3859 lines
149 KiB
C++
3859 lines
149 KiB
C++
// Provides a C++11 implementation of a multi-producer, multi-consumer lock-free queue.
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// An overview, including benchmark results, is provided here:
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// http://moodycamel.com/blog/2014/a-fast-general-purpose-lock-free-queue-for-c++
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// The full design is also described in excruciating detail at:
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// http://moodycamel.com/blog/2014/detailed-design-of-a-lock-free-queue
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// Simplified BSD license:
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// Copyright (c) 2013-2020, Cameron Desrochers.
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without modification,
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// are permitted provided that the following conditions are met:
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//
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// - Redistributions of source code must retain the above copyright notice, this list of
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// conditions and the following disclaimer.
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// - Redistributions in binary form must reproduce the above copyright notice, this list of
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// conditions and the following disclaimer in the documentation and/or other materials
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// provided with the distribution.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
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// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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// OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
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// TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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// EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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// Also dual-licensed under the Boost Software License (see LICENSE.md)
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#pragma once
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#if defined(__GNUC__) && !defined(__INTEL_COMPILER)
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// Disable -Wconversion warnings (spuriously triggered when Traits::size_t and
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// Traits::index_t are set to < 32 bits, causing integer promotion, causing warnings
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// upon assigning any computed values)
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wconversion"
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#ifdef MCDBGQ_USE_RELACY
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#pragma GCC diagnostic ignored "-Wint-to-pointer-cast"
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#endif
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#endif
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#if defined(_MSC_VER) && (!defined(_HAS_CXX17) || !_HAS_CXX17)
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// VS2019 with /W4 warns about constant conditional expressions but unless /std=c++17 or higher
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// does not support `if constexpr`, so we have no choice but to simply disable the warning
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#pragma warning(push)
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#pragma warning(disable: 4127) // conditional expression is constant
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#endif
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#if defined(__APPLE__)
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#include "TargetConditionals.h"
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#endif
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#ifdef MCDBGQ_USE_RELACY
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#include "relacy/relacy_std.hpp"
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#include "relacy_shims.h"
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// We only use malloc/free anyway, and the delete macro messes up `= delete` method declarations.
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// We'll override the default trait malloc ourselves without a macro.
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#undef new
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#undef delete
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#undef malloc
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#undef free
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#else
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#include <atomic> // Requires C++11. Sorry VS2010.
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#include <cassert>
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#endif
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#include <cstddef> // for max_align_t
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#include <cstdint>
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#include <cstdlib>
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#include <type_traits>
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#include <algorithm>
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#include <utility>
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#include <limits>
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#include <climits> // for CHAR_BIT
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#include <array>
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#include <thread> // partly for __WINPTHREADS_VERSION if on MinGW-w64 w/ POSIX threading
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#include <mutex> // used for thread exit synchronization
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// Platform-specific definitions of a numeric thread ID type and an invalid value
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namespace moodycamel { namespace details {
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template<typename thread_id_t> struct thread_id_converter {
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typedef thread_id_t thread_id_numeric_size_t;
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typedef thread_id_t thread_id_hash_t;
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static thread_id_hash_t prehash(thread_id_t const& x) { return x; }
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};
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} }
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#if defined(MCDBGQ_USE_RELACY)
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namespace moodycamel { namespace details {
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typedef std::uint32_t thread_id_t;
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static const thread_id_t invalid_thread_id = 0xFFFFFFFFU;
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static const thread_id_t invalid_thread_id2 = 0xFFFFFFFEU;
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static inline thread_id_t thread_id() { return rl::thread_index(); }
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} }
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#elif defined(_WIN32) || defined(__WINDOWS__) || defined(__WIN32__)
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// No sense pulling in windows.h in a header, we'll manually declare the function
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// we use and rely on backwards-compatibility for this not to break
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extern "C" __declspec(dllimport) unsigned long __stdcall GetCurrentThreadId(void);
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namespace moodycamel { namespace details {
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static_assert(sizeof(unsigned long) == sizeof(std::uint32_t), "Expected size of unsigned long to be 32 bits on Windows");
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typedef std::uint32_t thread_id_t;
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static const thread_id_t invalid_thread_id = 0; // See http://blogs.msdn.com/b/oldnewthing/archive/2004/02/23/78395.aspx
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static const thread_id_t invalid_thread_id2 = 0xFFFFFFFFU; // Not technically guaranteed to be invalid, but is never used in practice. Note that all Win32 thread IDs are presently multiples of 4.
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static inline thread_id_t thread_id() { return static_cast<thread_id_t>(::GetCurrentThreadId()); }
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} }
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#elif defined(__arm__) || defined(_M_ARM) || defined(__aarch64__) || (defined(__APPLE__) && TARGET_OS_IPHONE) || defined(__MVS__) || defined(MOODYCAMEL_NO_THREAD_LOCAL)
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namespace moodycamel { namespace details {
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static_assert(sizeof(std::thread::id) == 4 || sizeof(std::thread::id) == 8, "std::thread::id is expected to be either 4 or 8 bytes");
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typedef std::thread::id thread_id_t;
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static const thread_id_t invalid_thread_id; // Default ctor creates invalid ID
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// Note we don't define a invalid_thread_id2 since std::thread::id doesn't have one; it's
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// only used if MOODYCAMEL_CPP11_THREAD_LOCAL_SUPPORTED is defined anyway, which it won't
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// be.
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static inline thread_id_t thread_id() { return std::this_thread::get_id(); }
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template<std::size_t> struct thread_id_size { };
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template<> struct thread_id_size<4> { typedef std::uint32_t numeric_t; };
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template<> struct thread_id_size<8> { typedef std::uint64_t numeric_t; };
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template<> struct thread_id_converter<thread_id_t> {
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typedef thread_id_size<sizeof(thread_id_t)>::numeric_t thread_id_numeric_size_t;
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#ifndef __APPLE__
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typedef std::size_t thread_id_hash_t;
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#else
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typedef thread_id_numeric_size_t thread_id_hash_t;
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#endif
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static thread_id_hash_t prehash(thread_id_t const& x)
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{
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#ifndef __APPLE__
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return std::hash<std::thread::id>()(x);
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#else
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return *reinterpret_cast<thread_id_hash_t const*>(&x);
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#endif
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}
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};
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} }
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#else
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// Use a nice trick from this answer: http://stackoverflow.com/a/8438730/21475
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// In order to get a numeric thread ID in a platform-independent way, we use a thread-local
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// static variable's address as a thread identifier :-)
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#if defined(__GNUC__) || defined(__INTEL_COMPILER)
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#define MOODYCAMEL_THREADLOCAL __thread
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#elif defined(_MSC_VER)
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#define MOODYCAMEL_THREADLOCAL __declspec(thread)
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#else
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// Assume C++11 compliant compiler
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#define MOODYCAMEL_THREADLOCAL thread_local
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#endif
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namespace moodycamel { namespace details {
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typedef std::uintptr_t thread_id_t;
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static const thread_id_t invalid_thread_id = 0; // Address can't be nullptr
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static const thread_id_t invalid_thread_id2 = 1; // Member accesses off a null pointer are also generally invalid. Plus it's not aligned.
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inline thread_id_t thread_id() { static MOODYCAMEL_THREADLOCAL int x; return reinterpret_cast<thread_id_t>(&x); }
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} }
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#endif
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// Constexpr if
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#ifndef MOODYCAMEL_CONSTEXPR_IF
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#if (defined(_MSC_VER) && defined(_HAS_CXX17) && _HAS_CXX17) || __cplusplus > 201402L
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#define MOODYCAMEL_CONSTEXPR_IF if constexpr
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#define MOODYCAMEL_MAYBE_UNUSED [[maybe_unused]]
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#else
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#define MOODYCAMEL_CONSTEXPR_IF if
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#define MOODYCAMEL_MAYBE_UNUSED
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#endif
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#endif
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// Exceptions
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#ifndef MOODYCAMEL_EXCEPTIONS_ENABLED
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#if (defined(_MSC_VER) && defined(_CPPUNWIND)) || (defined(__GNUC__) && defined(__EXCEPTIONS)) || (!defined(_MSC_VER) && !defined(__GNUC__))
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#define MOODYCAMEL_EXCEPTIONS_ENABLED
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#endif
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#endif
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#ifdef MOODYCAMEL_EXCEPTIONS_ENABLED
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#define MOODYCAMEL_TRY try
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#define MOODYCAMEL_CATCH(...) catch(__VA_ARGS__)
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#define MOODYCAMEL_RETHROW throw
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#define MOODYCAMEL_THROW(expr) throw (expr)
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#else
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#define MOODYCAMEL_TRY MOODYCAMEL_CONSTEXPR_IF (true)
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#define MOODYCAMEL_CATCH(...) else MOODYCAMEL_CONSTEXPR_IF (false)
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#define MOODYCAMEL_RETHROW
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#define MOODYCAMEL_THROW(expr)
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#endif
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#ifndef MOODYCAMEL_NOEXCEPT
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#if !defined(MOODYCAMEL_EXCEPTIONS_ENABLED)
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#define MOODYCAMEL_NOEXCEPT
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#define MOODYCAMEL_NOEXCEPT_CTOR(type, valueType, expr) true
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#define MOODYCAMEL_NOEXCEPT_ASSIGN(type, valueType, expr) true
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#elif defined(_MSC_VER) && defined(_NOEXCEPT) && _MSC_VER < 1800
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// VS2012's std::is_nothrow_[move_]constructible is broken and returns true when it shouldn't :-(
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// We have to assume *all* non-trivial constructors may throw on VS2012!
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#define MOODYCAMEL_NOEXCEPT _NOEXCEPT
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#define MOODYCAMEL_NOEXCEPT_CTOR(type, valueType, expr) (std::is_rvalue_reference<valueType>::value && std::is_move_constructible<type>::value ? std::is_trivially_move_constructible<type>::value : std::is_trivially_copy_constructible<type>::value)
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#define MOODYCAMEL_NOEXCEPT_ASSIGN(type, valueType, expr) ((std::is_rvalue_reference<valueType>::value && std::is_move_assignable<type>::value ? std::is_trivially_move_assignable<type>::value || std::is_nothrow_move_assignable<type>::value : std::is_trivially_copy_assignable<type>::value || std::is_nothrow_copy_assignable<type>::value) && MOODYCAMEL_NOEXCEPT_CTOR(type, valueType, expr))
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#elif defined(_MSC_VER) && defined(_NOEXCEPT) && _MSC_VER < 1900
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#define MOODYCAMEL_NOEXCEPT _NOEXCEPT
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#define MOODYCAMEL_NOEXCEPT_CTOR(type, valueType, expr) (std::is_rvalue_reference<valueType>::value && std::is_move_constructible<type>::value ? std::is_trivially_move_constructible<type>::value || std::is_nothrow_move_constructible<type>::value : std::is_trivially_copy_constructible<type>::value || std::is_nothrow_copy_constructible<type>::value)
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#define MOODYCAMEL_NOEXCEPT_ASSIGN(type, valueType, expr) ((std::is_rvalue_reference<valueType>::value && std::is_move_assignable<type>::value ? std::is_trivially_move_assignable<type>::value || std::is_nothrow_move_assignable<type>::value : std::is_trivially_copy_assignable<type>::value || std::is_nothrow_copy_assignable<type>::value) && MOODYCAMEL_NOEXCEPT_CTOR(type, valueType, expr))
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#else
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#define MOODYCAMEL_NOEXCEPT noexcept
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#define MOODYCAMEL_NOEXCEPT_CTOR(type, valueType, expr) noexcept(expr)
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#define MOODYCAMEL_NOEXCEPT_ASSIGN(type, valueType, expr) noexcept(expr)
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#endif
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#endif
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#ifndef MOODYCAMEL_CPP11_THREAD_LOCAL_SUPPORTED
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#ifdef MCDBGQ_USE_RELACY
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#define MOODYCAMEL_CPP11_THREAD_LOCAL_SUPPORTED
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#else
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// VS2013 doesn't support `thread_local`, and MinGW-w64 w/ POSIX threading has a crippling bug: http://sourceforge.net/p/mingw-w64/bugs/445
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// g++ <=4.7 doesn't support thread_local either.
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// Finally, iOS/ARM doesn't have support for it either, and g++/ARM allows it to compile but it's unconfirmed to actually work
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#if (!defined(_MSC_VER) || _MSC_VER >= 1900) && (!defined(__MINGW32__) && !defined(__MINGW64__) || !defined(__WINPTHREADS_VERSION)) && (!defined(__GNUC__) || __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)) && (!defined(__APPLE__) || !TARGET_OS_IPHONE) && !defined(__arm__) && !defined(_M_ARM) && !defined(__aarch64__) && !defined(__MVS__)
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// Assume `thread_local` is fully supported in all other C++11 compilers/platforms
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#define MOODYCAMEL_CPP11_THREAD_LOCAL_SUPPORTED // tentatively enabled for now; years ago several users report having problems with it on
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#endif
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#endif
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#endif
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// VS2012 doesn't support deleted functions.
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// In this case, we declare the function normally but don't define it. A link error will be generated if the function is called.
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#ifndef MOODYCAMEL_DELETE_FUNCTION
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#if defined(_MSC_VER) && _MSC_VER < 1800
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#define MOODYCAMEL_DELETE_FUNCTION
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#else
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#define MOODYCAMEL_DELETE_FUNCTION = delete
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#endif
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#endif
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namespace moodycamel { namespace details {
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#ifndef MOODYCAMEL_ALIGNAS
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// VS2013 doesn't support alignas or alignof, and align() requires a constant literal
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#if defined(_MSC_VER) && _MSC_VER <= 1800
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#define MOODYCAMEL_ALIGNAS(alignment) __declspec(align(alignment))
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#define MOODYCAMEL_ALIGNOF(obj) __alignof(obj)
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#define MOODYCAMEL_ALIGNED_TYPE_LIKE(T, obj) typename details::Vs2013Aligned<std::alignment_of<obj>::value, T>::type
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template<int Align, typename T> struct Vs2013Aligned { }; // default, unsupported alignment
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template<typename T> struct Vs2013Aligned<1, T> { typedef __declspec(align(1)) T type; };
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template<typename T> struct Vs2013Aligned<2, T> { typedef __declspec(align(2)) T type; };
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template<typename T> struct Vs2013Aligned<4, T> { typedef __declspec(align(4)) T type; };
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template<typename T> struct Vs2013Aligned<8, T> { typedef __declspec(align(8)) T type; };
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template<typename T> struct Vs2013Aligned<16, T> { typedef __declspec(align(16)) T type; };
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template<typename T> struct Vs2013Aligned<32, T> { typedef __declspec(align(32)) T type; };
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template<typename T> struct Vs2013Aligned<64, T> { typedef __declspec(align(64)) T type; };
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template<typename T> struct Vs2013Aligned<128, T> { typedef __declspec(align(128)) T type; };
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template<typename T> struct Vs2013Aligned<256, T> { typedef __declspec(align(256)) T type; };
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#else
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template<typename T> struct identity { typedef T type; };
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#define MOODYCAMEL_ALIGNAS(alignment) alignas(alignment)
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#define MOODYCAMEL_ALIGNOF(obj) alignof(obj)
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#define MOODYCAMEL_ALIGNED_TYPE_LIKE(T, obj) alignas(alignof(obj)) typename details::identity<T>::type
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#endif
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#endif
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} }
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// TSAN can false report races in lock-free code. To enable TSAN to be used from projects that use this one,
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// we can apply per-function compile-time suppression.
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// See https://clang.llvm.org/docs/ThreadSanitizer.html#has-feature-thread-sanitizer
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#define MOODYCAMEL_NO_TSAN
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#if defined(__has_feature)
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#if __has_feature(thread_sanitizer)
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#undef MOODYCAMEL_NO_TSAN
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#define MOODYCAMEL_NO_TSAN __attribute__((no_sanitize("thread")))
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#endif // TSAN
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#endif // TSAN
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// Compiler-specific likely/unlikely hints
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namespace moodycamel { namespace details {
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#if defined(__GNUC__)
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static inline bool (likely)(bool x) { return __builtin_expect((x), true); }
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static inline bool (unlikely)(bool x) { return __builtin_expect((x), false); }
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#else
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static inline bool (likely)(bool x) { return x; }
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static inline bool (unlikely)(bool x) { return x; }
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#endif
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} }
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#ifdef MOODYCAMEL_QUEUE_INTERNAL_DEBUG
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#include "internal/concurrentqueue_internal_debug.h"
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#endif
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namespace moodycamel {
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namespace details {
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template<typename T>
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struct const_numeric_max {
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static_assert(std::is_integral<T>::value, "const_numeric_max can only be used with integers");
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static const T value = std::numeric_limits<T>::is_signed
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? (static_cast<T>(1) << (sizeof(T) * CHAR_BIT - 1)) - static_cast<T>(1)
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: static_cast<T>(-1);
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};
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#if defined(__GLIBCXX__)
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typedef ::max_align_t std_max_align_t; // libstdc++ forgot to add it to std:: for a while
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#else
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typedef std::max_align_t std_max_align_t; // Others (e.g. MSVC) insist it can *only* be accessed via std::
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#endif
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// Some platforms have incorrectly set max_align_t to a type with <8 bytes alignment even while supporting
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// 8-byte aligned scalar values (*cough* 32-bit iOS). Work around this with our own union. See issue #64.
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typedef union {
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std_max_align_t x;
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long long y;
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void* z;
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} max_align_t;
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}
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// Default traits for the ConcurrentQueue. To change some of the
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// traits without re-implementing all of them, inherit from this
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// struct and shadow the declarations you wish to be different;
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// since the traits are used as a template type parameter, the
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// shadowed declarations will be used where defined, and the defaults
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// otherwise.
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struct ConcurrentQueueDefaultTraits
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{
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// General-purpose size type. std::size_t is strongly recommended.
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typedef std::size_t size_t;
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// The type used for the enqueue and dequeue indices. Must be at least as
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// large as size_t. Should be significantly larger than the number of elements
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// you expect to hold at once, especially if you have a high turnover rate;
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// for example, on 32-bit x86, if you expect to have over a hundred million
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// elements or pump several million elements through your queue in a very
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// short space of time, using a 32-bit type *may* trigger a race condition.
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// A 64-bit int type is recommended in that case, and in practice will
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// prevent a race condition no matter the usage of the queue. Note that
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// whether the queue is lock-free with a 64-int type depends on the whether
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// std::atomic<std::uint64_t> is lock-free, which is platform-specific.
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typedef std::size_t index_t;
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// Internally, all elements are enqueued and dequeued from multi-element
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// blocks; this is the smallest controllable unit. If you expect few elements
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// but many producers, a smaller block size should be favoured. For few producers
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// and/or many elements, a larger block size is preferred. A sane default
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// is provided. Must be a power of 2.
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static const size_t BLOCK_SIZE = 32;
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// For explicit producers (i.e. when using a producer token), the block is
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// checked for being empty by iterating through a list of flags, one per element.
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// For large block sizes, this is too inefficient, and switching to an atomic
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// counter-based approach is faster. The switch is made for block sizes strictly
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// larger than this threshold.
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static const size_t EXPLICIT_BLOCK_EMPTY_COUNTER_THRESHOLD = 32;
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// How many full blocks can be expected for a single explicit producer? This should
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// reflect that number's maximum for optimal performance. Must be a power of 2.
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static const size_t EXPLICIT_INITIAL_INDEX_SIZE = 32;
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// How many full blocks can be expected for a single implicit producer? This should
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// reflect that number's maximum for optimal performance. Must be a power of 2.
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static const size_t IMPLICIT_INITIAL_INDEX_SIZE = 32;
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// The initial size of the hash table mapping thread IDs to implicit producers.
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// Note that the hash is resized every time it becomes half full.
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// Must be a power of two, and either 0 or at least 1. If 0, implicit production
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// (using the enqueue methods without an explicit producer token) is disabled.
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static const size_t INITIAL_IMPLICIT_PRODUCER_HASH_SIZE = 32;
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// Controls the number of items that an explicit consumer (i.e. one with a token)
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// must consume before it causes all consumers to rotate and move on to the next
|
|
// internal queue.
|
|
static const std::uint32_t EXPLICIT_CONSUMER_CONSUMPTION_QUOTA_BEFORE_ROTATE = 256;
|
|
|
|
// The maximum number of elements (inclusive) that can be enqueued to a sub-queue.
|
|
// Enqueue operations that would cause this limit to be surpassed will fail. Note
|
|
// that this limit is enforced at the block level (for performance reasons), i.e.
|
|
|
|
// it's rounded up to the nearest block size.
|
|
static const size_t MAX_SUBQUEUE_SIZE = details::const_numeric_max<size_t>::value;
|
|
|
|
// The number of times to spin before sleeping when waiting on a semaphore.
|
|
// Recommended values are on the order of 1000-10000 unless the number of
|
|
// consumer threads exceeds the number of idle cores (in which case try 0-100).
|
|
// Only affects instances of the BlockingConcurrentQueue.
|
|
static const int MAX_SEMA_SPINS = 10000;
|
|
|
|
// Whether to recycle dynamically-allocated blocks into an internal free list or
|
|
// not. If false, only pre-allocated blocks (controlled by the constructor
|
|
// arguments) will be recycled, and all others will be `free`d back to the heap.
|
|
|
|
// Note that blocks consumed by explicit producers are only freed on destruction
|
|
// of the queue (not following destruction of the token) regardless of this trait.
|
|
static const bool RECYCLE_ALLOCATED_BLOCKS = false;
|
|
|
|
|
|
#ifndef MCDBGQ_USE_RELACY
|
|
// Memory allocation can be customized if needed.
|
|
// malloc should return nullptr on failure, and handle alignment like std::malloc.
|
|
#if defined(malloc) || defined(free)
|
|
// Gah, this is 2015, stop defining macros that break standard code already!
|
|
// Work around malloc/free being special macros:
|
|
static inline void* WORKAROUND_malloc(size_t size) { return malloc(size); }
|
|
static inline void WORKAROUND_free(void* ptr) { return free(ptr); }
|
|
static inline void* (malloc)(size_t size) { return WORKAROUND_malloc(size); }
|
|
static inline void (free)(void* ptr) { return WORKAROUND_free(ptr); }
|
|
#else
|
|
static inline void* malloc(size_t size) { return std::malloc(size); }
|
|
static inline void free(void* ptr) { return std::free(ptr); }
|
|
#endif
|
|
#else
|
|
// Debug versions when running under the Relacy race detector (ignore
|
|
// these in user code)
|
|
static inline void* malloc(size_t size) { return rl::rl_malloc(size, $); }
|
|
static inline void free(void* ptr) { return rl::rl_free(ptr, $); }
|
|
#endif
|
|
};
|
|
|
|
|
|
// When producing or consuming many elements, the most efficient way is to:
|
|
// 1) Use one of the bulk-operation methods of the queue with a token
|
|
// 2) Failing that, use the bulk-operation methods without a token
|
|
// 3) Failing that, create a token and use that with the single-item methods
|
|
// 4) Failing that, use the single-parameter methods of the queue
|
|
// Having said that, don't create tokens willy-nilly -- ideally there should be
|
|
// a maximum of one token per thread (of each kind).
