diff --git a/src/common/concurrent_blocking_queue.h b/src/common/concurrent_blocking_queue.h
index aab39895b119..2713c8bc2a5c 100644
--- a/src/common/concurrent_blocking_queue.h
+++ b/src/common/concurrent_blocking_queue.h
@@ -31,7 +31,7 @@ template<typename T> class ConcurrentBlockingQueue {
         queue_.pop_front();
         if (queue_.empty())
           has_elmt_ = false;
-        return false;
+        return true;
       }
     }
     {
@@ -44,9 +44,9 @@ template<typename T> class ConcurrentBlockingQueue {
         queue_.pop_front();
         if (queue_.empty())
           has_elmt_ = false;
-        return false;
+        return true;
       } else {
-        return true;        
+        return false;        
       }
     }
   }
diff --git a/src/common/spin_lock.h b/src/common/spin_lock.h
deleted file mode 100644
index 5a0cc3f786e6..000000000000
--- a/src/common/spin_lock.h
+++ /dev/null
@@ -1,45 +0,0 @@
-#ifndef _SPINLOCK_XCHG_H
-#define _SPINLOCK_XCHG_H
-
-/* Spin lock using xchg.
- * Copied from http://locklessinc.com/articles/locks/
- */
-
-/* Compile read-write barrier */
-#define barrier() asm volatile("": : :"memory")
-
-/* Pause instruction to prevent excess processor bus usage */
-#define cpu_relax() asm volatile("pause\n": : :"memory")
-
-static inline unsigned short xchg_8(void *ptr, unsigned char x) {
-  __asm__ __volatile__("xchgb %0,%1"
-      :"=r" (x)
-      :"m" (*(volatile unsigned char *)ptr), "0" (x)
-      :"memory");
-
-  return x;
-}
-
-#define BUSY 1
-typedef unsigned char spinlock;
-
-#define SPINLOCK_INITIALIZER 0
-
-static inline void spin_lock(spinlock *lock) {
-  while (1) {
-    if (!xchg_8(lock, BUSY)) return;
-
-    while (*lock) cpu_relax();
-  }
-}
-
-static inline void spin_unlock(spinlock *lock) {
-  barrier();
-  *lock = 0;
-}
-
-static inline int spin_trylock(spinlock *lock) {
-  return xchg_8(lock, BUSY);
-}
-
-#endif /* _SPINLOCK_XCHG_H */
diff --git a/src/common/spinlock.h b/src/common/spinlock.h
new file mode 100644
index 000000000000..fb7285b5702e
--- /dev/null
+++ b/src/common/spinlock.h
@@ -0,0 +1,44 @@
+#ifndef MXNET_COMMON_SPINLOCK_H_
+#define MXNET_COMMON_SPINLOCK_H_
+
+#include <atomic>
+
+namespace mxnet {
+namespace common {
+
+/*!
+ * \brief Simple userspace spinlock implementation.
+ */
+class Spinlock {
+ public:
+  Spinlock() = default;
+  /*!
+   * \brief Disable copy and move.
+   */
+  Spinlock(Spinlock const&) = delete;
+  Spinlock(Spinlock&&) = delete;
+  Spinlock& operator=(Spinlock const&) = delete;
+  Spinlock& operator=(Spinlock&&) = delete;
+  ~Spinlock() = default;
+  /*!
+   * \brief Acquire lock.
+   */
+  void lock() noexcept {
+    while (lock_.test_and_set(std::memory_order_acquire));
+  }
+  /*!
+   * \brief Release lock.
+   */
+  void unlock() noexcept {
+    lock_.clear(std::memory_order_release);
+  }
+
+ private:
+  std::atomic_flag lock_ = ATOMIC_FLAG_INIT;
+};
+
+}  // namespace common
+}  // namespace mxnet
+
+#endif  // MXNET_COMMON_SPINLOCK_H_
+
diff --git a/src/dag_engine/threaded_engine.cc b/src/dag_engine/threaded_engine.cc
index 143b5e72f413..32325ba4f1a8 100644
--- a/src/dag_engine/threaded_engine.cc
+++ b/src/dag_engine/threaded_engine.cc
@@ -159,7 +159,7 @@ class ThreadedEngine : public DAGEngine {
   }
   void WorkerRoutine(int thrid) {
     OpDescr* opd = nullptr;
-    while(! worker_queues_[thrid]->Pop(opd)) {
+    while(worker_queues_[thrid]->Pop(opd)) {
       LOG(INFO) << "worker thread #" << thrid << " got operator " << opd;
       opd->op(GetRunContext(opd->exec_ctx), [this, opd] () { this->OnOpFinished(opd); });
       opd = nullptr;