// Allocator details. // Copyright (C) 2004, 2005, 2006, 2009 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 // . // // ISO C++ 14882: // #include #include #include #include namespace { #ifdef __GTHREADS struct __freelist { typedef __gnu_cxx::__pool::_Thread_record _Thread_record; _Thread_record* _M_thread_freelist; _Thread_record* _M_thread_freelist_array; size_t _M_max_threads; __gthread_key_t _M_key; ~__freelist() { if (_M_thread_freelist_array) { __gthread_key_delete(_M_key); ::operator delete(static_cast(_M_thread_freelist_array)); } } }; __freelist& get_freelist() { static __freelist freelist; return freelist; } __gnu_cxx::__mutex& get_freelist_mutex() { static __gnu_cxx::__mutex freelist_mutex; return freelist_mutex; } static void _M_destroy_thread_key(void* __id) { // Return this thread id record to the front of thread_freelist. __freelist& freelist = get_freelist(); { __gnu_cxx::__scoped_lock sentry(get_freelist_mutex()); size_t _M_id = reinterpret_cast(__id); typedef __gnu_cxx::__pool::_Thread_record _Thread_record; _Thread_record* __tr = &freelist._M_thread_freelist_array[_M_id - 1]; __tr->_M_next = freelist._M_thread_freelist; freelist._M_thread_freelist = __tr; } } #endif } // anonymous namespace _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx) void __pool::_M_destroy() throw() { if (_M_init && !_M_options._M_force_new) { for (size_t __n = 0; __n < _M_bin_size; ++__n) { _Bin_record& __bin = _M_bin[__n]; while (__bin._M_address) { _Block_address* __tmp = __bin._M_address->_M_next; ::operator delete(__bin._M_address->_M_initial); __bin._M_address = __tmp; } ::operator delete(__bin._M_first); } ::operator delete(_M_bin); ::operator delete(_M_binmap); } } void __pool::_M_reclaim_block(char* __p, size_t __bytes) { // Round up to power of 2 and figure out which bin to use. const size_t __which = _M_binmap[__bytes]; _Bin_record& __bin = _M_bin[__which]; char* __c = __p - _M_get_align(); _Block_record* __block = reinterpret_cast<_Block_record*>(__c); // Single threaded application - return to global pool. __block->_M_next = __bin._M_first[0]; __bin._M_first[0] = __block; } char* __pool::_M_reserve_block(size_t __bytes, const size_t __thread_id) { // Round up to power of 2 and figure out which bin to use. const size_t __which = _M_binmap[__bytes]; _Bin_record& __bin = _M_bin[__which]; const _Tune& __options = _M_get_options(); const size_t __bin_size = (__options._M_min_bin << __which) + __options._M_align; size_t __block_count = __options._M_chunk_size - sizeof(_Block_address); __block_count /= __bin_size; // Get a new block dynamically, set it up for use. void* __v = ::operator new(__options._M_chunk_size); _Block_address* __address = static_cast<_Block_address*>(__v); __address->_M_initial = __v; __address->_M_next = __bin._M_address; __bin._M_address = __address; char* __c = static_cast(__v) + sizeof(_Block_address); _Block_record* __block = reinterpret_cast<_Block_record*>(__c); __bin._M_first[__thread_id] = __block; while (--__block_count > 0) { __c += __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] = __block->_M_next; // NB: For alignment reasons, we can't use the first _M_align // bytes, even when sizeof(_Block_record) < _M_align. return reinterpret_cast(__block) + __options._M_align; } void __pool::_M_initialize() { // _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 (_M_options._M_force_new) { _M_init = true; return; } // Create the bins. // Calculate the number of bins required based on _M_max_bytes. // _M_bin_size is statically-initialized to one. size_t __bin_size = _M_options._M_min_bin; while (_M_options._M_max_bytes > __bin_size) { __bin_size <<= 1; ++_M_bin_size; } // Setup the bin map for quick lookup of the relevant bin. const size_t __j = (_M_options._M_max_bytes + 1) * sizeof(_Binmap_type); _M_binmap = static_cast<_Binmap_type*>(::operator new(__j)); _Binmap_type* __bp = _M_binmap; _Binmap_type __bin_max = _M_options._M_min_bin; _Binmap_type __bint = 0; for (_Binmap_type __ct = 0; __ct <= _M_options._M_max_bytes; ++__ct) { if (__ct > __bin_max) { __bin_max <<= 1; ++__bint; } *__bp++ = __bint; } // Initialize _M_bin and its members. void* __v = ::operator new(sizeof(_Bin_record) * _M_bin_size); _M_bin = static_cast<_Bin_record*>(__v); for (size_t __n = 0; __n < _M_bin_size; ++__n) { _Bin_record& __bin = _M_bin[__n]; __v = ::operator new(sizeof(_Block_record*)); __bin._M_first = static_cast<_Block_record**>(__v); __bin._M_first[0] = NULL; __bin._M_address = NULL; } _M_init = true; } #ifdef __GTHREADS void __pool::_M_destroy() throw() { if (_M_init && !_M_options._M_force_new) { if (__gthread_active_p()) { for (size_t __n = 0; __n < _M_bin_size; ++__n) { _Bin_record& __bin = _M_bin[__n]; while (__bin._M_address) { _Block_address* __tmp = __bin._M_address->_M_next; ::operator delete(__bin._M_address->_M_initial); __bin._M_address = __tmp; } ::operator delete(__bin._M_first); ::operator delete(__bin._M_free); ::operator delete(__bin._M_used); ::operator delete(__bin._M_mutex); } } else { for (size_t __n = 0; __n < _M_bin_size; ++__n) { _Bin_record& __bin = _M_bin[__n]; while (__bin._M_address) { _Block_address* __tmp = __bin._M_address->_M_next; ::operator delete(__bin._M_address->_M_initial); __bin._M_address = __tmp; } ::operator delete(__bin._M_first); } } ::operator delete(_M_bin); ::operator delete(_M_binmap); } } void __pool::_M_reclaim_block(char* __p, size_t __bytes) { // Round up to power of 2 and figure out which bin to use. const size_t __which = _M_binmap[__bytes]; const _Bin_record& __bin = _M_bin[__which]; // Know __p not null, assume valid block. char* __c = __p - _M_get_align(); _Block_record* __block = reinterpret_cast<_Block_record*>(__c); if (__gthread_active_p()) { // 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 = _M_get_thread_id(); const _Tune& __options = _M_get_options(); const size_t __limit = (100 * (_M_bin_size - __which) * __options._M_freelist_headroom); size_t __remove = __bin._M_free[__thread_id]; __remove *= __options._M_freelist_headroom; // NB: We assume that reads of _Atomic_words are atomic. const size_t __max_threads = __options._M_max_threads + 1; _Atomic_word* const __reclaimed_base = reinterpret_cast<_Atomic_word*>(__bin._M_used + __max_threads); const _Atomic_word __reclaimed = __reclaimed_base[__thread_id]; const size_t __net_used = __bin._M_used[__thread_id] - __reclaimed; // NB: For performance sake we don't resync every time, in order // to spare atomic ops. Note that if __reclaimed increased by, // say, 1024, since the last sync, it means that the other // threads executed the atomic in the else below at least the // same number of times (at least, because _M_reserve_block may // have decreased the counter), therefore one more cannot hurt. if (__reclaimed > 1024) { __bin._M_used[__thread_id] -= __reclaimed; __atomic_add(&__reclaimed_base[__thread_id], -__reclaimed); } if (__remove >= __net_used) __remove -= __net_used; else __remove = 0; if (__remove > __limit && __remove > __bin._M_free[__thread_id]) { _Block_record* __first = __bin._M_first[__thread_id]; _Block_record* __tmp = __first; __remove /= __options._M_freelist_headroom; const size_t __removed = __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); } // Return this block to our list and update counters and // owner id as needed. if (__block->_M_thread_id == __thread_id) --__bin._M_used[__thread_id]; else __atomic_add(&__reclaimed_base[__block->_M_thread_id], 1); __block->_M_next = __bin._M_first[__thread_id]; __bin._M_first[__thread_id] = __block; ++__bin._M_free[__thread_id]; } else { // Not using threads, so single threaded application - return // to global pool. __block->_M_next = __bin._M_first[0]; __bin._M_first[0] = __block; } } char* __pool::_M_reserve_block(size_t __bytes, const size_t __thread_id) { // Round up to power of 2 and figure out which bin to use. const size_t __which = _M_binmap[__bytes]; const _Tune& __options = _M_get_options(); const size_t __bin_size = ((__options._M_min_bin << __which) + __options._M_align); size_t __block_count = __options._M_chunk_size - sizeof(_Block_address); __block_count /= __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. _Bin_record& __bin = _M_bin[__which]; _Block_record* __block = NULL; if (__gthread_active_p()) { // Resync the _M_used counters. const size_t __max_threads = __options._M_max_threads + 1; _Atomic_word* const __reclaimed_base = reinterpret_cast<_Atomic_word*>(__bin._M_used + __max_threads); const _Atomic_word __reclaimed = __reclaimed_base[__thread_id]; __bin._M_used[__thread_id] -= __reclaimed; __atomic_add(&__reclaimed_base[__thread_id], -__reclaimed); __gthread_mutex_lock(__bin._M_mutex); if (__bin._M_first[0] == NULL) { void* __v = ::operator new(__options._M_chunk_size); _Block_address* __address = static_cast<_Block_address*>(__v); __address->_M_initial = __v; __address->_M_next = __bin._M_address; __bin._M_address = __address; __gthread_mutex_unlock(__bin._M_mutex); // No need to hold the lock when we are adding a whole // chunk to our own list. char* __c = static_cast(__v) + sizeof(_Block_address); __block = reinterpret_cast<_Block_record*>(__c); __bin._M_free[__thread_id] = __block_count; __bin._M_first[__thread_id] = __block; while (--__block_count > 0) { __c += __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 = __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 { void* __v = ::operator new(__options._M_chunk_size); _Block_address* __address = static_cast<_Block_address*>(__v); __address->_M_initial = __v; __address->_M_next = __bin._M_address; __bin._M_address = __address; char* __c = static_cast(__v) + sizeof(_Block_address); __block = reinterpret_cast<_Block_record*>(__c); __bin._M_first[0] = __block; while (--__block_count > 0) { __c += __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] = __block->_M_next; if (__gthread_active_p()) { __block->_M_thread_id = __thread_id; --__bin._M_free[__thread_id]; ++__bin._M_used[__thread_id]; } // NB: For alignment reasons, we can't use the first _M_align // bytes, even when sizeof(_Block_record) < _M_align. return reinterpret_cast(__block) + __options._M_align; } void __pool::_M_initialize() { // _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 (_M_options._M_force_new) { _M_init = true; return; } // Create the bins. // Calculate the number of bins required based on _M_max_bytes. // _M_bin_size is statically-initialized to one. size_t __bin_size = _M_options._M_min_bin; while (_M_options._M_max_bytes > __bin_size) { __bin_size <<= 1; ++_M_bin_size; } // Setup the bin map for quick lookup of the relevant bin. const size_t __j = (_M_options._M_max_bytes + 1) * sizeof(_Binmap_type); _M_binmap = static_cast<_Binmap_type*>(::operator new(__j)); _Binmap_type* __bp = _M_binmap; _Binmap_type __bin_max = _M_options._M_min_bin; _Binmap_type __bint = 0; for (_Binmap_type __ct = 0; __ct <= _M_options._M_max_bytes; ++__ct) { if (__ct > __bin_max) { __bin_max <<= 