On Thu, May 19, 2022 at 1:15 PM Felix Kuehling <felix.kuehling@xxxxxxx> wrote:
>
>
> Am 2022-05-19 um 10:34 schrieb Alex Deucher:
> > The current somewhat strange logic is in place because certain
> > GL unit tests for large textures can cause problems with the
> > OOM killer since there is no way to link this memory to a
> > process. The problem is this limit is often too low for many
> > modern games on systems with more memory so limit the logic to
> > systems with less than 8GB of main memory. For systems with 8
> > or more GB of system memory, set the GTT size to 3/4 of system
> > memory.
>
> Well, I've been railing against this limit for years, and was always
> told it's unchangeable for reasons. So we found other ways to use more
> system memory in ROCm. Good to see that I'm no longer the only one who
> thinks this GTT limit is a problem.
>
> Acked-by: Felix Kuehling <Felix.Kuehling@xxxxxxx>
After further discussions with Marek, I just sent a v2 to simplify this further.
Alex
>
>
> >
> > Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
> > ---
> > drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 25 ++++++++++++++++++++-----
> > 1 file changed, 20 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> > index 4b9ee6e27f74..daa0babcf869 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> > @@ -1801,15 +1801,30 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
> > /* Compute GTT size, either bsaed on 3/4th the size of RAM size
> > * or whatever the user passed on module init */
> > if (amdgpu_gtt_size == -1) {
> > + const u64 eight_GB = 8192ULL * 1024 * 1024;
> > struct sysinfo si;
> > + u64 total_memory, default_gtt_size;
> >
> > si_meminfo(&si);
> > - gtt_size = min(max((AMDGPU_DEFAULT_GTT_SIZE_MB << 20),
> > - adev->gmc.mc_vram_size),
> > - ((uint64_t)si.totalram * si.mem_unit * 3/4));
> > - }
> > - else
> > + total_memory = (u64)si.totalram * si.mem_unit;
> > + default_gtt_size = total_memory * 3 / 4;
> > + /* This somewhat strange logic is in place because certain GL unit
> > + * tests for large textures can cause problems with the OOM killer
> > + * since there is no way to link this memory to a process.
> > + * The problem is this limit is often too low for many modern games
> > + * on systems with more memory so limit the logic to systems with
> > + * less than 8GB of main memory.
> > + */
> > + if (total_memory < eight_GB) {
> > + gtt_size = min(max((AMDGPU_DEFAULT_GTT_SIZE_MB << 20),
> > + adev->gmc.mc_vram_size),
> > + default_gtt_size);
> > + } else {
> > + gtt_size = default_gtt_size;
> > + }
> > + } else {
> > gtt_size = (uint64_t)amdgpu_gtt_size << 20;
> > + }
> >
> > /* Initialize GTT memory pool */
> > r = amdgpu_gtt_mgr_init(adev, gtt_size);