|
|
struct ProducerToken;
|
|
struct ConsumerToken;
|
|
|
|
|
|
template<typename T, typename Traits> class ConcurrentQueue;
|
|
template<typename T, typename Traits> class BlockingConcurrentQueue;
|
|
class ConcurrentQueueTests;
|
|
|
|
|
|
namespace details
|
|
{
|
|
struct ConcurrentQueueProducerTypelessBase
|
|
{
|
|
ConcurrentQueueProducerTypelessBase* next;
|
|
std::atomic<bool> inactive;
|
|
ProducerToken* token;
|
|
|
|
ConcurrentQueueProducerTypelessBase()
|
|
: next(nullptr), inactive(false), token(nullptr)
|
|
|
|
{
|
|
}
|
|
};
|
|
|
|
template<bool use32> struct _hash_32_or_64 {
|
|
static inline std::uint32_t hash(std::uint32_t h)
|
|
{
|
|
// MurmurHash3 finalizer -- see https://code.google.com/p/smhasher/source/browse/trunk/MurmurHash3.cpp
|
|
// Since the thread ID is already unique, all we really want to do is propagate that
|
|
// uniqueness evenly across all the bits, so that we can use a subset of the bits while
|
|
// reducing collisions significantly
|
|
h ^= h >> 16;
|
|
|
|
h *= 0x85ebca6b;
|
|
h ^= h >> 13;
|
|
h *= 0xc2b2ae35;
|
|
return h ^ (h >> 16);
|
|
}
|
|
};
|
|
template<> struct _hash_32_or_64<1> {
|
|
static inline std::uint64_t hash(std::uint64_t h)
|
|
{
|
|
h ^= h >> 33;
|
|
h *= 0xff51afd7ed558ccd;
|
|
h ^= h >> 33;
|
|
h *= 0xc4ceb9fe1a85ec53;
|
|
return h ^ (h >> 33);
|
|
}
|
|
};
|
|
template<std::size_t size> struct hash_32_or_64 : public _hash_32_or_64<(size > 4)> { };
|
|
|
|
static inline size_t hash_thread_id(thread_id_t id)
|
|
{
|
|
static_assert(sizeof(thread_id_t) <= 8, "Expected a platform where thread IDs are at most 64-bit values");
|
|
return static_cast<size_t>(hash_32_or_64<sizeof(thread_id_converter<thread_id_t>::thread_id_hash_t)>::hash(
|
|
|
|
thread_id_converter<thread_id_t>::prehash(id)));
|
|
}
|
|
|
|
template<typename T>
|
|
static inline bool circular_less_than(T a, T b)
|
|
{
|
|
static_assert(std::is_integral<T>::value && !std::numeric_limits<T>::is_signed, "circular_less_than is intended to be used only with unsigned integer types");
|
|
return static_cast<T>(a - b) > static_cast<T>(static_cast<T>(1) << (static_cast<T>(sizeof(T) * CHAR_BIT - 1)));
|
|
// Note: extra parens around rhs of operator<< is MSVC bug: https://developercommunity2.visualstudio.com/t/C4554-triggers-when-both-lhs-and-rhs-is/10034931
|
|
// silencing the bug requires #pragma warning(disable: 4554) around the calling code and has no effect when done here.
|
|
}
|
|
|
|
template<typename U>
|
|
static inline char* align_for(char* ptr)
|
|
{
|
|
const std::size_t alignment = std::alignment_of<U>::value;
|
|
return ptr + (alignment - (reinterpret_cast<std::uintptr_t>(ptr) % alignment)) % alignment;
|
|
}
|
|
|
|
template<typename T>
|
|
static inline T ceil_to_pow_2(T x)
|
|
{
|
|
static_assert(std::is_integral<T>::value && !std::numeric_limits<T>::is_signed, "ceil_to_pow_2 is intended to be used only with unsigned integer types");
|
|
|
|
// Adapted from http://graphics.stanford.edu/~seander/bithacks.html#RoundUpPowerOf2
|
|
--x;
|
|
x |= x >> 1;
|
|
x |= x >> 2;
|
|
x |= x >> 4;
|
|
for (std::size_t i = 1; i < sizeof(T); i <<= 1) {
|
|
x |= x >> (i << 3);
|
|
}
|
|
++x;
|
|
return x;
|
|
}
|
|
|
|
template<typename T>
|
|
static inline void swap_relaxed(std::atomic<T>& left, std::atomic<T>& right)
|
|
{
|
|
T temp = std::move(left.load(std::memory_order_relaxed));
|
|
left.store(std::move(right.load(std::memory_order_relaxed)), std::memory_order_relaxed);
|
|
right.store(std::move(temp), std::memory_order_relaxed);
|
|
}
|
|
|
|
template<typename T>
|
|
static inline T const& nomove(T const& x)
|
|
{
|
|
return x;
|
|
}
|
|
|
|
template<bool Enable>
|
|
struct nomove_if
|
|
{
|
|
template<typename T>
|
|
static inline T const& eval(T const& x)
|
|
{
|
|
return x;
|
|
}
|
|
};
|
|
|
|
template<>
|
|
struct nomove_if<false>
|
|
{
|
|
template<typename U>
|
|
static inline auto eval(U&& x)
|
|
-> decltype(std::forward<U>(x))
|
|
{
|
|
return std::forward<U>(x);
|
|
}
|
|
};
|
|
|
|
template<typename It>
|
|
static inline auto deref_noexcept(It& it) MOODYCAMEL_NOEXCEPT -> decltype(*it)
|
|
{
|
|
return *it;
|
|
}
|
|
|
|
#if defined(__clang__) || !defined(__GNUC__) || __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)
|
|
template<typename T> struct is_trivially_destructible : std::is_trivially_destructible<T> { };
|
|
#else
|
|
template<typename T> struct is_trivially_destructible : std::has_trivial_destructor<T> { };
|
|
#endif
|
|
|
|
|
|
#ifdef MOODYCAMEL_CPP11_THREAD_LOCAL_SUPPORTED
|
|
#ifdef MCDBGQ_USE_RELACY
|
|
typedef RelacyThreadExitListener ThreadExitListener;
|
|
typedef RelacyThreadExitNotifier ThreadExitNotifier;
|
|
#else
|
|
class ThreadExitNotifier;
|
|
|
|
struct ThreadExitListener
|
|
{
|
|
typedef void (*callback_t)(void*);
|
|
callback_t callback;
|
|
void* userData;
|
|
|
|
ThreadExitListener* next; // reserved for use by the ThreadExitNotifier
|
|
ThreadExitNotifier* chain; // reserved for use by the ThreadExitNotifier
|
|
};
|
|
|
|
class ThreadExitNotifier
|
|
{
|
|
public:
|
|
static void subscribe(ThreadExitListener* listener)
|
|
{
|
|
auto& tlsInst = instance();
|
|
std::lock_guard<std::mutex> guard(mutex());
|
|
listener->next = tlsInst.tail;
|
|
listener->chain = &tlsInst;
|
|
tlsInst.tail = listener;
|
|
}
|
|
|
|
static void unsubscribe(ThreadExitListener* listener)
|
|
{
|
|
std::lock_guard<std::mutex> guard(mutex());
|
|
if (!listener->chain) {
|
|
return; // race with ~ThreadExitNotifier
|
|
}
|
|
auto& tlsInst = *listener->chain;
|
|
listener->chain = nullptr;
|
|
ThreadExitListener** prev = &tlsInst.tail;
|
|
for (auto ptr = tlsInst.tail; ptr != nullptr; ptr = ptr->next) {
|
|
if (ptr == listener) {
|
|
*prev = ptr->next;
|
|
break;
|
|
}
|
|
prev = &ptr->next;
|
|
}
|
|
}
|
|
|
|
private:
|
|
ThreadExitNotifier() : tail(nullptr) { }
|
|
ThreadExitNotifier(ThreadExitNotifier const&) MOODYCAMEL_DELETE_FUNCTION;
|
|
ThreadExitNotifier& operator=(ThreadExitNotifier const&) MOODYCAMEL_DELETE_FUNCTION;
|
|
|
|
~ThreadExitNotifier()
|
|
{
|
|
// This thread is about to exit, let everyone know!
|
|
assert(this == &instance() && "If this assert fails, you likely have a buggy compiler! Change the preprocessor conditions such that MOODYCAMEL_CPP11_THREAD_LOCAL_SUPPORTED is no longer defined.");
|
|
std::lock_guard<std::mutex> guard(mutex());
|
|
for (auto ptr = tail; ptr != nullptr; ptr = ptr->next) {
|
|
ptr->chain = nullptr;
|
|
ptr->callback(ptr->userData);
|
|
}
|
|
}
|
|
|
|
// Thread-local
|
|
static inline ThreadExitNotifier& instance()
|
|
{
|
|
static thread_local ThreadExitNotifier notifier;
|
|
return notifier;
|
|
}
|
|
|
|
static inline std::mutex& mutex()
|
|
{
|
|
// Must be static because the ThreadExitNotifier could be destroyed while unsubscribe is called
|
|
static std::mutex mutex;
|
|
return mutex;
|
|
}
|
|
|
|
private:
|
|
ThreadExitListener* tail;
|
|
};
|
|
#endif
|
|
#endif
|
|
|
|
template<typename T> struct static_is_lock_free_num { enum { value = 0 }; };
|
|
template<> struct static_is_lock_free_num<signed char> { enum { value = ATOMIC_CHAR_LOCK_FREE }; };
|
|
template<> struct static_is_lock_free_num<short> { enum { value = ATOMIC_SHORT_LOCK_FREE }; };
|
|
template<> struct static_is_lock_free_num<int> { enum { value = ATOMIC_INT_LOCK_FREE }; };
|
|
template<> struct static_is_lock_free_num<long> { enum { value = ATOMIC_LONG_LOCK_FREE }; };
|
|
|
|
template<> struct static_is_lock_free_num<long long> { enum { value = ATOMIC_LLONG_LOCK_FREE }; };
|
|
template<typename T> struct static_is_lock_free : static_is_lock_free_num<typename std::make_signed<T>::type> { };
|
|
template<> struct static_is_lock_free<bool> { enum { value = ATOMIC_BOOL_LOCK_FREE }; };
|
|
template<typename U> struct static_is_lock_free<U*> { enum { value = ATOMIC_POINTER_LOCK_FREE }; };
|
|
}
|
|
|
|
|
|
struct ProducerToken
|
|
{
|
|
template<typename T, typename Traits>
|
|
explicit ProducerToken(ConcurrentQueue<T, Traits>& queue);
|
|
|
|
template<typename T, typename Traits>
|
|
explicit ProducerToken(BlockingConcurrentQueue<T, Traits>& queue);
|
|
|
|
ProducerToken(ProducerToken&& other) MOODYCAMEL_NOEXCEPT
|
|
: producer(other.producer)
|
|
{
|
|
other.producer = nullptr;
|
|
if (producer != nullptr) {
|
|
producer->token = this;
|
|
}
|
|
}
|
|
|
|
inline ProducerToken& operator=(ProducerToken&& other) MOODYCAMEL_NOEXCEPT
|
|
{
|
|
swap(other);
|
|
return *this;
|
|
}
|
|
|
|
void swap(ProducerToken& other) MOODYCAMEL_NOEXCEPT
|
|
{
|
|
std::swap(producer, other.producer);
|
|
if (producer != nullptr) {
|
|
producer->token = this;
|
|
}
|
|
if (other.producer != nullptr) {
|
|
other.producer->token = &other;
|
|
}
|
|
}
|
|
|
|
// A token is always valid unless:
|
|
// 1) Memory allocation failed during construction
|
|
// 2) It was moved via the move constructor
|
|
// (Note: assignment does a swap, leaving both potentially valid)
|
|
// 3) The associated queue was destroyed
|
|
// Note that if valid() returns true, that only indicates
|
|
// that the token is valid for use with a specific queue,
|
|
// but not which one; that's up to the user to track.
|
|
inline bool valid() const { return producer != nullptr; }
|
|
|
|
~ProducerToken()
|
|
{
|
|
if (producer != nullptr) {
|
|
producer->token = nullptr;
|
|
producer->inactive.store(true, std::memory_order_release);
|
|
}
|
|
}
|
|
|
|
// Disable copying and assignment
|
|
ProducerToken(ProducerToken const&) MOODYCAMEL_DELETE_FUNCTION;
|
|
ProducerToken& operator=(ProducerToken const&) MOODYCAMEL_DELETE_FUNCTION;
|
|
|
|
private:
|
|
template<typename T, typename Traits> friend class ConcurrentQueue;
|
|
friend class ConcurrentQueueTests;
|
|
|
|
protected:
|
|
details::ConcurrentQueueProducerTypelessBase* producer;
|
|
};
|
|
|
|
|
|
struct ConsumerToken
|
|
{
|
|
template<typename T, typename Traits>
|
|
explicit ConsumerToken(ConcurrentQueue<T, Traits>& q);
|
|
|
|
template<typename T, typename Traits>
|
|
explicit ConsumerToken(BlockingConcurrentQueue<T, Traits>& q);
|
|
|
|
ConsumerToken(ConsumerToken&& other) MOODYCAMEL_NOEXCEPT
|
|
: initialOffset(other.initialOffset), lastKnownGlobalOffset(other.lastKnownGlobalOffset), itemsConsumedFromCurrent(other.itemsConsumedFromCurrent), currentProducer(other.currentProducer), desiredProducer(other.desiredProducer)
|
|
{
|
|
}
|
|
|
|
inline ConsumerToken& operator=(ConsumerToken&& other) MOODYCAMEL_NOEXCEPT
|
|
{
|
|
swap(other);
|
|
return *this;
|
|
}
|
|
|
|
void swap(ConsumerToken& other) MOODYCAMEL_NOEXCEPT
|
|
{
|
|
std::swap(initialOffset, other.initialOffset);
|
|
std::swap(lastKnownGlobalOffset, other.lastKnownGlobalOffset);
|
|
std::swap(itemsConsumedFromCurrent, other.itemsConsumedFromCurrent);
|
|
std::swap(currentProducer, other.currentProducer);
|
|
std::swap(desiredProducer, other.desiredProducer);
|
|
}
|
|
|
|
// Disable copying and assignment
|
|
ConsumerToken(ConsumerToken const&) MOODYCAMEL_DELETE_FUNCTION;
|
|
ConsumerToken& operator=(ConsumerToken const&) MOODYCAMEL_DELETE_FUNCTION;
|
|
|
|
private:
|
|
template<typename T, typename Traits> friend class ConcurrentQueue;
|
|
friend class ConcurrentQueueTests;
|
|
|
|
private: // but shared with ConcurrentQueue
|
|
std::uint32_t initialOffset;
|
|
std::uint32_t lastKnownGlobalOffset;
|
|
std::uint32_t itemsConsumedFromCurrent;
|
|
details::ConcurrentQueueProducerTypelessBase* currentProducer;
|
|
details::ConcurrentQueueProducerTypelessBase* desiredProducer;
|
|
};
|
|
|
|
// Need to forward-declare this swap because it's in a namespace.
|
|
// See http://stackoverflow.com/questions/4492062/why-does-a-c-friend-class-need-a-forward-declaration-only-in-other-namespaces
|
|
template<typename T, typename Traits>
|
|
inline void swap(typename ConcurrentQueue<T, Traits>::ImplicitProducerKVP& a, typename ConcurrentQueue<T, Traits>::ImplicitProducerKVP& b) MOODYCAMEL_NOEXCEPT;
|
|
|
|
|
|
template<typename T, typename Traits = ConcurrentQueueDefaultTraits>
|
|
class ConcurrentQueue
|
|
{
|
|
public:
|
|
typedef ::moodycamel::ProducerToken producer_token_t;
|
|
typedef ::moodycamel::ConsumerToken consumer_token_t;
|
|
|
|
typedef typename Traits::index_t index_t;
|
|
typedef typename Traits::size_t size_t;
|
|
|
|
static const size_t BLOCK_SIZE = static_cast<size_t>(Traits::BLOCK_SIZE);
|
|
static const size_t EXPLICIT_BLOCK_EMPTY_COUNTER_THRESHOLD = static_cast<size_t>(Traits::EXPLICIT_BLOCK_EMPTY_COUNTER_THRESHOLD);
|
|
static const size_t EXPLICIT_INITIAL_INDEX_SIZE = static_cast<size_t>(Traits::EXPLICIT_INITIAL_INDEX_SIZE);
|
|
static const size_t IMPLICIT_INITIAL_INDEX_SIZE = static_cast<size_t>(Traits::IMPLICIT_INITIAL_INDEX_SIZE);
|
|
static const size_t INITIAL_IMPLICIT_PRODUCER_HASH_SIZE = static_cast<size_t>(Traits::INITIAL_IMPLICIT_PRODUCER_HASH_SIZE);
|
|
static const std::uint32_t EXPLICIT_CONSUMER_CONSUMPTION_QUOTA_BEFORE_ROTATE = static_cast<std::uint32_t>(Traits::EXPLICIT_CONSUMER_CONSUMPTION_QUOTA_BEFORE_ROTATE);
|
|
#ifdef _MSC_VER
|
|
#pragma warning(push)
|
|
#pragma warning(disable: 4307) // + integral constant overflow (that's what the ternary expression is for!)
|
|
#pragma warning(disable: 4309) // static_cast: Truncation of constant value
|
|
#endif
|
|
static const size_t MAX_SUBQUEUE_SIZE = (details::const_numeric_max<size_t>::value - static_cast<size_t>(Traits::MAX_SUBQUEUE_SIZE) < BLOCK_SIZE) ? details::const_numeric_max<size_t>::value : ((static_cast<size_t>(Traits::MAX_SUBQUEUE_SIZE) + (BLOCK_SIZE - 1)) / BLOCK_SIZE * BLOCK_SIZE);
|
|
#ifdef _MSC_VER
|
|
#pragma warning(pop)
|
|
#endif
|
|
|
|
static_assert(!std::numeric_limits<size_t>::is_signed && std::is_integral<size_t>::value, "Traits::size_t must be an unsigned integral type");
|
|
static_assert(!std::numeric_limits<index_t>::is_signed && std::is_integral<index_t>::value, "Traits::index_t must be an unsigned integral type");
|
|
static_assert(sizeof(index_t) >= sizeof(size_t), "Traits::index_t must be at least as wide as Traits::size_t");
|
|
static_assert((BLOCK_SIZE > 1) && !(BLOCK_SIZE & (BLOCK_SIZE - 1)), "Traits::BLOCK_SIZE must be a power of 2 (and at least 2)");
|
|
static_assert((EXPLICIT_BLOCK_EMPTY_COUNTER_THRESHOLD > 1) && !(EXPLICIT_BLOCK_EMPTY_COUNTER_THRESHOLD & (EXPLICIT_BLOCK_EMPTY_COUNTER_THRESHOLD - 1)), "Traits::EXPLICIT_BLOCK_EMPTY_COUNTER_THRESHOLD must be a power of 2 (and greater than 1)");
|
|
static_assert((EXPLICIT_INITIAL_INDEX_SIZE > 1) && !(EXPLICIT_INITIAL_INDEX_SIZE & (EXPLICIT_INITIAL_INDEX_SIZE - 1)), "Traits::EXPLICIT_INITIAL_INDEX_SIZE must be a power of 2 (and greater than 1)");
|
|
static_assert((IMPLICIT_INITIAL_INDEX_SIZE > 1) && !(IMPLICIT_INITIAL_INDEX_SIZE & (IMPLICIT_INITIAL_INDEX_SIZE - 1)), "Traits::IMPLICIT_INITIAL_INDEX_SIZE must be a power of 2 (and greater than 1)");
|
|
static_assert((INITIAL_IMPLICIT_PRODUCER_HASH_SIZE == 0) || !(INITIAL_IMPLICIT_PRODUCER_HASH_SIZE & (INITIAL_IMPLICIT_PRODUCER_HASH_SIZE - 1)), "Traits::INITIAL_IMPLICIT_PRODUCER_HASH_SIZE must be a power of 2");
|
|
static_assert(INITIAL_IMPLICIT_PRODUCER_HASH_SIZE == 0 || INITIAL_IMPLICIT_PRODUCER_HASH_SIZE >= 1, "Traits::INITIAL_IMPLICIT_PRODUCER_HASH_SIZE must be at least 1 (or 0 to disable implicit enqueueing)");
|
|
|
|
public:
|
|
// Creates a queue with at least `capacity` element slots; note that the
|
|
// actual number of elements that can be inserted without additional memory
|
|
// allocation depends on the number of producers and the block size (e.g. if
|
|
// the block size is equal to `capacity`, only a single block will be allocated
|
|
// up-front, which means only a single producer will be able to enqueue elements
|
|
// without an extra allocation -- blocks aren't shared between producers).
|
|
// This method is not thread safe -- it is up to the user to ensure that the
|
|
// queue is fully constructed before it starts being used by other threads (this
|
|
// includes making the memory effects of construction visible, possibly with a
|
|
// memory barrier).
|
|
explicit ConcurrentQueue(size_t capacity = 32 * BLOCK_SIZE)
|
|
: producerListTail(nullptr),
|
|
|
|
producerCount(0),
|
|
initialBlockPoolIndex(0),
|
|
nextExplicitConsumerId(0),
|
|
globalExplicitConsumerOffset(0)
|
|
{
|
|
implicitProducerHashResizeInProgress.clear(std::memory_order_relaxed);
|
|
populate_initial_implicit_producer_hash();
|
|
populate_initial_block_list(capacity / BLOCK_SIZE + ((capacity & (BLOCK_SIZE - 1)) == 0 ? 0 : 1));
|
|
|
|
#ifdef MOODYCAMEL_QUEUE_INTERNAL_DEBUG
|
|
// Track all the producers using a fully-resolved typed list for
|
|
// each kind; this makes it possible to debug them starting from
|
|
// the root queue object (otherwise wacky casts are needed that
|
|
// don't compile in the debugger's expression evaluator).
|
|
explicitProducers.store(nullptr, std::memory_order_relaxed);
|
|
implicitProducers.store(nullptr, std::memory_order_relaxed);
|
|
#endif
|
|
}
|
|
|
|
// Computes the correct amount of pre-allocated blocks for you based
|
|
// on the minimum number of elements you want available at any given
|
|
// time, and the maximum concurrent number of each type of producer.
|
|
ConcurrentQueue(size_t minCapacity, size_t maxExplicitProducers, size_t maxImplicitProducers)
|
|
: producerListTail(nullptr),
|
|
producerCount(0),
|
|
initialBlockPoolIndex(0),
|
|
nextExplicitConsumerId(0),
|
|
globalExplicitConsumerOffset(0)
|
|
{
|
|
implicitProducerHashResizeInProgress.clear(std::memory_order_relaxed);
|
|
populate_initial_implicit_producer_hash();
|
|
size_t blocks = (((minCapacity + BLOCK_SIZE - 1) / BLOCK_SIZE) - 1) * (maxExplicitProducers + 1) + 2 * (maxExplicitProducers + maxImplicitProducers);
|
|
populate_initial_block_list(blocks);
|
|
|
|
#ifdef MOODYCAMEL_QUEUE_INTERNAL_DEBUG
|
|
explicitProducers.store(nullptr, std::memory_order_relaxed);
|
|
implicitProducers.store(nullptr, std::memory_order_relaxed);
|
|
#endif
|
|
}
|
|
|
|
// Note: The queue should not be accessed concurrently while it's
|
|
// being deleted. It's up to the user to synchronize this.
|
|
// This method is not thread safe.
|
|
~ConcurrentQueue()
|
|
{
|
|
// Destroy producers
|
|
auto ptr = producerListTail.load(std::memory_order_relaxed);
|
|
while (ptr != nullptr) {
|
|
auto next = ptr->next_prod();
|
|
if (ptr->token != nullptr) {
|
|
ptr->token->producer = nullptr;
|
|
}
|
|
destroy(ptr);
|
|
ptr = next;
|
|
}
|
|
|
|
// Destroy implicit producer hash tables
|
|
MOODYCAMEL_CONSTEXPR_IF (INITIAL_IMPLICIT_PRODUCER_HASH_SIZE != 0) {
|
|
auto hash = implicitProducerHash.load(std::memory_order_relaxed);
|
|
while (hash != nullptr) {
|
|
auto prev = hash->prev;
|
|
if (prev != nullptr) { // The last hash is part of this object and was not allocated dynamically
|
|
for (size_t i = 0; i != hash->capacity; ++i) {
|
|
hash->entries[i].~ImplicitProducerKVP();
|
|
}
|
|
hash->~ImplicitProducerHash();
|
|
(Traits::free)(hash);
|
|
}
|
|
hash = prev;
|
|
}
|
|
}
|
|
|
|
// Destroy global free list
|
|
auto block = freeList.head_unsafe();
|
|
while (block != nullptr) {
|
|
auto next = block->freeListNext.load(std::memory_order_relaxed);
|
|
if (block->dynamicallyAllocated) {
|
|
destroy(block);
|
|
}
|
|
block = next;
|
|
}
|
|
|
|
// Destroy initial free list
|
|
destroy_array(initialBlockPool, initialBlockPoolSize);
|
|
}
|
|
|
|
// Disable copying and copy assignment
|
|
ConcurrentQueue(ConcurrentQueue const&) MOODYCAMEL_DELETE_FUNCTION;
|
|
ConcurrentQueue& operator=(ConcurrentQueue const&) MOODYCAMEL_DELETE_FUNCTION;
|
|
|
|
// Moving is supported, but note that it is *not* a thread-safe operation.
