Use acquire() and release() for spinlocks

It is more idiomatick than lock() and unlock()

No functional change.

src/thread.h

@@ -41,16 +41,17 @@ const size_t MAX_SPLITPOINTS_PER_THREAD = 8;
 const size_t MAX_SLAVES_PER_SPLITPOINT = 4;
 
 class Spinlock {
-  std::atomic_int _lock;
+
+  std::atomic_int lock;
 
 public:
-  Spinlock() { _lock = 1; } // Init here to workaround a bug with MSVC 2013
-  void lock() {
-      while (_lock.fetch_sub(1, std::memory_order_acquire) != 1)
-          for (int cnt = 0; _lock.load(std::memory_order_relaxed) <= 0; ++cnt)
+  Spinlock() { lock = 1; } // Init here to workaround a bug with MSVC 2013
+  void acquire() {
+      while (lock.fetch_sub(1, std::memory_order_acquire) != 1)
+          for (int cnt = 0; lock.load(std::memory_order_relaxed) <= 0; ++cnt)
               if (cnt >= 10000) std::this_thread::yield(); // Be nice to hyperthreading
   }
-  void unlock() { _lock.store(1, std::memory_order_release); }
+  void release() { lock.store(1, std::memory_order_release); }
 };
 
 
@@ -73,7 +74,7 @@ struct SplitPoint {
   SplitPoint* parentSplitPoint;
 
   // Shared variable data
-  Spinlock mutex;
+  Spinlock spinlock;
   std::bitset<MAX_THREADS> slavesMask;
   volatile bool allSlavesSearching;
   volatile uint64_t nodes;
@@ -97,6 +98,7 @@ struct ThreadBase {
 
   std::thread nativeThread;
   Mutex mutex;
+  Spinlock spinlock;
   ConditionVariable sleepCondition;
   volatile bool exit = false;
 };
@@ -127,7 +129,6 @@ struct Thread : public ThreadBase {
   SplitPoint* volatile activeSplitPoint;
   volatile size_t splitPointsSize;
   volatile bool searching;
-  Spinlock allocMutex;
 };