Am 23.02.2018 um 10:46 schrieb He, Roger:
-----Original Message-----
From: dri-devel [mailto:dri-devel-bounces@xxxxxxxxxxxxxxxxxxxxx] On Behalf Of Christian K?nig
Sent: Tuesday, February 20, 2018 8:58 PM
To: amd-gfx@xxxxxxxxxxxxxxxxxxxxx; dri-devel@xxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
Subject: [PATCH 3/4] drm/ttm: handle already locked BOs during eviction and swapout.
This solves the problem that when we swapout a BO from a domain we sometimes couldn't make room for it because holding the lock blocks all other BOs with this reservation object.
Signed-off-by: Christian König <christian.koenig@xxxxxxx>
---
drivers/gpu/drm/ttm/ttm_bo.c | 33 ++++++++++++++++-----------------
1 file changed, 16 insertions(+), 17 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index d90b1cf10b27..3a44c2ee4155 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -713,31 +713,30 @@ bool ttm_bo_eviction_valuable(struct ttm_buffer_object *bo, EXPORT_SYMBOL(ttm_bo_eviction_valuable);
/**
- * Check the target bo is allowable to be evicted or swapout, including cases:
- *
- * a. if share same reservation object with ctx->resv, have assumption
- * reservation objects should already be locked, so not lock again and
- * return true directly when either the opreation allow_reserved_eviction
- * or the target bo already is in delayed free list;
- *
- * b. Otherwise, trylock it.
+ * Check if the target bo is allowed to be evicted or swapedout.
*/
static bool ttm_bo_evict_swapout_allowable(struct ttm_buffer_object *bo,
- struct ttm_operation_ctx *ctx, bool *locked)
+ struct ttm_operation_ctx *ctx,
+ bool *locked)
{
- bool ret = false;
+ /* First check if we can lock it */
+ *locked = reservation_object_trylock(bo->resv);
+ if (*locked)
+ return true;
- *locked = false;
+ /* Check if it's locked because it is part of the current operation */
if (bo->resv == ctx->resv) {
reservation_object_assert_held(bo->resv);
- if (ctx->allow_reserved_eviction || !list_empty(&bo->ddestroy))
- ret = true;
- } else {
- *locked = reservation_object_trylock(bo->resv);
- ret = *locked;
+ return ctx->allow_reserved_eviction ||
+ !list_empty(&bo->ddestroy);
}
- return ret;
+ /* Check if it's locked because it was already evicted */
+ if (ww_mutex_is_owned_by(&bo->resv->lock, NULL))
+ return true;
For the special case: when command submission with Per-VM-BO enabled,
All BOs a/b/c are always valid BO. After the validation of BOs a and b,
when validation of BO c, is it possible to return true and then evict BO a and b by mistake ?
Because a/b/c share same task_struct.
No, that's why I check the context as well. BOs explicitly reserved have
a non NULL context while BOs trylocked for swapout have a NULL context.
Christian.
Thanks
Roger(Hongbo.He)
+ /* Some other thread is using it, don't touch it */
+ return false;
}
static int ttm_mem_evict_first(struct ttm_bo_device *bdev,
--
2.14.1
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