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)

v3(Christian):
  - keep contiguous flag handling outside of pages_per_block
    calculation
  - remove the hacky implementation in contiguous flag error
    handling code

Signed-off-by: Arunpravin Paneer Selvam <[email protected]>
Suggested-by: Christian König <[email protected]>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_object.c   |  8 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 83 ++++++++++++++------
 2 files changed, 65 insertions(+), 26 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
index 492aebc44e51..c594d2a5978e 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
@@ -154,8 +154,10 @@ 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++;
        }
 
@@ -965,6 +967,10 @@ 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);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
index e494f5bf136a..17c5d9ce9927 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
@@ -88,6 +88,23 @@ static inline u64 amdgpu_vram_mgr_blocks_size(struct 
list_head *head)
        return size;
 }
 
+static inline void amdgpu_vram_mgr_limit_min_block_size(unsigned long 
pages_per_block,
+                                                       u64 size,
+                                                       u64 *min_block_size,
+                                                       bool contiguous_enabled)
+{
+       if (contiguous_enabled)
+               return;
+
+       /*
+        * if size >= 2MiB, limit the min_block_size to 2MiB
+        * for better TLB usage.
+        */
+       if ((size >= (u64)pages_per_block << PAGE_SHIFT) &&
+           !(size & (((u64)pages_per_block << PAGE_SHIFT) - 1)))
+               *min_block_size = (u64)pages_per_block << PAGE_SHIFT;
+}
+
 /**
  * DOC: mem_info_vram_total
  *
@@ -452,11 +469,12 @@ static int amdgpu_vram_mgr_new(struct 
ttm_resource_manager *man,
        struct amdgpu_device *adev = to_amdgpu_device(mgr);
        struct amdgpu_bo *bo = ttm_to_amdgpu_bo(tbo);
        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;
        struct drm_buddy *mm = &mgr->mm;
-       struct drm_buddy_block *block;
        unsigned long pages_per_block;
+       struct drm_buddy_block *block;
        int r;
 
        lpfn = (u64)place->lpfn << PAGE_SHIFT;
@@ -469,18 +487,14 @@ 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
+       if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
                pages_per_block = HPAGE_PMD_NR;
-#else
-               /* default to 2MB */
+       else
+               /* default to 2MiB */
                pages_per_block = 2UL << (20UL - PAGE_SHIFT);
-#endif
-               pages_per_block = max_t(uint32_t, pages_per_block,
-                                       tbo->page_alignment);
-       }
+
+       pages_per_block = max_t(uint32_t, pages_per_block,
+                               tbo->page_alignment);
 
        vres = kzalloc(sizeof(*vres), GFP_KERNEL);
        if (!vres)
@@ -499,7 +513,7 @@ 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;
 
        if (bo->flags & AMDGPU_GEM_CREATE_VRAM_CLEARED)
@@ -509,23 +523,23 @@ static int amdgpu_vram_mgr_new(struct 
ttm_resource_manager *man,
                /* Allocate blocks in desired range */
                vres->flags |= DRM_BUDDY_RANGE_ALLOCATION;
 
+       if (tbo->page_alignment)
+               min_block_size = (u64)tbo->page_alignment << PAGE_SHIFT;
+       else
+               min_block_size = mgr->default_page_size;
+
        remaining_size = (u64)vres->base.size;
 
        mutex_lock(&mgr->lock);
        while (remaining_size) {
-               if (tbo->page_alignment)
-                       min_block_size = (u64)tbo->page_alignment << PAGE_SHIFT;
-               else
-                       min_block_size = mgr->default_page_size;
-
-               BUG_ON(min_block_size < mm->chunk_size);
-
                /* Limit maximum size to 2GiB due to SG table limitations */
                size = min(remaining_size, 2ULL << 30);
-
-               if ((size >= (u64)pages_per_block << PAGE_SHIFT) &&
-                               !(size & (((u64)pages_per_block << PAGE_SHIFT) 
- 1)))
-                       min_block_size = (u64)pages_per_block << PAGE_SHIFT;
+               amdgpu_vram_mgr_limit_min_block_size(pages_per_block,
+                                                    size,
+                                                    &min_block_size,
+                                                    bo->flags &
+                                                    
AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS);
+               BUG_ON(min_block_size < mm->chunk_size);
 
                r = drm_buddy_alloc_blocks(mm, fpfn,
                                           lpfn,
@@ -533,8 +547,27 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager 
*man,
                                           min_block_size,
                                           &vres->blocks,
                                           vres->flags);
-               if (unlikely(r))
-                       goto error_free_blocks;
+               if (unlikely(r)) {
+                       if (bo->flags & AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS &&
+                           !(place->flags & TTM_PL_FLAG_CONTIGUOUS)) {
+                               /* Fallback to non-contiguous allocation */
+                               
amdgpu_vram_mgr_limit_min_block_size(pages_per_block,
+                                                                    size,
+                                                                    
&min_block_size,
+                                                                    
!(bo->flags &
+                                                                    
AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS));
+                               r = drm_buddy_alloc_blocks(mm, fpfn,
+                                                          lpfn,
+                                                          size,
+                                                          min_block_size,
+                                                          &vres->blocks,
+                                                          vres->flags);
+                               if (unlikely(r))
+                                       goto error_free_blocks;
+                       } else {
+                               goto error_free_blocks;
+                       }
+               }
 
                if (size > remaining_size)
                        remaining_size = 0;
-- 
2.25.1

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