c++ - 共享内存中的 boost::lockfree::queue 出现问题(boost 1.53、gcc 4.7.2/clang 3.0-6ubuntu3)

Question

我在放置 boost::lockfree::queue<<T, fixed_sized<false>, ..> 时遇到问题在共享内存中。我需要它，因为我必须能够将超过 65535 条消息插入队列，而 fixed_sized 队列限制为 65535。
以下代码工作正常(但 capacity<...> 选项暗示 fixed_sized<true> ):

typedef boost::interprocess::allocator<
    MessageT, 
    boost::interprocess::managed_shared_memory::segment_manager>
        ShmemAllocator;
typedef boost::lockfree::queue<
    MessageT,
    boost::lockfree::capacity<65535>,
    boost::lockfree::allocator<ShmemAllocator> >
        Queue;
m_segment = new boost::interprocess::managed_shared_memory(
    boost::interprocess::create_only, segmentName, size);
Queue* m_queue = m_segment->construct<Queue>(
    queueName)(
    m_segment->get_segment_manager());
...
m_queue->bounded_push(message);

下面的代码也能正常工作(但它不使用共享内存):

boost::lockfree::queue<MessageT> q;
....
q.bounded_push(message);

但是当我尝试组合它时:

typedef boost::interprocess::allocator<
    MessageT, 
    boost::interprocess::managed_shared_memory::segment_manager>
        ShmemAllocator;
typedef boost::lockfree::queue<
    MessageT,
    boost::lockfree::allocator<ShmemAllocator> >
        Queue;
m_segment = new boost::interprocess::managed_shared_memory(
    boost::interprocess::create_only, segmentName, size);
Queue* m_queue = m_segment->construct<Queue>(
    queueName)(
    m_segment->get_segment_manager());
...
m_queue->bounded_push(message);

编译失败，日志如下:

In file included from src/model/Queue.h:16:

In file included from /home/uppi/lib/include/boost/lockfree/queue.hpp:24:

/home/uppi/lib/include/boost/lockfree/detail/freelist.hpp:171:28: error: no viable conversion from 'pointer' (aka 'offset_ptr<boost::lockfree::queue<PacketMessage,
      boost::lockfree::allocator<boost::interprocess::allocator<PacketMessage, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family,
      boost::interprocess::offset_ptr<void, long, unsigned long, 0>, 0>, iset_index> > >, boost::parameter::void_, boost::parameter::void_>::node, long, unsigned long, 0UL>') to
      'boost::lockfree::queue<PacketMessage, boost::lockfree::allocator<boost::interprocess::allocator<PacketMessage, boost::interprocess::segment_manager<char,
      boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0>, 0>, iset_index> > >, boost::parameter::void_,
      boost::parameter::void_>::node *'
                    return Alloc::allocate(1);
                           ~~~~~~~~~~~~~~~~~

/home/uppi/lib/include/boost/lockfree/detail/freelist.hpp:157:20: note: in instantiation of function template specialization 'boost::lockfree::detail::freelist_stack<boost::lockfree::queue<PacketMessage,
      boost::lockfree::allocator<boost::interprocess::allocator<PacketMessage, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family,
      boost::interprocess::offset_ptr<void, long, unsigned long, 0>, 0>, iset_index> > >, boost::parameter::void_, boost::parameter::void_>::node,
      boost::interprocess::allocator<boost::lockfree::queue<PacketMessage, boost::lockfree::allocator<boost::interprocess::allocator<PacketMessage, boost::interprocess::segment_manager<char,
      boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0>, 0>, iset_index> > >, boost::parameter::void_,
      boost::parameter::void_>::node, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned
      long, 0>, 0>, iset_index> > >::allocate_impl<true>' requested here
            return allocate_impl<Bounded>();


/home/uppi/lib/include/boost/lockfree/detail/freelist.hpp:89:20: note: in instantiation of function template specialization 'boost::lockfree::detail::freelist_stack<boost::lockfree::queue<PacketMessage,
      boost::lockfree::allocator<boost::interprocess::allocator<PacketMessage, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family,
      boost::interprocess::offset_ptr<void, long, unsigned long, 0>, 0>, iset_index> > >, boost::parameter::void_, boost::parameter::void_>::node,
      boost::interprocess::allocator<boost::lockfree::queue<PacketMessage, boost::lockfree::allocator<boost::interprocess::allocator<PacketMessage, boost::interprocess::segment_manager<char,
      boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0>, 0>, iset_index> > >, boost::parameter::void_,
      boost::parameter::void_>::node, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned
      long, 0>, 0>, iset_index> > >::allocate<true, true>' requested here
        T * node = allocate<ThreadSafe, Bounded>();


/home/uppi/lib/include/boost/lockfree/queue.hpp:281:34: note: in instantiation of function template specialization 'boost::lockfree::detail::freelist_stack<boost::lockfree::queue<PacketMessage,
      boost::lockfree::allocator<boost::interprocess::allocator<PacketMessage, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family,
      boost::interprocess::offset_ptr<void, long, unsigned long, 0>, 0>, iset_index> > >, boost::parameter::void_, boost::parameter::void_>::node,
      boost::interprocess::allocator<boost::lockfree::queue<PacketMessage, boost::lockfree::allocator<boost::interprocess::allocator<PacketMessage, boost::interprocess::segment_manager<char,
      boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0>, 0>, iset_index> > >, boost::parameter::void_,
      boost::parameter::void_>::node, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned
      long, 0>, 0>, iset_index> > >::construct<true, true, PacketMessage, boost::lockfree::queue<PacketMessage, boost::lockfree::allocator<boost::interprocess::allocator<PacketMessage,
      boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0>, 0>, iset_index> > >,
      boost::parameter::void_, boost::parameter::void_>::node *>' requested here
        node * n = pool.template construct<true, Bounded>(t, pool.null_handle());


/home/uppi/lib/include/boost/lockfree/queue.hpp:270:16: note: in instantiation of function template specialization 'boost::lockfree::queue<PacketMessage,
      boost::lockfree::allocator<boost::interprocess::allocator<PacketMessage, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family,
      boost::interprocess::offset_ptr<void, long, unsigned long, 0>, 0>, iset_index> > >, boost::parameter::void_, boost::parameter::void_>::do_push<true>' requested here
        return do_push<true>(t);


src/model/Queue.inl:4:18: note: in instantiation of member function 'boost::lockfree::queue<PacketMessage, boost::lockfree::allocator<boost::interprocess::allocator<PacketMessage,
      boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0>, 0>, iset_index> > >,
      boost::parameter::void_, boost::parameter::void_>::bounded_push' requested here
        return m_queue->bounded_push(message);                         

/home/uppi/lib/include/boost/interprocess/offset_ptr.hpp:450:4: note: candidate function
   operator unspecified_bool_type() const

请告诉我我错过了什么

Answer 1

出于兼容性原因，在共享内存中使用 boost::lockfree::queue 或 boost::lockfree::stack 限制为 65535 个元素。如果您有单一生产者、单一消费者用例，您可能希望使用 boost::lockfree::spsc_queue。然而，这也不是动态大小的。

原因是限制是 32 位兼容性。对于 64 位平台，可以调整 boost.lockfree 代码以使用 32 位而不是 16 位索引。但它需要一些重要的更改才能正确实现。