From ebdf565169af006ee3be8c40eecbfc77d28a3b84 Mon Sep 17 00:00:00 2001 From: Dave Airlie Date: Thu, 29 Oct 2020 13:58:52 +1000 Subject: drm/ttm: add multihop infrastrucutre (v3) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently drivers get called to move a buffer, but if they have to move it temporarily through another space (SYSTEM->VRAM via TT) then they can end up with a lot of ttm->driver->ttm call stacks, if the temprorary space moves requires eviction. Instead of letting the driver do all the placement/space for the temporary, allow it to report back (-EMULTIHOP) and a placement (hop) to the move code, which will then do the temporary move, and the correct placement move afterwards. This removes a lot of code from drivers, at the expense of adding some midlayering. I've some further ideas on how to turn it inside out, but I think this is a good solution to the call stack problems. v2: separate out the driver patches, add WARN for getting MULTHOP in paths we shouldn't (Daniel) v3: use memset (Christian) Reviewed-by: Daniel Vetter Reviewed-by: hristian König Signed-off-by: Dave Airlie Link: https://patchwork.freedesktop.org/patch/msgid/20201109005432.861936-2-airlied@gmail.com --- include/drm/ttm/ttm_bo_driver.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h index da8208f43378..f02f7cf9ae90 100644 --- a/include/drm/ttm/ttm_bo_driver.h +++ b/include/drm/ttm/ttm_bo_driver.h @@ -121,6 +121,8 @@ struct ttm_bo_driver { * Return the bo flags for a buffer which is not mapped to the hardware. * These will be placed in proposed_flags so that when the move is * finished, they'll end up in bo->mem.flags + * This should not cause multihop evictions, and the core will warn + * if one is proposed. */ void (*evict_flags)(struct ttm_buffer_object *bo, @@ -134,12 +136,15 @@ struct ttm_bo_driver { * the graphics address space * @ctx: context for this move with parameters * @new_mem: the new memory region receiving the buffer + @ @hop: placement for driver directed intermediate hop * * Move a buffer between two memory regions. + * Returns errno -EMULTIHOP if driver requests a hop */ int (*move)(struct ttm_buffer_object *bo, bool evict, struct ttm_operation_ctx *ctx, - struct ttm_resource *new_mem); + struct ttm_resource *new_mem, + struct ttm_place *hop); /** * struct ttm_bo_driver_member verify_access -- cgit v1.2.3