[PATCH v2] drm/xe: Use DRM_BUDDY_CONTIGUOUS_ALLOCATION for contiguous allocations

[Sanjay Yadav <sanjay.kumar.yadav@intel.com>]

The VRAM/stolen memory managers do not currently set
DRM_BUDDY_CONTIGUOUS_ALLOCATION for contiguous allocations. Enabling
this flag activates the buddy allocator's try_harder path, which helps
handle fragmented memory scenarios.

This enables the __alloc_contig_try_harder fallback in the buddy
allocator, allowing contiguous allocation requests to succeed even when
memory is fragmented by combining allocations from both(RHS and LHS)
sides of a large free block.

v2: (Matt B)
- Remove redundant logic for rounding allocation size and trimming when
  TTM_PL_FLAG_CONTIGUOUS is set, since drm_buddy now handles this when
  DRM_BUDDY_CONTIGUOUS_ALLOCATION is enabled

Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/6713
Suggested-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Sanjay Yadav <sanjay.kumar.yadav@intel.com>
---
 drivers/gpu/drm/xe/xe_ttm_vram_mgr.c | 16 +++-------------
 1 file changed, 3 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
index 9f70802fce92..1a819b627afe 100644
--- a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
+++ b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
@@ -82,6 +82,9 @@ static int xe_ttm_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)
+		vres->flags |= DRM_BUDDY_CONTIGUOUS_ALLOCATION;
+
 	if (place->fpfn || lpfn != man->size >> PAGE_SHIFT)
 		vres->flags |= DRM_BUDDY_RANGE_ALLOCATION;
 
@@ -111,25 +114,12 @@ static int xe_ttm_vram_mgr_new(struct ttm_resource_manager *man,
 		goto error_unlock;
 	}
 
-	if (place->fpfn + (size >> PAGE_SHIFT) != lpfn &&
-	    place->flags & TTM_PL_FLAG_CONTIGUOUS) {
-		size = roundup_pow_of_two(size);
-		min_page_size = size;
-
-		lpfn = max_t(unsigned long, place->fpfn + (size >> PAGE_SHIFT), lpfn);
-	}
-
 	err = drm_buddy_alloc_blocks(mm, (u64)place->fpfn << PAGE_SHIFT,
 				     (u64)lpfn << PAGE_SHIFT, size,
 				     min_page_size, &vres->blocks, vres->flags);
 	if (err)
 		goto error_unlock;
 
-	if (place->flags & TTM_PL_FLAG_CONTIGUOUS) {
-		if (!drm_buddy_block_trim(mm, NULL, vres->base.size, &vres->blocks))
-			size = vres->base.size;
-	}
-
 	if (lpfn <= mgr->visible_size >> PAGE_SHIFT) {
 		vres->used_visible_size = size;
 	} else {
-- 
2.52.0