diff options
Diffstat (limited to 'contrib/libstdc++/include/ext/mt_allocator.h')
| -rw-r--r-- | contrib/libstdc++/include/ext/mt_allocator.h | 1196 |
1 files changed, 612 insertions, 584 deletions
diff --git a/contrib/libstdc++/include/ext/mt_allocator.h b/contrib/libstdc++/include/ext/mt_allocator.h index f0ee2eb..bc2d61f 100644 --- a/contrib/libstdc++/include/ext/mt_allocator.h +++ b/contrib/libstdc++/include/ext/mt_allocator.h @@ -1,6 +1,6 @@ // MT-optimized allocator -*- C++ -*- -// Copyright (C) 2003, 2004 Free Software Foundation, Inc. +// Copyright (C) 2003, 2004, 2005, 2006 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 @@ -15,7 +15,7 @@ // You should have received a copy of the GNU General Public License along // with this library; see the file COPYING. If not, write to the Free -// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, +// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, // USA. // As a special exception, you may use this file as part of a free software @@ -29,7 +29,6 @@ /** @file ext/mt_allocator.h * This file is a GNU extension to the Standard C++ Library. - * You should only include this header if you are using GCC 3 or later. */ #ifndef _MT_ALLOCATOR_H @@ -38,170 +37,231 @@ #include <new> #include <cstdlib> #include <bits/functexcept.h> -#include <bits/gthr.h> -#include <bits/atomicity.h> - -namespace __gnu_cxx -{ - /** - * 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 "global" one. Steps are taken to limit - * the per thread freelist sizes (by returning excess back to - * "global"). - * - * Further details: - * http://gcc.gnu.org/onlinedocs/libstdc++/ext/mt_allocator.html - */ - template<typename _Tp> - class __mt_alloc +#include <ext/atomicity.h> + +_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx) + + using std::size_t; + using std::ptrdiff_t; + + typedef void (*__destroy_handler)(void*); + + /// @brief 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 choosen 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 { - 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; + void* _M_initial; + _Block_address* _M_next; + }; + + const _Tune& + _M_get_options() const + { return _M_options; } - template<typename _Tp1> - struct rebind - { typedef __mt_alloc<_Tp1> other; }; + void + _M_set_options(_Tune __t) + { + if (!_M_init) + _M_options = __t; + } - __mt_alloc() throw() - { - // XXX - } + bool + _M_check_threshold(size_t __bytes) + { return __bytes > _M_options._M_max_bytes || _M_options._M_force_new; } - __mt_alloc(const __mt_alloc&) throw() - { - // XXX - } + size_t + _M_get_binmap(size_t __bytes) + { return _M_binmap[__bytes]; } - template<typename _Tp1> - __mt_alloc(const __mt_alloc<_Tp1>& obj) throw() - { - // XXX - } + const size_t + _M_get_align() + { return _M_options._M_align; } - ~__mt_alloc() throw() { } + explicit + __pool_base() + : _M_options(_Tune()), _M_binmap(NULL), _M_init(false) { } - pointer - address(reference __x) const - { return &__x; } + explicit + __pool_base(const _Tune& __options) + : _M_options(__options), _M_binmap(NULL), _M_init(false) { } - const_pointer - address(const_reference __x) const - { return &__x; } + private: + explicit + __pool_base(const __pool_base&); - size_type - max_size() const throw() - { return size_t(-1) / sizeof(_Tp); } + __pool_base& + operator=(const __pool_base&); - // _GLIBCXX_RESOLVE_LIB_DEFECTS - // 402. wrong new expression in [some_] allocator::construct - void - construct(pointer __p, const _Tp& __val) - { ::new(__p) _Tp(__val); } + protected: + // Configuration options. + _Tune _M_options; + + _Binmap_type* _M_binmap; - void - destroy(pointer __p) { __p->~_Tp(); } + // 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; + }; - pointer - allocate(size_type __n, const void* = 0); - void - deallocate(pointer __p, size_type __n); + /** + * @brief Data describing the underlying memory pool, parameterized on + * threading support. + */ + template<bool _Thread> + class __pool; - // Variables used to configure the