From 3439cc46619a3f31780cbd4f820384f9586d5ee1 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= Date: Mon, 26 Jun 2023 20:17:39 +0200 Subject: [PATCH] drm/xe/bo: Avoid creating a system resource when allocating a fresh VRAM bo MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When creating a new bo, on the first move the bo->resource is typically NULL. Our move callback rejected that instructing TTM to create a system resource. In addition a struct ttm_tt with a page-vector was created, although not populated with pages. Similarly when the clearing of VRAM was complete, the system resource was put on a ghost object and freed using the TTM delayed destroy mechanism. This is a lot of pointless work. So avoid creating the system resource and instead change the code to cope with a NULL bo->resource. v2: - Add some code comments (Matthew Brost) v3: - Fix a dereference of old_mem which might be NULL. Signed-off-by: Thomas Hellström Reviewed-by: Matthew Auld Link: https://patchwork.freedesktop.org/patch/msgid/20230626181741.32820-3-thomas.hellstrom@linux.intel.com Signed-off-by: Rodrigo Vivi --- drivers/gpu/drm/xe/xe_bo.c | 48 +++++++++++++++++++++----------------- 1 file changed, 27 insertions(+), 21 deletions(-) diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c index bdeef3bf40fc..8920405b0182 100644 --- a/drivers/gpu/drm/xe/xe_bo.c +++ b/drivers/gpu/drm/xe/xe_bo.c @@ -479,7 +479,6 @@ static int xe_bo_trigger_rebind(struct xe_device *xe, struct xe_bo *bo, * to unconditionally call unmap_attachment() when moving out to system. */ static int xe_bo_move_dmabuf(struct ttm_buffer_object *ttm_bo, - struct ttm_resource *old_res, struct ttm_resource *new_res) { struct dma_buf_attachment *attach = ttm_bo->base.import_attach; @@ -564,6 +563,7 @@ static int xe_bo_move(struct ttm_buffer_object *ttm_bo, bool evict, struct xe_device *xe = ttm_to_xe_device(ttm_bo->bdev); struct xe_bo *bo = ttm_to_xe_bo(ttm_bo); struct ttm_resource *old_mem = ttm_bo->resource; + u32 old_mem_type = old_mem ? old_mem->mem_type : XE_PL_SYSTEM; struct ttm_tt *ttm = ttm_bo->ttm; struct xe_tile *tile = NULL; struct dma_fence *fence; @@ -572,35 +572,29 @@ static int xe_bo_move(struct ttm_buffer_object *ttm_bo, bool evict, bool needs_clear; int ret = 0; - if (!old_mem) { - if (new_mem->mem_type != TTM_PL_SYSTEM) { - hop->mem_type = TTM_PL_SYSTEM; - hop->flags = TTM_PL_FLAG_TEMPORARY; - ret = -EMULTIHOP; - goto out; - } - + /* Bo creation path, moving to system or TT. No clearing required. */ + if (!old_mem && ttm) { ttm_bo_move_null(ttm_bo, new_mem); - goto out; + return 0; } if (ttm_bo->type == ttm_bo_type_sg) { ret = xe_bo_move_notify(bo, ctx); if (!ret) - ret = xe_bo_move_dmabuf(ttm_bo, old_mem, new_mem); + ret = xe_bo_move_dmabuf(ttm_bo, new_mem); goto out; } tt_has_data = ttm && (ttm_tt_is_populated(ttm) || (ttm->page_flags & TTM_TT_FLAG_SWAPPED)); - move_lacks_source = !resource_is_vram(old_mem) && !tt_has_data; + move_lacks_source = !mem_type_is_vram(old_mem_type) && !tt_has_data; needs_clear = (ttm && ttm->page_flags & TTM_TT_FLAG_ZERO_ALLOC) || (!ttm && ttm_bo->type == ttm_bo_type_device); if ((move_lacks_source && !needs_clear) || - (old_mem->mem_type == XE_PL_SYSTEM && + (old_mem_type == XE_PL_SYSTEM && new_mem->mem_type == XE_PL_TT)) { ttm_bo_move_null(ttm_bo, new_mem); goto out; @@ -610,7 +604,7 @@ static int xe_bo_move(struct ttm_buffer_object *ttm_bo, bool evict, * Failed multi-hop where the old_mem is still marked as * TTM_PL_FLAG_TEMPORARY, should just be a dummy move. */ - if (old_mem->mem_type == XE_PL_TT && + if (old_mem_type == XE_PL_TT && new_mem->mem_type == XE_PL_TT) { ttm_bo_move_null(ttm_bo, new_mem); goto out; @@ -622,7 +616,7 @@ static int xe_bo_move(struct ttm_buffer_object *ttm_bo, bool evict, goto out; } - if (old_mem->mem_type == XE_PL_TT && + if (old_mem_type == XE_PL_TT && new_mem->mem_type == XE_PL_SYSTEM) { long timeout = dma_resv_wait_timeout(ttm_bo->base.resv, DMA_RESV_USAGE_BOOKKEEP, @@ -637,8 +631,8 @@ static int xe_bo_move(struct ttm_buffer_object *ttm_bo, bool evict, } if (!move_lacks_source && - ((old_mem->mem_type == XE_PL_SYSTEM && resource_is_vram(new_mem)) || - (resource_is_vram(old_mem) && + ((old_mem_type == XE_PL_SYSTEM && resource_is_vram(new_mem)) || + (mem_type_is_vram(old_mem_type) && new_mem->mem_type == XE_PL_SYSTEM))) { hop->fpfn = 0; hop->lpfn = 0; @@ -652,8 +646,8 @@ static int xe_bo_move(struct ttm_buffer_object *ttm_bo, bool evict, tile = bo->tile; else if (resource_is_vram(new_mem)) tile = mem_type_to_tile(xe, new_mem->mem_type); - else if (resource_is_vram(old_mem)) - tile = mem_type_to_tile(xe, old_mem->mem_type); + else if (mem_type_is_vram(old_mem_type)) + tile = mem_type_to_tile(xe, old_mem_type); XE_BUG_ON(!tile); XE_BUG_ON(!tile->migrate); @@ -703,8 +697,20 @@ static int xe_bo_move(struct ttm_buffer_object *ttm_bo, bool evict, xe_device_mem_access_put(xe); goto out; } - ret = ttm_bo_move_accel_cleanup(ttm_bo, fence, evict, true, - new_mem); + if (!move_lacks_source) { + ret = ttm_bo_move_accel_cleanup(ttm_bo, fence, evict, + true, new_mem); + } else { + /* + * ttm_bo_move_accel_cleanup() may blow up if + * bo->resource == NULL, so just attach the + * fence and set the new resource. + */ + dma_resv_add_fence(ttm_bo->base.resv, fence, + DMA_RESV_USAGE_KERNEL); + ttm_bo_move_null(ttm_bo, new_mem); + } + dma_fence_put(fence); }