|
|
// Nobody can use the queue while it's being moved, and the memory effects
|
|
// of that move must be propagated to other threads before they can use it.
|
|
// Note: When a queue is moved, its tokens are still valid but can only be
|
|
// used with the destination queue (i.e. semantically they are moved along
|
|
// with the queue itself).
|
|
ConcurrentQueue(ConcurrentQueue&& other) MOODYCAMEL_NOEXCEPT
|
|
: producerListTail(other.producerListTail.load(std::memory_order_relaxed)),
|
|
producerCount(other.producerCount.load(std::memory_order_relaxed)),
|
|
initialBlockPoolIndex(other.initialBlockPoolIndex.load(std::memory_order_relaxed)),
|
|
initialBlockPool(other.initialBlockPool),
|
|
initialBlockPoolSize(other.initialBlockPoolSize),
|
|
freeList(std::move(other.freeList)),
|
|
nextExplicitConsumerId(other.nextExplicitConsumerId.load(std::memory_order_relaxed)),
|
|
globalExplicitConsumerOffset(other.globalExplicitConsumerOffset.load(std::memory_order_relaxed))
|
|
{
|
|
// Move the other one into this, and leave the other one as an empty queue
|
|
implicitProducerHashResizeInProgress.clear(std::memory_order_relaxed);
|
|
populate_initial_implicit_producer_hash();
|
|
swap_implicit_producer_hashes(other);
|
|
|
|
other.producerListTail.store(nullptr, std::memory_order_relaxed);
|
|
other.producerCount.store(0, std::memory_order_relaxed);
|
|
other.nextExplicitConsumerId.store(0, std::memory_order_relaxed);
|
|
other.globalExplicitConsumerOffset.store(0, std::memory_order_relaxed);
|
|
|
|
#ifdef MOODYCAMEL_QUEUE_INTERNAL_DEBUG
|
|
explicitProducers.store(other.explicitProducers.load(std::memory_order_relaxed), std::memory_order_relaxed);
|
|
other.explicitProducers.store(nullptr, std::memory_order_relaxed);
|
|
implicitProducers.store(other.implicitProducers.load(std::memory_order_relaxed), std::memory_order_relaxed);
|
|
other.implicitProducers.store(nullptr, std::memory_order_relaxed);
|
|
#endif
|
|
|
|
other.initialBlockPoolIndex.store(0, std::memory_order_relaxed);
|
|
other.initialBlockPoolSize = 0;
|
|
other.initialBlockPool = nullptr;
|
|
|
|
reown_producers();
|
|
}
|
|
|
|
inline ConcurrentQueue& operator=(ConcurrentQueue&& other) MOODYCAMEL_NOEXCEPT
|
|
{
|
|
return swap_internal(other);
|
|
}
|
|
|
|
// Swaps this queue's state with the other's. Not thread-safe.
|
|
// Swapping two queues does not invalidate their tokens, however
|
|
// the tokens that were created for one queue must be used with
|
|
// only the swapped queue (i.e. the tokens are tied to the
|
|
// queue's movable state, not the object itself).
|
|
inline void swap(ConcurrentQueue& other) MOODYCAMEL_NOEXCEPT
|
|
{
|
|
swap_internal(other);
|
|
}
|
|
|
|
private:
|
|
ConcurrentQueue& swap_internal(ConcurrentQueue& other)
|
|
{
|
|
if (this == &other) {
|
|
return *this;
|
|
}
|
|
|
|
details::swap_relaxed(producerListTail, other.producerListTail);
|
|
details::swap_relaxed(producerCount, other.producerCount);
|
|
details::swap_relaxed(initialBlockPoolIndex, other.initialBlockPoolIndex);
|
|
std::swap(initialBlockPool, other.initialBlockPool);
|
|
std::swap(initialBlockPoolSize, other.initialBlockPoolSize);
|
|
freeList.swap(other.freeList);
|
|
details::swap_relaxed(nextExplicitConsumerId, other.nextExplicitConsumerId);
|
|
details::swap_relaxed(globalExplicitConsumerOffset, other.globalExplicitConsumerOffset);
|
|
|
|
swap_implicit_producer_hashes(other);
|
|
|
|
reown_producers();
|
|
other.reown_producers();
|
|
|
|
#ifdef MOODYCAMEL_QUEUE_INTERNAL_DEBUG
|
|
details::swap_relaxed(explicitProducers, other.explicitProducers);
|
|
details::swap_relaxed(implicitProducers, other.implicitProducers);
|
|
#endif
|
|
|
|
return *this;
|
|
}
|
|
|
|
public:
|
|
// Enqueues a single item (by copying it).
|
|
// Allocates memory if required. Only fails if memory allocation fails (or implicit
|
|
// production is disabled because Traits::INITIAL_IMPLICIT_PRODUCER_HASH_SIZE is 0,
|
|
// or Traits::MAX_SUBQUEUE_SIZE has been defined and would be surpassed).
|
|
// Thread-safe.
|
|
inline bool enqueue(T const& item)
|
|
{
|
|
MOODYCAMEL_CONSTEXPR_IF (INITIAL_IMPLICIT_PRODUCER_HASH_SIZE == 0) return false;
|
|
else return inner_enqueue<CanAlloc>(item);
|
|
}
|
|
|
|
// Enqueues a single item (by moving it, if possible).
|
|
// Allocates memory if required. Only fails if memory allocation fails (or implicit
|
|
// production is disabled because Traits::INITIAL_IMPLICIT_PRODUCER_HASH_SIZE is 0,
|
|
// or Traits::MAX_SUBQUEUE_SIZE has been defined and would be surpassed).
|
|
// Thread-safe.
|
|
inline bool enqueue(T&& item)
|
|
{
|
|
MOODYCAMEL_CONSTEXPR_IF (INITIAL_IMPLICIT_PRODUCER_HASH_SIZE == 0) return false;
|
|
else return inner_enqueue<CanAlloc>(std::move(item));
|
|
}
|
|
|
|
// Enqueues a single item (by copying it) using an explicit producer token.
|
|
// Allocates memory if required. Only fails if memory allocation fails (or
|
|
// Traits::MAX_SUBQUEUE_SIZE has been defined and would be surpassed).
|
|
// Thread-safe.
|
|
inline bool enqueue(producer_token_t const& token, T const& item)
|
|
{
|
|
return inner_enqueue<CanAlloc>(token, item);
|
|
}
|
|
|
|
// Enqueues a single item (by moving it, if possible) using an explicit producer token.
|
|
// Allocates memory if required. Only fails if memory allocation fails (or
|
|
// Traits::MAX_SUBQUEUE_SIZE has been defined and would be surpassed).
|
|
// Thread-safe.
|
|
inline bool enqueue(producer_token_t const& token, T&& item)
|
|
{
|
|
return inner_enqueue<CanAlloc>(token, std::move(item));
|
|
}
|
|
|
|
// Enqueues several items.
|
|
// Allocates memory if required. Only fails if memory allocation fails (or
|
|
// implicit production is disabled because Traits::INITIAL_IMPLICIT_PRODUCER_HASH_SIZE
|
|
// is 0, or Traits::MAX_SUBQUEUE_SIZE has been defined and would be surpassed).
|
|
|
|
// Note: Use std::make_move_iterator if the elements should be moved instead of copied.
|
|
// Thread-safe.
|
|
template<typename It>
|
|
bool enqueue_bulk(It itemFirst, size_t count)
|
|
{
|
|
MOODYCAMEL_CONSTEXPR_IF (INITIAL_IMPLICIT_PRODUCER_HASH_SIZE == 0) return false;
|
|
else return inner_enqueue_bulk<CanAlloc>(itemFirst, count);
|
|
}
|
|
|
|
// Enqueues several items using an explicit producer token.
|
|
// Allocates memory if required. Only fails if memory allocation fails
|
|
// (or Traits::MAX_SUBQUEUE_SIZE has been defined and would be surpassed).
|
|
// Note: Use std::make_move_iterator if the elements should be moved
|
|
// instead of copied.
|
|
// Thread-safe.
|
|
template<typename It>
|
|
bool enqueue_bulk(producer_token_t const& token, It itemFirst, size_t count)
|
|
{
|
|
return inner_enqueue_bulk<CanAlloc>(token, itemFirst, count);
|
|
}
|
|
|
|
// Enqueues a single item (by copying it).
|
|
|
|
// Does not allocate memory. Fails if not enough room to enqueue (or implicit
|
|
// production is disabled because Traits::INITIAL_IMPLICIT_PRODUCER_HASH_SIZE
|
|
// is 0).
|
|
// Thread-safe.
|
|
inline bool try_enqueue(T const& item)
|
|
{
|
|
MOODYCAMEL_CONSTEXPR_IF (INITIAL_IMPLICIT_PRODUCER_HASH_SIZE == 0) return false;
|
|
else return inner_enqueue<CannotAlloc>(item);
|
|
}
|
|
|
|
// Enqueues a single item (by moving it, if possible).
|
|
// Does not allocate memory (except for one-time implicit producer).
|
|
// Fails if not enough room to enqueue (or implicit production is
|
|
// disabled because Traits::INITIAL_IMPLICIT_PRODUCER_HASH_SIZE is 0).
|
|
// Thread-safe.
|
|
inline bool try_enqueue(T&& item)
|
|
{
|
|
MOODYCAMEL_CONSTEXPR_IF (INITIAL_IMPLICIT_PRODUCER_HASH_SIZE == 0) return false;
|
|
else return inner_enqueue<CannotAlloc>(std::move(item));
|
|
}
|
|
|
|
// Enqueues a single item (by copying it) using an explicit producer token.
|
|
// Does not allocate memory. Fails if not enough room to enqueue.
|
|
// Thread-safe.
|
|
inline bool try_enqueue(producer_token_t const& token, T const& item)
|
|
{
|
|
return inner_enqueue<CannotAlloc>(token, item);
|
|
}
|
|
|
|
// Enqueues a single item (by moving it, if possible) using an explicit producer token.
|
|
// Does not allocate memory. Fails if not enough room to enqueue.
|
|
// Thread-safe.
|
|
inline bool try_enqueue(producer_token_t const& token, T&& item)
|
|
{
|
|
return inner_enqueue<CannotAlloc>(token, std::move(item));
|
|
}
|
|
|
|
// Enqueues several items.
|
|
// Does not allocate memory (except for one-time implicit producer).
|
|
// Fails if not enough room to enqueue (or implicit production is
|
|
// disabled because Traits::INITIAL_IMPLICIT_PRODUCER_HASH_SIZE is 0).
|
|
// Note: Use std::make_move_iterator if the elements should be moved
|
|
// instead of copied.
|
|
// Thread-safe.
|
|
template<typename It>
|
|
bool try_enqueue_bulk(It itemFirst, size_t count)
|
|
{
|
|
MOODYCAMEL_CONSTEXPR_IF (INITIAL_IMPLICIT_PRODUCER_HASH_SIZE == 0) return false;
|
|
else return inner_enqueue_bulk<CannotAlloc>(itemFirst, count);
|
|
|
|
}
|
|
|
|
// Enqueues several items using an explicit producer token.
|
|
// Does not allocate memory. Fails if not enough room to enqueue.
|
|
// Note: Use std::make_move_iterator if the elements should be moved
|
|
// instead of copied.
|
|
// Thread-safe.
|
|
template<typename It>
|
|
bool try_enqueue_bulk(producer_token_t const& token, It itemFirst, size_t count)
|
|
{
|
|
return inner_enqueue_bulk<CannotAlloc>(token, itemFirst, count);
|
|
}
|
|
|
|
|
|
|
|
// Attempts to dequeue from the queue.
|
|
|
|
// Returns false if all producer streams appeared empty at the time they
|
|
// were checked (so, the queue is likely but not guaranteed to be empty).
|
|
// Never allocates. Thread-safe.
|
|
template<typename U>
|
|
bool try_dequeue(U& item)
|
|
{
|
|
// Instead of simply trying each producer in turn (which could cause needless contention on the first
|
|
// producer), we score them heuristically.
|
|
size_t nonEmptyCount = 0;
|
|
ProducerBase* best = nullptr;
|
|
size_t bestSize = 0;
|
|
for (auto ptr = producerListTail.load(std::memory_order_acquire); nonEmptyCount < 3 && ptr != nullptr; ptr = ptr->next_prod()) {
|
|
auto size = ptr->size_approx();
|
|
if (size > 0) {
|
|
if (size > bestSize) {
|
|
bestSize = size;
|
|
best = ptr;
|
|
}
|
|
++nonEmptyCount;
|
|
}
|
|
|
|
}
|
|
|
|
// If there was at least one non-empty queue but it appears empty at the time
|
|
// we try to dequeue from it, we need to make sure every queue's been tried
|
|
if (nonEmptyCount > 0) {
|
|
if ((details::likely)(best->dequeue(item))) {
|
|
return true;
|
|
}
|
|
for (auto ptr = producerListTail.load(std::memory_order_acquire); ptr != nullptr; ptr = ptr->next_prod()) {
|
|
if (ptr != best && ptr->dequeue(item)) {
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// Attempts to dequeue from the queue.
|
|
// Returns false if all producer streams appeared empty at the time they
|
|
// were checked (so, the queue is likely but not guaranteed to be empty).
|
|
// This differs from the try_dequeue(item) method in that this one does
|
|
// not attempt to reduce contention by interleaving the order that producer
|
|
// streams are dequeued from. So, using this method can reduce overall throughput
|
|
// under contention, but will give more predictable results in single-threaded
|
|
// consumer scenarios. This is mostly only useful for internal unit tests.
|
|
// Never allocates. Thread-safe.
|
|
template<typename U>
|
|
bool try_dequeue_non_interleaved(U& item)
|
|
{
|
|
for (auto ptr = producerListTail.load(std::memory_order_acquire); ptr != nullptr; ptr = ptr->next_prod()) {
|
|
if (ptr->dequeue(item)) {
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// Attempts to dequeue from the queue using an explicit consumer token.
|
|
// Returns false if all producer streams appeared empty at the time they
|
|
// were checked (so, the queue is likely but not guaranteed to be empty).
|
|
// Never allocates. Thread-safe.
|
|
template<typename U>
|
|
|
|
bool try_dequeue(consumer_token_t& token, U& item)
|
|
{
|
|
// The idea is roughly as follows:
|
|
// Every 256 items from one producer, make everyone rotate (increase the global offset) -> this means the highest efficiency consumer dictates the rotation speed of everyone else, more or less
|
|
// If you see that the global offset has changed, you must reset your consumption counter and move to your designated place
|
|
// If there's no items where you're supposed to be, keep moving until you find a producer with some items
|
|
// If the global offset has not changed but you've run out of items to consume, move over from your current position until you find an producer with something in it
|
|
|
|
if (token.desiredProducer == nullptr || token.lastKnownGlobalOffset != globalExplicitConsumerOffset.load(std::memory_order_relaxed)) {
|
|
if (!update_current_producer_after_rotation(token)) {
|
|
|
|
return false;
|
|
}
|
|
}
|
|
|
|
// If there was at least one non-empty queue but it appears empty at the time
|
|
// we try to dequeue from it, we need to make sure every queue's been tried
|
|
if (static_cast<ProducerBase*>(token.currentProducer)->dequeue(item)) {
|
|
if (++token.itemsConsumedFromCurrent == EXPLICIT_CONSUMER_CONSUMPTION_QUOTA_BEFORE_ROTATE) {
|
|
globalExplicitConsumerOffset.fetch_add(1, std::memory_order_relaxed);
|
|
}
|
|
return true;
|
|
}
|
|
|
|
auto tail = producerListTail.load(std::memory_order_acquire);
|
|
auto ptr = static_cast<ProducerBase*>(token.currentProducer)->next_prod();
|
|
if (ptr == nullptr) {
|
|
ptr = tail;
|
|
}
|
|
while (ptr != static_cast<ProducerBase*>(token.currentProducer)) {
|
|
if (ptr->dequeue(item)) {
|
|
token.currentProducer = ptr;
|
|
token.itemsConsumedFromCurrent = 1;
|
|
return true;
|
|
}
|
|
ptr = ptr->next_prod();
|
|
if (ptr == nullptr) {
|
|
ptr = tail;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// Attempts to dequeue several elements from the queue.
|
|
// Returns the number of items actually dequeued.
|
|
// Returns 0 if all producer streams appeared empty at the time they
|
|
// were checked (so, the queue is likely but not guaranteed to be empty).
|
|
// Never allocates. Thread-safe.
|
|
template<typename It>
|
|
size_t try_dequeue_bulk(It itemFirst, size_t max)
|
|
{
|
|
size_t count = 0;
|
|
for (auto ptr = producerListTail.load(std::memory_order_acquire); ptr != nullptr; ptr = ptr->next_prod()) {
|
|
count += ptr->dequeue_bulk(itemFirst, max - count);
|
|
if (count == max) {
|
|
break;
|
|
}
|
|
}
|
|
return count;
|
|
}
|
|
|
|
// Attempts to dequeue several elements from the queue using an explicit consumer token.
|
|
// Returns the number of items actually dequeued.
|
|
// Returns 0 if all producer streams appeared empty at the time they
|
|
// were checked (so, the queue is likely but not guaranteed to be empty).
|
|
// Never allocates. Thread-safe.
|
|
template<typename It>
|
|
size_t try_dequeue_bulk(consumer_token_t& token, It itemFirst, size_t max)
|
|
{
|
|
if (token.desiredProducer == nullptr || token.lastKnownGlobalOffset != globalExplicitConsumerOffset.load(std::memory_order_relaxed)) {
|
|
if (!update_current_producer_after_rotation(token)) {
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
|
|
size_t count = static_cast<ProducerBase*>(token.currentProducer)->dequeue_bulk(itemFirst, max);
|
|
if (count == max) {
|
|
if ((token.itemsConsumedFromCurrent += static_cast<std::uint32_t>(max)) >= EXPLICIT_CONSUMER_CONSUMPTION_QUOTA_BEFORE_ROTATE) {
|
|
globalExplicitConsumerOffset.fetch_add(1, std::memory_order_relaxed);
|
|
}
|
|
return max;
|
|
}
|
|
token.itemsConsumedFromCurrent += static_cast<std::uint32_t>(count);
|
|
max -= count;
|
|
|
|
|
|
auto tail = producerListTail.load(std::memory_order_acquire);
|
|
auto ptr = static_cast<ProducerBase*>(token.currentProducer)->next_prod();
|
|
if (ptr == nullptr) {
|
|
ptr = tail;
|
|
}
|
|
|
|
while (ptr != static_cast<ProducerBase*>(token.currentProducer)) {
|
|
auto dequeued = ptr->dequeue_bulk(itemFirst, max);
|
|
count += dequeued;
|
|
if (dequeued != 0) {
|
|
token.currentProducer = ptr;
|
|
token.itemsConsumedFromCurrent = static_cast<std::uint32_t>(dequeued);
|
|
}
|
|
if (dequeued == max) {
|
|
break;
|
|
}
|
|
max -= dequeued;
|
|
ptr = ptr->next_prod();
|
|
if (ptr == nullptr) {
|
|
ptr = tail;
|
|
}
|
|
}
|
|
return count;
|
|
}
|
|
|
|
|
|
|
|
// Attempts to dequeue from a specific producer's inner queue.
|
|
// If you happen to know which producer you want to dequeue from, this
|
|
// is significantly faster than using the general-case try_dequeue methods.
|
|
// Returns false if the producer's queue appeared empty at the time it
|
|
// was checked (so, the queue is likely but not guaranteed to be empty).
|
|
// Never allocates. Thread-safe.
|
|
template<typename U>
|
|
inline bool try_dequeue_from_producer(producer_token_t const& producer, U& item)
|
|
{
|
|
return static_cast<ExplicitProducer*>(producer.producer)->dequeue(item);
|
|
}
|
|
|
|
// Attempts to dequeue several elements from a specific producer's inner queue.
|
|
// Returns the number of items actually dequeued.
|
|
// If you happen to know which producer you want to dequeue from, this
|
|
// is significantly faster than using the general-case try_dequeue methods.
|
|
// Returns 0 if the producer's queue appeared empty at the time it
|
|
// was checked (so, the queue is likely but not guaranteed to be empty).
|
|
// Never allocates. Thread-safe.
|
|
|
|
template<typename It>
|
|
inline size_t try_dequeue_bulk_from_producer(producer_token_t const& producer, It itemFirst, size_t max)
|
|
{
|
|
return static_cast<ExplicitProducer*>(producer.producer)->dequeue_bulk(itemFirst, max);
|
|
}
|
|
|
|
|
|
// Returns an estimate of the total number of elements currently in the queue. This
|
|
// estimate is only accurate if the queue has completely stabilized before it is called
|
|
// (i.e. all enqueue and dequeue operations have completed and their memory effects are
|
|
// visible on the calling thread, and no further operations start while this method is
|
|
// being called).
|
|
// Thread-safe.
|
|
size_t size_approx() const
|
|
{
|
|
size_t size = 0;
|
|
for (auto ptr = producerListTail.load(std::memory_order_acquire); ptr != nullptr; ptr = ptr->next_prod()) {
|
|
size += ptr->size_approx();
|
|
}
|
|
return size;
|
|
}
|
|
|
|
|
|
// Returns true if the underlying atomic variables used by
|
|
// the queue are lock-free (they should be on most platforms).
|
|
// Thread-safe.
|
|
static constexpr bool is_lock_free()
|
|
{
|
|
return
|
|
details::static_is_lock_free<bool>::value == 2 &&
|
|
details::static_is_lock_free<size_t>::value == 2 &&
|
|
details::static_is_lock_free<std::uint32_t>::value == 2 &&
|
|
details::static_is_lock_free<index_t>::value == 2 &&
|
|
details::static_is_lock_free<void*>::value == 2 &&
|
|
details::static_is_lock_free<typename details::thread_id_converter<details::thread_id_t>::thread_id_numeric_size_t>::value == 2;
|
|
}
|
|
|
|
|
|
private:
|
|
friend struct ProducerToken;
|
|
friend struct ConsumerToken;
|
|
struct ExplicitProducer;
|
|
friend struct ExplicitProducer;
|
|
struct ImplicitProducer;
|
|
friend struct ImplicitProducer;
|
|
friend class ConcurrentQueueTests;
|
|
|
|
enum AllocationMode { CanAlloc, CannotAlloc };
|
|
|
|
|
|
|
|
///////////////////////////////
|
|
// Queue methods
|
|
///////////////////////////////
|
|
|
|
template<AllocationMode canAlloc, typename U>
|
|
inline bool inner_enqueue(producer_token_t const& token, U&& element)
|
|
{
|
|
return static_cast<ExplicitProducer*>(token.producer)->ConcurrentQueue::ExplicitProducer::template enqueue<canAlloc>(std::forward<U>(element));
|
|
}
|
|
|
|
template<AllocationMode canAlloc, typename U>
|
|
inline bool inner_enqueue(U&& element)
|
|
{
|
|
auto producer = get_or_add_implicit_producer();
|
|
return producer == nullptr ? false : producer->ConcurrentQueue::ImplicitProducer::template enqueue<canAlloc>(std::forward<U>(element));
|
|
}
|
|
|
|
template<AllocationMode canAlloc, typename It>
|
|
inline bool inner_enqueue_bulk(producer_token_t const& token, It itemFirst, size_t count)
|
|
{
|
|
return static_cast<ExplicitProducer*>(token.producer)->ConcurrentQueue::ExplicitProducer::template enqueue_bulk<canAlloc>(itemFirst, count);
|
|
}
|
|
|
|
template<AllocationMode canAlloc, typename It>
|
|
inline bool inner_enqueue_bulk(It itemFirst, size_t count)
|
|
{
|
|
auto producer = get_or_add_implicit_producer();
|
|
return producer == nullptr ? false : producer->ConcurrentQueue::ImplicitProducer::template enqueue_bulk<canAlloc>(itemFirst, count);
|
|
}
|
|
|
|
inline bool update_current_producer_after_rotation(consumer_token_t& token)
|
|
{
|
|
// Ah, there's been a rotation, figure out where we should be!
