Allocating small bos from one end and large ones from the other helps improve the quality of fragmentation.

I have measured a suitable threshold to reduce eviction by up to 20%, and to cause no harm in normal cases that fit VRAM fully (PTS gaming suite). In some cases, even the VRAM-fitting cases improved slightly (openarena, urban terror).

This depends on "drm: Optionally create mm blocks from top-to-bottom" by Chris Wilson, and so is just RFC for now. --- drivers/gpu/drm/ttm/ttm_bo.c | 4 +++- drivers/gpu/drm/ttm/ttm_bo_manager.c | 12 +++++++++--- include/drm/ttm/ttm_bo_driver.h | 5 ++++- 3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index a066513..7f30c2d 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -1450,7 +1450,8 @@ int ttm_bo_device_init(struct ttm_bo_device *bdev, struct ttm_bo_global *glob, struct ttm_bo_driver *driver, uint64_t file_page_offset, - bool need_dma32) + bool need_dma32, + uint32_t alloc_threshold) { int ret = -EINVAL;

@@ -1473,6 +1474,7 @@ int ttm_bo_device_init(struct ttm_bo_device *bdev, bdev->dev_mapping = NULL; bdev->glob = glob; bdev->need_dma32 = need_dma32; + bdev->alloc_threshold = alloc_threshold; bdev->val_seq = 0; spin_lock_init(&bdev->fence_lock); mutex_lock(&glob->device_list_mutex); diff --git a/drivers/gpu/drm/ttm/ttm_bo_manager.c b/drivers/gpu/drm/ttm/ttm_bo_manager.c index c58eba33..bd1cbf1 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_manager.c +++ b/drivers/gpu/drm/ttm/ttm_bo_manager.c @@ -55,6 +55,7 @@ static int ttm_bo_man_get_node(struct ttm_mem_type_manager *man, struct ttm_range_manager *rman = (struct ttm_range_manager *) man->priv; struct drm_mm *mm = &rman->mm; struct drm_mm_node *node = NULL; + enum drm_mm_allocator_flags aflags = DRM_MM_CREATE_DEFAULT; unsigned long lpfn; int ret;

@@ -66,11 +67,16 @@ static int ttm_bo_man_get_node(struct ttm_mem_type_manager *man, if (!node) return -ENOMEM;

+ if (man->bdev->alloc_threshold && + man->bdev->alloc_threshold < (mem->num_pages * PAGE_SIZE)) + aflags = DRM_MM_CREATE_TOP; + spin_lock(&rman->lock); - ret = drm_mm_insert_node_in_range(mm, node, mem->num_pages, - mem->page_alignment, + ret = drm_mm_insert_node_in_range_generic(mm, node, mem->num_pages, + mem->page_alignment, 0, placement->fpfn, lpfn, - DRM_MM_SEARCH_BEST); + DRM_MM_SEARCH_BEST, + aflags); spin_unlock(&rman->lock);

if (unlikely(ret)) { diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h index 32d34eb..831320e 100644 --- a/include/drm/ttm/ttm_bo_driver.h +++ b/include/drm/ttm/ttm_bo_driver.h @@ -565,6 +565,7 @@ struct ttm_bo_device { struct delayed_work wq;

bool need_dma32; + uint32_t alloc_threshold; };

/** @@ -758,7 +759,9 @@ extern int ttm_bo_device_release(struct ttm_bo_device *bdev); extern int ttm_bo_device_init(struct ttm_bo_device *bdev, struct ttm_bo_global *glob, struct ttm_bo_driver *driver, - uint64_t file_page_offset, bool need_dma32); + uint64_t file_page_offset, + bool need_dma32, + uint32_t alloc_threshold);

/** * ttm_bo_unmap_virtual