Statically allocate futex array

[folly.git] / folly / ProducerConsumerQueue.h

diff --git a/folly/ProducerConsumerQueue.h b/folly/ProducerConsumerQueue.h
index d0bf3ec8c3436976a9fe95927f815d7919cf051b..16de57d35486a8207fcb1def59c48d59a1360fd3 100644 (file)
--- a/folly/ProducerConsumerQueue.h
+++ b/folly/ProducerConsumerQueue.h
@@ -27,7 +27,7 @@
 #include <type_traits>
 #include <utility>
 
-#include <folly/detail/CacheLocality.h>
+#include <folly/concurrency/CacheLocality.h>
 
 namespace folly {
 
@@ -35,7 +35,7 @@ namespace folly {
  * ProducerConsumerQueue is a one producer and one consumer queue
  * without locks.
  */
-template<class T>
+template <class T>
 struct ProducerConsumerQueue {
   typedef T value_type;
 
@@ -77,7 +77,7 @@ struct ProducerConsumerQueue {
     std::free(records_);
   }
 
-  template<class ...Args>
+  template <class... Args>
   bool write(Args&&... recordArgs) {
     auto const currentWrite = writeIndex_.load(std::memory_order_relaxed);
     auto nextRecord = currentWrite + 1;
@@ -167,15 +167,20 @@ struct ProducerConsumerQueue {
     return ret;
   }
 
-private:
-  char pad0_[detail::CacheLocality::kFalseSharingRange];
+  // maximum number of items in the queue.
+  size_t capacity() const {
+    return size_ - 1;
+  }
+
+ private:
+  char pad0_[CacheLocality::kFalseSharingRange];
   const uint32_t size_;
   T* const records_;
 
   FOLLY_ALIGN_TO_AVOID_FALSE_SHARING std::atomic<unsigned int> readIndex_;
   FOLLY_ALIGN_TO_AVOID_FALSE_SHARING std::atomic<unsigned int> writeIndex_;
 
-  char pad1_[detail::CacheLocality::kFalseSharingRange - sizeof(writeIndex_)];
+  char pad1_[CacheLocality::kFalseSharingRange - sizeof(writeIndex_)];
 };
 
-}
+} // namespace folly