On 3.06.2024 11:30, Thomas Hellström wrote:
On Mon, 2024-06-03 at 10:28 +0200, Karolina Stolarek wrote:
diff --git a/drivers/gpu/drm/ttm/tests/ttm_kunit_helpers.c
b/drivers/gpu/drm/ttm/tests/ttm_kunit_helpers.c
index 2f590bae53f8..2a2585b37118 100644
--- a/drivers/gpu/drm/ttm/tests/ttm_kunit_helpers.c
+++ b/drivers/gpu/drm/ttm/tests/ttm_kunit_helpers.c
@@ -27,8 +27,42 @@ static int mock_move(struct
ttm_buffer_object
*bo,
bool evict,
struct ttm_resource *new_mem,
struct ttm_place *hop)
{
(...)
+
+ if (ret)
+ return ret;
+
+ ttm_resource_free(bo, &bo->resource);
+ ttm_bo_assign_mem(bo, new_mem);
+ return 0;
+ }
+
+ return ttm_bo_move_memcpy(bo, ctx, new_mem);
Do we hit this move_memcpy()? Since the mock manager doesn't
actually
reserve any memory to manager, I'd expect this to run into
problems?
We do. The mock manager has use_tt=true, so on move, we'd use
ttm_kmap_iter_tt_init() for src and dest and copy the pages. I'm
not
sure if that's the right approach, but it enables me to test if
ttm_operation_ctx's bytes_moved is correctly updated.
Ah, ok. It's probably not a common use-case since with both src and
dst
having use_tt, IIRC ttm should keep the pages and their content
mostly
intact across a move. So you would memcpy the source on itself?
But it would give some coverage of the copy code though.
I dug around and it looks like, in the current scenario,
ttm_bo_move_memcpy() is just ttm_bo_move_sync_cleanup()
(ttm_resource_free + ttm_bo_assign_mem). That means I should revisit
the
definitions of move and mock manager... I'll try to simplify them.
Do I understand correctly that we'd prefer to have a mock manager
with
user_tt=false?
Yes, but then you need to allocate a chunk of contigous memory for the
mock manager to manage. And instead of using drm_buddy you'd have to
use drm_mm to manage it, since the ttm_kmap_iter default iterators can
only handle either
a) Contigous memory regions as returned from the drm_mm manager.
b) Fragmented memory regions as returned from the drm_buddy manager,
but in that case, they currently only handle pci io memory.
So I'd suggest to go with the current code and mark as a TODO: to
implement a) above.
I understand, thank you for your explanation, that would require some
rewrite indeed. I'll follow your suggestion and include it in the TODO file.
All the best,
Karolina
