mt_allocator.h revision 132720
161452Sdfr// MT-optimized allocator -*- C++ -*- 261452Sdfr 361452Sdfr// Copyright (C) 2003, 2004 Free Software Foundation, Inc. 461452Sdfr// 561452Sdfr// This file is part of the GNU ISO C++ Library. This library is free 661452Sdfr// software; you can redistribute it and/or modify it under the 761452Sdfr// terms of the GNU General Public License as published by the 861452Sdfr// Free Software Foundation; either version 2, or (at your option) 961452Sdfr// any later version. 1061452Sdfr 1161452Sdfr// This library is distributed in the hope that it will be useful, 1261452Sdfr// but WITHOUT ANY WARRANTY; without even the implied warranty of 1361452Sdfr// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 1461452Sdfr// GNU General Public License for more details. 1561452Sdfr 1661452Sdfr// You should have received a copy of the GNU General Public License along 1761452Sdfr// with this library; see the file COPYING. If not, write to the Free 1861452Sdfr// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, 1961452Sdfr// USA. 2061452Sdfr 2161452Sdfr// As a special exception, you may use this file as part of a free software 2261452Sdfr// library without restriction. Specifically, if other files instantiate 2361452Sdfr// templates or use macros or inline functions from this file, or you compile 2461452Sdfr// this file and link it with other files to produce an executable, this 2561452Sdfr// file does not by itself cause the resulting executable to be covered by 2661452Sdfr// the GNU General Public License. This exception does not however 27116192Sobrien// invalidate any other reasons why the executable file might be covered by 28116192Sobrien// the GNU General Public License. 29116192Sobrien 3061452Sdfr/** @file ext/mt_allocator.h 3161452Sdfr * This file is a GNU extension to the Standard C++ Library. 3261452Sdfr * You should only include this header if you are using GCC 3 or later. 3361452Sdfr */ 34129878Sphk 3561452Sdfr#ifndef _MT_ALLOCATOR_H 3661452Sdfr#define _MT_ALLOCATOR_H 1 3776827Salfred 3879339Sjhb#include <new> 3961452Sdfr#include <cstdlib> 40173573Sjhb#include <bits/functexcept.h> 41173573Sjhb#include <bits/gthr.h> 42119288Simp#include <bits/atomicity.h> 43119288Simp 4461452Sdfrnamespace __gnu_cxx 4561452Sdfr{ 4661452Sdfr /** 4761452Sdfr * This is a fixed size (power of 2) allocator which - when 4861452Sdfr * compiled with thread support - will maintain one freelist per 49129189Sjhb * size per thread plus a "global" one. Steps are taken to limit 50129189Sjhb * the per thread freelist sizes (by returning excess back to 51129189Sjhb * "global"). 52129189Sjhb * 5361452Sdfr * Further details: 5461452Sdfr * http://gcc.gnu.org/onlinedocs/libstdc++/ext/mt_allocator.html 5561452Sdfr */ 5661452Sdfr template<typename _Tp> 57129189Sjhb class __mt_alloc 5861452Sdfr { 5961452Sdfr public: 60129189Sjhb typedef size_t size_type; 61129189Sjhb typedef ptrdiff_t difference_type; 62129189Sjhb typedef _Tp* pointer; 63129189Sjhb typedef const _Tp* const_pointer; 64129189Sjhb typedef _Tp& reference; 6561452Sdfr typedef const _Tp& const_reference; 6661452Sdfr typedef _Tp value_type; 6761452Sdfr 6861452Sdfr template<typename _Tp1> 6961452Sdfr struct rebind 7061452Sdfr { typedef __mt_alloc<_Tp1> other; }; 7161452Sdfr 7261452Sdfr __mt_alloc() throw() 7361452Sdfr { 7461452Sdfr // XXX 7561452Sdfr } 76139431Sanholt 77139431Sanholt __mt_alloc(const __mt_alloc&) throw() 