1 // MT-optimized allocator -*- C++ -*- 2 3 // Copyright (C) 2003-2013 Free Software Foundation, Inc. 4 // 5 // This file is part of the GNU ISO C++ Library. This library is free 6 // software; you can redistribute it and/or modify it under the 7 // terms of the GNU General Public License as published by the 8 // Free Software Foundation; either version 3, or (at your option) 9 // any later version. 10 11 // This library is distributed in the hope that it will be useful, 12 // but WITHOUT ANY WARRANTY; without even the implied warranty of 13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 // GNU General Public License for more details. 15 16 // Under Section 7 of GPL version 3, you are granted additional 17 // permissions described in the GCC Runtime Library Exception, version 18 // 3.1, as published by the Free Software Foundation. 19 20 // You should have received a copy of the GNU General Public License and 21 // a copy of the GCC Runtime Library Exception along with this program; 22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 // <http://www.gnu.org/licenses/>. 24 25 /** @file ext/mt_allocator.h 26 * This file is a GNU extension to the Standard C++ Library. 27 */ 28 29 #ifndef _MT_ALLOCATOR_H 30 #define _MT_ALLOCATOR_H 1 31 32 #include <new> 33 #include <cstdlib> 34 #include <bits/functexcept.h> 35 #include <ext/atomicity.h> 36 #include <bits/move.h> 37 #if __cplusplus >= 201103L 38 #include <type_traits> 39 #endif 40 41 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) 42 { 43 _GLIBCXX_BEGIN_NAMESPACE_VERSION 44 45 using std::size_t; 46 using std::ptrdiff_t; 47 48 typedef void (*__destroy_handler)(void*); 49 50 /// Base class for pool object. 51 struct __pool_base 52 { 53 // Using short int as type for the binmap implies we are never 54 // caching blocks larger than 32768 with this allocator. 55 typedef unsigned short int _Binmap_type; 56 57 // Variables used to configure the behavior of the allocator, 58 // assigned and explained in detail below. 59 struct _Tune 60 { 61 // Compile time constants for the default _Tune values. 62 enum { _S_align = 8 }; 63 enum { _S_max_bytes = 128 }; 64 enum { _S_min_bin = 8 }; 65 enum { _S_chunk_size = 4096 - 4 * sizeof(void*) }; 66 enum { _S_max_threads = 4096 }; 67 enum { _S_freelist_headroom = 10 }; 68 69 // Alignment needed. 70 // NB: In any case must be >= sizeof(_Block_record), that 71 // is 4 on 32 bit machines and 8 on 64 bit machines. 72 size_t _M_align; 73 74 // Allocation requests (after round-up to power of 2) below 75 // this value will be handled by the allocator. A raw new/ 76 // call will be used for requests larger than this value. 77 // NB: Must be much smaller than _M_chunk_size and in any 78 // case <= 32768. 79 size_t _M_max_bytes; 80 81 // Size in bytes of the smallest bin. 82 // NB: Must be a power of 2 and >= _M_align (and of course 83 // much smaller than _M_max_bytes). 84 size_t _M_min_bin; 85 86 // In order to avoid fragmenting and minimize the number of 87 // new() calls we always request new memory using this 88 // value. Based on previous discussions on the libstdc++ 89 // mailing list we have chosen the value below. 90 // See http://gcc.gnu.org/ml/libstdc++/2001-07/msg00077.html 91 // NB: At least one order of magnitude > _M_max_bytes. 