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-rw-r--r--src/util/u_queue.h92
1 files changed, 92 insertions, 0 deletions
diff --git a/src/util/u_queue.h b/src/util/u_queue.h
index a3e12260e30..dfe21532817 100644
--- a/src/util/u_queue.h
+++ b/src/util/u_queue.h
@@ -35,7 +35,10 @@
#include <string.h>
+#include "util/futex.h"
#include "util/list.h"
+#include "util/macros.h"
+#include "util/u_atomic.h"
#include "util/u_thread.h"
#ifdef __cplusplus
@@ -45,6 +48,94 @@ extern "C" {
#define UTIL_QUEUE_INIT_USE_MINIMUM_PRIORITY (1 << 0)
#define UTIL_QUEUE_INIT_RESIZE_IF_FULL (1 << 1)
+#if defined(__GNUC__) && defined(HAVE_FUTEX)
+#define UTIL_QUEUE_FENCE_FUTEX
+#else
+#define UTIL_QUEUE_FENCE_STANDARD
+#endif
+
+#ifdef UTIL_QUEUE_FENCE_FUTEX
+/* Job completion fence.
+ * Put this into your job structure.
+ */
+struct util_queue_fence {
+ /* The fence can be in one of three states:
+ * 0 - signaled
+ * 1 - unsignaled
+ * 2 - unsignaled, may have waiters
+ */
+ uint32_t val;
+};
+
+static inline void
+util_queue_fence_init(struct util_queue_fence *fence)
+{
+ fence->val = 0;
+}
+
+static inline void
+util_queue_fence_destroy(struct util_queue_fence *fence)
+{
+ assert(fence->val == 0);
+ /* no-op */
+}
+
+static inline void
+util_queue_fence_wait(struct util_queue_fence *fence)
+{
+ uint32_t v = fence->val;
+
+ if (likely(v == 0))
+ return;
+
+ do {
+ if (v != 2) {
+ v = p_atomic_cmpxchg(&fence->val, 1, 2);
+ if (v == 0)
+ return;
+ }
+
+ futex_wait(&fence->val, 2);
+ v = fence->val;
+ } while(v != 0);
+}
+
+static inline void
+util_queue_fence_signal(struct util_queue_fence *fence)
+{
+ uint32_t val = p_atomic_xchg(&fence->val, 0);
+
+ assert(val != 0);
+
+ if (val == 2)
+ futex_wake(&fence->val, INT_MAX);
+}
+
+/**
+ * Move \p fence back into unsignalled state.
+ *
+ * \warning The caller must ensure that no other thread may currently be
+ * waiting (or about to wait) on the fence.
+ */
+static inline void
+util_queue_fence_reset(struct util_queue_fence *fence)
+{
+#ifdef NDEBUG
+ fence->val = 1;
+#else
+ uint32_t v = p_atomic_xchg(&fence->val, 1);
+ assert(v == 0);
+#endif
+}
+
+static inline bool
+util_queue_fence_is_signalled(struct util_queue_fence *fence)
+{
+ return fence->val == 0;
+}
+#endif
+
+#ifdef UTIL_QUEUE_FENCE_STANDARD
/* Job completion fence.
* Put this into your job structure.
*/
@@ -77,6 +168,7 @@ util_queue_fence_is_signalled(struct util_queue_fence *fence)
{
return fence->signalled != 0;
}
+#endif
typedef void (*util_queue_execute_func)(void *job, int thread_index);