78139431Sanholt { 79139431Sanholt // XXX 80139431Sanholt } 81139431Sanholt 82139431Sanholt template<typename _Tp1> 83139431Sanholt __mt_alloc(const __mt_alloc<_Tp1>& obj) throw() 84116921Sjhb { 85139431Sanholt // XXX 86187633Sjkim } 87187633Sjkim 88172262Skevlo ~__mt_alloc() throw() { } 89172262Skevlo 90187633Sjkim pointer 91187633Sjkim address(reference __x) const 92187633Sjkim { return &__x; } 93187633Sjkim 94139431Sanholt const_pointer 95139431Sanholt address(const_reference __x) const 9661452Sdfr { return &__x; } 9761452Sdfr 9861452Sdfr size_type 9961452Sdfr max_size() const throw() 10061452Sdfr { return size_t(-1) / sizeof(_Tp); } 10161452Sdfr 102139431Sanholt // _GLIBCXX_RESOLVE_LIB_DEFECTS 103139431Sanholt // 402. wrong new expression in [some_] allocator::construct 104116921Sjhb void 105116921Sjhb construct(pointer __p, const _Tp& __val) 10661452Sdfr { ::new(__p) _Tp(__val); } 10761452Sdfr 108139431Sanholt void 109139431Sanholt destroy(pointer __p) { __p->~_Tp(); } 110139431Sanholt 111139431Sanholt pointer 112139431Sanholt allocate(size_type __n, const void* = 0); 113139431Sanholt 114139431Sanholt void 115139431Sanholt deallocate(pointer __p, size_type __n); 116139431Sanholt 117139431Sanholt // Variables used to configure the behavior of the allocator, 118139431Sanholt // assigned and explained in detail below. 119139431Sanholt struct _Tune 120139431Sanholt { 121139431Sanholt // Alignment needed. 122139431Sanholt // NB: In any case must be >= sizeof(_Block_record), that 123139431Sanholt // is 4 on 32 bit machines and 8 on 64 bit machines. 124139431Sanholt size_t _M_align; 125139431Sanholt 126139431Sanholt // Allocation requests (after round-up to power of 2) below 127139431Sanholt // this value will be handled by the allocator. A raw new/ 128131433Sjhb // call will be used for requests larger than this value. 129131433Sjhb size_t _M_max_bytes; 130139431Sanholt 131139431Sanholt // Size in bytes of the smallest bin. 132139431Sanholt // NB: Must be a power of 2 and >= _M_align. 133139431Sanholt size_t _M_min_bin; 134139431Sanholt 135139431Sanholt // In order to avoid fragmenting and minimize the number of 136139431Sanholt // new() calls we always request new memory using this 137139431Sanholt // value. Based on previous discussions on the libstdc++ 138244926Santoine // mailing list we have choosen the value below. 13961452Sdfr // See http://gcc.gnu.org/ml/libstdc++/2001-07/msg00077.html 14061452Sdfr size_t _M_chunk_size; 14161452Sdfr 14261452Sdfr // The maximum number of supported threads. Our Linux 2.4.18 14361452Sdfr // reports 4070 in /proc/sys/kernel/threads-max 14461452Sdfr size_t _M_max_threads; 14561452Sdfr 14661452Sdfr // Each time a deallocation occurs in a threaded application 14761452Sdfr // we make sure that there are no more than 148241885Seadler // _M_freelist_headroom % of used memory on the freelist. If 149241885Seadler // the number of additional records is more than 15061452Sdfr // _M_freelist_headroom % of the freelist, we move these 15161452Sdfr // records back to the global pool. 15261452Sdfr size_t _M_freelist_headroom; 153142398Simp 15461452Sdfr // Set to true forces all allocations to use new(). 