runtime: add lock-free stack
This is factored out part of the:
https://golang.org/cl/5279048/
(parallel GC)
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5993043
diff --git a/src/pkg/runtime/runtime.h b/src/pkg/runtime/runtime.h
index 20355e0..672e05b 100644
--- a/src/pkg/runtime/runtime.h
+++ b/src/pkg/runtime/runtime.h
@@ -72,6 +72,7 @@
typedef struct Timers Timers;
typedef struct Timer Timer;
typedef struct GCStats GCStats;
+typedef struct LFNode LFNode;
/*
* per-cpu declaration.
@@ -351,6 +352,13 @@
Eface arg;
};
+// Lock-free stack node.
+struct LFNode
+{
+ LFNode *next;
+ uintptr pushcnt;
+};
+
/*
* defined macros
* you need super-gopher-guru privilege
@@ -652,6 +660,15 @@
void runtime·futexwakeup(uint32*, uint32);
/*
+ * Lock-free stack.
+ * Initialize uint64 head to 0, compare with 0 to test for emptiness.
+ * The stack does not keep pointers to nodes,
+ * so they can be garbage collected if there are no other pointers to nodes.
+ */
+void runtime·lfstackpush(uint64 *head, LFNode *node);
+LFNode* runtime·lfstackpop(uint64 *head);
+
+/*
* This is consistent across Linux and BSD.
* If a new OS is added that is different, move this to
* $GOOS/$GOARCH/defs.h.
