Re: [PATCH] drm/amdgpu: always allocate cleared VRAM for GEM allocations

["Michel Dänzer" <michel.daenzer@mailbox.org>]

On 2024-07-26 17:25, Alex Deucher wrote:
> On Fri, Jul 26, 2024 at 9:50 AM Alex Deucher <alexander.deucher@amd.com> wrote:
>>
>> This adds allocation latency, but aligns better with user
>> expectations.  The latency should improve with the drm buddy
>> clearing patches that Arun has been working on.
>>
>> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
>> ---
>>  drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>> index ebb3f87ef4f6..768840e8937d 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>> @@ -347,6 +347,10 @@ int amdgpu_gem_create_ioctl(struct drm_device *dev, void *data,
>>                 return -EINVAL;
>>         }
>>
>> +       /* always clear VRAM */
>> +       if (args->in.domains & AMDGPU_GEM_DOMAIN_VRAM)
>> +               flags |= AMDGPU_GEM_CREATE_VRAM_CLEARED;
> 
> Alternatively, we can set AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE here,
> although for cases like reboots, we probably want clear on create.

I agree. Thanks for doing this!

Reviewed-by: Michel Dänzer <mdaenzer@redhat.com>


BTW, maybe this allows reducing the use of AMDGPU_GEM_CREATE_VRAM_WIPE_ON_RELEASE, or even eliminating it altogether? Does this leave any way for user space to access uncleared VRAM?


-- 
Earthling Michel Dänzer            |                  https://redhat.com
Libre software enthusiast          |         Mesa and Xwayland developer