On 10 August 2017 at 23:56, Emil Velikov <emil.l.velikov at gmail.com> wrote:
> Hi Dave,
>
> On 18 July 2017 at 04:52, Dave Airlie <airlied at gmail.com> wrote:
>
>> +int amdgpu_cs_submit_raw(amdgpu_device_handle dev,
>> + amdgpu_context_handle context,
>> + amdgpu_bo_list_handle bo_list_handle,
>> + int num_chunks,
>> + struct drm_amdgpu_cs_chunk *chunks,
>> + uint64_t *seq_no)
>> +{
>> + union drm_amdgpu_cs cs = {0};
>> + uint64_t *chunk_array;
>> + int i, r;
>> + if (num_chunks == 0)
>> + return -EINVAL;
>> +
>> + chunk_array = alloca(sizeof(uint64_t) * num_chunks);
> Out of curiosity:
> Does malloc/free produce noticeable overhead that lead you you alloca?
The preexisting code for these ioctls used alloca so I just followed
the existing pattern.
I doubt we'd notice malloc/free, but we shouldn't also be sending more
than 5-10 chunks
even in the future, so stack alloc should be fine.
> num_chunks is signed - should we bail on negative values, can we make
> it unsigned?
Possibly, I don't see random users of this API appearing though, but yeah could
change the if <= 0.
Dave.
