Am 24.07.20 um 04:56 schrieb Felix Kuehling:
Am 2020-07-23 um 9:58 p.m. schrieb philip yang:
On 2020-07-23 7:02 p.m., Felix Kuehling wrote:
Am 2020-07-23 um 5:00 a.m. schrieb Christian König:
We can't pipeline that during eviction because the memory needs
to be available immediately.
Signed-off-by: Christian König <christian.koenig@xxxxxxx>
---
drivers/gpu/drm/ttm/ttm_bo.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c
b/drivers/gpu/drm/ttm/ttm_bo.c
index bc2230ecb7e3..122040056a07 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -651,8 +651,16 @@ static int ttm_bo_evict(struct
ttm_buffer_object *bo,
placement.num_busy_placement = 0;
bdev->driver->evict_flags(bo, &placement);
- if (!placement.num_placement && !placement.num_busy_placement)
- return ttm_bo_pipeline_gutting(bo);
+ if (!placement.num_placement && !placement.num_busy_placement) {
+ ttm_bo_wait(bo, false, false);
+
+ ttm_tt_destroy(bo->ttm);
+
+ memset(&bo->mem, 0, sizeof(bo->mem));
Where does the memory in the bo->mem (ttm_mem_reg) get destroyed? It
doesn't get attached to a ghost BO in this case, so someone will have to
call ttm_bo_mem_put explicitly before you wipe out bo->mem.
After migrating to ram,
svm_range_bo_unref-->amdgpu_unref_bo->ttm_bo_put->ttm_bo_release calls
ttm_bo_mem_put.
amdgpu_bo_unref won't free anything if the reference count doesn't go to
0. And TTM is still holding a reference here. The BO won't be freed
until ttm_mem_evict_first calls ttm_bo_put.
The memset above overwrites the ttm_mem_reg structure, which means it
will forget about the VRAM nodes held by the BO. They need to be
released first. That's what frees the space that ttm_bo_evict was trying
to make available in the first place.
Yeah, Felix is right that this is a bug.
Going to send a v2 in a minute.
Thanks,
Christian.
Regards,
Felix
vram is already freed before we signal fence, right?
Regards,
Philip
Regards,
Felix
+ bo->mem.mem_type = TTM_PL_SYSTEM;
+ bo->ttm = NULL;
+ return 0;
+ }
evict_mem = bo->mem;
evict_mem.mm_node = NULL;
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