Am 17.04.24 um 08:21 schrieb Arunpravin Paneer Selvam:
Now we have two flags for contiguous VRAM buffer allocation.
If the application request for AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS,
it would set the ttm place TTM_PL_FLAG_CONTIGUOUS flag in the
buffer's placement function.
This patch will change the default behaviour of the two flags.
When we set AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS
- This means contiguous is not mandatory.
- we will try to allocate the contiguous buffer. Say if the
allocation fails, we fallback to allocate the individual pages.
When we setTTM_PL_FLAG_CONTIGUOUS
- This means contiguous allocation is mandatory.
- we are setting this in amdgpu_bo_pin_restricted() before bo validation
and check this flag in the vram manager file.
- if this is set, we should allocate the buffer pages contiguously.
the allocation fails, we return -ENOSPC.
v2:
- keep the mem_flags and bo->flags check as is(Christian)
- place the TTM_PL_FLAG_CONTIGUOUS flag setting into the
amdgpu_bo_pin_restricted function placement range iteration
loop(Christian)
- rename find_pages with amdgpu_vram_mgr_calculate_pages_per_block
(Christian)
- Keep the kernel BO allocation as is(Christain)
- If BO pin vram allocation failed, we need to return -ENOSPC as
RDMA cannot work with scattered VRAM pages(Philip)
Signed-off-by: Arunpravin Paneer Selvam <arunpravin.paneersel...@amd.com>
Suggested-by: Christian König <christian.koe...@amd.com>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 8 ++-
drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 57 +++++++++++++++-----
2 files changed, 50 insertions(+), 15 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
index 8bc79924d171..caaef7b1df49 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
@@ -153,8 +153,10 @@ void amdgpu_bo_placement_from_domain(struct amdgpu_bo
*abo, u32 domain)
else
places[c].flags |= TTM_PL_FLAG_TOPDOWN;
- if (flags & AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS)
+ if (abo->tbo.type == ttm_bo_type_kernel &&
+ flags & AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS)
places[c].flags |= TTM_PL_FLAG_CONTIGUOUS;
+
c++;
}
@@ -966,6 +968,10 @@ int amdgpu_bo_pin_restricted(struct amdgpu_bo *bo, u32 domain,
if (!bo->placements[i].lpfn ||
(lpfn && lpfn < bo->placements[i].lpfn))
bo->placements[i].lpfn = lpfn;
+
+ if (bo->flags & AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS &&
+ bo->placements[i].mem_type == TTM_PL_VRAM)
+ bo->placements[i].flags |= TTM_PL_FLAG_CONTIGUOUS;
}
r = ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
Nice work, up till here that looks exactly right as far as I can see.
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
index 8db880244324..4be8b091099a 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
@@ -88,6 +88,29 @@ static inline u64 amdgpu_vram_mgr_blocks_size(struct
list_head *head)
return size;
}
+static inline unsigned long
+amdgpu_vram_mgr_calculate_pages_per_block(struct ttm_buffer_object *tbo,
+ const struct ttm_place *place,
+ unsigned long bo_flags)
+{
+ unsigned long pages_per_block;
+
+ if (bo_flags & AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS) {
+ pages_per_block = ~0ul;
If I understand it correctly this here enforces the allocation of a
contiguous buffer in the way that it says we should have only one giant
page for the whole BO.
+ } else {
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ pages_per_block = HPAGE_PMD_NR;
+#else
+ /* default to 2MB */
+ pages_per_block = 2UL << (20UL - PAGE_SHIFT);
+#endif
+ pages_per_block = max_t(uint32_t, pages_per_block,
+ tbo->page_alignment);
+ }
+
+ return pages_per_block;
+}
+
/**
* DOC: mem_info_vram_total
*
@@ -451,8 +474,10 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager
*man,
struct amdgpu_vram_mgr *mgr = to_vram_mgr(man);
struct amdgpu_device *adev = to_amdgpu_device(mgr);
u64 vis_usage = 0, max_bytes, min_block_size;
+ struct amdgpu_bo *bo = ttm_to_amdgpu_bo(tbo);
struct amdgpu_vram_mgr_resource *vres;
u64 size, remaining_size, lpfn, fpfn;
+ unsigned long bo_flags = bo->flags;
struct drm_buddy *mm = &mgr->mm;
struct drm_buddy_block *block;
unsigned long pages_per_block;
@@ -468,18 +493,9 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager
*man,
if (tbo->type != ttm_bo_type_kernel)
max_bytes -= AMDGPU_VM_RESERVED_VRAM;
- if (place->flags & TTM_PL_FLAG_CONTIGUOUS) {
- pages_per_block = ~0ul;
- } else {
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
- pages_per_block = HPAGE_PMD_NR;
-#else
- /* default to 2MB */
- pages_per_block = 2UL << (20UL - PAGE_SHIFT);
-#endif
- pages_per_block = max_t(uint32_t, pages_per_block,
- tbo->page_alignment);
- }
+ pages_per_block =
+ amdgpu_vram_mgr_calculate_pages_per_block(tbo, place,
+ bo_flags);
vres = kzalloc(sizeof(*vres), GFP_KERNEL);
if (!vres)
@@ -498,7 +514,7 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager
*man,
if (place->flags & TTM_PL_FLAG_TOPDOWN)
vres->flags |= DRM_BUDDY_TOPDOWN_ALLOCATION;
- if (place->flags & TTM_PL_FLAG_CONTIGUOUS)
+ if (bo_flags & AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS)
vres->flags |= DRM_BUDDY_CONTIGUOUS_ALLOCATION;
And this here just optimizes it in the way that it says try harder to
make it look contiguous.
Question is if that also works with pages_per_block of 2MiB or does that
only kick in when pages_per_block is maximal?
if (fpfn || lpfn != mgr->mm.size)
@@ -529,8 +545,21 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager
*man,
min_block_size,
&vres->blocks,
vres->flags);
- if (unlikely(r))
+ if (unlikely(r)) {
+ if (bo_flags & AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS &&
+ !(place->flags & TTM_PL_FLAG_CONTIGUOUS)) {
+ /* Fallback to non contiguous allocation */
+ vres->flags &= ~DRM_BUDDY_CONTIGUOUS_ALLOCATION;
+ bo_flags &= ~AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS;
Well I would say that this is a rather hacky implementation and should
be avoided if possible.
+
+ pages_per_block =
+
amdgpu_vram_mgr_calculate_pages_per_block(tbo,
+
place,
+
bo_flags);
Rather move the AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS handling out of
amdgpu_vram_mgr_calculate_pages_per_block().
Regards,
Christian.
+ continue;
+ }
goto error_free_blocks;
+ }
if (size > remaining_size)
remaining_size = 0;