15561452Sdfr bool _M_force_new; 15661452Sdfr 15761452Sdfr explicit 15861452Sdfr _Tune() 15961452Sdfr : _M_align(8), _M_max_bytes(128), _M_min_bin(8), 16061452Sdfr _M_chunk_size(4096 - 4 * sizeof(void*)), 16161452Sdfr _M_max_threads(4096), _M_freelist_headroom(10), 16261452Sdfr _M_force_new(getenv("GLIBCXX_FORCE_NEW") ? true : false) 16361452Sdfr { } 16461452Sdfr 165133406Sanholt explicit 166200764Srnoland _Tune(size_t __align, size_t __maxb, size_t __minbin, 16761452Sdfr size_t __chunk, size_t __maxthreads, size_t __headroom, 168200764Srnoland bool __force) 169200764Srnoland : _M_align(__align), _M_max_bytes(__maxb), _M_min_bin(__minbin), 170200764Srnoland _M_chunk_size(__chunk), _M_max_threads(__maxthreads), 171200764Srnoland _M_freelist_headroom(__headroom), _M_force_new(__force) 172200764Srnoland { } 173133406Sanholt }; 174133406Sanholt 175133406Sanholt private: 176129189Sjhb // We need to create the initial lists and set up some variables 177129189Sjhb // before we can answer to the first request for memory. 17861452Sdfr#ifdef __GTHREADS 17961452Sdfr static __gthread_once_t _S_once; 18061452Sdfr#endif 18161452Sdfr static bool _S_init; 18261452Sdfr 18361452Sdfr static void 18461452Sdfr _S_initialize(); 18561452Sdfr 18661452Sdfr // Configuration options. 18761452Sdfr static _Tune _S_options; 18861452Sdfr 18961452Sdfr static const _Tune 19061452Sdfr _S_get_options() 19161452Sdfr { return _S_options; } 19261452Sdfr 19361452Sdfr static void 19461452Sdfr _S_set_options(_Tune __t) 19561452Sdfr { 19661452Sdfr if (!_S_init) 19761452Sdfr _S_options = __t; 19861452Sdfr } 19961452Sdfr 200147606Sanholt // Using short int as type for the binmap implies we are never 201147606Sanholt // caching blocks larger than 65535 with this allocator 202147606Sanholt typedef unsigned short int _Binmap_type; 203147606Sanholt static _Binmap_type* _S_binmap; 204147606Sanholt 205147606Sanholt // Each requesting thread is assigned an id ranging from 1 to 206147606Sanholt // _S_max_threads. Thread id 0 is used as a global memory pool. 207147606Sanholt // In order to get constant performance on the thread assignment 20861452Sdfr // routine, we keep a list of free ids. When a thread first 209147606Sanholt // requests memory we remove the first record in this list and 210147606Sanholt // stores the address in a __gthread_key. When initializing the 211147606Sanholt // __gthread_key we specify a destructor. When this destructor 212147606Sanholt // (i.e. the thread dies) is called, we return the thread id to 213200764Srnoland // the front of this list. 214147606Sanholt#ifdef __GTHREADS 215147606Sanholt struct _Thread_record 216147606Sanholt { 217172262Skevlo // Points to next free thread id record. NULL if last record in list. 218172262Skevlo _Thread_record* volatile _M_next; 219172262Skevlo 22061452Sdfr // Thread id ranging from 1 to _S_max_threads. 22161452Sdfr size_t _M_id; 22261452Sdfr }; 22361452Sdfr 22461452Sdfr static _Thread_record* volatile _S_thread_freelist_first; 22561452Sdfr static __gthread_mutex_t _S_thread_freelist_mutex; 22661452Sdfr static __gthread_key_t _S_thread_key; 22761452Sdfr 228173203Sjhb static void 22961452Sdfr _S_destroy_thread_key(void* __freelist_pos); 230129189Sjhb#endif 231129189Sjhb 23261452Sdfr static size_t 23361452Sdfr _S_get_thread_id(); 234173203Sjhb 23561452Sdfr union _Block_record 23661452Sdfr { 23761452Sdfr // Points to the block_record of the next free block. 23861452Sdfr _Block_record* volatile _M_next; 23961452Sdfr 24061452Sdfr#ifdef __GTHREADS 24161452Sdfr // The thread id of the thread which has requested this block. 