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Diffstat (limited to 'libstdc++-v3/include/ext/mt_allocator.h')
| -rw-r--r-- | libstdc++-v3/include/ext/mt_allocator.h | 754 |
1 files changed, 754 insertions, 0 deletions
diff --git a/libstdc++-v3/include/ext/mt_allocator.h b/libstdc++-v3/include/ext/mt_allocator.h new file mode 100644 index 000000000..91eac24f2 --- /dev/null +++ b/libstdc++-v3/include/ext/mt_allocator.h @@ -0,0 +1,754 @@ +// MT-optimized allocator -*- C++ -*- + +// Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 +// Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. + +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +// Under Section 7 of GPL version 3, you are granted additional +// permissions described in the GCC Runtime Library Exception, version +// 3.1, as published by the Free Software Foundation. + +// You should have received a copy of the GNU General Public License and +// a copy of the GCC Runtime Library Exception along with this program; +// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see +// <http://www.gnu.org/licenses/>. + +/** @file ext/mt_allocator.h + * This file is a GNU extension to the Standard C++ Library. + */ + +#ifndef _MT_ALLOCATOR_H +#define _MT_ALLOCATOR_H 1 + +#include <new> +#include <cstdlib> +#include <bits/functexcept.h> +#include <ext/atomicity.h> +#include <bits/move.h> + +namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) +{ +_GLIBCXX_BEGIN_NAMESPACE_VERSION + + using std::size_t; + using std::ptrdiff_t; + + typedef void (*__destroy_handler)(void*); + + /// Base class for pool object. + struct __pool_base + { + // Using short int as type for the binmap implies we are never + // caching blocks larger than 32768 with this allocator. + typedef unsigned short int _Binmap_type; + + // Variables used to configure the behavior of the allocator, + // assigned and explained in detail below. + struct _Tune + { + // Compile time constants for the default _Tune values. + enum { _S_align = 8 }; + enum { _S_max_bytes = 128 }; + enum { _S_min_bin = 8 }; + enum { _S_chunk_size = 4096 - 4 * sizeof(void*) }; + enum { _S_max_threads = 4096 }; + enum { _S_freelist_headroom = 10 }; + + // Alignment needed. + // NB: In any case must be >= sizeof(_Block_record), that + // is 4 on 32 bit machines and 8 on 64 bit machines. + size_t _M_align; + + // Allocation requests (after round-up to power of 2) below + // this value will be handled by the allocator. A raw new/ + // call will be used for requests larger than this value. + // NB: Must be much smaller than _M_chunk_size and in any + // case <= 32768. + size_t _M_max_bytes; + + // Size in bytes of the smallest bin. + // NB: Must be a power of 2 and >= _M_align (and of course + // much smaller than _M_max_bytes). + size_t _M_min_bin; + + // In order to avoid fragmenting and minimize the number of + // new() calls we always request new memory using this + // value. Based on previous discussions on the libstdc++ + // mailing list we have chosen the value below. + // See http://gcc.gnu.org/ml/libstdc++/2001-07/msg00077.html + // NB: At least one order of magnitude > _M_max_bytes. + size_t _M_chunk_size; + + // The maximum number of supported threads. For + // single-threaded operation, use one. Maximum values will + // vary depending on details of the underlying system. (For + // instance, Linux 2.4.18 reports 4070 in + // /proc/sys/kernel/threads-max, while Linux 2.6.6 reports + // 65534) + size_t _M_max_threads; + + // Each time a deallocation occurs in a threaded application + // we make sure that there are no more than + // _M_freelist_headroom % of used memory on the freelist. If + // the number of additional records is more than + // _M_freelist_headroom % of the freelist, we move these + // records back to the global pool. + size_t _M_freelist_headroom; + + // Set to true forces all allocations to use new(). + bool _M_force_new; + + explicit + _Tune() + : _M_align(_S_align), _M_max_bytes(_S_max_bytes), _M_min_bin(_S_min_bin), + _M_chunk_size(_S_chunk_size), _M_max_threads(_S_max_threads), + _M_freelist_headroom(_S_freelist_headroom), + _M_force_new(std::getenv("GLIBCXX_FORCE_NEW") ? true : false) + { } + + explicit + _Tune(size_t __align, size_t __maxb, size_t __minbin, size_t __chunk, + size_t __maxthreads, size_t __headroom, bool __force) + : _M_align(__align), _M_max_bytes(__maxb), _M_min_bin(__minbin), + _M_chunk_size(__chunk), _M_max_threads(__maxthreads), + _M_freelist_headroom(__headroom), _M_force_new(__force) + { } + }; + + struct _Block_address + { + void* _M_initial; + _Block_address* _M_next; + }; + + const _Tune& + _M_get_options() const + { return _M_options; } + + void + _M_set_options(_Tune __t) + { + if (!