1; ++__bint; } *__bp++ = __bint; } // Initialize _M_bin and its members. void* __v = ::operator new(sizeof(_Bin_record) * _M_bin_size); _M_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. if (__gthread_active_p()) { __freelist& freelist = get_freelist(); { __gnu_cxx::__scoped_lock sentry(get_freelist_mutex()); if (!freelist._M_thread_freelist_array || freelist._M_max_threads < _M_options._M_max_threads) { const size_t __k = sizeof(_Thread_record) * _M_options._M_max_threads; __v = ::operator new(__k); _M_thread_freelist = 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 < _M_options._M_max_threads; ++__i) { _Thread_record& __tr = _M_thread_freelist[__i - 1]; __tr._M_next = &_M_thread_freelist[__i]; __tr._M_id = __i; } // Set last record. _M_thread_freelist[__i - 1]._M_next = NULL; _M_thread_freelist[__i - 1]._M_id = __i; if (!freelist._M_thread_freelist_array) { // Initialize per thread key to hold pointer to // _M_thread_freelist. __gthread_key_create(&freelist._M_key, ::_M_destroy_thread_key); freelist._M_thread_freelist = _M_thread_freelist; } else { _Thread_record* _M_old_freelist = freelist._M_thread_freelist; _Thread_record* _M_old_array = freelist._M_thread_freelist_array; freelist._M_thread_freelist = &_M_thread_freelist[_M_old_freelist - _M_old_array]; while (_M_old_freelist) { size_t next_id; if (_M_old_freelist->_M_next) next_id = _M_old_freelist->_M_next - _M_old_array; else next_id = freelist._M_max_threads; _M_thread_freelist[_M_old_freelist->_M_id - 1]._M_next = &_M_thread_freelist[next_id]; _M_old_freelist = _M_old_freelist->_M_next; } ::operator delete(static_cast(_M_old_array)); } freelist._M_thread_freelist_array = _M_thread_freelist; freelist._M_max_threads = _M_options._M_max_threads; } } const size_t __max_threads = _M_options._M_max_threads + 1; for (size_t __n = 0; __n < _M_bin_size; ++__n) { _Bin_record& __bin = _M_bin[__n]; __v = ::operator new(sizeof(_Block_record*) * __max_threads); std::memset(__v, 0, sizeof(_Block_record*) * __max_threads); __bin._M_first = static_cast<_Block_record**>(__v); __bin._M_address = NULL; __v = ::operator new(sizeof(size_t) * __max_threads); std::memset(__v, 0, sizeof(size_t) * __max_threads); __bin._M_free = static_cast(__v); __v = ::operator new(sizeof(size_t) * __max_threads + sizeof(_Atomic_word) * __max_threads); std::memset(__v, 0, (sizeof(size_t) * __max_threads + sizeof(_Atomic_word) * __max_threads)); __bin._M_used = static_cast(__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 } } else { for (size_t __n = 0; __n < _M_bin_size; ++__n) { _Bin_record& __bin = _M_bin[__n]; __v = ::operator new(sizeof(_Block_record*)); __bin._M_first = static_cast<_Block_record**>(__v); __bin._M_first[0] = NULL; __bin._M_address = NULL; } } _M_init = true; } size_t __pool::_M_get_thread_id() { // 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 _M_thread_freelist and sets the key and // returns its id. if (__gthread_active_p()) { __freelist& freelist = get_freelist(); void* v = __gthread_getspecific(freelist._M_key); size_t _M_id = (size_t)v; if (_M_id == 0) { { __gnu_cxx::__scoped_lock sentry(get_freelist_mutex()); if (freelist._M_thread_freelist) { _M_id = freelist._M_thread_freelist->_M_id; freelist._M_thread_freelist = freelist._M_thread_freelist->_M_next; } } __gthread_setspecific(freelist._M_key, (void*)_M_id); } return _M_id >= _M_options._M_max_threads ? 