diff --git a/libc/Android.mk b/libc/Android.mk
index 2849591..99a841a 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -584,6 +584,7 @@
     bionic/pthread_setname_np.cpp \
     bionic/pthread_setschedparam.cpp \
     bionic/pthread_sigmask.cpp \
+    bionic/pthread_spinlock.cpp \
 
 libc_thread_atexit_impl_src_files := \
     bionic/__cxa_thread_atexit_impl.cpp \
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;
+}
diff --git a/libc/include/pthread.h b/libc/include/pthread.h
index 48b2bca..21d34fb 100644
--- a/libc/include/pthread.h
+++ b/libc/include/pthread.h
@@ -108,6 +108,14 @@
 
 #define PTHREAD_BARRIER_SERIAL_THREAD -1
 
+typedef struct {
+#if defined(__LP64__)
+  int64_t __private;
+#else
+  int32_t __private[2];
+#endif
+} pthread_spinlock_t;
+
 #if defined(__LP64__)
 #define PTHREAD_STACK_MIN (4 * PAGE_SIZE)
 #else
@@ -229,6 +237,12 @@
 int pthread_barrier_destroy(pthread_barrier_t*) __nonnull((1));
 int pthread_barrier_wait(pthread_barrier_t*) __nonnull((1));
 
+int pthread_spin_destroy(pthread_spinlock_t*) __nonnull((1));
+int pthread_spin_init(pthread_spinlock_t*, int) __nonnull((1));
+int pthread_spin_lock(pthread_spinlock_t*) __nonnull((1));
+int pthread_spin_trylock(pthread_spinlock_t*) __nonnull((1));
+int pthread_spin_unlock(pthread_spinlock_t*) __nonnull((1));
+
 pthread_t pthread_self(void) __pure2;
 
 int pthread_setname_np(pthread_t, const char*) __nonnull((2));
diff --git a/libc/libc.arm.map b/libc/libc.arm.map
index f7805fe..69aa272 100644
--- a/libc/libc.arm.map
+++ b/libc/libc.arm.map
@@ -1323,6 +1323,11 @@
     pthread_barrier_destroy;
     pthread_barrier_init;
     pthread_barrier_wait;
+    pthread_spin_destroy;
+    pthread_spin_init;
+    pthread_spin_lock;
+    pthread_spin_trylock;
+    pthread_spin_unlock;
     pwritev;
     pwritev64;
     scandirat;
diff --git a/libc/libc.arm64.map b/libc/libc.arm64.map
index d5fe262..763f77e 100644
--- a/libc/libc.arm64.map
+++ b/libc/libc.arm64.map
@@ -1168,6 +1168,11 @@
     pthread_barrier_destroy;
     pthread_barrier_init;
     pthread_barrier_wait;
+    pthread_spin_destroy;
+    pthread_spin_init;
+    pthread_spin_lock;
+    pthread_spin_trylock;
+    pthread_spin_unlock;
     pwritev;
     pwritev64;
     scandirat;
diff --git a/libc/libc.map.txt b/libc/libc.map.txt
index 738836c..76cb168 100644
--- a/libc/libc.map.txt
+++ b/libc/libc.map.txt
@@ -1350,6 +1350,11 @@
     pthread_barrier_destroy;
     pthread_barrier_init;
     pthread_barrier_wait;
+    pthread_spin_destroy;
+    pthread_spin_init;
+    pthread_spin_lock;
+    pthread_spin_trylock;
+    pthread_spin_unlock;
     pwritev;
     pwritev64;
     scandirat;
diff --git a/libc/libc.mips.map b/libc/libc.mips.map
index 2121ba7..e268bad 100644
--- a/libc/libc.mips.map
+++ b/libc/libc.mips.map
@@ -1286,6 +1286,11 @@
     pthread_barrier_destroy;
     pthread_barrier_init;
     pthread_barrier_wait;
+    pthread_spin_destroy;
+    pthread_spin_init;
+    pthread_spin_lock;
+    pthread_spin_trylock;
+    pthread_spin_unlock;
     pwritev;
     pwritev64;
     scandirat;
diff --git a/libc/libc.mips64.map b/libc/libc.mips64.map
index d5fe262..763f77e 100644
--- a/libc/libc.mips64.map
+++ b/libc/libc.mips64.map
@@ -1168,6 +1168,11 @@
     pthread_barrier_destroy;
     pthread_barrier_init;
     pthread_barrier_wait;
+    pthread_spin_destroy;
+    pthread_spin_init;
+    pthread_spin_lock;
+    pthread_spin_trylock;
+    pthread_spin_unlock;
     pwritev;
     pwritev64;
     scandirat;
diff --git a/libc/libc.x86.map b/libc/libc.x86.map
index fdee2c6..6578370 100644
--- a/libc/libc.x86.map
+++ b/libc/libc.x86.map
@@ -1284,6 +1284,11 @@
     pthread_barrier_destroy;
     pthread_barrier_init;
     pthread_barrier_wait;
+    pthread_spin_destroy;
+    pthread_spin_init;
+    pthread_spin_lock;
+    pthread_spin_trylock;
+    pthread_spin_unlock;
     pwritev;
     pwritev64;
     scandirat;
diff --git a/libc/libc.x86_64.map b/libc/libc.x86_64.map
index d5fe262..763f77e 100644
--- a/libc/libc.x86_64.map
+++ b/libc/libc.x86_64.map
@@ -1168,6 +1168,11 @@
     pthread_barrier_destroy;
     pthread_barrier_init;
     pthread_barrier_wait;
+    pthread_spin_destroy;
+    pthread_spin_init;
+    pthread_spin_lock;
+    pthread_spin_trylock;
+    pthread_spin_unlock;
     pwritev;
     pwritev64;
     scandirat;
diff --git a/libc/private/bionic_lock.h b/libc/private/bionic_lock.h
index a36d1ed..238ace4 100644
--- a/libc/private/bionic_lock.h
+++ b/libc/private/bionic_lock.h
@@ -30,6 +30,7 @@
 
 #include <stdatomic.h>
 #include "private/bionic_futex.h"
+#include "private/bionic_macros.h"
 
 // Lock is used in places like pthread_rwlock_t, which can be initialized without calling
 // an initialization function. So make sure Lock can be initialized by setting its memory to 0.
@@ -49,6 +50,12 @@
     this->process_shared = process_shared;
   }
 
+  bool trylock() {
+    LockState old_state = Unlocked;
+    return __predict_true(atomic_compare_exchange_strong_explicit(&state, &old_state,
+                        LockedWithoutWaiter, memory_order_acquire, memory_order_relaxed));
+  }
+
   void lock() {
     LockState old_state = Unlocked;
     if (__predict_true(atomic_compare_exchange_strong_explicit(&state, &old_state,