @@ -238,6 +244,10 @@ static int mes_v12_0_submit_pkt_and_poll_completion(struct amdgpu_mes *mes,
>   	amdgpu_device_wb_free(adev, status_offset);
>   	return 0;
>   
> +error_undo:
> +	dev_err(adev->dev, "MES ring buffer is full.\n");
> +	amdgpu_ring_undo(ring);
> +
>   error_unlock_free:
>   	spin_unlock_irqrestore(&mes->ring_lock, flags);
>