[Mesa-dev] [PATCH v2 8/8] radeonsi: reduce the scope of sel->mutex in si_shader_select_with_key

[Nicolai Hähnle]

From: Nicolai Hähnle <nicolai.haehnle at amd.com>

We only need the lock to guard changes in the variant linked list. The
actual compilation can happen outside the lock, since we use the ready
fence as a guard.

v2: fix double-unlock

Reviewed-by: Marek Olšák <marek.olsak at amd.com>
---
 src/gallium/drivers/radeonsi/si_state_shaders.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/gallium/drivers/radeonsi/si_state_shaders.c b/src/gallium/drivers/radeonsi/si_state_shaders.c
index 4c0292404e6..75b16487480 100644
--- a/src/gallium/drivers/radeonsi/si_state_shaders.c
+++ b/src/gallium/drivers/radeonsi/si_state_shaders.c
@@ -1614,41 +1614,40 @@ current_not_ready:
 	if (thread_index < 0)
 		util_queue_fence_wait(&sel->ready);
 
 	mtx_lock(&sel->mutex);
 
 	/* Find the shader variant. */
 	for (iter = sel->first_variant; iter; iter = iter->next_variant) {
 		/* Don't check the "current" shader. We checked it above. */
 		if (current != iter &&
 		    memcmp(&iter->key, key, sizeof(*key)) == 0) {
+			mtx_unlock(&sel->mutex);
+
 			if (unlikely(!util_queue_fence_is_signalled(&iter->ready))) {
 				/* If it's an optimized shader and its compilation has
 				 * been started but isn't done, use the unoptimized
 				 * shader so as not to cause a stall due to compilation.
 				 */
 				if (iter->is_optimized) {
 					memset(&key->opt, 0, sizeof(key->opt));
-					mtx_unlock(&sel->mutex);
 					goto again;
 				}
 
 				util_queue_fence_wait(&iter->ready);
 			}
 
 			if (iter->compilation_failed) {
-				mtx_unlock(&sel->mutex);
 				return -1; /* skip the draw call */
 			}
 
 			state->current = iter;
-			mtx_unlock(&sel->mutex);
 			return 0;
 		}
 	}
 
 	/* Build a new shader. */
 	shader = CALLOC_STRUCT(si_shader);
 	if (!shader) {
 		mtx_unlock(&sel->mutex);
 		return -ENOMEM;
 	}
@@ -1761,29 +1760,30 @@ current_not_ready:
 	util_queue_fence_reset(&shader->ready);
 
 	if (!sel->last_variant) {
 		sel->first_variant = shader;
 		sel->last_variant = shader;
 	} else {
 		sel->last_variant->next_variant = shader;
 		sel->last_variant = shader;
 	}
 
+	mtx_unlock(&sel->mutex);
+
 	assert(!shader->is_optimized);
 	si_build_shader_variant(shader, thread_index, false);
 
 	util_queue_fence_signal(&shader->ready);
 
 	if (!shader->compilation_failed)
 		state->current = shader;
 
-	mtx_unlock(&sel->mutex);
 	return shader->compilation_failed ? -1 : 0;
 }
 
 static int si_shader_select(struct pipe_context *ctx,
 			    struct si_shader_ctx_state *state,
 			    struct si_compiler_ctx_state *compiler_state)
 {
 	struct si_context *sctx = (struct si_context *)ctx;
 	struct si_shader_key key;
 
-- 
2.11.0