242129189Sjhb size_t _M_thread_id; 24361452Sdfr#endif 24461452Sdfr }; 245172262Skevlo 246200764Srnoland struct _Bin_record 24761452Sdfr { 248172262Skevlo // An "array" of pointers to the first free block for each 249172262Skevlo // thread id. Memory to this "array" is allocated in _S_initialize() 250172262Skevlo // for _S_max_threads + global pool 0. 251172262Skevlo _Block_record** volatile _M_first; 252172262Skevlo 253172262Skevlo#ifdef __GTHREADS 254172262Skevlo // An "array" of counters used to keep track of the amount of 255172262Skevlo // blocks that are on the freelist/used for each thread id. 256172262Skevlo // Memory to these "arrays" is allocated in _S_initialize() for 257172262Skevlo // _S_max_threads + global pool 0. 258172262Skevlo size_t* volatile _M_free; 259172262Skevlo size_t* volatile _M_used; 260172262Skevlo 261172262Skevlo // Each bin has its own mutex which is used to ensure data 262172262Skevlo // integrity while changing "ownership" on a block. The mutex 263172262Skevlo // is initialized in _S_initialize(). 264172262Skevlo __gthread_mutex_t* _M_mutex; 265172262Skevlo#endif 266172262Skevlo }; 267172262Skevlo 268172262Skevlo // An "array" of bin_records each of which represents a specific 269172262Skevlo // power of 2 size. Memory to this "array" is allocated in 270172262Skevlo // _S_initialize(). 271172262Skevlo static _Bin_record* volatile _S_bin; 272172262Skevlo 273200764Srnoland // Actual value calculated in _S_initialize(). 274200764Srnoland static size_t _S_bin_size; 275200764Srnoland }; 276200764Srnoland 277200764Srnoland template<typename _Tp> 278200764Srnoland typename __mt_alloc<_Tp>::pointer 279172262Skevlo __mt_alloc<_Tp>:: 280200764Srnoland allocate(size_type __n, const void*) 281172262Skevlo { 282172262Skevlo // Although the test in __gthread_once() would suffice, we wrap 283172262Skevlo // test of the once condition in our own unlocked check. This 284172262Skevlo // saves one function call to pthread_once() (which itself only 28561452Sdfr // tests for the once value unlocked anyway and immediately 28661452Sdfr // returns if set) 28761452Sdfr if (!_S_init) 28861452Sdfr { 28961452Sdfr#ifdef __GTHREADS 290129189Sjhb if (__gthread_active_p()) 291172262Skevlo __gthread_once(&_S_once, _S_initialize); 29261452Sdfr#endif 293172262Skevlo if (!_S_init) 294172262Skevlo _S_initialize(); 295172262Skevlo } 296172262Skevlo 297172262Skevlo // Requests larger than _M_max_bytes are handled by new/delete 29861452Sdfr // directly. 299172262Skevlo const size_t __bytes = __n * sizeof(_Tp); 300172262Skevlo if (__bytes > _S_options._M_max_bytes || _S_options._M_force_new) 301172262Skevlo { 302172262Skevlo void* __ret = ::operator new(__bytes); 303172262Skevlo return static_cast<_Tp*>(__ret); 30461452Sdfr } 305172262Skevlo 306172262Skevlo // Round up to power of 2 and figure out which bin to use. 307172262Skevlo const size_t __which = _S_binmap[__bytes]; 308172262Skevlo const size_t __thread_id = _S_get_thread_id(); 309172262Skevlo 310172262Skevlo // Find out if we have blocks on our freelist. If so, go ahead 311172262Skevlo // and use them directly without having to lock anything. 312172262Skevlo const _Bin_record& __bin = _S_bin[__which]; 313172262Skevlo _Block_record* __block = NULL; 314172262Skevlo if (__bin._M_first[__thread_id] == NULL) 315172262Skevlo { 316172262Skevlo // NB: For alignment reasons, we can't use the first _M_align 317172262Skevlo // bytes, even when sizeof(_Block_record) < _M_align. 