behavior of the allocator, - // assigned and explained in detail below. - struct _Tune + /// Specialization for single thread. + template<> + class __pool<false> : public __pool_base + { + public: + union _Block_record { - // 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. - size_t _M_max_bytes; - - // Size in bytes of the smallest bin. - // NB: Must be a power of 2 and >= _M_align. - 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 choosen the value below. - // See http://gcc.gnu.org/ml/libstdc++/2001-07/msg00077.html - size_t _M_chunk_size; - - // The maximum number of supported threads. Our Linux 2.4.18 - // reports 4070 in /proc/sys/kernel/threads-max - 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(8), _M_max_bytes(128), _M_min_bin(8), - _M_chunk_size(4096 - 4 * sizeof(void*)), - _M_max_threads(4096), _M_freelist_headroom(10), - _M_force_new(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) - { } + // Points to the block_record of the next free block. + _Block_record* _M_next; }; - private: - // We need to create the initial lists and set up some variables - // before we can answer to the first request for memory. -#ifdef __GTHREADS - static __gthread_once_t _S_once; -#endif - static bool _S_init; + struct _Bin_record + { + // An "array" of pointers to the first free block. + _Block_record** _M_first; - static void - _S_initialize(); + // 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(); + } - // Configuration options. - static _Tune _S_options; + void + _M_destroy() throw(); - static const _Tune - _S_get_options() - { return _S_options; } + char* + _M_reserve_block(size_t __bytes, const size_t __thread_id); + + void + _M_reclaim_block(char* __p, size_t __bytes); + + 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) + { } - static void - _S_set_options(_Tune __t) - { - if (!_S_init) - _S_options = __t; - } + explicit __pool() + : _M_bin(NULL), _M_bin_size(1) { } + + explicit __pool(const __pool_base::_Tune& __tune) + : __pool_base(__tune), _M_bin(NULL), _M_bin_size(1) { } - // Using short int as type for the binmap implies we are never - // caching blocks larger than 65535 with this allocator - typedef unsigned short int _Binmap_type; - static _Binmap_type* _S_binmap; + 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 @@ -211,508 +271,476 @@ namespace __gnu_cxx // __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. -#ifdef __GTHREADS struct _Thread_record { - // Points to next free thread id record. NULL if last record in list. - _Thread_record* volatile _M_next; - + // 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; + size_t _M_id; }; - - static _Thread_record* volatile _S_thread_freelist_first; - static __gthread_mutex_t _S_thread_freelist_mutex; - static __gthread_key_t _S_thread_key; - - static void - _S_destroy_thread_key(void* __freelist_pos); -#endif - - static size_t - _S_get_thread_id(); - + union _Block_record { // Points to the block_record of the next free block. - _Block_record* volatile _M_next; - -#ifdef __GTHREADS + _Block_record* _M_next; + // The thread id of the thread which has requested this block. - size_t _M_thread_id; -#endif + 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** volatile _M_first; + // 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; -#ifdef __GTHREADS // An "array" of counters used to keep track of the amount of // blocks that are on the freelist/used for each thread id. - // Memory to these "arrays" is allocated in _S_initialize() for - // _S_max_threads + global pool 0. - size_t* volatile _M_free; - size_t* volatile _M_used; - + // - 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; -#endif + __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); + + 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 + void + _M_destroy_thread_key(void*); + + size_t + _M_get_thread_id(); + + explicit __pool() + : _M_bin(NULL), _M_bin_size(1), _M_thread_freelist(NULL) + { } + + explicit __pool(const __pool_base::_Tune& __tune) + : __pool_base(__tune), _M_bin(NULL), _M_bin_size(1), + _M_thread_freelist(NULL) + { } + + private: // An "array" of bin_records each of which represents a specific // power of 2 size. Memory to this "array" is allocated in - // _S_initialize(). - static _Bin_record* volatile _S_bin; + // _M_initialize(). + _Bin_record* _M_bin; + + // Actual value calculated in _M_initialize(). + size_t _M_bin_size; - // Actual value calculated in _S_initialize(). - static size_t _S_bin_size; + _Thread_record* _M_thread_freelist; + void* _M_thread_freelist_initial; + + void + _M_initialize(); }; +#endif - template<typename _Tp> - typename __mt_alloc<_Tp>::pointer - __mt_alloc<_Tp>:: - allocate(size_type __n, const void*) + template<template <bool> class _PoolTp, bool _Thread> + struct __common_pool { - // Although the test in __gthread_once() would suffice, we wrap - // test of the once condition in our own unlocked check. This - // saves one function call to pthread_once() (which itself only - // tests for the once value unlocked anyway and immediately - // returns if set) - if (!_S_init) - { + 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 - if (__gthread_active_p()) - __gthread_once(&_S_once, _S_initialize); -#endif - if (!_S_init) - _S_initialize(); - } + template<template <bool> class _PoolTp> + struct __common_pool_base<_PoolTp, true> + : public __common_pool<_PoolTp, true> + { + using __common_pool<_PoolTp, true>::_S_get_pool; - // Requests larger than _M_max_bytes are handled by new/delete - // directly. - const size_t __bytes = __n * sizeof(_Tp); - if (__bytes > _S_options._M_max_bytes || _S_options._M_force_new) - { - void* __ret = ::operator new(__bytes); - return static_cast<_Tp*>(__ret); - } + static void + _S_initialize() + { _S_get_pool()._M_initialize_once(); } - // Round up to power of 2 and figure out which bin to use. - const size_t __which = _S_binmap[__bytes]; - const size_t __thread_id = _S_get_thread_id(); + 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 + + /// @brief 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; - // Find out if we have blocks on our freelist. If so, go ahead - // and use them directly without having to lock anything. - const _Bin_record& __bin = _S_bin[__which]; - _Block_record* __block = NULL; - if (__bin._M_first[__thread_id] == NULL) - { - // NB: For alignment reasons, we can't use the first _M_align - // bytes, even when sizeof(_Block_record) < _M_align. - const size_t __bin_size = ((_S_options._M_min_bin << __which) - + _S_options._M_align); - size_t __block_count = _S_options._M_chunk_size / __bin_size; - - // Are we using threads? - // - Yes, check if there are free blocks on the global - // list. If so, grab up to __block_count blocks in one - // lock and change ownership. If the global list is - // empty, we allocate a new chunk and add those blocks - // directly to our own freelist (with us as owner). - // - No, all operations are made directly to global pool 0 - // no need to lock or change ownership but check for free - // blocks on global list (and if not add new ones) and - // get the first one. -#ifdef __GTHREADS - if (__gthread_active_p()) - { - __gthread_mutex_lock(__bin._M_mutex); - if (__bin._M_first[0] == NULL) - { - // No need to hold the lock when we are adding a - // whole chunk to our own list. - __gthread_mutex_unlock(__bin._M_mutex); - - void* __v = ::operator new(_S_options._M_chunk_size); - __bin._M_first[__thread_id] = static_cast<_Block_record*>(__v); - __bin._M_free[__thread_id] = __block_count; - - --__block_count; - __block = __bin._M_first[__thread_id]; - while (__block_count-- > 0) - { - char* __c = reinterpret_cast<char*>(__block) + __bin_size; - __block->_M_next = reinterpret_cast<_Block_record*>(__c); - __block = __block->_M_next; - } - __block->_M_next = NULL; - } - else - { - // Is the number of required blocks greater than or - // equal to the number that can be provided by the - // global free list? - __bin._M_first[__thread_id] = __bin._M_first[0]; - if (__block_count >= __bin._M_free[0]) - { - __bin._M_free[__thread_id] = __bin._M_free[0]; - __bin._M_free[0] = 0; - __bin._M_first[0] = NULL; - } - else - { - __bin._M_free[__thread_id] = __block_count; - __bin._M_free[0] -= __block_count; - --__block_count; - __block = __bin._M_first[0]; - while (__block_count-- > 0) - __block = __block->_M_next; - __bin._M_first[0] = __block->_M_next; - __block->_M_next = NULL; - } - __gthread_mutex_unlock(__bin._M_mutex); - } - } - else + 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 - { - void* __v = ::operator new(_S_options._M_chunk_size); - __bin._M_first[0] = static_cast<_Block_record*>(__v); - - --__block_count; - __block = __bin._M_first[0]; - while (__block_count-- > 0) - { - char* __c = reinterpret_cast<char*>(__block) + __bin_size; - __block->_M_next = reinterpret_cast<_Block_record*>(__c); - __block = __block->_M_next; - } - __block->_M_next = NULL; - } - } - __block = __bin._M_first[__thread_id]; - __bin._M_first[__thread_id] = __bin._M_first[__thread_id]->_M_next; + /// @brief 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; + }; + + + /// @brief 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 &__x; } + + const_pointer + address(const_reference __x) const + { return &__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(__p) _Tp(__val); } + + void + destroy(pointer __p) { __p->~_Tp(); } + }; + #ifdef __GTHREADS - if (__gthread_active_p()) - { - __block->_M_thread_id = __thread_id; - --__bin._M_free[__thread_id]; - ++__bin._M_used[__thread_id]; - } +#define __thread_default true +#else +#define __thread_default false #endif - char* __c = reinterpret_cast<char*>(__block) + _S_options._M_align; - return static_cast<_Tp*>(static_cast<void*>(__c)); - } - - template<typename _Tp> - void - __mt_alloc<_Tp>:: - deallocate(pointer __p, size_type __n) + /** + * @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 "global" one. Steps are taken to limit + * the per thread freelist sizes (by returning excess back to + * the "global" list). + * + * Further details: + * http://gcc.gnu.org/onlinedocs/libstdc++/ext/mt_allocator.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*) { - // Requests larger than _M_max_bytes are handled by operators + if (__builtin_expect(__n > this->max_size(), false)) + 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 (__bytes > _S_options._M_max_bytes || _S_options._M_force_new) + if (__pool._M_check_threshold(__bytes)) { - ::operator delete(__p); - return; + 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 = _S_binmap[__bytes]; - const _Bin_record& __bin = _S_bin[__which]; - - char* __c = reinterpret_cast<char*>(__p) - _S_options._M_align; - _Block_record* __block = reinterpret_cast<_Block_record*>(__c); + const size_t __which = __pool._M_get_binmap(__bytes); + const size_t __thread_id = __pool._M_get_thread_id(); -#ifdef __GTHREADS - if (__gthread_active_p()) + // 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]) { - // Calculate the number of records to remove from our freelist: - // in order to avoid too much contention we wait until the - // number of records is "high enough". - const size_t __thread_id = _S_get_thread_id(); - - long __remove = ((__bin._M_free[__thread_id] - * _S_options._M_freelist_headroom) - - __bin._M_used[__thread_id]); - if (__remove > static_cast<long>(100 * (_S_bin_size - __which) - * _S_options._M_freelist_headroom) - && __remove > static_cast<long>(__bin._M_free[__thread_id])) - { - _Block_record* __tmp = __bin._M_first[__thread_id]; - _Block_record* __first = __tmp; - __remove /= _S_options._M_freelist_headroom; - const long __removed = __remove; - --__remove; - while (__remove-- > 0) - __tmp = __tmp->_M_next; - __bin._M_first[__thread_id] = __tmp->_M_next; - __bin._M_free[__thread_id] -= __removed; - - __gthread_mutex_lock(__bin._M_mutex); - __tmp->_M_next = __bin._M_first[0]; - __bin._M_first[0] = __first; - __bin._M_free[0] += __removed; - __gthread_mutex_unlock(__bin._M_mutex); - } + // 