On 2022-02-11 03:24, Ken Xue wrote:
KMD reports a warning on holding a lock from drm_syncobj_find_fence,
when running amdgpu_test case “syncobj timeline test”.
ctx->lock was designed to prevent concurrent "amdgpu_ctx_wait_prev_fence"
calls and avoid dead reservation lock from GPU reset.
Just to help me understand - what do you mean by the dead reservation
lock above ? Can you point me to earlier code version where this did
take place ?
since no reservation
lock is held in lates GPU reset any more,
Same here - can you point me when was it was held before and
not being held now ?
Andrey
ctx->lock can be simply removed
and concurrent "amdgpu_ctx_wait_prev_fence" call also can be prevented by
PD root bo reservation lock.
call stacks:
=================
//hold lock
amdgpu_cs_ioctl->amdgpu_cs_parser_init->mutex_lock(&parser->ctx->lock);
…
//report warning
amdgpu_cs_dependencies->amdgpu_cs_process_syncobj_timeline_in_dep \
->amdgpu_syncobj_lookup_and_add_to_sync -> drm_syncobj_find_fence \
-> lockdep_assert_none_held_once
…
amdgpu_cs_ioctl->amdgpu_cs_parser_fini->mutex_unlock(&parser->ctx->lock);
Signed-off-by: Ken Xue <[email protected]>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 16 +++++++++++-----
drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c | 2 --
drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.h | 1 -
3 files changed, 11 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index 1cd677bd5d7e..b32a7cfbe1e2 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -127,8 +127,6 @@ static int amdgpu_cs_parser_init(struct amdgpu_cs_parser
*p, union drm_amdgpu_cs
goto free_chunk;
}
- mutex_lock(&p->ctx->lock);
-
/* skip guilty context job */
if (atomic_read(&p->ctx->guilty) == 1) {
ret = -ECANCELED;
@@ -571,6 +569,16 @@ static int amdgpu_cs_parser_bos(struct amdgpu_cs_parser *p,
goto out;
}
+ /* Move fence waiting after getting reservation lock of
+ * PD root. Then there is no need on a ctx mutex lock.
+ */
+ r = amdgpu_ctx_wait_prev_fence(p->ctx, p->entity);
+ if (unlikely(r != 0)) {
+ if (r != -ERESTARTSYS)
+ DRM_ERROR("amdgpu_ctx_wait_prev_fence failed.\n");
+ goto error_validate;
+ }
+
amdgpu_cs_get_threshold_for_moves(p->adev, &p->bytes_moved_threshold,
&p->bytes_moved_vis_threshold);
p->bytes_moved = 0;
@@ -682,7 +690,6 @@ static void amdgpu_cs_parser_fini(struct amdgpu_cs_parser
*parser, int error,
dma_fence_put(parser->fence);
if (parser->ctx) {
- mutex_unlock(&parser->ctx->lock);
amdgpu_ctx_put(parser->ctx);
}
if (parser->bo_list)
@@ -926,7 +933,7 @@ static int amdgpu_cs_ib_fill(struct amdgpu_device *adev,
if (parser->job->uf_addr && ring->funcs->no_user_fence)
return -EINVAL;
- return amdgpu_ctx_wait_prev_fence(parser->ctx, parser->entity);
+ return 0;
}
static int amdgpu_cs_process_fence_dep(struct amdgpu_cs_parser *p,
@@ -1321,7 +1328,6 @@ int amdgpu_cs_ioctl(struct drm_device *dev, void *data,
struct drm_file *filp)
goto out;
r = amdgpu_cs_submit(&parser, cs);
-
out:
amdgpu_cs_parser_fini(&parser, r, reserved_buffers);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
index 2c929fa40379..1c72f6095f08 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
@@ -230,7 +230,6 @@ static int amdgpu_ctx_init(struct amdgpu_device *adev,
kref_init(&ctx->refcount);
spin_lock_init(&ctx->ring_lock);
- mutex_init(&ctx->lock);
ctx->reset_counter = atomic_read(&adev->gpu_reset_counter);
ctx->reset_counter_query = ctx->reset_counter;
@@ -352,7 +351,6 @@ static void amdgpu_ctx_fini(struct kref *ref)
}
}
amdgpu_ctx_set_stable_pstate(ctx, AMDGPU_CTX_STABLE_PSTATE_NONE);
- mutex_destroy(&ctx->lock);
kfree(ctx);
}
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.h
index 142f2f87d44c..d0cbfcea90f7 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.h
@@ -49,7 +49,6 @@ struct amdgpu_ctx {
bool preamble_presented;
int32_t init_priority;
int32_t override_priority;
- struct mutex lock;
atomic_t guilty;
unsigned long ras_counter_ce;
unsigned long ras_counter_ue;