318172262Skevlo const size_t __bin_size = ((_S_options._M_min_bin << __which) 319172262Skevlo + _S_options._M_align); 320172262Skevlo size_t __block_count = _S_options._M_chunk_size / __bin_size; 321172262Skevlo 322172262Skevlo // Are we using threads? 323172262Skevlo // - Yes, check if there are free blocks on the global 324172262Skevlo // list. If so, grab up to __block_count blocks in one 325172262Skevlo // lock and change ownership. If the global list is 326172262Skevlo // empty, we allocate a new chunk and add those blocks 327172262Skevlo // directly to our own freelist (with us as owner). 328172262Skevlo // - No, all operations are made directly to global pool 0 329200764Srnoland // no need to lock or change ownership but check for free 330200764Srnoland // blocks on global list (and if not add new ones) and 331200764Srnoland // get the first one. 332200764Srnoland#ifdef __GTHREADS 333200764Srnoland if (__gthread_active_p()) 334200764Srnoland { 335200764Srnoland __gthread_mutex_lock(__bin._M_mutex); 336200764Srnoland if (__bin._M_first[0] == NULL) 337200764Srnoland { 338172262Skevlo // No need to hold the lock when we are adding a 339172262Skevlo // whole chunk to our own list. 340172262Skevlo __gthread_mutex_unlock(__bin._M_mutex); 341172262Skevlo 342172262Skevlo void* __v = ::operator new(_S_options._M_chunk_size); 343172262Skevlo __bin._M_first[__thread_id] = static_cast<_Block_record*>(__v); 344172262Skevlo __bin._M_free[__thread_id] = __block_count; 345172262Skevlo 346172262Skevlo --__block_count; 34761452Sdfr __block = __bin._M_first[__thread_id]; 34861452Sdfr while (__block_count-- > 0) 34961452Sdfr { 35061452Sdfr char* __c = reinterpret_cast<char*>(__block) + __bin_size; 351189578Simp __block->_M_next = reinterpret_cast<_Block_record*>(__c); 35261452Sdfr __block = __block->_M_next; 35361452Sdfr } 35461452Sdfr __block->_M_next = NULL; 355190169Srnoland } 35661452Sdfr else 35761452Sdfr { 35861452Sdfr // Is the number of required blocks greater than or 35961452Sdfr // equal to the number that can be provided by the 36061452Sdfr // global free list? 36161452Sdfr __bin._M_first[__thread_id] = __bin._M_first[0]; 36261452Sdfr if (__block_count >= __bin._M_free[0]) 363189578Simp { 36461452Sdfr __bin._M_free[__thread_id] = __bin._M_free[0]; 36561452Sdfr __bin._M_free[0] = 0; 36661452Sdfr __bin._M_first[0] = NULL; 367190169Srnoland } 36861452Sdfr else 36961452Sdfr { 37061452Sdfr __bin._M_free[__thread_id] = __block_count; 37161452Sdfr __bin._M_free[0] -= __block_count; 37261452Sdfr --__block_count; 37361452Sdfr __block = __bin._M_first[0]; 37461452Sdfr while (__block_count-- > 0) 37561452Sdfr __block = __block->_M_next; 37661452Sdfr __bin._M_first[0] = __block->_M_next; 377129189Sjhb __block->_M_next = NULL; 378147606Sanholt } 379129189Sjhb __gthread_mutex_unlock(__bin._M_mutex); 380147606Sanholt } 381147606Sanholt } 382147606Sanholt else 383147606Sanholt#endif 384147606Sanholt { 385147606Sanholt void* __v = ::operator new(_S_options._M_chunk_size); 386147606Sanholt __bin._M_first[0] = static_cast<_Block_record*>(__v); 387147606Sanholt 388147606Sanholt --__block_count; 389147606Sanholt __block = __bin._M_first[0]; 39061452Sdfr while (__block_count-- > 0) 39161452Sdfr { 39261452Sdfr char* __c = reinterpret_cast<char*>(__block) + __bin_size; 39361452Sdfr __block->_M_next = reinterpret_cast<_Block_record*>(__c); 39461452Sdfr __block = __block->_M_next; 39561452Sdfr } 39661452Sdfr __block->_M_next = NULL; 