[PATCH v2 1/2] drm/amdgpu: move error log from ring write to commit

[Khatri, Sunil]

On 10/7/2024 7:18 PM, Christian König wrote:
> Am 03.10.24 um 10:28 schrieb Sunil Khatri:
>> Move the error message from ring write as an optimization
>> to avoid printing that message on every write instead
>> print once during commit if it exceeds write the allocated
>> size i.e ring->count_dw.
>>
>> Also we do not want to log the error message in between a
>> ring write and complete the write as its mostly not harmful
>> as it will overwrite stale data only as GPU read from ring
>> is faster than CPU write to ring.
>>
>> This reduces the size of amdgpu.ko module by around
>> 600 Kb as write is very often used function and hence
>> the print.
>>
>> Signed-off-by: Sunil Khatri <sunil.khatri at amd.com>
>> Suggested-by: Christian König <christian.koenig at amd.com>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c | 3 +++
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h | 2 --
>>   2 files changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c 
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
>> index 690976665cf6..05b3480ecec7 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
>> @@ -141,6 +141,9 @@ void amdgpu_ring_commit(struct amdgpu_ring *ring)
>>   {
>>       uint32_t count;
>>   +    if (ring->count_dw <= 0)
>> +        DRM_ERROR("amdgpu: writing more dwords to the ring than 
>> expected!\n");
>> +
>
> Oh, I missed this on the first review a count_dw of 0 is actually ok 
> since that means we have written exactly as much dw as estimated.
Sure i will replace it with below code

  if (ring->count_dw < 0)

Regards
Sunil khatri

>
> Regards,
> Christian.
>
>>       /* We pad to match fetch size */
>>       count = ring->funcs->align_mask + 1 -
>>           (ring->wptr & ring->funcs->align_mask);
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h 
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
>> index f93f51002201..af8824e8da49 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
>> @@ -377,8 +377,6 @@ static inline void amdgpu_ring_clear_ring(struct 
>> amdgpu_ring *ring)
>>     static inline void amdgpu_ring_write(struct amdgpu_ring *ring, 
>> uint32_t v)
>>   {
>> -    if (ring->count_dw <= 0)
>> -        DRM_ERROR("amdgpu: writing more dwords to the ring than 
>> expected!\n");
>>       ring->ring[ring->wptr++ & ring->buf_mask] = v;
>>       ring->wptr &= ring->ptr_mask;
>>       ring->count_dw--;
>