|
|
auto tail = producerListTail.load(std::memory_order_acquire);
|
|
if (token.desiredProducer == nullptr && tail == nullptr) {
|
|
return false;
|
|
}
|
|
auto prodCount = producerCount.load(std::memory_order_relaxed);
|
|
auto globalOffset = globalExplicitConsumerOffset.load(std::memory_order_relaxed);
|
|
if ((details::unlikely)(token.desiredProducer == nullptr)) {
|
|
// Aha, first time we're dequeueing anything.
|
|
// Figure out our local position
|
|
// Note: offset is from start, not end, but we're traversing from end -- subtract from count first
|
|
std::uint32_t offset = prodCount - 1 - (token.initialOffset % prodCount);
|
|
token.desiredProducer = tail;
|
|
for (std::uint32_t i = 0; i != offset; ++i) {
|
|
token.desiredProducer = static_cast<ProducerBase*>(token.desiredProducer)->next_prod();
|
|
if (token.desiredProducer == nullptr) {
|
|
token.desiredProducer = tail;
|
|
}
|
|
}
|
|
}
|
|
|
|
std::uint32_t delta = globalOffset - token.lastKnownGlobalOffset;
|
|
if (delta >= prodCount) {
|
|
delta = delta % prodCount;
|
|
}
|
|
for (std::uint32_t i = 0; i != delta; ++i) {
|
|
token.desiredProducer = static_cast<ProducerBase*>(token.desiredProducer)->next_prod();
|
|
if (token.desiredProducer == nullptr) {
|
|
token.desiredProducer = tail;
|
|
}
|
|
}
|
|
|
|
token.lastKnownGlobalOffset = globalOffset;
|
|
token.currentProducer = token.desiredProducer;
|
|
token.itemsConsumedFromCurrent = 0;
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
///////////////////////////
|
|
// Free list
|
|
///////////////////////////
|
|
|
|
template <typename N>
|
|
struct FreeListNode
|
|
{
|
|
FreeListNode() : freeListRefs(0), freeListNext(nullptr) { }
|
|
|
|
std::atomic<std::uint32_t> freeListRefs;
|
|
std::atomic<N*> freeListNext;
|
|
};
|
|
|
|
// A simple CAS-based lock-free free list. Not the fastest thing in the world under heavy contention, but
|
|
|
|
// simple and correct (assuming nodes are never freed until after the free list is destroyed), and fairly
|
|
// speedy under low contention.
|
|
template<typename N> // N must inherit FreeListNode or have the same fields (and initialization of them)
|
|
struct FreeList
|
|
{
|
|
FreeList() : freeListHead(nullptr) { }
|
|
FreeList(FreeList&& other) : freeListHead(other.freeListHead.load(std::memory_order_relaxed)) { other.freeListHead.store(nullptr, std::memory_order_relaxed); }
|
|
void swap(FreeList& other) { details::swap_relaxed(freeListHead, other.freeListHead); }
|
|
|
|
FreeList(FreeList const&) MOODYCAMEL_DELETE_FUNCTION;
|
|
|
|
FreeList& operator=(FreeList const&) MOODYCAMEL_DELETE_FUNCTION;
|
|
|
|
inline void add(N* node)
|
|
{
|
|
#ifdef MCDBGQ_NOLOCKFREE_FREELIST
|
|
debug::DebugLock lock(mutex);
|
|
#endif
|
|
// We know that the should-be-on-freelist bit is 0 at this point, so it's safe to
|
|
// set it using a fetch_add
|
|
if (node->freeListRefs.fetch_add(SHOULD_BE_ON_FREELIST, std::memory_order_acq_rel) == 0) {
|
|
// Oh look! We were the last ones referencing this node, and we know
|
|
// we want to add it to the free list, so let's do it!
|
|
add_knowing_refcount_is_zero(node);
|
|
}
|
|
}
|
|
|
|
inline N* try_get()
|
|
{
|
|
#ifdef MCDBGQ_NOLOCKFREE_FREELIST
|
|
debug::DebugLock lock(mutex);
|
|
#endif
|
|
auto head = freeListHead.load(std::memory_order_acquire);
|
|
while (head != nullptr) {
|
|
auto prevHead = head;
|
|
auto refs = head->freeListRefs.load(std::memory_order_relaxed);
|
|
if ((refs & REFS_MASK) == 0 || !head->freeListRefs.compare_exchange_strong(refs, refs + 1, std::memory_order_acquire, std::memory_order_relaxed)) {
|
|
|
|
head = freeListHead.load(std::memory_order_acquire);
|
|
continue;
|
|
}
|
|
|
|
// Good, reference count has been incremented (it wasn't at zero), which means we can read the
|
|
// next and not worry about it changing between now and the time we do the CAS
|
|
auto next = head->freeListNext.load(std::memory_order_relaxed);
|
|
if (freeListHead.compare_exchange_strong(head, next, std::memory_order_acquire, std::memory_order_relaxed)) {
|
|
// Yay, got the node. This means it was on the list, which means shouldBeOnFreeList must be false no
|
|
// matter the refcount (because nobody else knows it's been taken off yet, it can't have been put back on).
|
|
|
|
assert((head->freeListRefs.load(std::memory_order_relaxed) & SHOULD_BE_ON_FREELIST) == 0);
|
|
|
|
// Decrease refcount twice, once for our ref, and once for the list's ref
|
|
head->freeListRefs.fetch_sub(2, std::memory_order_release);
|
|
return head;
|
|
}
|
|
|
|
|
|
// OK, the head must have changed on us, but we still need to decrease the refcount we increased.
|
|
// Note that we don't need to release any memory effects, but we do need to ensure that the reference
|
|
// count decrement happens-after the CAS on the head.
|
|
refs = prevHead->freeListRefs.fetch_sub(1, std::memory_order_acq_rel);
|
|
if (refs == SHOULD_BE_ON_FREELIST + 1) {
|
|
add_knowing_refcount_is_zero(prevHead);
|
|
}
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
|
|
// Useful for traversing the list when there's no contention (e.g. to destroy remaining nodes)
|
|
N* head_unsafe() const { return freeListHead.load(std::memory_order_relaxed); }
|
|
|
|
private:
|
|
inline void add_knowing_refcount_is_zero(N* node)
|
|
{
|
|
// Since the refcount is zero, and nobody can increase it once it's zero (except us, and we run
|
|
// only one copy of this method per node at a time, i.e. the single thread case), then we know
|
|
// we can safely change the next pointer of the node; however, once the refcount is back above
|
|
// zero, then other threads could increase it (happens under heavy contention, when the refcount
|
|
// goes to zero in between a load and a refcount increment of a node in try_get, then back up to
|
|
// something non-zero, then the refcount increment is done by the other thread) -- so, if the CAS
|
|
// to add the node to the actual list fails, decrease the refcount and leave the add operation to
|
|
// the next thread who puts the refcount back at zero (which could be us, hence the loop).
|
|
auto head = freeListHead.load(std::memory_order_relaxed);
|
|
while (true) {
|
|
node->freeListNext.store(head, std::memory_order_relaxed);
|
|
node->freeListRefs.store(1, std::memory_order_release);
|
|
if (!freeListHead.compare_exchange_strong(head, node, std::memory_order_release, std::memory_order_relaxed)) {
|
|
// Hmm, the add failed, but we can only try again when the refcount goes back to zero
|
|
if (node->freeListRefs.fetch_add(SHOULD_BE_ON_FREELIST - 1, std::memory_order_release) == 1) {
|
|
continue;
|
|
}
|
|
}
|
|
|
|
return;
|
|
}
|
|
}
|
|
|
|
private:
|
|
// Implemented like a stack, but where node order doesn't matter (nodes are inserted out of order under contention)
|
|
std::atomic<N*> freeListHead;
|
|
|
|
static const std::uint32_t REFS_MASK = 0x7FFFFFFF;
|
|
static const std::uint32_t SHOULD_BE_ON_FREELIST = 0x80000000;
|
|
|
|
#ifdef MCDBGQ_NOLOCKFREE_FREELIST
|
|
debug::DebugMutex mutex;
|
|
#endif
|
|
};
|
|
|
|
|
|
///////////////////////////
|
|
// Block
|
|
///////////////////////////
|
|
|
|
|
|
enum InnerQueueContext { implicit_context = 0, explicit_context = 1 };
|
|
|
|
struct Block
|
|
{
|
|
Block()
|
|
: next(nullptr), elementsCompletelyDequeued(0), freeListRefs(0), freeListNext(nullptr), dynamicallyAllocated(true)
|
|
{
|
|
#ifdef MCDBGQ_TRACKMEM
|
|
owner = nullptr;
|
|
#endif
|
|
}
|
|
|
|
template<InnerQueueContext context>
|
|
inline bool is_empty() const
|
|
{
|
|
MOODYCAMEL_CONSTEXPR_IF (context == explicit_context && BLOCK_SIZE <= EXPLICIT_BLOCK_EMPTY_COUNTER_THRESHOLD) {
|
|
// Check flags
|
|
for (size_t i = 0; i < BLOCK_SIZE; ++i) {
|
|
if (!emptyFlags[i].load(std::memory_order_relaxed)) {
|
|
return false;
|
|
}
|
|
}
|
|
|
|
// Aha, empty; make sure we have all other memory effects that happened before the empty flags were set
|
|
std::atomic_thread_fence(std::memory_order_acquire);
|
|
return true;
|
|
}
|
|
else {
|
|
// Check counter
|
|
if (elementsCompletelyDequeued.load(std::memory_order_relaxed) == BLOCK_SIZE) {
|
|
std::atomic_thread_fence(std::memory_order_acquire);
|
|
return true;
|
|
}
|
|
assert(elementsCompletelyDequeued.load(std::memory_order_relaxed) <= BLOCK_SIZE);
|
|
return false;
|
|
}
|
|
}
|
|
|
|
// Returns true if the block is now empty (does not apply in explicit context)
|
|
|
|
template<InnerQueueContext context>
|
|
inline bool set_empty(MOODYCAMEL_MAYBE_UNUSED index_t i)
|
|
{
|
|
MOODYCAMEL_CONSTEXPR_IF (context == explicit_context && BLOCK_SIZE <= EXPLICIT_BLOCK_EMPTY_COUNTER_THRESHOLD) {
|
|
// Set flag
|
|
assert(!emptyFlags[BLOCK_SIZE - 1 - static_cast<size_t>(i & static_cast<index_t>(BLOCK_SIZE - 1))].load(std::memory_order_relaxed));
|
|
emptyFlags[BLOCK_SIZE - 1 - static_cast<size_t>(i & static_cast<index_t>(BLOCK_SIZE - 1))].store(true, std::memory_order_release);
|
|
return false;
|
|
}
|
|
else {
|
|
// Increment counter
|
|
auto prevVal = elementsCompletelyDequeued.fetch_add(1, std::memory_order_release);
|
|
assert(prevVal < BLOCK_SIZE);
|
|
return prevVal == BLOCK_SIZE - 1;
|
|
}
|
|
}
|
|
|
|
// Sets multiple contiguous item statuses to 'empty' (assumes no wrapping and count > 0).
|
|
// Returns true if the block is now empty (does not apply in explicit context).
|
|
template<InnerQueueContext context>
|
|
inline bool set_many_empty(MOODYCAMEL_MAYBE_UNUSED index_t i, size_t count)
|
|
{
|
|
MOODYCAMEL_CONSTEXPR_IF (context == explicit_context && BLOCK_SIZE <= EXPLICIT_BLOCK_EMPTY_COUNTER_THRESHOLD) {
|
|
// Set flags
|
|
std::atomic_thread_fence(std::memory_order_release);
|
|
i = BLOCK_SIZE - 1 - static_cast<size_t>(i & static_cast<index_t>(BLOCK_SIZE - 1)) - count + 1;
|
|
|
|
for (size_t j = 0; j != count; ++j) {
|
|
assert(!emptyFlags[i + j].load(std::memory_order_relaxed));
|
|
emptyFlags[i + j].store(true, std::memory_order_relaxed);
|
|
}
|
|
return false;
|
|
}
|
|
else {
|
|
// Increment counter
|
|
|
|
auto prevVal = elementsCompletelyDequeued.fetch_add(count, std::memory_order_release);
|
|
assert(prevVal + count <= BLOCK_SIZE);
|
|
return prevVal + count == BLOCK_SIZE;
|
|
}
|
|
}
|
|
|
|
template<InnerQueueContext context>
|
|
inline void set_all_empty()
|
|
{
|
|
MOODYCAMEL_CONSTEXPR_IF (context == explicit_context && BLOCK_SIZE <= EXPLICIT_BLOCK_EMPTY_COUNTER_THRESHOLD) {
|
|
// Set all flags
|
|
for (size_t i = 0; i != BLOCK_SIZE; ++i) {
|
|
emptyFlags[i].store(true, std::memory_order_relaxed);
|
|
}
|
|
}
|
|
else {
|
|
// Reset counter
|
|
elementsCompletelyDequeued.store(BLOCK_SIZE, std::memory_order_relaxed);
|
|
}
|
|
}
|
|
|
|
template<InnerQueueContext context>
|
|
inline void reset_empty()
|
|
{
|
|
MOODYCAMEL_CONSTEXPR_IF (context == explicit_context && BLOCK_SIZE <= EXPLICIT_BLOCK_EMPTY_COUNTER_THRESHOLD) {
|
|
// Reset flags
|
|
for (size_t i = 0; i != BLOCK_SIZE; ++i) {
|
|
emptyFlags[i].store(false, std::memory_order_relaxed);
|
|
}
|
|
}
|
|
else {
|
|
// Reset counter
|
|
elementsCompletelyDequeued.store(0, std::memory_order_relaxed);
|
|
}
|
|
}
|
|
|
|
|
|
inline T* operator[](index_t idx) MOODYCAMEL_NOEXCEPT { return static_cast<T*>(static_cast<void*>(elements)) + static_cast<size_t>(idx & static_cast<index_t>(BLOCK_SIZE - 1)); }
|
|
inline T const* operator[](index_t idx) const MOODYCAMEL_NOEXCEPT { return static_cast<T const*>(static_cast<void const*>(elements)) + static_cast<size_t>(idx & static_cast<index_t>(BLOCK_SIZE - 1)); }
|
|
|
|
private:
|
|
static_assert(std::alignment_of<T>::value <= sizeof(T), "The queue does not support types with an alignment greater than their size at this time");
|
|
MOODYCAMEL_ALIGNED_TYPE_LIKE(char[sizeof(T) * BLOCK_SIZE], T) elements;
|
|
public:
|
|
Block* next;
|
|
std::atomic<size_t> elementsCompletelyDequeued;
|
|
std::atomic<bool> emptyFlags[BLOCK_SIZE <= EXPLICIT_BLOCK_EMPTY_COUNTER_THRESHOLD ? BLOCK_SIZE : 1];
|
|
public:
|
|
|
|
std::atomic<std::uint32_t> freeListRefs;
|
|
std::atomic<Block*> freeListNext;
|
|
bool dynamicallyAllocated; // Perhaps a better name for this would be 'isNotPartOfInitialBlockPool'
|
|
|
|
#ifdef MCDBGQ_TRACKMEM
|
|
void* owner;
|
|
#endif
|
|
};
|
|
static_assert(std::alignment_of<Block>::value >= std::alignment_of<T>::value, "Internal error: Blocks must be at least as aligned as the type they are wrapping");
|
|
|
|
|
|
#ifdef MCDBGQ_TRACKMEM
|
|
public:
|
|
struct MemStats;
|
|
private:
|
|
#endif
|
|
|
|
///////////////////////////
|
|
// Producer base
|
|
///////////////////////////
|
|
|
|
struct ProducerBase : public details::ConcurrentQueueProducerTypelessBase
|
|
{
|
|
ProducerBase(ConcurrentQueue* parent_, bool isExplicit_) :
|
|
tailIndex(0),
|
|
headIndex(0),
|
|
dequeueOptimisticCount(0),
|
|
dequeueOvercommit(0),
|
|
tailBlock(nullptr),
|
|
isExplicit(isExplicit_),
|
|
parent(parent_)
|
|
{
|
|
}
|
|
|
|
virtual ~ProducerBase() { }
|
|
|
|
template<typename U>
|
|
inline bool dequeue(U& element)
|
|
{
|
|
if (isExplicit) {
|
|
return static_cast<ExplicitProducer*>(this)->dequeue(element);
|
|
}
|
|
else {
|
|
return static_cast<ImplicitProducer*>(this)->dequeue(element);
|
|
}
|
|
}
|
|
|
|
|
|
template<typename It>
|
|
inline size_t dequeue_bulk(It& itemFirst, size_t max)
|
|
{
|
|
if (isExplicit) {
|
|
return static_cast<ExplicitProducer*>(this)->dequeue_bulk(itemFirst, max);
|
|
}
|
|
else {
|
|
return static_cast<ImplicitProducer*>(this)->dequeue_bulk(itemFirst, max);
|
|
}
|
|
}
|
|
|
|
inline ProducerBase* next_prod() const { return static_cast<ProducerBase*>(next); }
|
|
|
|
inline size_t size_approx() const
|
|
{
|
|
auto tail = tailIndex.load(std::memory_order_relaxed);
|
|
auto head = headIndex.load(std::memory_order_relaxed);
|
|
return details::circular_less_than(head, tail) ? static_cast<size_t>(tail - head) : 0;
|
|
}
|
|
|
|
inline index_t getTail() const { return tailIndex.load(std::memory_order_relaxed); }
|
|
protected:
|
|
std::atomic<index_t> tailIndex; // Where to enqueue to next
|
|
std::atomic<index_t> headIndex; // Where to dequeue from next
|
|
|
|
std::atomic<index_t> dequeueOptimisticCount;
|
|
std::atomic<index_t> dequeueOvercommit;
|
|
|
|
Block* tailBlock;
|
|
|
|
public:
|
|
bool isExplicit;
|
|
ConcurrentQueue* parent;
|
|
|
|
protected:
|
|
#ifdef MCDBGQ_TRACKMEM
|
|
friend struct MemStats;
|
|
#endif
|
|
|
|
};
|
|
|
|
|
|
///////////////////////////
|
|
// Explicit queue
|
|
///////////////////////////
|
|
|
|
|
|
struct ExplicitProducer : public ProducerBase
|
|
{
|
|
explicit ExplicitProducer(ConcurrentQueue* parent_) :
|
|
ProducerBase(parent_, true),
|
|
blockIndex(nullptr),
|
|
pr_blockIndexSlotsUsed(0),
|
|
pr_blockIndexSize(EXPLICIT_INITIAL_INDEX_SIZE >> 1),
|
|
pr_blockIndexFront(0),
|
|
pr_blockIndexEntries(nullptr),
|
|
pr_blockIndexRaw(nullptr)
|
|
{
|
|
size_t poolBasedIndexSize = details::ceil_to_pow_2(parent_->initialBlockPoolSize) >> 1;
|
|
if (poolBasedIndexSize > pr_blockIndexSize) {
|
|
pr_blockIndexSize = poolBasedIndexSize;
|
|
}
|
|
|
|
new_block_index(0); // This creates an index with double the number of current entries, i.e. EXPLICIT_INITIAL_INDEX_SIZE
|
|
}
|
|
|
|
~ExplicitProducer()
|
|
{
|
|
// Destruct any elements not yet dequeued.
|
|
// Since we're in the destructor, we can assume all elements
|
|
// are either completely dequeued or completely not (no halfways).
|
|
if (this->tailBlock != nullptr) { // Note this means there must be a block index too
|
|
// First find the block that's partially dequeued, if any
|
|
Block* halfDequeuedBlock = nullptr;
|
|
if ((this->headIndex.load(std::memory_order_relaxed) & static_cast<index_t>(BLOCK_SIZE - 1)) != 0) {
|
|
// The head's not on a block boundary, meaning a block somewhere is partially dequeued
|
|
// (or the head block is the tail block and was fully dequeued, but the head/tail are still not on a boundary)
|
|
size_t i = (pr_blockIndexFront - pr_blockIndexSlotsUsed) & (pr_blockIndexSize - 1);
|
|
while (details::circular_less_than<index_t>(pr_blockIndexEntries[i].base + BLOCK_SIZE, this->headIndex.load(std::memory_order_relaxed))) {
|
|
i = (i + 1) & (pr_blockIndexSize - 1);
|
|
}
|
|
assert(details::circular_less_than<index_t>(pr_blockIndexEntries[i].base, this->headIndex.load(std::memory_order_relaxed)));
|
|
halfDequeuedBlock = pr_blockIndexEntries[i].block;
|
|
}
|
|
|
|
// Start at the head block (note the first line in the loop gives us the head from the tail on the first iteration)
|
|
auto block = this->tailBlock;
|
|
do {
|
|
block = block->next;
|
|
if (block->ConcurrentQueue::Block::template is_empty<explicit_context>()) {
|
|
continue;
|
|
}
|
|
|
|
size_t i = 0; // Offset into block
|
|
if (block == halfDequeuedBlock) {
|
|
i = static_cast<size_t>(this->headIndex.load(std::memory_order_relaxed) & static_cast<index_t>(BLOCK_SIZE - 1));
|
|
}
|
|
|
|
// Walk through all the items in the block; if this is the tail block, we need to stop when we reach the tail index
|
|
auto lastValidIndex = (this->tailIndex.load(std::memory_order_relaxed) & static_cast<index_t>(BLOCK_SIZE - 1)) == 0 ? BLOCK_SIZE : static_cast<size_t>(this->tailIndex.load(std::memory_order_relaxed) & static_cast<index_t>(BLOCK_SIZE - 1));
|
|
while (i != BLOCK_SIZE && (block != this->tailBlock || i != lastValidIndex)) {
|
|
(*block)[i++]->~T();
|
|
}
|
|
} while (block != this->tailBlock);
|
|
}
|
|
|
|
// Destroy all blocks that we own
|
|
if (this->tailBlock != nullptr) {
|
|
auto block = this->tailBlock;
|
|
do {
|
|
auto nextBlock = block->next;
|
|
this->parent->add_block_to_free_list(block);
|
|
block = nextBlock;
|
|
} while (block != this->tailBlock);
|
|
}
|
|
|
|
// Destroy the block indices
|
|
auto header = static_cast<BlockIndexHeader*>(pr_blockIndexRaw);
|
|
while (header != nullptr) {
|
|
auto prev = static_cast<BlockIndexHeader*>(header->prev);
|
|
header->~BlockIndexHeader();
|
|
(Traits::free)(header);
|
|
|
|
header = prev;
|
|
}
|
|
}
|
|
|
|
template<AllocationMode allocMode, typename U>
|
|
inline bool enqueue(U&& element)
|
|
{
|
|
index_t currentTailIndex = this->tailIndex.load(std::memory_order_relaxed);
|
|
index_t newTailIndex = 1 + currentTailIndex;
|
|
if ((currentTailIndex & static_cast<index_t>(BLOCK_SIZE - 1)) == 0) {
|
|
// We reached the end of a block, start a new one
|
|
auto startBlock = this->tailBlock;
|
|
auto originalBlockIndexSlotsUsed = pr_blockIndexSlotsUsed;
|
|
if (this->tailBlock != nullptr && this->tailBlock->next->ConcurrentQueue::Block::template is_empty<explicit_context>()) {
|
|
// We can re-use the block ahead of us, it's empty!
|
|
this->tailBlock = this->tailBlock->next;
|
|
this->tailBlock->ConcurrentQueue::Block::template reset_empty<explicit_context>();
|
|
|
|
// We'll put the block on the block index (guaranteed to be room since we're conceptually removing the
|
|
// last block from it first -- except instead of removing then adding, we can just overwrite).
