[PATCH 2/3] drm/amdgpu: Set GTT size equal to TTM mem limit

[Joshi, Mukul]

[AMD Official Use Only - General]



> -----Original Message-----
> From: Chen, Guchun <Guchun.Chen at amd.com>
> Sent: Wednesday, April 26, 2023 2:00 AM
> To: Joshi, Mukul <Mukul.Joshi at amd.com>; amd-gfx at lists.freedesktop.org;
> dri-devel at lists.freedesktop.org
> Cc: Joshi, Mukul <Mukul.Joshi at amd.com>; Kuehling, Felix
> <Felix.Kuehling at amd.com>; Koenig, Christian <Christian.Koenig at amd.com>
> Subject: RE: [PATCH 2/3] drm/amdgpu: Set GTT size equal to TTM mem limit
> 
> Looks you can drop macro 'AMDGPU_DEFAULT_GTT_SIZE_MB' as well.
> 
Thanks for catching this. Sorry I missed it. I will remove and send a v2.

Regards,
Mukul
> Regards,
> Guchun
> 
> > -----Original Message-----
> > From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of
> > Mukul Joshi
> > Sent: Wednesday, April 26, 2023 9:53 AM
> > To: amd-gfx at lists.freedesktop.org; dri-devel at lists.freedesktop.org
> > Cc: Joshi, Mukul <Mukul.Joshi at amd.com>; Kuehling, Felix
> > <Felix.Kuehling at amd.com>; Koenig, Christian
> <Christian.Koenig at amd.com>
> > Subject: [PATCH 2/3] drm/amdgpu: Set GTT size equal to TTM mem limit
> >
> > Use the helper function in TTM to get TTM mem limit and set GTT size
> > to be equal to TTL mem limit.
> >
> > Signed-off-by: Mukul Joshi <mukul.joshi at amd.com>
> > ---
> >  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 25
> > ++++++-------------------
> >  1 file changed, 6 insertions(+), 19 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> > b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> > index ce34b73d05bc..ac220c779fc8 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> > @@ -1807,26 +1807,13 @@ int amdgpu_ttm_init(struct amdgpu_device
> > *adev)
> >  	DRM_INFO("amdgpu: %uM of VRAM memory ready\n",
> >  		 (unsigned) (adev->gmc.real_vram_size / (1024 * 1024)));
> >
> > -	/* Compute GTT size, either based on 1/2 the size of RAM size
> > -	 * or whatever the user passed on module init */
> > -	if (amdgpu_gtt_size == -1) {
> > -		struct sysinfo si;
> > -
> > -		si_meminfo(&si);
> > -		/* 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.  This was originally mitigated (but not
> > necessarily
> > -		 * eliminated) by limiting the GTT size.  The problem is this
> > limit
> > -		 * is often too low for many modern games so just make the
> > limit 1/2
> > -		 * of system memory which aligns with TTM. The OOM
> > accounting needs
> > -		 * to be addressed, but we shouldn't prevent common 3D
> > applications
> > -		 * from being usable just to potentially mitigate that corner
> > case.
> > -		 */
> > -		gtt_size = max((AMDGPU_DEFAULT_GTT_SIZE_MB << 20),
> > -			       (u64)si.totalram * si.mem_unit / 2);
> > -	} else {
> > +	/* Compute GTT size, either based on TTM limit
> > +	 * or whatever the user passed on module init.
> > +	 */
> > +	if (amdgpu_gtt_size == -1)
> > +		gtt_size = ttm_tt_pages_limit() << PAGE_SHIFT;
> > +	else
> >  		gtt_size = (uint64_t)amdgpu_gtt_size << 20;
> > -	}
> >
> >  	/* Initialize GTT memory pool */
> >  	r = amdgpu_gtt_mgr_init(adev, gtt_size);
> > --
> > 2.35.1