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authorDave Airlie <airlied@redhat.com>2020-10-29 13:58:52 +1000
committerDave Airlie <airlied@redhat.com>2020-11-11 11:11:03 +1000
commitebdf565169af006ee3be8c40eecbfc77d28a3b84 (patch)
treeccc29cae7148ec2940d137a6492852dc1d6f1ff9 /include/drm
parent2dcab875e7637f1d3f9b978566e61ed1cbbba054 (diff)
drm/ttm: add multihop infrastrucutre (v3)
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 <daniel.vetter@ffwll.ch> Reviewed-by: hristian König <christian.koenig@amd.com> Signed-off-by: Dave Airlie <airlied@redhat.com> Link: https://patchwork.freedesktop.org/patch/msgid/20201109005432.861936-2-airlied@gmail.com
Diffstat (limited to 'include/drm')
-rw-r--r--include/drm/ttm/ttm_bo_driver.h7
1 files changed, 6 insertions, 1 deletions
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