On 1/5/21 10:10 PM, Alex Deucher wrote:
On Tue, Jan 5, 2021 at 5:05 PM Joshua Ashton <joshua@xxxxxxxxx> wrote:Since commit 24562523688b ("Revert "drm/amd/amdgpu: set gtt size according to system memory size only""), the GTT size was limited by 3GiB or VRAM size.The commit in question was to fix a hang with certain tests on APUs. That should be tested again before we re-enable this. If it is fixed, we should just revert the revert rather than special case dGPUs. Alex
I think the commit before the revert (ba851eed895c) has some fundamental problems:
It was always specifying max(3GiB, 3/4ths RAM) of GTT, even if that wouldn't fit into say, 1GiB or 2GiB of available RAM.
Limiting GTT to min(max(3GiB, VRAM), 3/4ths RAM) size on dGPUs makes sense also and is a sensible limit to avoid silly situations with overallocation and potential OOM.
This patch solves both of those issues. - Joshie 🐸✨
This is problematic on APUs, especially with a small carveout which can be as low as a fixed 128MiB, as there would be very a limited 3GiB available for video memory. This obviously does not meet the demands of modern applications. This patch makes it so the GTT size heuristic always uses 3/4ths of the system memory size on APUs (limiting the size by 3GiB/VRAM size only on devices with dedicated video memory). Fixes: 24562523688b ("Revert drm/amd/amdgpu: set gtt size according to system memory size only") Signed-off-by: Joshua Ashton <joshua@xxxxxxxxx> --- drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 5 +++-- drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 12 +++++++++--- 2 files changed, 12 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c index 72efd579ec5e..a5a41e9272d6 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c @@ -192,8 +192,9 @@ module_param_named(gartsize, amdgpu_gart_size, uint, 0600); /** * DOC: gttsize (int) - * Restrict the size of GTT domain in MiB for testing. The default is -1 (It's VRAM size if 3GB < VRAM < 3/4 RAM, - * otherwise 3/4 RAM size). + * Restrict the size of GTT domain in MiB for testing. The default is -1 (On APUs this is 3/4th + * of the system memory; on dGPUs this is 3GiB or VRAM sized, whichever is bigger, + * with an upper bound of 3/4th of system memory. */ MODULE_PARM_DESC(gttsize, "Size of the GTT domain in megabytes (-1 = auto)"); module_param_named(gttsize, amdgpu_gtt_size, int, 0600); diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c index 4d8f19ab1014..294f26f4f310 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c @@ -1865,9 +1865,15 @@ int amdgpu_ttm_init(struct amdgpu_device *adev) struct sysinfo si; 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)); + gtt_size = (uint64_t)si.totalram * si.mem_unit * 3/4; + /* If we have dedicated memory, limit our GTT size to + * 3GiB or VRAM size, whichever is bigger + */ + if (!(adev->flags & AMD_IS_APU)) { + gtt_size = min(max(AMDGPU_DEFAULT_GTT_SIZE_MB << 20, + adev->gmc.mc_vram_size), + gtt_size); + } } else gtt_size = (uint64_t)amdgpu_gtt_size << 20; -- 2.30.0 _______________________________________________ amd-gfx mailing list amd-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/amd-gfx
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