diff --git a/libc/bionic/pthread_spinlock.cpp b/libc/bionic/pthread_spinlock.cpp
new file mode 100644
index 0000000..f26f283
--- /dev/null
+++ b/libc/bionic/pthread_spinlock.cpp
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+#include <pthread.h>
+
+#include "private/bionic_lock.h"
+
+// User-level spinlocks can be hazardous to battery life on Android.
+// We implement a simple compromise that behaves mostly like a spinlock,
+// but prevents excessively long spinning.
+
+struct pthread_spinlock_internal_t {
+  Lock lock;
+};
+
+static_assert(sizeof(pthread_spinlock_t) == sizeof(pthread_spinlock_internal_t),
+              "pthread_spinlock_t should actually be pthread_spinlock_internal_t.");
+
+static_assert(alignof(pthread_spinlock_t) >= 4,
+              "pthread_spinlock_t should fulfill the alignment of pthread_spinlock_internal_t.");
+
+static inline pthread_spinlock_internal_t* __get_internal_spinlock(pthread_spinlock_t* lock) {
+  return reinterpret_cast<pthread_spinlock_internal_t*>(lock);
+}
+
+int pthread_spin_init(pthread_spinlock_t* lock_interface, int pshared) {
+  pthread_spinlock_internal_t* lock = __get_internal_spinlock(lock_interface);
+  lock->lock.init(pshared);
+  return 0;
+}
+
+int pthread_spin_destroy(pthread_spinlock_t* lock_interface) {
+  pthread_spinlock_internal_t* lock = __get_internal_spinlock(lock_interface);
+  return lock->lock.trylock() ? 0 : EBUSY;
+}
+
+int pthread_spin_trylock(pthread_spinlock_t* lock_interface) {
+  pthread_spinlock_internal_t* lock = __get_internal_spinlock(lock_interface);
+  return lock->lock.trylock() ? 0 : EBUSY;
+}
+
+int pthread_spin_lock(pthread_spinlock_t* lock_interface) {
+  pthread_spinlock_internal_t* lock = __get_internal_spinlock(lock_interface);
+  for (int i = 0; i < 10000; ++i) {
+    if (lock->lock.trylock()) {
+      return 0;
+    }
+  }
+  lock->lock.lock();
+  return 0;
+}
+
+int pthread_spin_unlock(pthread_spinlock_t* lock_interface) {
+  pthread_spinlock_internal_t* lock = __get_internal_spinlock(lock_interface);
+  lock->lock.unlock();
+  return 0;
+}