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; - // Return this block to our list and update counters and - // owner id as needed. - --__bin._M_used[__block->_M_thread_id]; - - __block->_M_next = __bin._M_first[__thread_id]; - __bin._M_first[__thread_id] = __block; - - ++__bin._M_free[__thread_id]; + __pool._M_adjust_freelist(__bin, __block, __thread_id); + __c = reinterpret_cast<char*>(__block) + __pool._M_get_align(); } else -#endif { - // Single threaded application - return to global pool. - __block->_M_next = __bin._M_first[0]; - __bin._M_first[0] = __block; + // Null, reserve. + __c = __pool._M_reserve_block(__bytes, __thread_id); } + return static_cast<_Tp*>(static_cast<void*>(__c)); } - template<typename _Tp> + template<typename _Tp, typename _Poolp> void - __mt_alloc<_Tp>:: - _S_initialize() + __mt_alloc<_Tp, _Poolp>:: + deallocate(pointer __p, size_type __n) { - // This method is called on the first allocation (when _S_init is still - // false) to create the bins. - - // Ensure that the static initialization of _S_options has - // happened. This depends on (a) _M_align == 0 being an invalid - // value that is only present at startup, and (b) the real - // static initialization that happens later not actually - // changing anything. - if (_S_options._M_align == 0) - new (&_S_options) _Tune; - - // _M_force_new must not change after the first allocate(), - // which in turn calls this method, so if it's false, it's false - // forever and we don't need to return here ever again. - if (_S_options._M_force_new) - { - _S_init = true; - return; - } - - // Calculate the number of bins required based on _M_max_bytes. - // _S_bin_size is statically-initialized to one. - size_t __bin_size = _S_options._M_min_bin; - while (_S_options._M_max_bytes > __bin_size) + if (__builtin_expect(__p != 0, true)) { - __bin_size <<= 1; - ++_S_bin_size; - } - - // Setup the bin map for quick lookup of the relevant bin. - const size_t __j = (_S_options._M_max_bytes + 1) * sizeof(_Binmap_type); - _S_binmap = static_cast<_Binmap_type*>(::operator new(__j)); - - _Binmap_type* __bp = _S_binmap; - _Binmap_type __bin_max = _S_options._M_min_bin; - _Binmap_type __bint = 0; - for (_Binmap_type __ct = 0; __ct <= _S_options._M_max_bytes; ++__ct) - { - if (__ct > __bin_max) - { - __bin_max <<= 1; - ++__bint; - } - *__bp++ = __bint; - } - - // Initialize _S_bin and its members. - void* __v = ::operator new(sizeof(_Bin_record) * _S_bin_size); - _S_bin = static_cast<_Bin_record*>(__v); - - // If __gthread_active_p() create and initialize the list of - // free thread ids. Single threaded applications use thread id 0 - // directly and have no need for this. -#ifdef __GTHREADS - if (__gthread_active_p()) - { - const size_t __k = sizeof(_Thread_record) * _S_options._M_max_threads; - __v = ::operator new(__k); - _S_thread_freelist_first = static_cast<_Thread_record*>(__v); - - // NOTE! The first assignable thread id is 1 since the - // global pool uses id 0 - size_t __i; - for (__i = 1; __i < _S_options._M_max_threads; ++__i) - { - _Thread_record& __tr = _S_thread_freelist_first[__i - 1]; - __tr._M_next = &_S_thread_freelist_first[__i]; - __tr._M_id = __i; - } - - // Set last record. - _S_thread_freelist_first[__i - 1]._M_next = NULL; - _S_thread_freelist_first[__i - 1]._M_id = __i; - - // Make sure this is initialized. -#ifndef __GTHREAD_MUTEX_INIT - __GTHREAD_MUTEX_INIT_FUNCTION(&_S_thread_freelist_mutex); -#endif - // Initialize per thread key to hold pointer to - // _S_thread_freelist. - __gthread_key_create(&_S_thread_key, _S_destroy_thread_key); - - const size_t __max_threads = _S_options._M_max_threads + 1; - for (size_t __n = 0; __n < _S_bin_size; ++__n) - { - _Bin_record& __bin = _S_bin[__n]; - __v = ::operator new(sizeof(_Block_record*) * __max_threads); - __bin._M_first = static_cast<_Block_record**>(__v); - - __v = ::operator new(sizeof(size_t) * __max_threads); - __bin._M_free = static_cast<size_t*>(__v); - - __v = ::operator