Implement yielding spin lock type

src/common/util/spin_lock.h

@@ -0,0 +1,35 @@
+#ifndef COMMON_UTIL_SPIN_LOCK_H_
+#define COMMON_UTIL_SPIN_LOCK_H_
+
+#include "common/util/thread.h"
+
+#include <stdatomic.h>
+#include <errno.h>
+
+typedef struct {
+	volatile atomic_flag flag;
+} SpinLock;
+
+HEADER_FN bool
+spin_lock_try_acquire(SpinLock *lock)
+{
+	return !atomic_flag_test_and_set(&lock->flag);
+}
+
+HEADER_FN void
+spin_lock_acquire(SpinLock *lock)
+{
+	int save_errno = errno;
+	while (!spin_lock_try_acquire(lock)) {
+		thread_yield();
+	}
+	errno = save_errno;
+}
+
+HEADER_FN void
+spin_lock_release(SpinLock *lock)
+{
+	atomic_flag_clear(&lock->flag);
+}
+
+#endif /* end of include guard: COMMON_UTIL_SPIN_LOCK_H_ */

src/server/main.c

@@ -4,6 +4,7 @@
 #include "common/util/hash_table.h"
 #include "common/util/byte_serdes.h"
 #include "common/util/thread.h"
+#include "common/util/spin_lock.h"
 
 int
 main(int argc, char **argv)