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authorMarek Olšák <marek.olsak@amd.com>2017-06-19 19:39:05 +0200
committerMarek Olšák <marek.olsak@amd.com>2017-06-20 12:53:46 +0200
commit58af1f6bb074168669aaec2755c7f369a8b58d62 (patch)
tree0888ec2d54cce7c7123001e0ad6f07899010942e
parentafeaa2e98a506bf3d4e3c31d07fe3b98b6820584 (diff)
winsys/amdgpu: fix a deadlock when waiting for submission_in_progress
First this happens: 1) amdgpu_cs_flush (lock bo_fence_lock) -> amdgpu_add_fence_dependency -> os_wait_until_zero (wait for submission_in_progress) - WAITING 2) amdgpu_bo_create -> pb_cache_reclaim_buffer (lock pb_cache::mutex) -> pb_cache_is_buffer_compat -> amdgpu_bo_wait (lock bo_fence_lock) - WAITING So both bo_fence_lock and pb_cache::mutex are held. amdgpu_bo_create can't continue. amdgpu_cs_flush is waiting for the CS ioctl to finish the job, but the CS ioctl is trying to release a buffer: 3) amdgpu_cs_submit_ib (CS thread - job entrypoint) -> amdgpu_cs_context_cleanup -> pb_reference -> pb_destroy -> amdgpu_bo_destroy_or_cache -> pb_cache_add_buffer (lock pb_cache::mutex) - DEADLOCK The simple solution is not to wait for submission_in_progress, which we need in order to create the list of dependencies for the CS ioctl. Instead of building the list of dependencies as a direct input to the CS ioctl, build the list of dependencies as a list of fences, and make the final list of dependencies in the CS thread itself. Therefore, amdgpu_cs_flush doesn't have to wait and can continue. Then, amdgpu_bo_create can continue and return. And then amdgpu_cs_submit_ib can continue. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101294 Cc: 17.1 <mesa-stable@lists.freedesktop.org> Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
-rw-r--r--src/gallium/winsys/amdgpu/drm/amdgpu_cs.c55
-rw-r--r--src/gallium/winsys/amdgpu/drm/amdgpu_cs.h4
2 files changed, 43 insertions, 16 deletions
diff --git a/src/gallium/winsys/amdgpu/drm/amdgpu_cs.c b/src/gallium/winsys/amdgpu/drm/amdgpu_cs.c
index a0ef8262967..c88be069d06 100644
--- a/src/gallium/winsys/amdgpu/drm/amdgpu_cs.c
+++ b/src/gallium/winsys/amdgpu/drm/amdgpu_cs.c
@@ -752,10 +752,13 @@ static void amdgpu_cs_context_cleanup(struct amdgpu_cs_context *cs)
p_atomic_dec(&cs->sparse_buffers[i].bo->num_cs_references);
amdgpu_winsys_bo_reference(&cs->sparse_buffers[i].bo, NULL);
}
+ for (i = 0; i < cs->num_fence_dependencies; i++)
+ amdgpu_fence_reference(&cs->fence_dependencies[i], NULL);
cs->num_real_buffers = 0;
cs->num_slab_buffers = 0;
cs->num_sparse_buffers = 0;
+ cs->num_fence_dependencies = 0;
amdgpu_fence_reference(&cs->fence, NULL);
memset(cs->buffer_indices_hashlist, -1, sizeof(cs->buffer_indices_hashlist));
@@ -770,7 +773,7 @@ static void amdgpu_destroy_cs_context(struct amdgpu_cs_context *cs)
FREE(cs->handles);
FREE(cs->slab_buffers);
FREE(cs->sparse_buffers);
- FREE(cs->request.dependencies);
+ FREE(cs->fence_dependencies);
}
@@ -981,7 +984,6 @@ static void amdgpu_add_fence_dependency(struct amdgpu_cs *acs,
{
struct amdgpu_cs_context *cs = acs->csc;
struct amdgpu_winsys_bo *bo = buffer->bo;
- struct amdgpu_cs_fence *dep;
unsigned new_num_fences = 0;
for (unsigned j = 0; j < bo->num_fences; ++j) {
