1 files changed, 12 insertions, 0 deletions
diff --git a/src/thread/__lock.c b/src/thread/__lock.c
new file mode 100644
index 00000000..557c6a62
--- /dev/null
+++ b/src/thread/__lock.c
@@ -0,0 +1,12 @@
+#define SYSCALL_RETURN_ERRNO
+#include "pthread_impl.h"
+
+void __lock(volatile int *l)
+{
+	int spins=100000;
+	/* Do not use futexes because we insist that unlocking is a simple
+	 * assignment to optimize non-pathological code with no contention. */
+	while (a_xchg(l, 1))
+		if (spins) spins--, a_spin();
+		else syscall0(__NR_sched_yield);
+}