|
|
// Note that there must be a valid block index here, since even if allocation failed in the ctor,
|
|
// it would have been re-attempted when adding the first block to the queue; since there is such
|
|
// a block, a block index must have been successfully allocated.
|
|
}
|
|
else {
|
|
// Whatever head value we see here is >= the last value we saw here (relatively),
|
|
// and <= its current value. Since we have the most recent tail, the head must be
|
|
// <= to it.
|
|
auto head = this->headIndex.load(std::memory_order_relaxed);
|
|
assert(!details::circular_less_than<index_t>(currentTailIndex, head));
|
|
if (!details::circular_less_than<index_t>(head, currentTailIndex + BLOCK_SIZE)
|
|
|| (MAX_SUBQUEUE_SIZE != details::const_numeric_max<size_t>::value && (MAX_SUBQUEUE_SIZE == 0 || MAX_SUBQUEUE_SIZE - BLOCK_SIZE < currentTailIndex - head))) {
|
|
// We can't enqueue in another block because there's not enough leeway -- the
|
|
// tail could surpass the head by the time the block fills up! (Or we'll exceed
|
|
// the size limit, if the second part of the condition was true.)
|
|
return false;
|
|
}
|
|
// We're going to need a new block; check that the block index has room
|
|
if (pr_blockIndexRaw == nullptr || pr_blockIndexSlotsUsed == pr_blockIndexSize) {
|
|
// Hmm, the circular block index is already full -- we'll need
|
|
// to allocate a new index. Note pr_blockIndexRaw can only be nullptr if
|
|
// the initial allocation failed in the constructor.
|
|
|
|
MOODYCAMEL_CONSTEXPR_IF (allocMode == CannotAlloc) {
|
|
return false;
|
|
}
|
|
else if (!new_block_index(pr_blockIndexSlotsUsed)) {
|
|
return false;
|
|
}
|
|
}
|
|
|
|
// Insert a new block in the circular linked list
|
|
auto newBlock = this->parent->ConcurrentQueue::template requisition_block<allocMode>();
|
|
if (newBlock == nullptr) {
|
|
return false;
|
|
}
|
|
#ifdef MCDBGQ_TRACKMEM
|
|
newBlock->owner = this;
|
|
#endif
|
|
newBlock->ConcurrentQueue::Block::template reset_empty<explicit_context>();
|
|
if (this->tailBlock == nullptr) {
|
|
newBlock->next = newBlock;
|
|
}
|
|
else {
|
|
newBlock->next = this->tailBlock->next;
|
|
this->tailBlock->next = newBlock;
|
|
}
|
|
this->tailBlock = newBlock;
|
|
++pr_blockIndexSlotsUsed;
|
|
}
|
|
|
|
MOODYCAMEL_CONSTEXPR_IF (!MOODYCAMEL_NOEXCEPT_CTOR(T, U, new (static_cast<T*>(nullptr)) T(std::forward<U>(element)))) {
|
|
// The constructor may throw. We want the element not to appear in the queue in
|
|
// that case (without corrupting the queue):
|
|
MOODYCAMEL_TRY {
|
|
new ((*this->tailBlock)[currentTailIndex]) T(std::forward<U>(element));
|
|
}
|
|
MOODYCAMEL_CATCH (...) {
|
|
// Revert change to the current block, but leave the new block available
|
|
// for next time
|
|
pr_blockIndexSlotsUsed = originalBlockIndexSlotsUsed;
|
|
this->tailBlock = startBlock == nullptr ? this->tailBlock : startBlock;
|
|
|
|
MOODYCAMEL_RETHROW;
|
|
}
|
|
|
|
}
|
|
else {
|
|
(void)startBlock;
|
|
(void)originalBlockIndexSlotsUsed;
|
|
}
|
|
|
|
// Add block to block index
|
|
auto& entry = blockIndex.load(std::memory_order_relaxed)->entries[pr_blockIndexFront];
|
|
entry.base = currentTailIndex;
|
|
entry.block = this->tailBlock;
|
|
blockIndex.load(std::memory_order_relaxed)->front.store(pr_blockIndexFront, std::memory_order_release);
|
|
pr_blockIndexFront = (pr_blockIndexFront + 1) & (pr_blockIndexSize - 1);
|
|
|
|
MOODYCAMEL_CONSTEXPR_IF (!MOODYCAMEL_NOEXCEPT_CTOR(T, U, new (static_cast<T*>(nullptr)) T(std::forward<U>(element)))) {
|
|
this->tailIndex.store(newTailIndex, std::memory_order_release);
|
|
return true;
|
|
}
|
|
}
|
|
|
|
// Enqueue
|
|
new ((*this->tailBlock)[currentTailIndex]) T(std::forward<U>(element));
|
|
|
|
this->tailIndex.store(newTailIndex, std::memory_order_release);
|
|
return true;
|
|
}
|
|
|
|
template<typename U>
|
|
bool dequeue(U& element)
|
|
{
|
|
auto tail = this->tailIndex.load(std::memory_order_relaxed);
|
|
auto overcommit = this->dequeueOvercommit.load(std::memory_order_relaxed);
|
|
if (details::circular_less_than<index_t>(this->dequeueOptimisticCount.load(std::memory_order_relaxed) - overcommit, tail)) {
|
|
// Might be something to dequeue, let's give it a try
|
|
|
|
// Note that this if is purely for performance purposes in the common case when the queue is
|
|
// empty and the values are eventually consistent -- we may enter here spuriously.
|
|
|
|
// Note that whatever the values of overcommit and tail are, they are not going to change (unless we
|
|
// change them) and must be the same value at this point (inside the if) as when the if condition was
|
|
// evaluated.
|
|
|
|
// We insert an acquire fence here to synchronize-with the release upon incrementing dequeueOvercommit below.
|
|
// This ensures that whatever the value we got loaded into overcommit, the load of dequeueOptisticCount in
|
|
// the fetch_add below will result in a value at least as recent as that (and therefore at least as large).
|
|
// Note that I believe a compiler (signal) fence here would be sufficient due to the nature of fetch_add (all
|
|
// read-modify-write operations are guaranteed to work on the latest value in the modification order), but
|
|
// unfortunately that can't be shown to be correct using only the C++11 standard.
|
|
// See http://stackoverflow.com/questions/18223161/what-are-the-c11-memory-ordering-guarantees-in-this-corner-case
|
|
std::atomic_thread_fence(std::memory_order_acquire);
|
|
|
|
// Increment optimistic counter, then check if it went over the boundary
|
|
auto myDequeueCount = this->dequeueOptimisticCount.fetch_add(1, std::memory_order_relaxed);
|
|
|
|
// Note that since dequeueOvercommit must be <= dequeueOptimisticCount (because dequeueOvercommit is only ever
|
|
// incremented after dequeueOptimisticCount -- this is enforced in the `else` block below), and since we now
|
|
// have a version of dequeueOptimisticCount that is at least as recent as overcommit (due to the release upon
|
|
// incrementing dequeueOvercommit and the acquire above that synchronizes with it), overcommit <= myDequeueCount.
|
|
// However, we can't assert this since both dequeueOptimisticCount and dequeueOvercommit may (independently)
|
|
// overflow; in such a case, though, the logic still holds since the difference between the two is maintained.
|
|
|
|
// Note that we reload tail here in case it changed; it will be the same value as before or greater, since
|
|
// this load is sequenced after (happens after) the earlier load above. This is supported by read-read
|
|
// coherency (as defined in the standard), explained here: http://en.cppreference.com/w/cpp/atomic/memory_order
|
|
tail = this->tailIndex.load(std::memory_order_acquire);
|
|
if ((details::likely)(details::circular_less_than<index_t>(myDequeueCount - overcommit, tail))) {
|
|
// Guaranteed to be at least one element to dequeue!
|
|
|
|
// Get the index. Note that since there's guaranteed to be at least one element, this
|
|
// will never exceed tail. We need to do an acquire-release fence here since it's possible
|
|
// that whatever condition got us to this point was for an earlier enqueued element (that
|
|
// we already see the memory effects for), but that by the time we increment somebody else
|
|
// has incremented it, and we need to see the memory effects for *that* element, which is
|
|
// in such a case is necessarily visible on the thread that incremented it in the first
|
|
// place with the more current condition (they must have acquired a tail that is at least
|
|
// as recent).
|
|
auto index = this->headIndex.fetch_add(1, std::memory_order_acq_rel);
|
|
|
|
|
|
// Determine which block the element is in
|
|
|
|
auto localBlockIndex = blockIndex.load(std::memory_order_acquire);
|
|
auto localBlockIndexHead = localBlockIndex->front.load(std::memory_order_acquire);
|
|
|
|
// We need to be careful here about subtracting and dividing because of index wrap-around.
|
|
// When an index wraps, we need to preserve the sign of the offset when dividing it by the
|
|
// block size (in order to get a correct signed block count offset in all cases):
|
|
auto headBase = localBlockIndex->entries[localBlockIndexHead].base;
|
|
auto blockBaseIndex = index & ~static_cast<index_t>(BLOCK_SIZE - 1);
|
|
auto offset = static_cast<size_t>(static_cast<typename std::make_signed<index_t>::type>(blockBaseIndex - headBase) / static_cast<typename std::make_signed<index_t>::type>(BLOCK_SIZE));
|
|
auto block = localBlockIndex->entries[(localBlockIndexHead + offset) & (localBlockIndex->size - 1)].block;
|
|
|
|
// Dequeue
|
|
auto& el = *((*block)[index]);
|
|
if (!MOODYCAMEL_NOEXCEPT_ASSIGN(T, T&&, element = std::move(el))) {
|
|
// Make sure the element is still fully dequeued and destroyed even if the assignment
|
|
// throws
|
|
struct Guard {
|
|
Block* block;
|
|
index_t index;
|
|
|
|
~Guard()
|
|
{
|
|
(*block)[index]->~T();
|
|
block->ConcurrentQueue::Block::template set_empty<explicit_context>(index);
|
|
}
|
|
} guard = { block, index };
|
|
|
|
element = std::move(el); // NOLINT
|
|
}
|
|
else {
|
|
element = std::move(el); // NOLINT
|
|
el.~T(); // NOLINT
|
|
block->ConcurrentQueue::Block::template set_empty<explicit_context>(index);
|
|
}
|
|
|
|
return true;
|
|
}
|
|
else {
|
|
// Wasn't anything to dequeue after all; make the effective dequeue count eventually consistent
|
|
this->dequeueOvercommit.fetch_add(1, std::memory_order_release); // Release so that the fetch_add on dequeueOptimisticCount is guaranteed to happen before this write
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
template<AllocationMode allocMode, typename It>
|
|
bool MOODYCAMEL_NO_TSAN enqueue_bulk(It itemFirst, size_t count)
|
|
{
|
|
// First, we need to make sure we have enough room to enqueue all of the elements;
|
|
// this means pre-allocating blocks and putting them in the block index (but only if
|
|
// all the allocations succeeded).
|
|
index_t startTailIndex = this->tailIndex.load(std::memory_order_relaxed);
|
|
auto startBlock = this->tailBlock;
|
|
auto originalBlockIndexFront = pr_blockIndexFront;
|
|
auto originalBlockIndexSlotsUsed = pr_blockIndexSlotsUsed;
|
|
|
|
Block* firstAllocatedBlock = nullptr;
|
|
|
|
// Figure out how many blocks we'll need to allocate, and do so
|
|
size_t blockBaseDiff = ((startTailIndex + count - 1) & ~static_cast<index_t>(BLOCK_SIZE - 1)) - ((startTailIndex - 1) & ~static_cast<index_t>(BLOCK_SIZE - 1));
|
|
index_t currentTailIndex = (startTailIndex - 1) & ~static_cast<index_t>(BLOCK_SIZE - 1);
|
|
if (blockBaseDiff > 0) {
|
|
// Allocate as many blocks as possible from ahead
|
|
while (blockBaseDiff > 0 && this->tailBlock != nullptr && this->tailBlock->next != firstAllocatedBlock && this->tailBlock->next->ConcurrentQueue::Block::template is_empty<explicit_context>()) {
|
|
blockBaseDiff -= static_cast<index_t>(BLOCK_SIZE);
|
|
currentTailIndex += static_cast<index_t>(BLOCK_SIZE);
|
|
|
|
this->tailBlock = this->tailBlock->next;
|
|
firstAllocatedBlock = firstAllocatedBlock == nullptr ? this->tailBlock : firstAllocatedBlock;
|
|
|
|
auto& entry = blockIndex.load(std::memory_order_relaxed)->entries[pr_blockIndexFront];
|
|
entry.base = currentTailIndex;
|
|
entry.block = this->tailBlock;
|
|
pr_blockIndexFront = (pr_blockIndexFront + 1) & (pr_blockIndexSize - 1);
|
|
}
|
|
|
|
// Now allocate as many blocks as necessary from the block pool
|
|
while (blockBaseDiff > 0) {
|
|
blockBaseDiff -= static_cast<index_t>(BLOCK_SIZE);
|
|
currentTailIndex += static_cast<index_t>(BLOCK_SIZE);
|
|
|
|
auto head = this->headIndex.load(std::memory_order_relaxed);
|
|
assert(!details::circular_less_than<index_t>(currentTailIndex, head));
|
|
bool full = !details::circular_less_than<index_t>(head, currentTailIndex + BLOCK_SIZE) || (MAX_SUBQUEUE_SIZE != details::const_numeric_max<size_t>::value && (MAX_SUBQUEUE_SIZE == 0 || MAX_SUBQUEUE_SIZE - BLOCK_SIZE < currentTailIndex - head));
|
|
if (pr_blockIndexRaw == nullptr || pr_blockIndexSlotsUsed == pr_blockIndexSize || full) {
|
|
MOODYCAMEL_CONSTEXPR_IF (allocMode == CannotAlloc) {
|
|
// Failed to allocate, undo changes (but keep injected blocks)
|
|
pr_blockIndexFront = originalBlockIndexFront;
|
|
pr_blockIndexSlotsUsed = originalBlockIndexSlotsUsed;
|
|
this->tailBlock = startBlock == nullptr ? firstAllocatedBlock : startBlock;
|
|
return false;
|
|
}
|
|
else if (full || !new_block_index(originalBlockIndexSlotsUsed)) {
|
|
// Failed to allocate, undo changes (but keep injected blocks)
|
|
pr_blockIndexFront = originalBlockIndexFront;
|
|
pr_blockIndexSlotsUsed = originalBlockIndexSlotsUsed;
|
|
this->tailBlock = startBlock == nullptr ? firstAllocatedBlock : startBlock;
|
|
return false;
|
|
|
|
}
|
|
|
|
// pr_blockIndexFront is updated inside new_block_index, so we need to
|
|
// update our fallback value too (since we keep the new index even if we
|
|
// later fail)
|
|
originalBlockIndexFront = originalBlockIndexSlotsUsed;
|
|
|
|
}
|
|
|
|
// Insert a new block in the circular linked list
|
|
auto newBlock = this->parent->ConcurrentQueue::template requisition_block<allocMode>();
|
|
if (newBlock == nullptr) {
|
|
pr_blockIndexFront = originalBlockIndexFront;
|
|
pr_blockIndexSlotsUsed = originalBlockIndexSlotsUsed;
|
|
|
|
this->tailBlock = startBlock == nullptr ? firstAllocatedBlock : startBlock;
|
|
return false;
|
|
}
|
|
|
|
#ifdef MCDBGQ_TRACKMEM
|
|
newBlock->owner = this;
|
|
#endif
|
|
newBlock->ConcurrentQueue::Block::template set_all_empty<explicit_context>();
|
|
if (this->tailBlock == nullptr) {
|
|
newBlock->next = newBlock;
|
|
}
|
|
else {
|
|
newBlock->next = this->tailBlock->next;
|
|
this->tailBlock->next = newBlock;
|
|
}
|
|
this->tailBlock = newBlock;
|
|
firstAllocatedBlock = firstAllocatedBlock == nullptr ? this->tailBlock : firstAllocatedBlock;
|
|
|
|
++pr_blockIndexSlotsUsed;
|
|
|
|
auto& entry = blockIndex.load(std::memory_order_relaxed)->entries[pr_blockIndexFront];
|
|
entry.base = currentTailIndex;
|
|
entry.block = this->tailBlock;
|
|
pr_blockIndexFront = (pr_blockIndexFront + 1) & (pr_blockIndexSize - 1);
|
|
}
|
|
|
|
// Excellent, all allocations succeeded. Reset each block's emptiness before we fill them up, and
|
|
// publish the new block index front
|
|
auto block = firstAllocatedBlock;
|
|
while (true) {
|
|
block->ConcurrentQueue::Block::template reset_empty<explicit_context>();
|
|
if (block == this->tailBlock) {
|
|
break;
|
|
}
|
|
block = block->next;
|
|
}
|
|
|
|
MOODYCAMEL_CONSTEXPR_IF (MOODYCAMEL_NOEXCEPT_CTOR(T, decltype(*itemFirst), new (static_cast<T*>(nullptr)) T(details::deref_noexcept(itemFirst)))) {
|
|
blockIndex.load(std::memory_order_relaxed)->front.store((pr_blockIndexFront - 1) & (pr_blockIndexSize - 1), std::memory_order_release);
|
|
}
|
|
}
|
|
|
|
// Enqueue, one block at a time
|
|
index_t newTailIndex = startTailIndex + static_cast<index_t>(count);
|
|
currentTailIndex = startTailIndex;
|
|
auto endBlock = this->tailBlock;
|
|
this->tailBlock = startBlock;
|
|
assert((startTailIndex & static_cast<index_t>(BLOCK_SIZE - 1)) != 0 || firstAllocatedBlock != nullptr || count == 0);
|
|
if ((startTailIndex & static_cast<index_t>(BLOCK_SIZE - 1)) == 0 && firstAllocatedBlock != nullptr) {
|
|
this->tailBlock = firstAllocatedBlock;
|
|
}
|
|
while (true) {
|
|
|
|
index_t stopIndex = (currentTailIndex & ~static_cast<index_t>(BLOCK_SIZE - 1)) + static_cast<index_t>(BLOCK_SIZE);
|
|
if (details::circular_less_than<index_t>(newTailIndex, stopIndex)) {
|
|
stopIndex = newTailIndex;
|
|
|
|
}
|
|
MOODYCAMEL_CONSTEXPR_IF (MOODYCAMEL_NOEXCEPT_CTOR(T, decltype(*itemFirst), new (static_cast<T*>(nullptr)) T(details::deref_noexcept(itemFirst)))) {
|
|
while (currentTailIndex != stopIndex) {
|
|
new ((*this->tailBlock)[currentTailIndex++]) T(*itemFirst++);
|
|
}
|
|
}
|
|
else {
|
|
MOODYCAMEL_TRY {
|
|
while (currentTailIndex != stopIndex) {
|
|
// Must use copy constructor even if move constructor is available
|
|
// because we may have to revert if there's an exception.
|
|
// Sorry about the horrible templated next line, but it was the only way
|
|
// to disable moving *at compile time*, which is important because a type
|
|
// may only define a (noexcept) move constructor, and so calls to the
|
|
// cctor will not compile, even if they are in an if branch that will never
|
|
// be executed
|
|
new ((*this->tailBlock)[currentTailIndex]) T(details::nomove_if<!MOODYCAMEL_NOEXCEPT_CTOR(T, decltype(*itemFirst), new (static_cast<T*>(nullptr)) T(details::deref_noexcept(itemFirst)))>::eval(*itemFirst));
|
|
++currentTailIndex;
|
|
++itemFirst;
|
|
}
|
|
}
|
|
MOODYCAMEL_CATCH (...) {
|
|
// Oh dear, an exception's been thrown -- destroy the elements that
|
|
// were enqueued so far and revert the entire bulk operation (we'll keep
|
|
// any allocated blocks in our linked list for later, though).
|
|
auto constructedStopIndex = currentTailIndex;
|
|
auto lastBlockEnqueued = this->tailBlock;
|
|
|
|
pr_blockIndexFront = originalBlockIndexFront;
|
|
pr_blockIndexSlotsUsed = originalBlockIndexSlotsUsed;
|
|
this->tailBlock = startBlock == nullptr ? firstAllocatedBlock : startBlock;
|
|
|
|
if (!details::is_trivially_destructible<T>::value) {
|
|
auto block = startBlock;
|
|
if ((startTailIndex & static_cast<index_t>(BLOCK_SIZE - 1)) == 0) {
|
|
block = firstAllocatedBlock;
|
|
}
|
|
currentTailIndex = startTailIndex;
|
|
while (true) {
|
|
stopIndex = (currentTailIndex & ~static_cast<index_t>(BLOCK_SIZE - 1)) + static_cast<index_t>(BLOCK_SIZE);
|
|
if (details::circular_less_than<index_t>(constructedStopIndex, stopIndex)) {
|
|
stopIndex = constructedStopIndex;
|
|
}
|
|
while (currentTailIndex != stopIndex) {
|
|
(*block)[currentTailIndex++]->~T();
|
|
}
|
|
if (block == lastBlockEnqueued) {
|
|
break;
|
|
|
|
}
|
|
block = block->next;
|
|
}
|
|
}
|
|
MOODYCAMEL_RETHROW;
|
|
}
|
|
}
|
|
|
|
if (this->tailBlock == endBlock) {
|
|
assert(currentTailIndex == newTailIndex);
|
|
break;
|
|
}
|
|
this->tailBlock = this->tailBlock->next;
|
|
}
|
|
|
|
MOODYCAMEL_CONSTEXPR_IF (!MOODYCAMEL_NOEXCEPT_CTOR(T, decltype(*itemFirst), new (static_cast<T*>(nullptr)) T(details::deref_noexcept(itemFirst)))) {
|
|
if (firstAllocatedBlock != nullptr)
|
|
|
|
blockIndex.load(std::memory_order_relaxed)->front.store((pr_blockIndexFront - 1) & (pr_blockIndexSize - 1), std::memory_order_release);
|
|
|
|
}
|
|
|
|
this->tailIndex.store(newTailIndex, std::memory_order_release);
|
|
return true;
|
|
}
|
|
|
|
template<typename It>
|
|
size_t dequeue_bulk(It& itemFirst, size_t max)
|
|
{
|
|
auto tail = this->tailIndex.load(std::memory_order_relaxed);
|
|
auto overcommit = this->dequeueOvercommit.load(std::memory_order_relaxed);
|
|
auto desiredCount = static_cast<size_t>(tail - (this->dequeueOptimisticCount.load(std::memory_order_relaxed) - overcommit));
|
|
if (details::circular_less_than<size_t>(0, desiredCount)) {
|
|
desiredCount = desiredCount < max ? desiredCount : max;
|
|
std::atomic_thread_fence(std::memory_order_acquire);
|
|
|
|
auto myDequeueCount = this->dequeueOptimisticCount.fetch_add(desiredCount, std::memory_order_relaxed);
|
|
|
|
tail = this->tailIndex.load(std::memory_order_acquire);
|
|
auto actualCount = static_cast<size_t>(tail - (myDequeueCount - overcommit));
|
|
if (details::circular_less_than<size_t>(0, actualCount)) {
|
|
actualCount = desiredCount < actualCount ? desiredCount : actualCount;
|
|
if (actualCount < desiredCount) {
|
|
this->dequeueOvercommit.fetch_add(desiredCount - actualCount, std::memory_order_release);
|
|
}
|
|
|
|
// Get the first index. Note that since there's guaranteed to be at least actualCount elements, this
|
|
// will never exceed tail.