_M_init) + _M_options = __t; + } + + bool + _M_check_threshold(size_t __bytes) + { return __bytes > _M_options._M_max_bytes || _M_options._M_force_new; } + + size_t + _M_get_binmap(size_t __bytes) + { return _M_binmap[__bytes]; } + + size_t + _M_get_align() + { return _M_options._M_align; } + + explicit + __pool_base() + : _M_options(_Tune()), _M_binmap(0), _M_init(false) { } + + explicit + __pool_base(const _Tune& __options) + : _M_options(__options), _M_binmap(0), _M_init(false) { } + + private: + explicit + __pool_base(const __pool_base&); + + __pool_base& + operator=(const __pool_base&); + + protected: + // Configuration options. + _Tune _M_options; + + _Binmap_type* _M_binmap; + + // Configuration of the pool object via _M_options can happen + // after construction but before initialization. After + // initialization is complete, this variable is set to true. + bool _M_init; + }; + + + /** + * @brief Data describing the underlying memory pool, parameterized on + * threading support. + */ + template<bool _Thread> + class __pool; + + /// Specialization for single thread. + template<> + class __pool<false> : public __pool_base + { + public: + union _Block_record + { + // Points to the block_record of the next free block. + _Block_record* _M_next; + }; + + struct _Bin_record + { + // An "array" of pointers to the first free block. + _Block_record** _M_first; + + // A list of the initial addresses of all allocated blocks. + _Block_address* _M_address; + }; + + void + _M_initialize_once() + { + if (__builtin_expect(_M_init == false, false)) + _M_initialize(); + } + + void + _M_destroy() throw(); + + char* + _M_reserve_block(size_t __bytes, const size_t __thread_id); + + void + _M_reclaim_block(char* __p, size_t __bytes) throw (); + + size_t + _M_get_thread_id() { return 0; } + + const _Bin_record& + _M_get_bin(size_t __which) + { return _M_bin[__which]; } + + void + _M_adjust_freelist(const _Bin_record&, _Block_record*, size_t) + { } + + explicit __pool() + : _M_bin(0), _M_bin_size(1) { } + + explicit __pool(const __pool_base::_Tune& __tune) + : __pool_base(__tune), _M_bin(0), _M_bin_size(1) { } + + private: + // An "array" of bin_records each of which represents a specific + // power of 2 size. Memory to this "array" is allocated in + // _M_initialize(). + _Bin_record* _M_bin; + + // Actual value calculated in _M_initialize(). + size_t _M_bin_size; + + void + _M_initialize(); + }; + +#ifdef __GTHREADS + /// Specialization for thread enabled, via gthreads.h. + template<> + class __pool<true> : public __pool_base + { + public: + // Each requesting thread is assigned an id ranging from 1 to + // _S_max_threads. Thread id 0 is used as a global memory pool. + // In order to get constant performance on the thread assignment + // routine, we keep a list of free ids. When a thread first + // requests memory we remove the first record in this list and + // stores the address in a __gthread_key. When initializing the + // __gthread_key we specify a destructor. When this destructor + // (i.e. the thread dies) is called, we return the thread id to + // the front of this list. + struct _Thread_record + { + // Points to next free thread id record. NULL if last record in list. + _Thread_record* _M_next; + + // Thread id ranging from 1 to _S_max_threads. + size_t _M_id; + }; + + union _Block_record + { + // Points to the block_record of the next free block. + _Block_record* _M_next; + + // The thread id of the thread which has requested this block. + size_t _M_thread_id; + }; + + struct _Bin_record + { + // An "array" of pointers to the first free block for each + // thread id. Memory to this "array" is allocated in + // _S_initialize() for _S_max_threads + global pool 0. + _Block_record** _M_first; + + // A list of the initial addresses of all allocated blocks. + _Block_address* _M_address; + + // An "array" of counters used to keep track of the amount of + // blocks that are on the freelist/used for each thread id. + // - Note that the second part of the allocated _M_used "array" + // actually hosts (atomic) counters of reclaimed blocks: in + // _M_reserve_block and in _M_reclaim_block those numbers are + // subtracted from the first ones to obtain the actual size + // of the "working set" of the given thread. + // - Memory to these "arrays" is allocated in _S_initialize() + // for _S_max_threads + global pool 0. + size_t* _M_free; + size_t* _M_used; + + // Each bin has its own mutex which is used to ensure data + // integrity while changing "ownership" on a block. The mutex + // is initialized in _S_initialize(). + __gthread_mutex_t* _M_mutex; + }; + + // XXX GLIBCXX_ABI Deprecated + void + _M_initialize(__destroy_handler); + + void + _M_initialize_once() + { + if (__builtin_expect(_M_init == false, false)) + _M_initialize(); + } + + void + _M_destroy() throw(); + + char* + _M_reserve_block(size_t __bytes, const size_t __thread_id); + + void + _M_reclaim_block(char* __p, size_t __bytes) throw (); + + const _Bin_record& + _M_get_bin(size_t __which) + { return _M_bin[__which]; } + + void + _M_adjust_freelist(const _Bin_record& __bin, _Block_record* __block, + size_t __thread_id) + { + if (__gthread_active_p()) + { + __block->_M_thread_id = __thread_id; + --__bin._M_free[__thread_id]; + ++__bin._M_used[__thread_id]; + } + } + + // XXX GLIBCXX_ABI Deprecated + _GLIBCXX_CONST void + _M_destroy_thread_key(void*) throw (); + + size_t + _M_get_thread_id(); + + explicit __pool() + : _M_bin(0), _M_bin_size(1), _M_thread_freelist(0) + { } + + explicit __pool(const __pool_base::_Tune& __tune) + : __pool_base(__tune), _M_bin(0), _M_bin_size(1), + _M_thread_freelist(0) + { } + + private: + // An "array" of bin_records each of which represents a specific + // power of 2 size. Memory to this "array" is allocated in + // _M_initialize(). + _Bin_record* _M_bin; + + // Actual value calculated in _M_initialize(). + size_t _M_bin_size; + + _Thread_record* _M_thread_freelist; + void* _M_thread_freelist_initial; + + void + _M_initialize(); + }; +#endif + + template<template <bool> class _PoolTp, bool _Thread> + struct __common_pool + { + typedef _PoolTp<_Thread> pool_type; + + static pool_type& + _S_get_pool() + { + static pool_type _S_pool; + return _S_pool; + } + }; + + template<template <bool> class _PoolTp, bool _Thread> + struct __common_pool_base; + + template<template <bool> class _PoolTp> + struct __common_pool_base<_PoolTp, false> + : public __common_pool<_PoolTp, false> + { + using __common_pool<_PoolTp, false>::_S_get_pool; + + static void + _S_initialize_once() + { + static bool __init; + if (__builtin_expect(__init == false, false)) + { + _S_get_pool()._M_initialize_once(); + __init = true; + } + } + }; + +#ifdef __GTHREADS + template<template <bool> class _PoolTp> + struct __common_pool_base<_PoolTp, true> + : public __common_pool<_PoolTp, true> + { + using __common_pool<_PoolTp, true>::_S_get_pool; + + static void + _S_initialize() + { _S_get_pool()._M_initialize_once(); } + + static void + _S_initialize_once() + { + static bool __init; + if (__builtin_expect(__init == false, false)) + { + if (__gthread_active_p()) + { + // On some platforms, __gthread_once_t is an aggregate. + static __gthread_once_t __once = __GTHREAD_ONCE_INIT; + __gthread_once(&__once, _S_initialize); + } + + // Double check initialization. May be necessary on some + // systems for proper construction when not compiling with + // thread flags. + _S_get_pool()._M_initialize_once(); + __init = true; + } + } + }; +#endif + + /// Policy for shared __pool objects. + template<template <bool> class _PoolTp, bool _Thread> + struct __common_pool_policy : public __common_pool_base<_PoolTp, _Thread> + { + template<typename _Tp1, template <bool> class _PoolTp1 = _PoolTp, + bool _Thread1 = _Thread> + struct _M_rebind + { typedef __common_pool_policy<_PoolTp1, _Thread1> other; }; + + using __common_pool_base<_PoolTp, _Thread>::_S_get_pool; + using __common_pool_base<_PoolTp, _Thread>::_S_initialize_once; + }; + + + template<typename _Tp, template <bool> class _PoolTp, bool _Thread> + struct __per_type_pool + { + typedef _Tp value_type; + typedef _PoolTp<_Thread> pool_type; + + static pool_type& + _S_get_pool() + { + // Sane defaults for the _PoolTp. + typedef typename pool_type::_Block_record _Block_record; + const static size_t __a = (__alignof__(_Tp) >= sizeof(_Block_record) + ? __alignof__(_Tp) : sizeof(_Block_record)); + + typedef typename __pool_base::_Tune _Tune; + static _Tune _S_tune(__a, sizeof(_Tp) * 64, + sizeof(_Tp) * 2 >= __a ? sizeof(_Tp) * 2 : __a, + sizeof(_Tp) * size_t(_Tune::_S_chunk_size), + _Tune::_S_max_threads, + _Tune::_S_freelist_headroom, + std::getenv("GLIBCXX_FORCE_NEW") ? true : false); + static pool_type _S_pool(_S_tune); + return _S_pool; + } + }; + + template<typename _Tp, template <bool> class _PoolTp, bool _Thread> + struct __per_type_pool_base; + + template<typename _Tp, template <bool> class _PoolTp> + struct __per_type_pool_base<_Tp, _PoolTp, false> + : public __per_type_pool<_Tp, _PoolTp, false> + { + using __per_type_pool<_Tp, _PoolTp, false>::_S_get_pool; + + static void + _S_initialize_once() + { + static bool __init; + if (__builtin_expect(__init == false, false)) + { + _S_get_pool()._M_initialize_once(); + __init = true; + } + } + }; + + #ifdef __GTHREADS + template<typename _Tp, template <bool> class _PoolTp> + struct __per_type_pool_base<_Tp, _PoolTp, true> + : public __per_type_pool<_Tp, _PoolTp, true> + { + using __per_type_pool<_Tp, _PoolTp, true>::_S_get_pool; + + static void + _S_initialize() + { _S_get_pool()._M_initialize_once(); } + + static void + _S_initialize_once() + { + static bool __init; + if (__builtin_expect(__init == false, false)) + { + if (__gthread_active_p()) + { + // On some platforms, __gthread_once_t is an aggregate. + static __gthread_once_t __once = __GTHREAD_ONCE_INIT; + __gthread_once(&__once, _S_initialize); + } + + // Double check initialization. May be necessary on some + // systems for proper construction when not compiling with + // thread flags. + _S_get_pool()._M_initialize_once(); + __init = true; + } + } + }; +#endif + + /// Policy for individual __pool objects. + template<typename _Tp, template <bool> class _PoolTp, bool _Thread> + struct __per_type_pool_policy + : public __per_type_pool_base<_Tp, _PoolTp, _Thread> + { + template<typename _Tp1, template <bool> class _PoolTp1 = _PoolTp, + bool _Thread1 = _Thread> + struct _M_rebind + { typedef __per_type_pool_policy<_Tp1, _PoolTp1, _Thread1> other; }; + + using __per_type_pool_base<_Tp, _PoolTp, _Thread>::_S_get_pool; + using __per_type_pool_base<_Tp, _PoolTp, _Thread>::_S_initialize_once; + }; + + + /// Base class for _Tp dependent member functions. + template<typename _Tp> + class __mt_alloc_base + { + public: + typedef size_t size_type; + typedef ptrdiff_t difference_type; + typedef _Tp* pointer; + typedef const _Tp* const_pointer; + typedef _Tp& reference; + typedef const _Tp& const_reference; + typedef _Tp value_type; + + pointer + address(reference __x) const + { return std::__addressof(__x); } + + const_pointer + address(const_reference __x) const + { return std::__addressof(__x); } + + size_type + max_size() const throw() + { return size_t(-1) / sizeof(_Tp); } + + // _GLIBCXX_RESOLVE_LIB_DEFECTS + // 402. wrong new expression in [some_] allocator::construct + void + construct(pointer __p, const _Tp& __val) + { ::new((void *)__p) _Tp(__val); } + +#ifdef __GXX_EXPERIMENTAL_CXX0X__ + template<typename... _Args> + void + construct(pointer __p, _Args&&... __args) + { ::new((void *)__p) _Tp(std::forward<_Args>(__args)...); } +#endif + + void + destroy(pointer __p) { __p->~_Tp(); } + }; + +#ifdef __GTHREADS +#define __thread_default true +#else +#define __thread_default false +#endif + + /** + * @brief This is a fixed size (power of 2) allocator which - when + * compiled with thread support - will maintain one freelist per + * size per thread plus a @a global one. Steps are taken to limit + * the per thread freelist sizes (by returning excess back to + * the @a global list). + * @ingroup allocators + * + * Further details: + * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt12ch32.html + */ + template<typename _Tp, + typename _Poolp = __common_pool_policy<__pool, __thread_default> > + class __mt_alloc : public __mt_alloc_base<_Tp> + { + public: + typedef size_t size_type; + typedef ptrdiff_t difference_type; + typedef _Tp* pointer; + typedef const _Tp* const_pointer; + typedef _Tp& reference; + typedef const _Tp& const_reference; + typedef _Tp value_type; + typedef _Poolp __policy_type; + typedef typename _Poolp::pool_type __pool_type; + + template<typename _Tp1, typename _Poolp1 = _Poolp> + struct rebind + { + typedef typename _Poolp1::template _M_rebind<_Tp1>::other pol_type; + typedef __mt_alloc<_Tp1, pol_type> other; + }; + + __mt_alloc() throw() { } + + __mt_alloc(const __mt_alloc&) throw() { } + + template<typename _Tp1, typename _Poolp1> + __mt_alloc(const __mt_alloc<_Tp1, _Poolp1>&) throw() { } + + ~__mt_alloc() throw() { } + + pointer + allocate(size_type __n, const void* = 0); + + void + deallocate(pointer __p, size_type __n); + + const __pool_base::_Tune + _M_get_options() + { + // Return a copy, not a reference, for external consumption. + return __policy_type::_S_get_pool()._M_get_options(); + } + + void + _M_set_options(__pool_base::_Tune __t) + { __policy_type::_S_get_pool()._M_set_options(__t); } + }; + + template<typename _Tp, typename _Poolp> + typename __mt_alloc<_Tp, _Poolp>::pointer + __mt_alloc<_Tp, _Poolp>:: + allocate(size_type __n, const void*) + { + if (__n > this->max_size()) + std::__throw_bad_alloc(); + + __policy_type::_S_initialize_once(); + + // Requests larger than _M_max_bytes are handled by operator + // new/delete directly. + __pool_type& __pool = __policy_type::_S_get_pool(); + const size_t __bytes = __n * sizeof(_Tp); + if (__pool._M_check_threshold(__bytes)) + { + void* __ret = ::operator new(__bytes); + return static_cast<_Tp*>(__ret); + } + + // Round up to power of 2 and figure out which bin to use. + const size_t __which = __pool._M_get_binmap(__bytes); + const size_t __thread_id = __pool._M_get_thread_id(); + + // Find out if we have blocks on our freelist. If so, go ahead + // and use them directly without having to lock anything. + char* __c; + typedef typename __pool_type::_Bin_record _Bin_record; + const _Bin_record& __bin = __pool._M_get_bin(__which); + if (__bin._M_first[__thread_id]) + { + // Already reserved. + typedef typename __pool_type::_Block_record _Block_record; + _Block_record* __block = __bin._M_first[__thread_id]; + __bin._M_first[__thread_id] = __block->_M_next; + + __pool._M_adjust_freelist(__bin, __block, __thread_id); + __c = reinterpret_cast<char*>(__block) + __pool._M_get_align(); + } + else + { + // Null, reserve. + __c = __pool._M_reserve_block(__bytes, __thread_id); + } + return static_cast<_Tp*>(static_cast<void*>(__c)); + } + + template<typename _Tp, typename _Poolp> + void + __mt_alloc<_Tp, _Poolp>:: + deallocate(pointer __p, size_type __n) + { + if (__builtin_expect(__p != 0, true)) + { + // Requests larger than _M_max_bytes are handled by + // operators new/delete directly. + __pool_type& __pool = __policy_type::_S_get_pool(); + const size_t __bytes = __n * sizeof(_Tp); + if (__pool._M_check_threshold(__bytes)) + ::operator delete(__p); + else + __pool._M_reclaim_block(reinterpret_cast<char*>(__p), __bytes); + } + } + + template<typename _Tp, typename _Poolp> + inline bool + operator==(const __mt_alloc<_Tp, _Poolp>&, const __mt_alloc<_Tp, _Poolp>&) + { return true; } + + template<typename _Tp, typename _Poolp> + inline bool + operator!=(const __mt_alloc<_Tp, _Poolp>&, const __mt_alloc<_Tp, _Poolp>&) + { return false; } + +#undef __thread_default + +_GLIBCXX_END_NAMESPACE_VERSION +} // namespace + +#endif |