0 : _M_id; } // Otherwise (no thread support or inactive) all requests are // served from the global pool 0. return 0; } // XXX GLIBCXX_ABI Deprecated void __pool::_M_destroy_thread_key(void*) { } // XXX GLIBCXX_ABI Deprecated void __pool::_M_initialize(__destroy_handler) { // _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 (_M_options._M_force_new) { _M_init = true; return; } // Create the bins. // Calculate the number of bins required based on _M_max_bytes. // _M_bin_size is statically-initialized to one. size_t __bin_size = _M_options._M_min_bin; while (_M_options._M_max_bytes > __bin_size) { __bin_size <<= 1; ++_M_bin_size; } // Setup the bin map for quick lookup of the relevant bin. const size_t __j = (_M_options._M_max_bytes + 1) * sizeof(_Binmap_type); _M_binmap = static_cast<_Binmap_type*>(::operator new(__j)); _Binmap_type* __bp = _M_binmap; _Binmap_type __bin_max = _M_options._M_min_bin; _Binmap_type __bint = 0; for (_Binmap_type __ct = 0; __ct <= _M_options._M_max_bytes; ++__ct) { if (__ct > __bin_max) { __bin_max <<= 1; ++__bint; } *__bp++ = __bint; } // Initialize _M_bin and its members. void* __v = ::operator new(sizeof(_Bin_record) * _M_bin_size); _M_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. if (__gthread_active_p()) { __freelist& freelist = get_freelist(); { __gnu_cxx::__scoped_lock sentry(get_freelist_mutex()); if (!freelist._M_thread_freelist_array || freelist._M_max_threads < _M_options._M_max_threads) { const size_t __k = sizeof(_Thread_record) * _M_options._M_max_threads; __v = ::operator new(__k); _M_thread_freelist = 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 < _M_options._M_max_threads; ++__i) { _Thread_record& __tr = _M_thread_freelist[__i - 1]; __tr._M_next = &_M_thread_freelist[__i]; __tr._M_id = __i; } // Set last record. _M_thread_freelist[__i - 1]._M_next = NULL; _M_thread_freelist[__i - 1]._M_id = __i; if (!freelist._M_thread_freelist_array) { // Initialize per thread key to hold pointer to // _M_thread_freelist. __gthread_key_create(&freelist._M_key, ::_M_destroy_thread_key); freelist._M_thread_freelist = _M_thread_freelist; } else { _Thread_record* _M_old_freelist = freelist._M_thread_freelist; _Thread_record* _M_old_array = freelist._M_thread_freelist_array; freelist._M_thread_freelist = &_M_thread_freelist[_M_old_freelist - _M_old_array]; while (_M_old_freelist) { size_t next_id; if (_M_old_freelist->_M_next) next_id = _M_old_freelist->_M_next - _M_old_array; else next_id = freelist._M_max_threads; _M_thread_freelist[_M_old_freelist->_M_id - 1]._M_next = &_M_thread_freelist[next_id]; _M_old_freelist = _M_old_freelist->_M_next; } ::operator delete(static_cast(_M_old_array)); } freelist._M_thread_freelist_array = _M_thread_freelist; freelist._M_max_threads = _M_options._M_max_threads; } } const size_t __max_threads = _M_options._M_max_threads + 1; for (size_t __n = 0; __n < _M_bin_size; ++__n) { _Bin_record& __bin = _M_bin[__n]; __v = ::operator new(sizeof(_Block_record*) * __max_threads); std::memset(__v, 0, sizeof(_Block_record*) * __max_threads); __bin._M_first = static_cast<_Block_record**>(__v); __bin._M_address = NULL; __v = ::operator new(sizeof(size_t) * __max_threads); std::memset(__v, 0, sizeof(size_t) * __max_threads); __bin._M_free = static_cast(__v); __v = ::operator new(sizeof(size_t) * __max_threads + sizeof(_Atomic_word) * __max_threads); std::memset(__v, 0, (sizeof(size_t) * __max_threads + sizeof(_Atomic_word) * __max_threads)); __bin._M_used = static_cast(__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 } } else { for (size_t __n = 0; __n < _M_bin_size; ++__n) { _Bin_record& __bin = _M_bin[__n]; __v = ::operator new(sizeof(_Block_record*)); __bin._M_first = static_cast<_Block_record**>(__v); __bin._M_first[0] = NULL; __bin._M_address = NULL; } } _M_init = true; } #endif // Instantiations. template class __mt_alloc; template class __mt_alloc; _GLIBCXX_END_NAMESPACE