|
|
auto firstIndex = this->headIndex.fetch_add(actualCount, std::memory_order_acq_rel);
|
|
|
|
// Determine which block the first element is in
|
|
auto localBlockIndex = blockIndex.load(std::memory_order_acquire);
|
|
auto localBlockIndexHead = localBlockIndex->front.load(std::memory_order_acquire);
|
|
|
|
auto headBase = localBlockIndex->entries[localBlockIndexHead].base;
|
|
auto firstBlockBaseIndex = firstIndex & ~static_cast<index_t>(BLOCK_SIZE - 1);
|
|
auto offset = static_cast<size_t>(static_cast<typename std::make_signed<index_t>::type>(firstBlockBaseIndex - headBase) / static_cast<typename std::make_signed<index_t>::type>(BLOCK_SIZE));
|
|
auto indexIndex = (localBlockIndexHead + offset) & (localBlockIndex->size - 1);
|
|
|
|
// Iterate the blocks and dequeue
|
|
auto index = firstIndex;
|
|
do {
|
|
auto firstIndexInBlock = index;
|
|
index_t endIndex = (index & ~static_cast<index_t>(BLOCK_SIZE - 1)) + static_cast<index_t>(BLOCK_SIZE);
|
|
endIndex = details::circular_less_than<index_t>(firstIndex + static_cast<index_t>(actualCount), endIndex) ? firstIndex + static_cast<index_t>(actualCount) : endIndex;
|
|
auto block = localBlockIndex->entries[indexIndex].block;
|
|
if (MOODYCAMEL_NOEXCEPT_ASSIGN(T, T&&, details::deref_noexcept(itemFirst) = std::move((*(*block)[index])))) {
|
|
while (index != endIndex) {
|
|
auto& el = *((*block)[index]);
|
|
*itemFirst++ = std::move(el);
|
|
el.~T();
|
|
++index;
|
|
}
|
|
}
|
|
else {
|
|
MOODYCAMEL_TRY {
|
|
while (index != endIndex) {
|
|
auto& el = *((*block)[index]);
|
|
*itemFirst = std::move(el);
|
|
++itemFirst;
|
|
el.~T();
|
|
++index;
|
|
}
|
|
}
|
|
MOODYCAMEL_CATCH (...) {
|
|
// It's too late to revert the dequeue, but we can make sure that all
|
|
// the dequeued objects are properly destroyed and the block index
|
|
|
|
// (and empty count) are properly updated before we propagate the exception
|
|
do {
|
|
block = localBlockIndex->entries[indexIndex].block;
|
|
while (index != endIndex) {
|
|
(*block)[index++]->~T();
|
|
}
|
|
block->ConcurrentQueue::Block::template set_many_empty<explicit_context>(firstIndexInBlock, static_cast<size_t>(endIndex - firstIndexInBlock));
|
|
indexIndex = (indexIndex + 1) & (localBlockIndex->size - 1);
|
|
|
|
firstIndexInBlock = index;
|
|
endIndex = (index & ~static_cast<index_t>(BLOCK_SIZE - 1)) + static_cast<index_t>(BLOCK_SIZE);
|
|
endIndex = details::circular_less_than<index_t>(firstIndex + static_cast<index_t>(actualCount), endIndex) ? firstIndex + static_cast<index_t>(actualCount) : endIndex;
|
|
} while (index != firstIndex + actualCount);
|
|
|
|
MOODYCAMEL_RETHROW;
|
|
}
|
|
}
|
|
block->ConcurrentQueue::Block::template set_many_empty<explicit_context>(firstIndexInBlock, static_cast<size_t>(endIndex - firstIndexInBlock));
|
|
indexIndex = (indexIndex + 1) & (localBlockIndex->size - 1);
|
|
} while (index != firstIndex + actualCount);
|
|
|
|
return actualCount;
|
|
}
|
|
else {
|
|
// Wasn't anything to dequeue after all; make the effective dequeue count eventually consistent
|
|
this->dequeueOvercommit.fetch_add(desiredCount, std::memory_order_release);
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
private:
|
|
struct BlockIndexEntry
|
|
{
|
|
index_t base;
|
|
Block* block;
|
|
};
|
|
|
|
struct BlockIndexHeader
|
|
{
|
|
size_t size;
|
|
std::atomic<size_t> front; // Current slot (not next, like pr_blockIndexFront)
|
|
BlockIndexEntry* entries;
|
|
void* prev;
|
|
};
|
|
|
|
|
|
bool new_block_index(size_t numberOfFilledSlotsToExpose)
|
|
{
|
|
auto prevBlockSizeMask = pr_blockIndexSize - 1;
|
|
|
|
// Create the new block
|
|
pr_blockIndexSize <<= 1;
|
|
auto newRawPtr = static_cast<char*>((Traits::malloc)(sizeof(BlockIndexHeader) + std::alignment_of<BlockIndexEntry>::value - 1 + sizeof(BlockIndexEntry) * pr_blockIndexSize));
|
|
if (newRawPtr == nullptr) {
|
|
pr_blockIndexSize >>= 1; // Reset to allow graceful retry
|
|
return false;
|
|
}
|
|
|
|
auto newBlockIndexEntries = reinterpret_cast<BlockIndexEntry*>(details::align_for<BlockIndexEntry>(newRawPtr + sizeof(BlockIndexHeader)));
|
|
|
|
// Copy in all the old indices, if any
|
|
size_t j = 0;
|
|
if (pr_blockIndexSlotsUsed != 0) {
|
|
auto i = (pr_blockIndexFront - pr_blockIndexSlotsUsed) & prevBlockSizeMask;
|
|
do {
|
|
newBlockIndexEntries[j++] = pr_blockIndexEntries[i];
|
|
i = (i + 1) & prevBlockSizeMask;
|
|
} while (i != pr_blockIndexFront);
|
|
}
|
|
|
|
// Update everything
|
|
auto header = new (newRawPtr) BlockIndexHeader;
|
|
header->size = pr_blockIndexSize;
|
|
header->front.store(numberOfFilledSlotsToExpose - 1, std::memory_order_relaxed);
|
|
header->entries = newBlockIndexEntries;
|
|
|
|
header->prev = pr_blockIndexRaw; // we link the new block to the old one so we can free it later
|
|
|
|
pr_blockIndexFront = j;
|
|
pr_blockIndexEntries = newBlockIndexEntries;
|
|
pr_blockIndexRaw = newRawPtr;
|
|
blockIndex.store(header, std::memory_order_release);
|
|
|
|
return true;
|
|
}
|
|
|
|
private:
|
|
std::atomic<BlockIndexHeader*> blockIndex;
|
|
|
|
|
|
// To be used by producer only -- consumer must use the ones in referenced by blockIndex
|
|
size_t pr_blockIndexSlotsUsed;
|
|
size_t pr_blockIndexSize;
|
|
size_t pr_blockIndexFront; // Next slot (not current)
|
|
BlockIndexEntry* pr_blockIndexEntries;
|
|
void* pr_blockIndexRaw;
|
|
|
|
#ifdef MOODYCAMEL_QUEUE_INTERNAL_DEBUG
|
|
public:
|
|
ExplicitProducer* nextExplicitProducer;
|
|
private:
|
|
#endif
|
|
|
|
#ifdef MCDBGQ_TRACKMEM
|
|
friend struct MemStats;
|
|
#endif
|
|
};
|
|
|
|
|
|
|
|
//////////////////////////////////
|
|
// Implicit queue
|
|
//////////////////////////////////
|
|
|
|
struct ImplicitProducer : public ProducerBase
|
|
|
|
{
|
|
ImplicitProducer(ConcurrentQueue* parent_) :
|
|
ProducerBase(parent_, false),
|
|
nextBlockIndexCapacity(IMPLICIT_INITIAL_INDEX_SIZE),
|
|
blockIndex(nullptr)
|
|
{
|
|
|
|
new_block_index();
|
|
}
|
|
|
|
~ImplicitProducer()
|
|
{
|
|
// Note that since we're in the destructor we can assume that all enqueue/dequeue operations
|
|
// completed already; this means that all undequeued elements are placed contiguously across
|
|
// contiguous blocks, and that only the first and last remaining blocks can be only partially
|
|
// empty (all other remaining blocks must be completely full).
|
|
|
|
|
|
#ifdef MOODYCAMEL_CPP11_THREAD_LOCAL_SUPPORTED
|
|
// Unregister ourselves for thread termination notification
|
|
if (!this->inactive.load(std::memory_order_relaxed)) {
|
|
|
|
details::ThreadExitNotifier::unsubscribe(&threadExitListener);
|
|
}
|
|
#endif
|
|
|
|
// Destroy all remaining elements!
|
|
auto tail = this->tailIndex.load(std::memory_order_relaxed);
|
|
auto index = this->headIndex.load(std::memory_order_relaxed);
|
|
Block* block = nullptr;
|
|
assert(index == tail || details::circular_less_than(index, tail));
|
|
bool forceFreeLastBlock = index != tail; // If we enter the loop, then the last (tail) block will not be freed
|
|
while (index != tail) {
|
|
if ((index & static_cast<index_t>(BLOCK_SIZE - 1)) == 0 || block == nullptr) {
|
|
if (block != nullptr) {
|
|
// Free the old block
|
|
this->parent->add_block_to_free_list(block);
|
|
}
|
|
|
|
block = get_block_index_entry_for_index(index)->value.load(std::memory_order_relaxed);
|
|
}
|
|
|
|
((*block)[index])->~T();
|
|
++index;
|
|
}
|
|
// Even if the queue is empty, there's still one block that's not on the free list
|
|
// (unless the head index reached the end of it, in which case the tail will be poised
|
|
// to create a new block).
|
|
if (this->tailBlock != nullptr && (forceFreeLastBlock || (tail & static_cast<index_t>(BLOCK_SIZE - 1)) != 0)) {
|
|
this->parent->add_block_to_free_list(this->tailBlock);
|
|
}
|
|
|
|
// Destroy block index
|
|
auto localBlockIndex = blockIndex.load(std::memory_order_relaxed);
|
|
if (localBlockIndex != nullptr) {
|
|
for (size_t i = 0; i != localBlockIndex->capacity; ++i) {
|
|
localBlockIndex->index[i]->~BlockIndexEntry();
|
|
}
|
|
do {
|
|
auto prev = localBlockIndex->prev;
|
|
localBlockIndex->~BlockIndexHeader();
|
|
(Traits::free)(localBlockIndex);
|
|
localBlockIndex = prev;
|
|
} while (localBlockIndex != nullptr);
|
|
}
|
|
}
|
|
|
|
template<AllocationMode allocMode, typename U>
|
|
inline bool enqueue(U&& element)
|
|
{
|
|
index_t currentTailIndex = this->tailIndex.load(std::memory_order_relaxed);
|
|
index_t newTailIndex = 1 + currentTailIndex;
|
|
if ((currentTailIndex & static_cast<index_t>(BLOCK_SIZE - 1)) == 0) {
|
|
// We reached the end of a block, start a new one
|
|
auto head = this->headIndex.load(std::memory_order_relaxed);
|
|
assert(!details::circular_less_than<index_t>(currentTailIndex, head));
|
|
if (!details::circular_less_than<index_t>(head, currentTailIndex + BLOCK_SIZE) || (MAX_SUBQUEUE_SIZE != details::const_numeric_max<size_t>::value && (MAX_SUBQUEUE_SIZE == 0 || MAX_SUBQUEUE_SIZE - BLOCK_SIZE < currentTailIndex - head))) {
|
|
return false;
|
|
}
|
|
#ifdef MCDBGQ_NOLOCKFREE_IMPLICITPRODBLOCKINDEX
|
|
debug::DebugLock lock(mutex);
|
|
#endif
|
|
// Find out where we'll be inserting this block in the block index
|
|
BlockIndexEntry* idxEntry;
|
|
if (!insert_block_index_entry<allocMode>(idxEntry, currentTailIndex)) {
|
|
return false;
|
|
}
|
|
|
|
// Get ahold of a new block
|
|
auto newBlock = this->parent->ConcurrentQueue::template requisition_block<allocMode>();
|
|
if (newBlock == nullptr) {
|
|
rewind_block_index_tail();
|
|
idxEntry->value.store(nullptr, std::memory_order_relaxed);
|
|
return false;
|
|
}
|
|
#ifdef MCDBGQ_TRACKMEM
|
|
newBlock->owner = this;
|
|
#endif
|
|
newBlock->ConcurrentQueue::Block::template reset_empty<implicit_context>();
|
|
|
|
MOODYCAMEL_CONSTEXPR_IF (!MOODYCAMEL_NOEXCEPT_CTOR(T, U, new (static_cast<T*>(nullptr)) T(std::forward<U>(element)))) {
|
|
// May throw, try to insert now before we publish the fact that we have this new block
|
|
MOODYCAMEL_TRY {
|
|
new ((*newBlock)[currentTailIndex]) T(std::forward<U>(element));
|
|
}
|
|
MOODYCAMEL_CATCH (...) {
|
|
rewind_block_index_tail();
|
|
idxEntry->value.store(nullptr, std::memory_order_relaxed);
|
|
this->parent->add_block_to_free_list(newBlock);
|
|
MOODYCAMEL_RETHROW;
|
|
}
|
|
}
|
|
|
|
// Insert the new block into the index
|
|
idxEntry->value.store(newBlock, std::memory_order_relaxed);
|
|
|
|
this->tailBlock = newBlock;
|
|
|
|
MOODYCAMEL_CONSTEXPR_IF (!MOODYCAMEL_NOEXCEPT_CTOR(T, U, new (static_cast<T*>(nullptr)) T(std::forward<U>(element)))) {
|
|
this->tailIndex.store(newTailIndex, std::memory_order_release);
|
|
return true;
|
|
}
|
|
}
|
|
|
|
// Enqueue
|
|
new ((*this->tailBlock)[currentTailIndex]) T(std::forward<U>(element));
|
|
|
|
|
|
this->tailIndex.store(newTailIndex, std::memory_order_release);
|
|
return true;
|
|
}
|
|
|
|
template<typename U>
|
|
bool dequeue(U& element)
|
|
{
|
|
// See ExplicitProducer::dequeue for rationale and explanation
|
|
index_t tail = this->tailIndex.load(std::memory_order_relaxed);
|
|
index_t overcommit = this->dequeueOvercommit.load(std::memory_order_relaxed);
|
|
if (details::circular_less_than<index_t>(this->dequeueOptimisticCount.load(std::memory_order_relaxed) - overcommit, tail)) {
|
|
std::atomic_thread_fence(std::memory_order_acquire);
|
|
|
|
index_t myDequeueCount = this->dequeueOptimisticCount.fetch_add(1, std::memory_order_relaxed);
|
|
tail = this->tailIndex.load(std::memory_order_acquire);
|
|
if ((details::likely)(details::circular_less_than<index_t>(myDequeueCount - overcommit, tail))) {
|
|
index_t index = this->headIndex.fetch_add(1, std::memory_order_acq_rel);
|
|
|
|
// Determine which block the element is in
|
|
auto entry = get_block_index_entry_for_index(index);
|
|
|
|
// Dequeue
|
|
auto block = entry->value.load(std::memory_order_relaxed);
|
|
auto& el = *((*block)[index]);
|
|
|
|
if (!MOODYCAMEL_NOEXCEPT_ASSIGN(T, T&&, element = std::move(el))) {
|
|
#ifdef MCDBGQ_NOLOCKFREE_IMPLICITPRODBLOCKINDEX
|
|
// Note: Acquiring the mutex with every dequeue instead of only when a block
|
|
// is released is very sub-optimal, but it is, after all, purely debug code.
|
|
debug::DebugLock lock(producer->mutex);
|
|
#endif
|
|
struct Guard {
|
|
|
|
Block* block;
|
|
index_t index;
|
|
BlockIndexEntry* entry;
|
|
ConcurrentQueue* parent;
|
|
|
|
~Guard()
|
|
{
|
|
(*block)[index]->~T();
|
|
if (block->ConcurrentQueue::Block::template set_empty<implicit_context>(index)) {
|
|
entry->value.store(nullptr, std::memory_order_relaxed);
|
|
parent->add_block_to_free_list(block);
|
|
}
|
|
}
|
|
} guard = { block, index, entry, this->parent };
|
|
|
|
element = std::move(el); // NOLINT
|
|
}
|
|
else {
|
|
element = std::move(el); // NOLINT
|
|
el.~T(); // NOLINT
|
|
|
|
if (block->ConcurrentQueue::Block::template set_empty<implicit_context>(index)) {
|
|
|
|
{
|
|
#ifdef MCDBGQ_NOLOCKFREE_IMPLICITPRODBLOCKINDEX
|
|
debug::DebugLock lock(mutex);
|
|
#endif
|
|
// Add the block back into the global free pool (and remove from block index)
|
|
entry->value.store(nullptr, std::memory_order_relaxed);
|
|
}
|
|
this->parent->add_block_to_free_list(block); // releases the above store
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
else {
|
|
this->dequeueOvercommit.fetch_add(1, std::memory_order_release);
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
#ifdef _MSC_VER
|
|
#pragma warning(push)
|
|
#pragma warning(disable: 4706) // assignment within conditional expression
|
|
#endif
|
|
template<AllocationMode allocMode, typename It>
|
|
bool enqueue_bulk(It itemFirst, size_t count)
|
|
{
|
|
// First, we need to make sure we have enough room to enqueue all of the elements;
|
|
// this means pre-allocating blocks and putting them in the block index (but only if
|
|
// all the allocations succeeded).
|
|
|
|
// Note that the tailBlock we start off with may not be owned by us any more;
|
|
// this happens if it was filled up exactly to the top (setting tailIndex to
|
|
// the first index of the next block which is not yet allocated), then dequeued
|
|
// completely (putting it on the free list) before we enqueue again.
|
|
|
|
index_t startTailIndex = this->tailIndex.load(std::memory_order_relaxed);
|
|
auto startBlock = this->tailBlock;
|
|
Block* firstAllocatedBlock = nullptr;
|
|
auto endBlock = this->tailBlock;
|
|
|
|
// Figure out how many blocks we'll need to allocate, and do so
|
|
size_t blockBaseDiff = ((startTailIndex + count - 1) & ~static_cast<index_t>(BLOCK_SIZE - 1)) - ((startTailIndex - 1) & ~static_cast<index_t>(BLOCK_SIZE - 1));
|
|
index_t currentTailIndex = (startTailIndex - 1) & ~static_cast<index_t>(BLOCK_SIZE - 1);
|
|
if (blockBaseDiff > 0) {
|
|
#ifdef MCDBGQ_NOLOCKFREE_IMPLICITPRODBLOCKINDEX
|
|
debug::DebugLock lock(mutex);
|
|
#endif
|
|
do {
|
|
blockBaseDiff -= static_cast<index_t>(BLOCK_SIZE);
|
|
currentTailIndex += static_cast<index_t>(BLOCK_SIZE);
|
|
|
|
// Find out where we'll be inserting this block in the block index
|
|
BlockIndexEntry* idxEntry = nullptr; // initialization here unnecessary but compiler can't always tell
|
|
Block* newBlock;
|
|
bool indexInserted = false;
|
|
auto head = this->headIndex.load(std::memory_order_relaxed);
|
|
assert(!details::circular_less_than<index_t>(currentTailIndex, head));
|
|
bool full = !details::circular_less_than<index_t>(head, currentTailIndex + BLOCK_SIZE) || (MAX_SUBQUEUE_SIZE != details::const_numeric_max<size_t>::value && (MAX_SUBQUEUE_SIZE == 0 || MAX_SUBQUEUE_SIZE - BLOCK_SIZE < currentTailIndex - head));
|
|
|
|
if (full || !(indexInserted = insert_block_index_entry<allocMode>(idxEntry, currentTailIndex)) || (newBlock = this->parent->ConcurrentQueue::template requisition_block<allocMode>()) == nullptr) {
|
|
// Index allocation or block allocation failed; revert any other allocations
|
|
// and index insertions done so far for this operation
|
|
if (indexInserted) {
|
|
rewind_block_index_tail();
|
|
idxEntry->value.store(nullptr, std::memory_order_relaxed);
|
|
}
|
|
currentTailIndex = (startTailIndex - 1) & ~static_cast<index_t>(BLOCK_SIZE - 1);
|
|
for (auto block = firstAllocatedBlock; block != nullptr; block = block->next) {
|
|
currentTailIndex += static_cast<index_t>(BLOCK_SIZE);
|
|
idxEntry = get_block_index_entry_for_index(currentTailIndex);
|
|
idxEntry->value.store(nullptr, std::memory_order_relaxed);
|
|
rewind_block_index_tail();
|
|
}
|
|
this->parent->add_blocks_to_free_list(firstAllocatedBlock);
|
|
this->tailBlock = startBlock;
|
|
|
|
return false;
|
|
}
|
|
|
|
#ifdef MCDBGQ_TRACKMEM
|
|
newBlock->owner = this;
|
|
#endif
|
|
newBlock->ConcurrentQueue::Block::template reset_empty<implicit_context>();
|
|
newBlock->next = nullptr;
|
|
|
|
// Insert the new block into the index
|
|
idxEntry->value.store(newBlock, std::memory_order_relaxed);
|
|
|
|
// Store the chain of blocks so that we can undo if later allocations fail,
|
|
// and so that we can find the blocks when we do the actual enqueueing
|
|
if ((startTailIndex & static_cast<index_t>(BLOCK_SIZE - 1)) != 0 || firstAllocatedBlock != nullptr) {
|
|
assert(this->tailBlock != nullptr);
|
|
this->tailBlock->next = newBlock;
|
|
}
|
|
this->tailBlock = newBlock;
|
|
endBlock = newBlock;
|
|
firstAllocatedBlock = firstAllocatedBlock == nullptr ? newBlock : firstAllocatedBlock;
|
|
|
|
} while (blockBaseDiff > 0);
|
|
}
|
|
|
|
// Enqueue, one block at a time
|
|
index_t newTailIndex = startTailIndex + static_cast<index_t>(count);
|
|
currentTailIndex = startTailIndex;
|
|
this->tailBlock = startBlock;
|
|
assert((startTailIndex & static_cast<index_t>(BLOCK_SIZE - 1)) != 0 || firstAllocatedBlock != nullptr || count == 0);
|
|
if ((startTailIndex & static_cast<index_t>(BLOCK_SIZE - 1)) == 0 && firstAllocatedBlock != nullptr) {
|
|
this->tailBlock = firstAllocatedBlock;
|
|
}
|
|
while (true) {
|
|
index_t stopIndex = (currentTailIndex & ~static_cast<index_t>(BLOCK_SIZE - 1)) + static_cast<index_t>(BLOCK_SIZE);
|
|
if (details::circular_less_than<index_t>(newTailIndex, stopIndex)) {
|
|
stopIndex = newTailIndex;
|
|
}
|
|
MOODYCAMEL_CONSTEXPR_IF (MOODYCAMEL_NOEXCEPT_CTOR(T, decltype(*itemFirst), new (static_cast<T*>(nullptr)) T(details::deref_noexcept(itemFirst)))) {
|
|
while (currentTailIndex != stopIndex) {
|
|
new ((*this->tailBlock)[currentTailIndex++]) T(*itemFirst++);
|
|
}
|
|
}
|
|
else {
|
|
MOODYCAMEL_TRY {
|
|
while (currentTailIndex != stopIndex) {
|
|
new ((*this->tailBlock)[currentTailIndex]) T(details::nomove_if<!MOODYCAMEL_NOEXCEPT_CTOR(T, decltype(*itemFirst), new (static_cast<T*>(nullptr)) T(details::deref_noexcept(itemFirst)))>::eval(*itemFirst));
|
|
++currentTailIndex;
|
|
++itemFirst;
|
|
}
|
|
}
|
|
MOODYCAMEL_CATCH (...) {
|
|
auto constructedStopIndex = currentTailIndex;
|
|
auto lastBlockEnqueued = this->tailBlock;
|
|
|
|
if (!details::is_trivially_destructible<T>::value) {
|
|
auto block = startBlock;
|
|
if ((startTailIndex & static_cast<index_t>(BLOCK_SIZE - 1)) == 0) {
|
|
block = firstAllocatedBlock;
|
|
}
|
|
currentTailIndex = startTailIndex;
|
|
while (true) {
|
|
stopIndex = (currentTailIndex & ~static_cast<index_t>(BLOCK_SIZE - 1)) + static_cast<index_t>(BLOCK_SIZE);
|
|
if (details::circular_less_than<index_t>(constructedStopIndex, stopIndex)) {
|
|
stopIndex = constructedStopIndex;
|
|
}
|
|
while (currentTailIndex != stopIndex) {
|
|
(*block)[currentTailIndex++]->~T();
|
|
}
|
|
|
|
if (block == lastBlockEnqueued) {
|
|
break;
|
|
}
|
|
block = block->next;
|
|
|
|
}
|
|
}
|
|
|
|
currentTailIndex = (startTailIndex - 1) & ~static_cast<index_t>(BLOCK_SIZE - 1);
|
|
for (auto block = firstAllocatedBlock; block != nullptr; block = block->next) {
|
|
currentTailIndex += static_cast<index_t>(BLOCK_SIZE);
|
|
auto idxEntry = get_block_index_entry_for_index(currentTailIndex);
|
|
idxEntry->value.store(nullptr, std::memory_order_relaxed);
|
|
rewind_block_index_tail();
|
|
}
|
|
this->parent->add_blocks_to_free_list(firstAllocatedBlock);
|
|
this->tailBlock = startBlock;
|
|
MOODYCAMEL_RETHROW;
|
|
}
|
|
}
|
|
|
|
if (this->tailBlock == endBlock) {
|
|
assert(currentTailIndex == newTailIndex);
|
|
break;
|
|
}
|
|
this->tailBlock = this->tailBlock->next;
|
|
|
|
}
|
|
|
|
this->tailIndex.store(newTailIndex, std::memory_order_release);
|
|
return true;
|
|
}
|
|
|
|
#ifdef _MSC_VER
|
|
#pragma warning(pop)
|
|
#endif
|
|
|
|
template<typename It>
|
|
size_t dequeue_bulk(It& itemFirst, size_t max)
|
|
{
|
|
auto tail = this->tailIndex.load(std::memory_order_relaxed);
|
|
auto overcommit = this->dequeueOvercommit.load(std::memory_order_relaxed);
|
|
auto desiredCount = static_cast<size_t>(tail - (this->dequeueOptimisticCount.load(std::memory_order_relaxed) - overcommit));
|
|
if (details::circular_less_than<size_t>(0, desiredCount)) {
|
|
desiredCount = desiredCount < max ? desiredCount : max;
|
|
std::atomic_thread_fence(std::memory_order_acquire);
|
|
|
|
auto myDequeueCount = this->dequeueOptimisticCount.fetch_add(desiredCount, std::memory_order_relaxed);
|
|
|
|
|
|
tail = this->tailIndex.load(std::memory_order_acquire);
|
|
auto actualCount = static_cast<size_t>(tail - (myDequeueCount - overcommit));
|
|
if (details::circular_less_than<size_t>(0, actualCount)) {
|
|
actualCount = desiredCount < actualCount ? desiredCount : actualCount;
|
|
if (actualCount < desiredCount) {
|
|
this->dequeueOvercommit.fetch_add(desiredCount - actualCount, std::memory_order_release);
|
|
}
|
|
|
|
// Get the first index. Note that since there's guaranteed to be at least actualCount elements, this
|
|
// will never exceed tail.