39761452Sdfr } 39861452Sdfr } 39961452Sdfr 40061452Sdfr __block = __bin._M_first[__thread_id]; 40161452Sdfr __bin._M_first[__thread_id] = __bin._M_first[__thread_id]->_M_next; 40261452Sdfr#ifdef __GTHREADS 40361452Sdfr if (__gthread_active_p()) 40461452Sdfr { 40561452Sdfr __block->_M_thread_id = __thread_id; 40661452Sdfr --__bin._M_free[__thread_id]; 40761452Sdfr ++__bin._M_used[__thread_id]; 40861452Sdfr } 40961452Sdfr#endif 41061452Sdfr 41161452Sdfr char* __c = reinterpret_cast<char*>(__block) + _S_options._M_align; 41261452Sdfr return static_cast<_Tp*>(static_cast<void*>(__c)); 41361452Sdfr } 41461452Sdfr 41561452Sdfr template<typename _Tp> 41661452Sdfr void 41761452Sdfr __mt_alloc<_Tp>:: 41861452Sdfr deallocate(pointer __p, size_type __n) 41961452Sdfr { 42061452Sdfr // Requests larger than _M_max_bytes are handled by operators 42161452Sdfr // new/delete directly. 42261452Sdfr const size_t __bytes = __n * sizeof(_Tp); 42361452Sdfr if (__bytes > _S_options._M_max_bytes || _S_options._M_force_new) 424153572Sjhb { 425113506Smdodd ::operator delete(__p); 426113506Smdodd return; 427 } 428 429 // Round up to power of 2 and figure out which bin to use. 430 const size_t __which = _S_binmap[__bytes]; 431 const _Bin_record& __bin = _S_bin[__which]; 432 433 char* __c = reinterpret_cast<char*>(__p) - _S_options._M_align; 434 _Block_record* __block = reinterpret_cast<_Block_record*>(__c); 435 436#ifdef __GTHREADS 437 if (__gthread_active_p()) 438 { 439 // Calculate the number of records to remove from our freelist: 440 // in order to avoid too much contention we wait until the 441 // number of records is "high enough". 442 const size_t __thread_id = _S_get_thread_id(); 443 444 long __remove = ((__bin._M_free[__thread_id] 445 * _S_options._M_freelist_headroom) 446 - __bin._M_used[__thread_id]); 447 if (__remove > static_cast<long>(100 * (_S_bin_size - __which) 448 * _S_options._M_freelist_headroom) 449 && __remove > static_cast<long>(__bin._M_free[__thread_id])) 450 { 451 _Block_record* __tmp = __bin._M_first[__thread_id]; 452 _Block_record* __first = __tmp; 453 __remove /= _S_options._M_freelist_headroom; 454 const long __removed = __remove; 455 --__remove; 456 while (__remove-- > 0) 457 __tmp = __tmp->_M_next; 458 __bin._M_first[__thread_id] = __tmp->_M_next; 459 __bin._M_free[__thread_id] -= __removed; 460 461 __gthread_mutex_lock(__bin._M_mutex); 462 __tmp->_M_next = __bin._M_first[0]; 463 __bin._M_first[0] = __first; 464 __bin._M_free[0] += __removed; 465 __gthread_mutex_unlock(__bin._M_mutex); 466 } 467 468 // Return this block to our list and update counters and 469 // owner id as needed. 470 --__bin._M_used[__block->_M_thread_id]; 471 472 __block->_M_next = __bin._M_first[__thread_id]; 473 __bin._M_first[__thread_id] = __block; 474 475 ++__bin._M_free[__thread_id]; 476 } 477 else 478#endif 479 { 480 // Single threaded application - return to global pool. 481 __block->_M_next = __bin._M_first[0]; 482 __bin._M_first[0] = __block; 483 } 484 } 485 486 template<typename _Tp> 487 void 488 __mt_alloc<_Tp>:: 489 _S_initialize() 490 { 491 // This method is called on the first allocation (when _S_init is still 492 // false) to create the bins. 493 494 // Ensure that the static initialization of _S_options has 495 // happened. This depends on (a) _M_align == 0 being an invalid 496 // value that is only present at startup, and (b) the real 497 // static initialization that happens later not actually 498 // changing anything. 