From: Lyude Paul <lyude@xxxxxxxxxx>
Recently a regression was introduced which caused TTM's buffer eviction to
attempt to evict already-pinned BOs, causing issues with buffer eviction
under memory pressure along with suspend/resume:
nouveau 0000:1f:00.0: DRM: evicting buffers...
nouveau 0000:1f:00.0: DRM: Moving pinned object 00000000c428c3ff!
nouveau 0000:1f:00.0: fifo: fault 00 [READ] at 0000000000200000 engine 04
[BAR1] client 07 [HUB/HOST_CPU] reason 02 [PTE] on channel -1 [00ffeaa000
unknown]
nouveau 0000:1f:00.0: fifo: DROPPED_MMU_FAULT 00001000
nouveau 0000:1f:00.0: fifo: fault 01 [WRITE] at 0000000000020000 engine
0c [HOST6] client 07 [HUB/HOST_CPU] reason 02 [PTE] on channel 1
[00ffb28000 DRM]
nouveau 0000:1f:00.0: fifo: channel 1: killed
nouveau 0000:1f:00.0: fifo: runlist 0: scheduled for recovery
[TTM] Buffer eviction failed
nouveau 0000:1f:00.0: DRM: waiting for kernel channels to go idle...
nouveau 0000:1f:00.0: DRM: failed to idle channel 1 [DRM]
nouveau 0000:1f:00.0: DRM: resuming display...
After some bisection and investigation, it appears this resulted from the
recent changes to ttm_bo_move_to_lru_tail(). Previously when a buffer was
pinned, the buffer would be removed from the LRU once ttm_bo_unreserve
to maintain the LRU list when pinning or unpinning BOs. However, since:
commit 3d1a88e1051f ("drm/ttm: cleanup LRU handling further")
We've been exiting from ttm_bo_move_to_lru_tail() at the very beginning of
the function if the bo we're looking at is pinned, resulting in the pinned
BO never getting removed from the lru and as a result - causing issues when
it eventually becomes time for eviction.
So, let's fix this by calling ttm_bo_del_from_lru() from
ttm_bo_move_to_lru_tail() in the event that we're dealing with a pinned
buffer.
v2 (chk): reduce to only the fixing one liner since we always want to
call the callback whenever we would move on the LRU.
Signed-off-by: Lyude Paul <lyude@xxxxxxxxxx>
Fixes: 3d1a88e1051f ("drm/ttm: cleanup LRU handling further")
Cc: Christian König <christian.koenig@xxxxxxx>
Cc: Dave Airlie <airlied@xxxxxxxxxx>
---
drivers/gpu/drm/ttm/ttm_bo.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 31e8b3da5563..b65f4b12f986 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -138,8 +138,10 @@ void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo,
dma_resv_assert_held(bo->base.resv);
- if (bo->pin_count)
+ if (bo->pin_count) {
+ ttm_bo_del_from_lru(bo);
return;
+ }
man = ttm_manager_type(bdev, mem->mem_type);
list_move_tail(&bo->lru, &man->lru[bo->priority]);
--
2.25.1
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