|
|
|
|
auto firstIndex = this->headIndex.fetch_add(actualCount, std::memory_order_acq_rel);
|
|
|
|
|
|
// Iterate the blocks and dequeue
|
|
auto index = firstIndex;
|
|
BlockIndexHeader* localBlockIndex;
|
|
auto indexIndex = get_block_index_index_for_index(index, localBlockIndex);
|
|
do {
|
|
auto blockStartIndex = index;
|
|
index_t endIndex = (index & ~static_cast<index_t>(BLOCK_SIZE - 1)) + static_cast<index_t>(BLOCK_SIZE);
|
|
endIndex = details::circular_less_than<index_t>(firstIndex + static_cast<index_t>(actualCount), endIndex) ? firstIndex + static_cast<index_t>(actualCount) : endIndex;
|
|
|
|
auto entry = localBlockIndex->index[indexIndex];
|
|
auto block = entry->value.load(std::memory_order_relaxed);
|
|
if (MOODYCAMEL_NOEXCEPT_ASSIGN(T, T&&, details::deref_noexcept(itemFirst) = std::move((*(*block)[index])))) {
|
|
while (index != endIndex) {
|
|
auto& el = *((*block)[index]);
|
|
*itemFirst++ = std::move(el);
|
|
el.~T();
|
|
++index;
|
|
|
|
}
|
|
}
|
|
else {
|
|
MOODYCAMEL_TRY {
|
|
while (index != endIndex) {
|
|
auto& el = *((*block)[index]);
|
|
*itemFirst = std::move(el);
|
|
++itemFirst;
|
|
el.~T();
|
|
++index;
|
|
}
|
|
}
|
|
MOODYCAMEL_CATCH (...) {
|
|
do {
|
|
entry = localBlockIndex->index[indexIndex];
|
|
block = entry->value.load(std::memory_order_relaxed);
|
|
while (index != endIndex) {
|
|
(*block)[index++]->~T();
|
|
}
|
|
|
|
|
|
if (block->ConcurrentQueue::Block::template set_many_empty<implicit_context>(blockStartIndex, static_cast<size_t>(endIndex - blockStartIndex))) {
|
|
#ifdef MCDBGQ_NOLOCKFREE_IMPLICITPRODBLOCKINDEX
|
|
debug::DebugLock lock(mutex);
|
|
#endif
|
|
entry->value.store(nullptr, std::memory_order_relaxed);
|
|
this->parent->add_block_to_free_list(block);
|
|
}
|
|
indexIndex = (indexIndex + 1) & (localBlockIndex->capacity - 1);
|
|
|
|
|
|
blockStartIndex = index;
|
|
endIndex = (index & ~static_cast<index_t>(BLOCK_SIZE - 1)) + static_cast<index_t>(BLOCK_SIZE);
|
|
endIndex = details::circular_less_than<index_t>(firstIndex + static_cast<index_t>(actualCount), endIndex) ? firstIndex + static_cast<index_t>(actualCount) : endIndex;
|
|
} while (index != firstIndex + actualCount);
|
|
|
|
MOODYCAMEL_RETHROW;
|
|
}
|
|
}
|
|
if (block->ConcurrentQueue::Block::template set_many_empty<implicit_context>(blockStartIndex, static_cast<size_t>(endIndex - blockStartIndex))) {
|
|
{
|
|
#ifdef MCDBGQ_NOLOCKFREE_IMPLICITPRODBLOCKINDEX
|
|
debug::DebugLock lock(mutex);
|
|
#endif
|
|
// Note that the set_many_empty above did a release, meaning that anybody who acquires the block
|
|
// we're about to free can use it safely since our writes (and reads!) will have happened-before then.
|
|
entry->value.store(nullptr, std::memory_order_relaxed);
|
|
}
|
|
this->parent->add_block_to_free_list(block); // releases the above store
|
|
}
|
|
indexIndex = (indexIndex + 1) & (localBlockIndex->capacity - 1);
|
|
} while (index != firstIndex + actualCount);
|
|
|
|
return actualCount;
|
|
}
|
|
else {
|
|
this->dequeueOvercommit.fetch_add(desiredCount, std::memory_order_release);
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
private:
|
|
// The block size must be > 1, so any number with the low bit set is an invalid block base index
|
|
static const index_t INVALID_BLOCK_BASE = 1;
|
|
|
|
struct BlockIndexEntry
|
|
{
|
|
std::atomic<index_t> key;
|
|
std::atomic<Block*> value;
|
|
};
|
|
|
|
struct BlockIndexHeader
|
|
|
|
{
|
|
size_t capacity;
|
|
std::atomic<size_t> tail;
|
|
BlockIndexEntry* entries;
|
|
BlockIndexEntry** index;
|
|
BlockIndexHeader* prev;
|
|
};
|
|
|
|
template<AllocationMode allocMode>
|
|
inline bool insert_block_index_entry(BlockIndexEntry*& idxEntry, index_t blockStartIndex)
|
|
{
|
|
auto localBlockIndex = blockIndex.load(std::memory_order_relaxed); // We're the only writer thread, relaxed is OK
|
|
if (localBlockIndex == nullptr) {
|
|
return false; // this can happen if new_block_index failed in the constructor
|
|
}
|
|
size_t newTail = (localBlockIndex->tail.load(std::memory_order_relaxed) + 1) & (localBlockIndex->capacity - 1);
|
|
idxEntry = localBlockIndex->index[newTail];
|
|
if (idxEntry->key.load(std::memory_order_relaxed) == INVALID_BLOCK_BASE ||
|
|
idxEntry->value.load(std::memory_order_relaxed) == nullptr) {
|
|
|
|
idxEntry->key.store(blockStartIndex, std::memory_order_relaxed);
|
|
localBlockIndex->tail.store(newTail, std::memory_order_release);
|
|
return true;
|
|
}
|
|
|
|
// No room in the old block index, try to allocate another one!
|
|
MOODYCAMEL_CONSTEXPR_IF (allocMode == CannotAlloc) {
|
|
return false;
|
|
}
|
|
else if (!new_block_index()) {
|
|
return false;
|
|
}
|
|
else {
|
|
localBlockIndex = blockIndex.load(std::memory_order_relaxed);
|
|
newTail = (localBlockIndex->tail.load(std::memory_order_relaxed) + 1) & (localBlockIndex->capacity - 1);
|
|
idxEntry = localBlockIndex->index[newTail];
|
|
assert(idxEntry->key.load(std::memory_order_relaxed) == INVALID_BLOCK_BASE);
|
|
idxEntry->key.store(blockStartIndex, std::memory_order_relaxed);
|
|
localBlockIndex->tail.store(newTail, std::memory_order_release);
|
|
return true;
|
|
}
|
|
}
|
|
|
|
|
|
inline void rewind_block_index_tail()
|
|
{
|
|
auto localBlockIndex = blockIndex.load(std::memory_order_relaxed);
|
|
localBlockIndex->tail.store((localBlockIndex->tail.load(std::memory_order_relaxed) - 1) & (localBlockIndex->capacity - 1), std::memory_order_relaxed);
|
|
}
|
|
|
|
inline BlockIndexEntry* get_block_index_entry_for_index(index_t index) const
|
|
{
|
|
BlockIndexHeader* localBlockIndex;
|
|
auto idx = get_block_index_index_for_index(index, localBlockIndex);
|
|
return localBlockIndex->index[idx];
|
|
}
|
|
|
|
inline size_t get_block_index_index_for_index(index_t index, BlockIndexHeader*& localBlockIndex) const
|
|
{
|
|
#ifdef MCDBGQ_NOLOCKFREE_IMPLICITPRODBLOCKINDEX
|
|
debug::DebugLock lock(mutex);
|
|
#endif
|
|
index &= ~static_cast<index_t>(BLOCK_SIZE - 1);
|
|
localBlockIndex = blockIndex.load(std::memory_order_acquire);
|
|
auto tail = localBlockIndex->tail.load(std::memory_order_acquire);
|
|
auto tailBase = localBlockIndex->index[tail]->key.load(std::memory_order_relaxed);
|
|
assert(tailBase != INVALID_BLOCK_BASE);
|
|
// Note: Must use division instead of shift because the index may wrap around, causing a negative
|
|
// offset, whose negativity we want to preserve
|
|
auto offset = static_cast<size_t>(static_cast<typename std::make_signed<index_t>::type>(index - tailBase) / static_cast<typename std::make_signed<index_t>::type>(BLOCK_SIZE));
|
|
size_t idx = (tail + offset) & (localBlockIndex->capacity - 1);
|
|
assert(localBlockIndex->index[idx]->key.load(std::memory_order_relaxed) == index && localBlockIndex->index[idx]->value.load(std::memory_order_relaxed) != nullptr);
|
|
return idx;
|
|
}
|
|
|
|
bool new_block_index()
|
|
{
|
|
auto prev = blockIndex.load(std::memory_order_relaxed);
|
|
size_t prevCapacity = prev == nullptr ? 0 : prev->capacity;
|
|
auto entryCount = prev == nullptr ? nextBlockIndexCapacity : prevCapacity;
|
|
auto raw = static_cast<char*>((Traits::malloc)(
|
|
sizeof(BlockIndexHeader) +
|
|
std::alignment_of<BlockIndexEntry>::value - 1 + sizeof(BlockIndexEntry) * entryCount +
|
|
std::alignment_of<BlockIndexEntry*>::value - 1 + sizeof(BlockIndexEntry*) * nextBlockIndexCapacity));
|
|
if (raw == nullptr) {
|
|
return false;
|
|
}
|
|
|
|
auto header = new (raw) BlockIndexHeader;
|
|
auto entries = reinterpret_cast<BlockIndexEntry*>(details::align_for<BlockIndexEntry>(raw + sizeof(BlockIndexHeader)));
|
|
auto index = reinterpret_cast<BlockIndexEntry**>(details::align_for<BlockIndexEntry*>(reinterpret_cast<char*>(entries) + sizeof(BlockIndexEntry) * entryCount));
|
|
if (prev != nullptr) {
|
|
auto prevTail = prev->tail.load(std::memory_order_relaxed);
|
|
|
|
auto prevPos = prevTail;
|
|
size_t i = 0;
|
|
do {
|
|
prevPos = (prevPos + 1) & (prev->capacity - 1);
|
|
index[i++] = prev->index[prevPos];
|
|
} while (prevPos != prevTail);
|
|
assert(i == prevCapacity);
|
|
}
|
|
for (size_t i = 0; i != entryCount; ++i) {
|
|
new (entries + i) BlockIndexEntry;
|
|
entries[i].key.store(INVALID_BLOCK_BASE, std::memory_order_relaxed);
|
|
index[prevCapacity + i] = entries + i;
|
|
}
|
|
header->prev = prev;
|
|
header->entries = entries;
|
|
header->index = index;
|
|
header->capacity = nextBlockIndexCapacity;
|
|
header->tail.store((prevCapacity - 1) & (nextBlockIndexCapacity - 1), std::memory_order_relaxed);
|
|
|
|
blockIndex.store(header, std::memory_order_release);
|
|
|
|
nextBlockIndexCapacity <<= 1;
|
|
|
|
return true;
|
|
}
|
|
|
|
private:
|
|
size_t nextBlockIndexCapacity;
|
|
std::atomic<BlockIndexHeader*> blockIndex;
|
|
|
|
#ifdef MOODYCAMEL_CPP11_THREAD_LOCAL_SUPPORTED
|
|
public:
|
|
details::ThreadExitListener threadExitListener;
|
|
private:
|
|
|
|
#endif
|
|
|
|
#ifdef MOODYCAMEL_QUEUE_INTERNAL_DEBUG
|
|
public:
|
|
ImplicitProducer* nextImplicitProducer;
|
|
private:
|
|
#endif
|
|
|
|
#ifdef MCDBGQ_NOLOCKFREE_IMPLICITPRODBLOCKINDEX
|
|
mutable debug::DebugMutex mutex;
|
|
#endif
|
|
#ifdef MCDBGQ_TRACKMEM
|
|
friend struct MemStats;
|
|
#endif
|
|
};
|
|
|
|
|
|
//////////////////////////////////
|
|
// Block pool manipulation
|
|
//////////////////////////////////
|
|
|
|
|
|
void populate_initial_block_list(size_t blockCount)
|
|
{
|
|
initialBlockPoolSize = blockCount;
|
|
if (initialBlockPoolSize == 0) {
|
|
initialBlockPool = nullptr;
|
|
return;
|
|
}
|
|
|
|
initialBlockPool = create_array<Block>(blockCount);
|
|
if (initialBlockPool == nullptr) {
|
|
initialBlockPoolSize = 0;
|
|
}
|
|
for (size_t i = 0; i < initialBlockPoolSize; ++i) {
|
|
initialBlockPool[i].dynamicallyAllocated = false;
|
|
}
|
|
}
|
|
|
|
inline Block* try_get_block_from_initial_pool()
|
|
{
|
|
if (initialBlockPoolIndex.load(std::memory_order_relaxed) >= initialBlockPoolSize) {
|
|
return nullptr;
|
|
}
|
|
|
|
auto index = initialBlockPoolIndex.fetch_add(1, std::memory_order_relaxed);
|
|
|
|
return index < initialBlockPoolSize ? (initialBlockPool + index) : nullptr;
|
|
}
|
|
|
|
inline void add_block_to_free_list(Block* block)
|
|
{
|
|
#ifdef MCDBGQ_TRACKMEM
|
|
|
|
block->owner = nullptr;
|
|
#endif
|
|
if (!Traits::RECYCLE_ALLOCATED_BLOCKS && block->dynamicallyAllocated) {
|
|
destroy(block);
|
|
}
|
|
else {
|
|
freeList.add(block);
|
|
}
|
|
}
|
|
|
|
inline void add_blocks_to_free_list(Block* block)
|
|
{
|
|
while (block != nullptr) {
|
|
auto next = block->next;
|
|
add_block_to_free_list(block);
|
|
block = next;
|
|
}
|
|
}
|
|
|
|
inline Block* try_get_block_from_free_list()
|
|
{
|
|
return freeList.try_get();
|
|
}
|
|
|
|
// Gets a free block from one of the memory pools, or allocates a new one (if applicable)
|
|
template<AllocationMode canAlloc>
|
|
Block* requisition_block()
|
|
{
|
|
|
|
auto block = try_get_block_from_initial_pool();
|
|
if (block != nullptr) {
|
|
return block;
|
|
}
|
|
|
|
block = try_get_block_from_free_list();
|
|
if (block != nullptr) {
|
|
return block;
|
|
|
|
}
|
|
|
|
MOODYCAMEL_CONSTEXPR_IF (canAlloc == CanAlloc) {
|
|
return create<Block>();
|
|
}
|
|
else {
|
|
return nullptr;
|
|
}
|
|
}
|
|
|
|
|
|
#ifdef MCDBGQ_TRACKMEM
|
|
public:
|
|
struct MemStats {
|
|
size_t allocatedBlocks;
|
|
size_t usedBlocks;
|
|
size_t freeBlocks;
|
|
size_t ownedBlocksExplicit;
|
|
size_t ownedBlocksImplicit;
|
|
size_t implicitProducers;
|
|
size_t explicitProducers;
|
|
size_t elementsEnqueued;
|
|
size_t blockClassBytes;
|
|
size_t queueClassBytes;
|
|
size_t implicitBlockIndexBytes;
|
|
|
|
size_t explicitBlockIndexBytes;
|
|
|
|
friend class ConcurrentQueue;
|
|
|
|
private:
|
|
|
|
static MemStats getFor(ConcurrentQueue* q)
|
|
|
|
{
|
|
|
|
MemStats stats = { 0 };
|
|
|
|
stats.elementsEnqueued = q->size_approx();
|
|
|
|
auto block = q->freeList.head_unsafe();
|
|
while (block != nullptr) {
|
|
++stats.allocatedBlocks;
|
|
|
|
++stats.freeBlocks;
|
|
block = block->freeListNext.load(std::memory_order_relaxed);
|
|
}
|
|
|
|
for (auto ptr = q->producerListTail.load(std::memory_order_acquire); ptr != nullptr; ptr = ptr->next_prod()) {
|
|
bool implicit = dynamic_cast<ImplicitProducer*>(ptr) != nullptr;
|
|
stats.implicitProducers += implicit ? 1 : 0;
|
|
stats.explicitProducers += implicit ? 0 : 1;
|
|
|
|
if (implicit) {
|
|
auto prod = static_cast<ImplicitProducer*>(ptr);
|
|
stats.queueClassBytes += sizeof(ImplicitProducer);
|
|
auto head = prod->headIndex.load(std::memory_order_relaxed);
|
|
auto tail = prod->tailIndex.load(std::memory_order_relaxed);
|
|
auto hash = prod->blockIndex.load(std::memory_order_relaxed);
|
|
if (hash != nullptr) {
|
|
for (size_t i = 0; i != hash->capacity; ++i) {
|
|
if (hash->index[i]->key.load(std::memory_order_relaxed) != ImplicitProducer::INVALID_BLOCK_BASE && hash->index[i]->value.load(std::memory_order_relaxed) != nullptr) {
|
|
++stats.allocatedBlocks;
|
|
++stats.ownedBlocksImplicit;
|
|
}
|
|
}
|
|
stats.implicitBlockIndexBytes += hash->capacity * sizeof(typename ImplicitProducer::BlockIndexEntry);
|
|
for (; hash != nullptr; hash = hash->prev) {
|
|
stats.implicitBlockIndexBytes += sizeof(typename ImplicitProducer::BlockIndexHeader) + hash->capacity * sizeof(typename ImplicitProducer::BlockIndexEntry*);
|
|
}
|
|
}
|
|
for (; details::circular_less_than<index_t>(head, tail); head += BLOCK_SIZE) {
|
|
//auto block = prod->get_block_index_entry_for_index(head);
|
|
++stats.usedBlocks;
|
|
|
|
}
|
|
}
|
|
else {
|
|
auto prod = static_cast<ExplicitProducer*>(ptr);
|
|
stats.queueClassBytes += sizeof(ExplicitProducer);
|
|
auto tailBlock = prod->tailBlock;
|
|
bool wasNonEmpty = false;
|
|
if (tailBlock != nullptr) {
|
|
auto block = tailBlock;
|
|
do {
|
|
++stats.allocatedBlocks;
|
|
if (!block->ConcurrentQueue::Block::template is_empty<explicit_context>() || wasNonEmpty) {
|
|
++stats.usedBlocks;
|
|
wasNonEmpty = wasNonEmpty || block != tailBlock;
|
|
}
|
|
++stats.ownedBlocksExplicit;
|
|
block = block->next;
|
|
} while (block != tailBlock);
|
|
}
|
|
auto index = prod->blockIndex.load(std::memory_order_relaxed);
|
|
while (index != nullptr) {
|
|
stats.explicitBlockIndexBytes += sizeof(typename ExplicitProducer::BlockIndexHeader) + index->size * sizeof(typename ExplicitProducer::BlockIndexEntry);
|
|
index = static_cast<typename ExplicitProducer::BlockIndexHeader*>(index->prev);
|
|
}
|
|
}
|
|
}
|
|
|
|
auto freeOnInitialPool = q->initialBlockPoolIndex.load(std::memory_order_relaxed) >= q->initialBlockPoolSize ? 0 : q->initialBlockPoolSize - q->initialBlockPoolIndex.load(std::memory_order_relaxed);
|
|
stats.allocatedBlocks += freeOnInitialPool;
|
|
stats.freeBlocks += freeOnInitialPool;
|
|
|
|
stats.blockClassBytes = sizeof(Block) * stats.allocatedBlocks;
|
|
stats.queueClassBytes += sizeof(ConcurrentQueue);
|
|
|
|
return stats;
|
|
}
|
|
};
|
|
|
|
// For debugging only. Not thread-safe.