499 if (_S_options._M_align == 0) 500 new (&_S_options) _Tune; 501 502 // _M_force_new must not change after the first allocate(), 503 // which in turn calls this method, so if it's false, it's false 504 // forever and we don't need to return here ever again. 505 if (_S_options._M_force_new) 506 { 507 _S_init = true; 508 return; 509 } 510 511 // Calculate the number of bins required based on _M_max_bytes. 512 // _S_bin_size is statically-initialized to one. 513 size_t __bin_size = _S_options._M_min_bin; 514 while (_S_options._M_max_bytes > __bin_size) 515 { 516 __bin_size <<= 1; 517 ++_S_bin_size; 518 } 519 520 // Setup the bin map for quick lookup of the relevant bin. 521 const size_t __j = (_S_options._M_max_bytes + 1) * sizeof(_Binmap_type); 522 _S_binmap = static_cast<_Binmap_type*>(::operator new(__j)); 523 524 _Binmap_type* __bp = _S_binmap; 525 _Binmap_type __bin_max = _S_options._M_min_bin; 526 _Binmap_type __bint = 0; 527 for (_Binmap_type __ct = 0; __ct <= _S_options._M_max_bytes; ++__ct) 528 { 529 if (__ct > __bin_max) 530 { 531 __bin_max <<= 1; 532 ++__bint; 533 } 534 *__bp++ = __bint; 535 } 536 537 // Initialize _S_bin and its members. 538 void* __v = ::operator new(sizeof(_Bin_record) * _S_bin_size); 539 _S_bin = static_cast<_Bin_record*>(__v); 540 541 // If __gthread_active_p() create and initialize the list of 542 // free thread ids. Single threaded applications use thread id 0 543 // directly and have no need for this. 544#ifdef __GTHREADS 545 if (__gthread_active_p()) 546 { 547 const size_t __k = sizeof(_Thread_record) * _S_options._M_max_threads; 548 __v = ::operator new(__k); 549 _S_thread_freelist_first = static_cast<_Thread_record*>(__v); 550 551 // NOTE! The first assignable thread id is 1 since the 552 // global pool uses id 0 553 size_t __i; 554 for (__i = 1; __i < _S_options._M_max_threads; ++__i) 555 { 556 _Thread_record& __tr = _S_thread_freelist_first[__i - 1]; 557 __tr._M_next = &_S_thread_freelist_first[__i]; 558 __tr._M_id = __i; 559 } 560 561 // Set last record. 562 _S_thread_freelist_first[__i - 1]._M_next = NULL; 563 _S_thread_freelist_first[__i - 1]._M_id = __i; 564 565 // Make sure this is initialized. 566#ifndef __GTHREAD_MUTEX_INIT 567 __GTHREAD_MUTEX_INIT_FUNCTION(&_S_thread_freelist_mutex); 568#endif 569 // Initialize per thread key to hold pointer to 570 // _S_thread_freelist. 571 __gthread_key_create(&_S_thread_key, _S_destroy_thread_key); 572 573 const size_t __max_threads = _S_options._M_max_threads + 1; 574 for (size_t __n = 0; __n < _S_bin_size; ++__n) 575 { 576 _Bin_record& __bin = _S_bin[__n]; 577 __v = ::operator new(sizeof(_Block_record*) * __max_threads); 578 __bin._M_first = static_cast<_Block_record**>(__v); 579 580 __v = ::operator new(sizeof(size_t) * __max_threads); 581 __bin._M_free = static_cast<size_t*>(__v); 582 583 __v = ::operator new(sizeof(size_t) * __max_threads); 584 __bin._M_used = static_cast<size_t*>(__v); 585 586 __v = ::operator new(sizeof(__gthread_mutex_t)); 587 __bin._M_mutex = static_cast<__gthread_mutex_t*>(__v); 588 589#ifdef __GTHREAD_MUTEX_INIT 590 { 591 // Do not copy a POSIX/gthr mutex once in use. 592 __gthread_mutex_t __tmp = __GTHREAD_MUTEX_INIT; 593 *__bin._M_mutex = __tmp; 594 } 595#else 596 { __GTHREAD_MUTEX_INIT_FUNCTION(__bin._M_mutex); } 597#endif 598 599 for (size_t __threadn = 0; __threadn < __max_threads; 600 ++__threadn) 601 { 602 __bin._M_first[__threadn] = NULL; 603 __bin._M_free[__threadn] = 0; 604 __bin._M_used[__threadn] = 0; 605 } 606 } 607 } 608 else 609#endif 610 for (size_t __n = 0; __n < _S_bin_size; ++__n) 611 { 612 _Bin_record& __bin = _S_bin[__n]; 613 __v = ::operator new(sizeof(_Block_record*)); 614 __bin._M_first = static_cast<_Block_record**>(__v); 615 __bin._M_first[0] = NULL; 616 } 617 618 _S_init = true; 619 } 620 621 template<typename _Tp> 622 size_t 623 __mt_alloc<_Tp>:: 624 _S_get_thread_id() 625 { 626#ifdef __GTHREADS 627 // If we have thread support and it's active we check the thread 628 // key value and return its id or if it's not set we take the 629 // first record from _S_thread_freelist and sets the key and 630 // returns it's id. 631 if (__gthread_active_p()) 632 { 633 _Thread_record* __freelist_pos = 634 static_cast<_Thread_record*>(__gthread_getspecific(_S_thread_key)); 635 if (__freelist_pos == NULL) 636 { 637 // Since _S_options._M_max_threads must be larger than 638 // the theoretical max number of threads of the OS the 639 // list can never be empty. 640 __gthread_mutex_lock(&_S_thread_freelist_mutex); 641 __freelist_pos = _S_thread_freelist_first; 642 _S_thread_freelist_first = _S_thread_freelist_first->_M_next; 643 __gthread_mutex_unlock(&_S_thread_freelist_mutex); 644 645 __gthread_setspecific(_S_thread_key, 646 static_cast<void*>(__freelist_pos)); 647 } 648 return __freelist_pos->_M_id; 649 } 650#endif 651 // Otherwise (no thread support or inactive) all requests are 652 // served from the global pool 0. 653 return 0; 654 } 655 656#ifdef __GTHREADS 657 template<typename _Tp> 658 void 659 __mt_alloc<_Tp>:: 660 _S_destroy_thread_key(void* __freelist_pos) 661 { 662 // Return this thread id record to front of thread_freelist. 663 __gthread_mutex_lock(&_S_thread_freelist_mutex); 664 _Thread_record* __tr = static_cast<_Thread_record*>(__freelist_pos); 665 __tr->_M_next = _S_thread_freelist_first; 666 _S_thread_freelist_first = __tr; 667 __gthread_mutex_unlock(&_S_thread_freelist_mutex); 668 } 669#endif 670 671 template<typename _Tp> 672 inline bool 673 operator==(const __mt_alloc<_Tp>&, const __mt_alloc<_Tp>&) 674 { return true; } 675 676 template<typename _Tp> 677 inline bool 678 operator!=(const __mt_alloc<_Tp>&, const __mt_alloc<_Tp>&) 679 { return false; } 680 681 template<typename _Tp> 682 bool __mt_alloc<_Tp>::_S_init = false; 683 684 template<typename _Tp> 685 typename __mt_alloc<_Tp>::_Tune __mt_alloc<_Tp>::_S_options; 686 687 template<typename _Tp> 688 typename __mt_alloc<_Tp>::_Binmap_type* __mt_alloc<_Tp>::_S_binmap; 689 690 template<typename _Tp> 691 typename __mt_alloc<_Tp>::_Bin_record* volatile __mt_alloc<_Tp>::_S_bin; 692 693 template<typename _Tp> 694 size_t __mt_alloc<_Tp>::_S_bin_size = 1; 695 696 // Actual initialization in _S_initialize(). 697#ifdef __GTHREADS 698 template<typename _Tp> 699 __gthread_once_t __mt_alloc<_Tp>::_S_once = __GTHREAD_ONCE_INIT; 700 701 template<typename _Tp> 702 typename __mt_alloc<_Tp>::_Thread_record* 703 volatile __mt_alloc<_Tp>::_S_thread_freelist_first = NULL; 704 705 template<typename _Tp> 706 __gthread_key_t __mt_alloc<_Tp>::_S_thread_key; 707 708 template<typename _Tp> 709 __gthread_mutex_t 710#ifdef __GTHREAD_MUTEX_INIT 711 __mt_alloc<_Tp>::_S_thread_freelist_mutex = __GTHREAD_MUTEX_INIT; 712#else 713 __mt_alloc<_Tp>::_S_thread_freelist_mutex; 714#endif 715#endif 716} // namespace __gnu_cxx 717 718#endif 719