new(sizeof(size_t) * __max_threads); - __bin._M_used = static_cast<size_t*>(__v); - - __v = ::operator new(sizeof(__gthread_mutex_t)); - __bin._M_mutex = static_cast<__gthread_mutex_t*>(__v); - -#ifdef __GTHREAD_MUTEX_INIT - { - // Do not copy a POSIX/gthr mutex once in use. - __gthread_mutex_t __tmp = __GTHREAD_MUTEX_INIT; - *__bin._M_mutex = __tmp; - } -#else - { __GTHREAD_MUTEX_INIT_FUNCTION(__bin._M_mutex); } -#endif - - for (size_t __threadn = 0; __threadn < __max_threads; - ++__threadn) - { - __bin._M_first[__threadn] = NULL; - __bin._M_free[__threadn] = 0; - __bin._M_used[__threadn] = 0; - } - } + // 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); } - else -#endif - for (size_t __n = 0; __n < _S_bin_size; ++__n) - { - _Bin_record& __bin = _S_bin[__n]; - __v = ::operator new(sizeof(_Block_record*)); - __bin._M_first = static_cast<_Block_record**>(__v); - __bin._M_first[0] = NULL; - } - - _S_init = true; - } - - template<typename _Tp> - size_t - __mt_alloc<_Tp>:: - _S_get_thread_id() - { -#ifdef __GTHREADS - // If we have thread support and it's active we check the thread - // key value and return its id or if it's not set we take the - // first record from _S_thread_freelist and sets the key and - // returns it's id. - if (__gthread_active_p()) - { - _Thread_record* __freelist_pos = - static_cast<_Thread_record*>(__gthread_getspecific(_S_thread_key)); - if (__freelist_pos == NULL) - { - // Since _S_options._M_max_threads must be larger than - // the theoretical max number of threads of the OS the - // list can never be empty. - __gthread_mutex_lock(&_S_thread_freelist_mutex); - __freelist_pos = _S_thread_freelist_first; - _S_thread_freelist_first = _S_thread_freelist_first->_M_next; - __gthread_mutex_unlock(&_S_thread_freelist_mutex); - - __gthread_setspecific(_S_thread_key, - static_cast<void*>(__freelist_pos)); - } - return __freelist_pos->_M_id; - } -#endif - // Otherwise (no thread support or inactive) all requests are - // served from the global pool 0. - return 0; } - -#ifdef __GTHREADS - template<typename _Tp> - void - __mt_alloc<_Tp>:: - _S_destroy_thread_key(void* __freelist_pos) - { - // Return this thread id record to front of thread_freelist. - __gthread_mutex_lock(&_S_thread_freelist_mutex); - _Thread_record* __tr = static_cast<_Thread_record*>(__freelist_pos); - __tr->_M_next = _S_thread_freelist_first; - _S_thread_freelist_first = __tr; - __gthread_mutex_unlock(&_S_thread_freelist_mutex); - } -#endif - - template<typename _Tp> + + template<typename _Tp, typename _Poolp> inline bool - operator==(const __mt_alloc<_Tp>&, const __mt_alloc<_Tp>&) + operator==(const __mt_alloc<_Tp, _Poolp>&, const __mt_alloc<_Tp, _Poolp>&) { return true; } - template<typename _Tp> + template<typename _Tp, typename _Poolp> inline bool - operator!=(const __mt_alloc<_Tp>&, const __mt_alloc<_Tp>&) + operator!=(const __mt_alloc<_Tp, _Poolp>&, const __mt_alloc<_Tp, _Poolp>&) { return false; } - template<typename _Tp> - bool __mt_alloc<_Tp>::_S_init = false; - - template<typename _Tp> - typename __mt_alloc<_Tp>::_Tune __mt_alloc<_Tp>::_S_options; +#undef __thread_default - template<typename _Tp> - typename __mt_alloc<_Tp>::_Binmap_type* __mt_alloc<_Tp>::_S_binmap; - - template<typename _Tp> - typename __mt_alloc<_Tp>::_Bin_record* volatile __mt_alloc<_Tp>::_S_bin; - - template<typename _Tp> - size_t __mt_alloc<_Tp>::_S_bin_size = 1; - - // Actual initialization in _S_initialize(). -#ifdef __GTHREADS - template<typename _Tp> - __gthread_once_t __mt_alloc<_Tp>::_S_once = __GTHREAD_ONCE_INIT; - - template<typename _Tp> - typename __mt_alloc<_Tp>::_Thread_record* - volatile __mt_alloc<_Tp>::_S_thread_freelist_first = NULL; - - template<typename _Tp> - __gthread_key_t __mt_alloc<_Tp>::_S_thread_key; - - template<typename _Tp> - __gthread_mutex_t -#ifdef __GTHREAD_MUTEX_INIT - __mt_alloc<_Tp>::_S_thread_freelist_mutex = __GTHREAD_MUTEX_INIT; -#else - __mt_alloc<_Tp>::_S_thread_freelist_mutex; -#endif -#endif -} // namespace __gnu_cxx +_GLIBCXX_END_NAMESPACE #endif |