|
|
MemStats getMemStats()
|
|
{
|
|
return MemStats::getFor(this);
|
|
}
|
|
private:
|
|
friend struct MemStats;
|
|
#endif
|
|
|
|
|
|
//////////////////////////////////
|
|
// Producer list manipulation
|
|
//////////////////////////////////
|
|
|
|
|
|
ProducerBase* recycle_or_create_producer(bool isExplicit)
|
|
{
|
|
#ifdef MCDBGQ_NOLOCKFREE_IMPLICITPRODHASH
|
|
debug::DebugLock lock(implicitProdMutex);
|
|
#endif
|
|
// Try to re-use one first
|
|
for (auto ptr = producerListTail.load(std::memory_order_acquire); ptr != nullptr; ptr = ptr->next_prod()) {
|
|
if (ptr->inactive.load(std::memory_order_relaxed) && ptr->isExplicit == isExplicit) {
|
|
bool expected = true;
|
|
if (ptr->inactive.compare_exchange_strong(expected, /* desired */ false, std::memory_order_acquire, std::memory_order_relaxed)) {
|
|
// We caught one! It's been marked as activated, the caller can have it
|
|
return ptr;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
return add_producer(isExplicit ? static_cast<ProducerBase*>(create<ExplicitProducer>(this)) : create<ImplicitProducer>(this));
|
|
}
|
|
|
|
ProducerBase* add_producer(ProducerBase* producer)
|
|
{
|
|
// Handle failed memory allocation
|
|
if (producer == nullptr) {
|
|
return nullptr;
|
|
}
|
|
|
|
producerCount.fetch_add(1, std::memory_order_relaxed);
|
|
|
|
// Add it to the lock-free list
|
|
auto prevTail = producerListTail.load(std::memory_order_relaxed);
|
|
do {
|
|
producer->next = prevTail;
|
|
} while (!producerListTail.compare_exchange_weak(prevTail, producer, std::memory_order_release, std::memory_order_relaxed));
|
|
|
|
#ifdef MOODYCAMEL_QUEUE_INTERNAL_DEBUG
|
|
if (producer->isExplicit) {
|
|
auto prevTailExplicit = explicitProducers.load(std::memory_order_relaxed);
|
|
do {
|
|
static_cast<ExplicitProducer*>(producer)->nextExplicitProducer = prevTailExplicit;
|
|
} while (!explicitProducers.compare_exchange_weak(prevTailExplicit, static_cast<ExplicitProducer*>(producer), std::memory_order_release, std::memory_order_relaxed));
|
|
}
|
|
else {
|
|
auto prevTailImplicit = implicitProducers.load(std::memory_order_relaxed);
|
|
do {
|
|
static_cast<ImplicitProducer*>(producer)->nextImplicitProducer = prevTailImplicit;
|
|
} while (!implicitProducers.compare_exchange_weak(prevTailImplicit, static_cast<ImplicitProducer*>(producer), std::memory_order_release, std::memory_order_relaxed));
|
|
}
|
|
#endif
|
|
|
|
return producer;
|
|
}
|
|
|
|
void reown_producers()
|
|
{
|
|
// After another instance is moved-into/swapped-with this one, all the
|
|
// producers we stole still think their parents are the other queue.
|
|
// So fix them up!
|
|
for (auto ptr = producerListTail.load(std::memory_order_relaxed); ptr != nullptr; ptr = ptr->next_prod()) {
|
|
ptr->parent = this;
|
|
}
|
|
}
|
|
|
|
|
|
//////////////////////////////////
|
|
// Implicit producer hash
|
|
//////////////////////////////////
|
|
|
|
struct ImplicitProducerKVP
|
|
{
|
|
|
|
std::atomic<details::thread_id_t> key;
|
|
ImplicitProducer* value; // No need for atomicity since it's only read by the thread that sets it in the first place
|
|
|
|
ImplicitProducerKVP() : value(nullptr) { }
|
|
|
|
ImplicitProducerKVP(ImplicitProducerKVP&& other) MOODYCAMEL_NOEXCEPT
|
|
{
|
|
key.store(other.key.load(std::memory_order_relaxed), std::memory_order_relaxed);
|
|
value = other.value;
|
|
}
|
|
|
|
inline ImplicitProducerKVP& operator=(ImplicitProducerKVP&& other) MOODYCAMEL_NOEXCEPT
|
|
{
|
|
swap(other);
|
|
return *this;
|
|
}
|
|
|
|
inline void swap(ImplicitProducerKVP& other) MOODYCAMEL_NOEXCEPT
|
|
{
|
|
if (this != &other) {
|
|
details::swap_relaxed(key, other.key);
|
|
|
|
std::swap(value, other.value);
|
|
}
|
|
}
|
|
|
|
};
|
|
|
|
template<typename XT, typename XTraits>
|
|
friend void moodycamel::swap(typename ConcurrentQueue<XT, XTraits>::ImplicitProducerKVP&, typename ConcurrentQueue<XT, XTraits>::ImplicitProducerKVP&) MOODYCAMEL_NOEXCEPT;
|
|
|
|
struct ImplicitProducerHash
|
|
{
|
|
size_t capacity;
|
|
ImplicitProducerKVP* entries;
|
|
ImplicitProducerHash* prev;
|
|
};
|
|
|
|
inline void populate_initial_implicit_producer_hash()
|
|
{
|
|
|
|
MOODYCAMEL_CONSTEXPR_IF (INITIAL_IMPLICIT_PRODUCER_HASH_SIZE == 0) {
|
|
return;
|
|
}
|
|
else {
|
|
implicitProducerHashCount.store(0, std::memory_order_relaxed);
|
|
auto hash = &initialImplicitProducerHash;
|
|
hash->capacity = INITIAL_IMPLICIT_PRODUCER_HASH_SIZE;
|
|
hash->entries = &initialImplicitProducerHashEntries[0];
|
|
|
|
for (size_t i = 0; i != INITIAL_IMPLICIT_PRODUCER_HASH_SIZE; ++i) {
|
|
initialImplicitProducerHashEntries[i].key.store(details::invalid_thread_id, std::memory_order_relaxed);
|
|
}
|
|
hash->prev = nullptr;
|
|
implicitProducerHash.store(hash, std::memory_order_relaxed);
|
|
}
|
|
}
|
|
|
|
void swap_implicit_producer_hashes(ConcurrentQueue& other)
|
|
{
|
|
MOODYCAMEL_CONSTEXPR_IF (INITIAL_IMPLICIT_PRODUCER_HASH_SIZE == 0) {
|
|
return;
|
|
}
|
|
else {
|
|
// Swap (assumes our implicit producer hash is initialized)
|
|
initialImplicitProducerHashEntries.swap(other.initialImplicitProducerHashEntries);
|
|
initialImplicitProducerHash.entries = &initialImplicitProducerHashEntries[0];
|
|
other.initialImplicitProducerHash.entries = &other.initialImplicitProducerHashEntries[0];
|
|
|
|
|
|
details::swap_relaxed(implicitProducerHashCount, other.implicitProducerHashCount);
|
|
|
|
details::swap_relaxed(implicitProducerHash, other.implicitProducerHash);
|
|
if (implicitProducerHash.load(std::memory_order_relaxed) == &other.initialImplicitProducerHash) {
|
|
implicitProducerHash.store(&initialImplicitProducerHash, std::memory_order_relaxed);
|
|
}
|
|
else {
|
|
ImplicitProducerHash* hash;
|
|
for (hash = implicitProducerHash.load(std::memory_order_relaxed); hash->prev != &other.initialImplicitProducerHash; hash = hash->prev) {
|
|
continue;
|
|
}
|
|
hash->prev = &initialImplicitProducerHash;
|
|
}
|
|
if (other.implicitProducerHash.load(std::memory_order_relaxed) == &initialImplicitProducerHash) {
|
|
other.implicitProducerHash.store(&other.initialImplicitProducerHash, std::memory_order_relaxed);
|
|
|
|
}
|
|
|
|
else {
|
|
ImplicitProducerHash* hash;
|
|
for (hash = other.implicitProducerHash.load(std::memory_order_relaxed); hash->prev != &initialImplicitProducerHash; hash = hash->prev) {
|
|
continue;
|
|
}
|
|
hash->prev = &other.initialImplicitProducerHash;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Only fails (returns nullptr) if memory allocation fails
|
|
ImplicitProducer* get_or_add_implicit_producer()
|
|
{
|
|
// Note that since the data is essentially thread-local (key is thread ID),
|
|
// there's a reduced need for fences (memory ordering is already consistent
|
|
// for any individual thread), except for the current table itself.
|
|
|
|
// Start by looking for the thread ID in the current and all previous hash tables.
|
|
// If it's not found, it must not be in there yet, since this same thread would
|
|
// have added it previously to one of the tables that we traversed.
|
|
|
|
// Code and algorithm adapted from http://preshing.com/20130605/the-worlds-simplest-lock-free-hash-table
|
|
|
|
#ifdef MCDBGQ_NOLOCKFREE_IMPLICITPRODHASH
|
|
debug::DebugLock lock(implicitProdMutex);
|
|
#endif
|
|
|
|
auto id = details::thread_id();
|
|
auto hashedId = details::hash_thread_id(id);
|
|
|
|
auto mainHash = implicitProducerHash.load(std::memory_order_acquire);
|
|
assert(mainHash != nullptr); // silence clang-tidy and MSVC warnings (hash cannot be null)
|
|
for (auto hash = mainHash; hash != nullptr; hash = hash->prev) {
|
|
// Look for the id in this hash
|
|
auto index = hashedId;
|
|
while (true) { // Not an infinite loop because at least one slot is free in the hash table
|
|
index &= hash->capacity - 1u;
|
|
|
|
auto probedKey = hash->entries[index].key.load(std::memory_order_relaxed);
|
|
if (probedKey == id) {
|
|
// Found it! If we had to search several hashes deep, though, we should lazily add it
|
|
// to the current main hash table to avoid the extended search next time.
|
|
// Note there's guaranteed to be room in the current hash table since every subsequent
|
|
// table implicitly reserves space for all previous tables (there's only one
|
|
// implicitProducerHashCount).
|
|
auto value = hash->entries[index].value;
|
|
if (hash != mainHash) {
|
|
|
|
index = hashedId;
|
|
while (true) {
|
|
index &= mainHash->capacity - 1u;
|
|
auto empty = details::invalid_thread_id;
|
|
#ifdef MOODYCAMEL_CPP11_THREAD_LOCAL_SUPPORTED
|
|
auto reusable = details::invalid_thread_id2;
|
|
if (mainHash->entries[index].key.compare_exchange_strong(empty, id, std::memory_order_seq_cst, std::memory_order_relaxed) ||
|
|
mainHash->entries[index].key.compare_exchange_strong(reusable, id, std::memory_order_seq_cst, std::memory_order_relaxed)) {
|
|
#else
|
|
if (mainHash->entries[index].key.compare_exchange_strong(empty, id, std::memory_order_seq_cst, std::memory_order_relaxed)) {
|
|
#endif
|
|
mainHash->entries[index].value = value;
|
|
break;
|
|
}
|
|
++index;
|
|
}
|
|
}
|
|
|
|
return value;
|
|
}
|
|
if (probedKey == details::invalid_thread_id) {
|
|
break; // Not in this hash table
|
|
}
|
|
++index;
|
|
}
|
|
}
|
|
|
|
// Insert!
|
|
auto newCount = 1 + implicitProducerHashCount.fetch_add(1, std::memory_order_relaxed);
|
|
while (true) {
|
|
// NOLINTNEXTLINE(clang-analyzer-core.NullDereference)
|
|
if (newCount >= (mainHash->capacity >> 1) && !implicitProducerHashResizeInProgress.test_and_set(std::memory_order_acquire)) {
|
|
// We've acquired the resize lock, try to allocate a bigger hash table.
|
|
// Note the acquire fence synchronizes with the release fence at the end of this block, and hence when
|
|
// we reload implicitProducerHash it must be the most recent version (it only gets changed within this
|
|
// locked block).
|
|
mainHash = implicitProducerHash.load(std::memory_order_acquire);
|
|
if (newCount >= (mainHash->capacity >> 1)) {
|
|
size_t newCapacity = mainHash->capacity << 1;
|
|
|
|
while (newCount >= (newCapacity >> 1)) {
|
|
|
|
newCapacity <<= 1;
|
|
}
|
|
auto raw = static_cast<char*>((Traits::malloc)(sizeof(ImplicitProducerHash) + std::alignment_of<ImplicitProducerKVP>::value - 1 + sizeof(ImplicitProducerKVP) * newCapacity));
|
|
if (raw == nullptr) {
|
|
// Allocation failed
|
|
implicitProducerHashCount.fetch_sub(1, std::memory_order_relaxed);
|
|
implicitProducerHashResizeInProgress.clear(std::memory_order_relaxed);
|
|
return nullptr;
|
|
}
|
|
|
|
auto newHash = new (raw) ImplicitProducerHash;
|
|
newHash->capacity = static_cast<size_t>(newCapacity);
|
|
newHash->entries = reinterpret_cast<ImplicitProducerKVP*>(details::align_for<ImplicitProducerKVP>(raw + sizeof(ImplicitProducerHash)));
|
|
for (size_t i = 0; i != newCapacity; ++i) {
|
|
new (newHash->entries + i) ImplicitProducerKVP;
|
|
newHash->entries[i].key.store(details::invalid_thread_id, std::memory_order_relaxed);
|
|
}
|
|
newHash->prev = mainHash;
|
|
implicitProducerHash.store(newHash, std::memory_order_release);
|
|
implicitProducerHashResizeInProgress.clear(std::memory_order_release);
|
|
mainHash = newHash;
|
|
}
|
|
else {
|
|
implicitProducerHashResizeInProgress.clear(std::memory_order_release);
|
|
}
|
|
}
|
|
|
|
// If it's < three-quarters full, add to the old one anyway so that we don't have to wait for the next table
|
|
// to finish being allocated by another thread (and if we just finished allocating above, the condition will
|
|
// always be true)
|
|
if (newCount < (mainHash->capacity >> 1) + (mainHash->capacity >> 2)) {
|
|
auto producer = static_cast<ImplicitProducer*>(recycle_or_create_producer(false));
|
|
if (producer == nullptr) {
|
|
implicitProducerHashCount.fetch_sub(1, std::memory_order_relaxed);
|
|
return nullptr;
|
|
}
|
|
|
|
#ifdef MOODYCAMEL_CPP11_THREAD_LOCAL_SUPPORTED
|
|
producer->threadExitListener.callback = &ConcurrentQueue::implicit_producer_thread_exited_callback;
|
|
producer->threadExitListener.userData = producer;
|
|
details::ThreadExitNotifier::subscribe(&producer->threadExitListener);
|
|
#endif
|
|
|
|
auto index = hashedId;
|
|
while (true) {
|
|
index &= mainHash->capacity - 1u;
|
|
auto empty = details::invalid_thread_id;
|
|
#ifdef MOODYCAMEL_CPP11_THREAD_LOCAL_SUPPORTED
|
|
auto reusable = details::invalid_thread_id2;
|
|
if (mainHash->entries[index].key.compare_exchange_strong(reusable, id, std::memory_order_seq_cst, std::memory_order_relaxed)) {
|
|
implicitProducerHashCount.fetch_sub(1, std::memory_order_relaxed); // already counted as a used slot
|
|
mainHash->entries[index].value = producer;
|
|
break;
|
|
}
|
|
#endif
|
|
if (mainHash->entries[index].key.compare_exchange_strong(empty, id, std::memory_order_seq_cst, std::memory_order_relaxed)) {
|
|
mainHash->entries[index].value = producer;
|
|
break;
|
|
}
|
|
++index;
|
|
}
|
|
return producer;
|
|
}
|
|
|
|
// Hmm, the old hash is quite full and somebody else is busy allocating a new one.
|
|
// We need to wait for the allocating thread to finish (if it succeeds, we add, if not,
|
|
// we try to allocate ourselves).
|
|
mainHash = implicitProducerHash.load(std::memory_order_acquire);
|
|
}
|
|
}
|
|
|
|
#ifdef MOODYCAMEL_CPP11_THREAD_LOCAL_SUPPORTED
|
|
void implicit_producer_thread_exited(ImplicitProducer* producer)
|
|
{
|
|
// Remove from hash
|
|
#ifdef MCDBGQ_NOLOCKFREE_IMPLICITPRODHASH
|
|
debug::DebugLock lock(implicitProdMutex);
|
|
#endif
|
|
auto hash = implicitProducerHash.load(std::memory_order_acquire);
|
|
assert(hash != nullptr); // The thread exit listener is only registered if we were added to a hash in the first place
|
|
auto id = details::thread_id();
|
|
auto hashedId = details::hash_thread_id(id);
|
|
details::thread_id_t probedKey;
|
|
|
|
// We need to traverse all the hashes just in case other threads aren't on the current one yet and are
|
|
// trying to add an entry thinking there's a free slot (because they reused a producer)
|
|
for (; hash != nullptr; hash = hash->prev) {
|
|
auto index = hashedId;
|
|
do {
|
|
index &= hash->capacity - 1u;
|
|
probedKey = id;
|
|
if (hash->entries[index].key.compare_exchange_strong(probedKey, details::invalid_thread_id2, std::memory_order_seq_cst, std::memory_order_relaxed)) {
|
|
break;
|
|
}
|
|
++index;
|
|
} while (probedKey != details::invalid_thread_id); // Can happen if the hash has changed but we weren't put back in it yet, or if we weren't added to this hash in the first place
|
|
}
|
|
|
|
// Mark the queue as being recyclable
|
|
producer->inactive.store(true, std::memory_order_release);
|
|
}
|
|
|
|
static void implicit_producer_thread_exited_callback(void* userData)
|
|
{
|
|
auto producer = static_cast<ImplicitProducer*>(userData);
|
|
auto queue = producer->parent;
|
|
queue->implicit_producer_thread_exited(producer);
|
|
}
|
|
#endif
|
|
|
|
//////////////////////////////////
|
|
// Utility functions
|
|
//////////////////////////////////
|
|
|
|
template<typename TAlign>
|
|
static inline void* aligned_malloc(size_t size)
|
|
{
|
|
MOODYCAMEL_CONSTEXPR_IF (std::alignment_of<TAlign>::value <= std::alignment_of<details::max_align_t>::value)
|
|
return (Traits::malloc)(size);
|
|
else {
|
|
size_t alignment = std::alignment_of<TAlign>::value;
|
|
void* raw = (Traits::malloc)(size + alignment - 1 + sizeof(void*));
|
|
if (!raw)
|
|
return nullptr;
|
|
char* ptr = details::align_for<TAlign>(reinterpret_cast<char*>(raw) + sizeof(void*));
|
|
*(reinterpret_cast<void**>(ptr) - 1) = raw;
|
|
return ptr;
|
|
}
|
|
}
|
|
|
|
template<typename TAlign>
|
|
static inline void aligned_free(void* ptr)
|
|
{
|
|
MOODYCAMEL_CONSTEXPR_IF (std::alignment_of<TAlign>::value <= std::alignment_of<details::max_align_t>::value)
|
|
return (Traits::free)(ptr);
|
|
else
|
|
(Traits::free)(ptr ? *(reinterpret_cast<void**>(ptr) - 1) : nullptr);
|
|
}
|
|
|
|
template<typename U>
|
|
static inline U* create_array(size_t count)
|
|
{
|
|
assert(count > 0);
|
|
U* p = static_cast<U*>(aligned_malloc<U>(sizeof(U) * count));
|
|
if (p == nullptr)
|
|
return nullptr;
|
|
|
|
for (size_t i = 0; i != count; ++i)
|
|
new (p + i) U();
|
|
return p;
|
|
}
|
|
|
|
template<typename U>
|
|
static inline void destroy_array(U* p, size_t count)
|
|
{
|
|
if (p != nullptr) {
|
|
assert(count > 0);
|
|
for (size_t i = count; i != 0; )
|
|
(p + --i)->~U();
|
|
}
|
|
aligned_free<U>(p);
|
|
}
|
|
|
|
template<typename U>
|
|
static inline U* create()
|
|
{
|
|
void* p = aligned_malloc<U>(sizeof(U));
|
|
return p != nullptr ? new (p) U : nullptr;
|
|
}
|
|
|
|
template<typename U, typename A1>
|
|
static inline U* create(A1&& a1)
|
|
{
|
|
void* p = aligned_malloc<U>(sizeof(U));
|
|
return p != nullptr ? new (p) U(std::forward<A1>(a1)) : nullptr;
|
|
}
|
|
|
|
template<typename U>
|
|
static inline void destroy(U* p)
|
|
{
|
|
if (p != nullptr)
|
|
p->~U();
|
|
aligned_free<U>(p);
|
|
}
|
|
|
|
private:
|
|
std::atomic<ProducerBase*> producerListTail;
|
|
std::atomic<std::uint32_t> producerCount;
|
|
|
|
std::atomic<size_t> initialBlockPoolIndex;
|
|
Block* initialBlockPool;
|
|
size_t initialBlockPoolSize;
|
|
|
|
#ifndef MCDBGQ_USEDEBUGFREELIST
|
|
FreeList<Block> freeList;
|
|
#else
|
|
debug::DebugFreeList<Block> freeList;
|
|
#endif
|
|
|
|
std::atomic<ImplicitProducerHash*> implicitProducerHash;
|
|
std::atomic<size_t> implicitProducerHashCount; // Number of slots logically used
|
|
ImplicitProducerHash initialImplicitProducerHash;
|
|
std::array<ImplicitProducerKVP, INITIAL_IMPLICIT_PRODUCER_HASH_SIZE> initialImplicitProducerHashEntries;
|
|
std::atomic_flag implicitProducerHashResizeInProgress;
|
|
|
|
std::atomic<std::uint32_t> nextExplicitConsumerId;
|
|
std::atomic<std::uint32_t> globalExplicitConsumerOffset;
|
|
|
|
#ifdef MCDBGQ_NOLOCKFREE_IMPLICITPRODHASH
|
|
debug::DebugMutex implicitProdMutex;
|
|
#endif
|
|
|
|
#ifdef MOODYCAMEL_QUEUE_INTERNAL_DEBUG
|
|
std::atomic<ExplicitProducer*> explicitProducers;
|
|
std::atomic<ImplicitProducer*> implicitProducers;
|
|
#endif
|
|
};
|
|
|
|
|
|
template<typename T, typename Traits>
|
|
ProducerToken::ProducerToken(ConcurrentQueue<T, Traits>& queue)
|
|
: producer(queue.recycle_or_create_producer(true))
|
|
{
|
|
if (producer != nullptr) {
|
|
producer->token = this;
|
|
}
|
|
}
|
|
|
|
template<typename T, typename Traits>
|
|
ProducerToken::ProducerToken(BlockingConcurrentQueue<T, Traits>& queue)
|
|
: producer(reinterpret_cast<ConcurrentQueue<T, Traits>*>(&queue)->recycle_or_create_producer(true))
|
|
{
|
|
if (producer != nullptr) {
|
|
producer->token = this;
|
|
}
|
|
}
|
|
|
|
template<typename T, typename Traits>
|
|
ConsumerToken::ConsumerToken(ConcurrentQueue<T, Traits>& queue)
|
|
: itemsConsumedFromCurrent(0), currentProducer(nullptr), desiredProducer(nullptr)
|
|
{
|
|
initialOffset = queue.nextExplicitConsumerId.fetch_add(1, std::memory_order_release);
|
|
lastKnownGlobalOffset = static_cast<std::uint32_t>(-1);
|
|
}
|
|
|
|
template<typename T, typename Traits>
|
|
ConsumerToken::ConsumerToken(BlockingConcurrentQueue<T, Traits>& queue)
|
|
: itemsConsumedFromCurrent(0), currentProducer(nullptr), desiredProducer(nullptr)
|
|
{
|
|
initialOffset = reinterpret_cast<ConcurrentQueue<T, Traits>*>(&queue)->nextExplicitConsumerId.fetch_add(1, std::memory_order_release);
|
|
lastKnownGlobalOffset = static_cast<std::uint32_t>(-1);
|
|
}
|
|
|
|
template<typename T, typename Traits>
|
|
inline void swap(ConcurrentQueue<T, Traits>& a, ConcurrentQueue<T, Traits>& b) MOODYCAMEL_NOEXCEPT
|
|
{
|
|
|
|
a.swap(b);
|
|
}
|
|
|
|
inline void swap(ProducerToken& a, ProducerToken& b) MOODYCAMEL_NOEXCEPT
|
|
{
|
|
a.swap(b);
|
|
}
|
|
|
|
inline void swap(ConsumerToken& a, ConsumerToken& b) MOODYCAMEL_NOEXCEPT
|
|
{
|
|
a.swap(b);
|
|
}
|
|
|
|
template<typename T, typename Traits>
|
|
inline void swap(typename ConcurrentQueue<T, Traits>::ImplicitProducerKVP& a, typename ConcurrentQueue<T, Traits>::ImplicitProducerKVP& b) MOODYCAMEL_NOEXCEPT
|
|
{
|
|
a.swap(b);
|
|
}
|
|
|
|
}
|
|
|
|
#if defined(_MSC_VER) && (!defined(_HAS_CXX17) || !_HAS_CXX17)
|
|
#pragma warning(pop)
|
|
#endif
|
|
|
|
#if defined(__GNUC__) && !defined(__INTEL_COMPILER)
|
|
#pragma GCC diagnostic pop
|
|
#endif
|