@@ -1003,21 +1005,21 @@ static void amdgpu_add_fence_dependency(struct amdgpu_cs *acs,
if (!(buffer->usage & RADEON_USAGE_SYNCHRONIZED))
continue;
- if (bo_fence->submission_in_progress)
- os_wait_until_zero(&bo_fence->submission_in_progress,
- PIPE_TIMEOUT_INFINITE);
-
- idx = cs->request.number_of_dependencies++;
- if (idx >= cs->max_dependencies) {
+ idx = cs->num_fence_dependencies++;
+ if (idx >= cs->max_fence_dependencies) {
unsigned size;
-
- cs->max_dependencies = idx + 8;
- size = cs->max_dependencies * sizeof(struct amdgpu_cs_fence);
- cs->request.dependencies = realloc(cs->request.dependencies, size);
+ const unsigned increment = 8;
+
+ cs->max_fence_dependencies = idx + increment;
+ size = cs->max_fence_dependencies * sizeof(cs->fence_dependencies[0]);
+ cs->fence_dependencies = realloc(cs->fence_dependencies, size);
+ /* Clear the newly-allocated elements. */
+ memset(cs->fence_dependencies + idx, 0,
+ increment * sizeof(cs->fence_dependencies[0]));
}
- dep = &cs->request.dependencies[idx];
- memcpy(dep, &bo_fence->fence, sizeof(*dep));
+ amdgpu_fence_reference(&cs->fence_dependencies[idx],
+ (struct pipe_fence_handle*)bo_fence);
}
for (unsigned j = new_num_fences; j < bo->num_fences; ++j)
@@ -1088,7 +1090,7 @@ static void amdgpu_add_fence_dependencies(struct amdgpu_cs *acs)
{
struct amdgpu_cs_context *cs = acs->csc;
- cs->request.number_of_dependencies = 0;
+ cs->num_fence_dependencies = 0;
amdgpu_add_fence_dependencies_list(acs, cs->fence, cs->num_real_buffers, cs->real_buffers);
amdgpu_add_fence_dependencies_list(acs, cs->fence, cs->num_slab_buffers, cs->slab_buffers);
@@ -1136,7 +1138,30 @@ void amdgpu_cs_submit_ib(void *job, int thread_index)
struct amdgpu_winsys *ws = acs->ctx->ws;
struct amdgpu_cs_context *cs = acs->cst;
int i, r;
+ struct amdgpu_cs_fence *dependencies = NULL;
+
+ /* Set dependencies (input fences). */
+ if (cs->num_fence_dependencies) {
+ dependencies = alloca(sizeof(dependencies[0]) *
+ cs->num_fence_dependencies);
+ unsigned num = 0;
+
+ for (i = 0; i < cs->num_fence_dependencies; i++) {
+ struct amdgpu_fence *fence =
+ (struct amdgpu_fence*)cs->fence_dependencies[i];
+
+ /* Past fences can't be unsubmitted because we have only 1 CS thread. */
+ assert(!fence->submission_in_progress);
+ memcpy(&dependencies[num++], &fence->fence, sizeof(dependencies[0]));
+ }
+ cs->request.dependencies = dependencies;
+ cs->request.number_of_dependencies = num;
+ } else {
+ cs->request.dependencies = NULL;
+ cs->request.number_of_dependencies = 0;
+ }
+ /* Set the output fence. */
cs->request.fence_info.handle = NULL;
if (amdgpu_cs_has_user_fence(cs)) {
cs->request.fence_info.handle = acs->ctx->user_fence_bo;
diff --git a/src/gallium/winsys/amdgpu/drm/amdgpu_cs.h b/src/gallium/winsys/amdgpu/drm/amdgpu_cs.h
index d700b8c4cbd..d83c1e0fe19 100644
--- a/src/gallium/winsys/amdgpu/drm/amdgpu_cs.h
+++ b/src/gallium/winsys/amdgpu/drm/amdgpu_cs.h
@@ -105,7 +105,9 @@ struct amdgpu_cs_context {
unsigned last_added_bo_usage;
uint64_t last_added_bo_priority_usage;
- unsigned max_dependencies;
+ struct pipe_fence_handle **fence_dependencies;
+ unsigned num_fence_dependencies;
+ unsigned max_fence_dependencies;
struct pipe_fence_handle *fence;