92 size_t _M_chunk_size; 93 94 // The maximum number of supported threads. For 95 // single-threaded operation, use one. Maximum values will 96 // vary depending on details of the underlying system. (For 97 // instance, Linux 2.4.18 reports 4070 in 98 // /proc/sys/kernel/threads-max, while Linux 2.6.6 reports 99 // 65534) 100 size_t _M_max_threads; 101 102 // Each time a deallocation occurs in a threaded application 103 // we make sure that there are no more than 104 // _M_freelist_headroom % of used memory on the freelist. If 105 // the number of additional records is more than 106 // _M_freelist_headroom % of the freelist, we move these 107 // records back to the global pool. 108 size_t _M_freelist_headroom; 109 110 // Set to true forces all allocations to use new(). 111 bool _M_force_new; 112 113 explicit 114 _Tune() 115 : _M_align(_S_align), _M_max_bytes(_S_max_bytes), _M_min_bin(_S_min_bin), 116 _M_chunk_size(_S_chunk_size), _M_max_threads(_S_max_threads), 117 _M_freelist_headroom(_S_freelist_headroom), 118 _M_force_new(std::getenv("GLIBCXX_FORCE_NEW") ? true : false) 119 { } 120 121 explicit 122 _Tune(size_t __align, size_t __maxb, size_t __minbin, size_t __chunk, 123 size_t __maxthreads, size_t __headroom, bool __force) 124 : _M_align(__align), _M_max_bytes(__maxb), _M_min_bin(__minbin), 125 _M_chunk_size(__chunk), _M_max_threads(__maxthreads), 126 _M_freelist_headroom(__headroom), _M_force_new(__force) 127 { } 128 }; 129 130 struct _Block_address 131 { 132 void* _M_initial; 133 _Block_address* _M_next; 134 }; 135 136 const _Tune& 137 _M_get_options() const 138 { return _M_options; } 139 140 void 141 _M_set_options(_Tune __t) 142 { 143 if (!_M_init) 144 _M_options = __t; 145 } 146 147 bool 148 _M_check_threshold(size_t __bytes) 149 { return __bytes > _M_options._M_max_bytes || _M_options._M_force_new; } 150 151 size_t 152 _M_get_binmap(size_t __bytes) 153 { return _M_binmap[__bytes]; } 154 155 size_t 156 _M_get_align() 157 { return _M_options._M_align; } 158 159 explicit 160 __pool_base() 161 : _M_options(_Tune()), _M_binmap(0), _M_init(false) { } 162 163 explicit 164 __pool_base(const _Tune& __options) 165 : _M_options(__options), _M_binmap(0), _M_init(false) { } 166 167 private: 168 explicit 169 __pool_base(const __pool_base&); 170 171 __pool_base& 172 operator=(const __pool_base&); 173 174 protected: 175 // Configuration options. 176 _Tune _M_options; 177 178 _Binmap_type* _M_binmap; 179 180 // Configuration of the pool object via _M_options can happen 181 // after construction but before initialization. After 182 // initialization is complete, this variable is set to true. 183 bool _M_init; 184 }; 185 186 187 /** 188 * @brief Data describing the underlying memory pool, parameterized on 189 * threading support. 190 */ 191 template<bool _Thread> 192 class __pool; 193 194 /// Specialization for single thread. 195 template<> 196 class __pool<false> : public __pool_base 197 { 198 public: 199 union _Block_record 200 { 201 // Points to the block_record of the next free block. 202 _Block_record* _M_next; 203 }; 204 205 struct _Bin_record 206 { 207 // An "array" of pointers to the first free block. 208 _Block_record** _M_first; 209 210 // A list of the initial addresses of all allocated blocks. 211 _Block_address* _M_address; 212 }; 213 214 void 215 _M_initialize_once() 216 { 217 if (__builtin_expect(_M_init == false, false)) 218 _M_initialize(); 219 } 220 221 void 222 _M_destroy() throw(); 223 224 char* 225 _M_reserve_block(size_t __bytes, const size_t __thread_id); 226 227 void 228 _M_reclaim_block(char* __p, size_t __bytes) throw (); 229 230 size_t 231 _M_get_thread_id() { return 0; } 232 233 const _Bin_record& 234 _M_get_bin(size_t __which) 235 { return _M_bin[__which]; } 236 237 void 238 _M_adjust_freelist(const _Bin_record&, _Block_record*, size_t) 239 { } 240 241 explicit __pool() 242 : _M_bin(0), _M_bin_size(1) { } 243 244 explicit __pool(const __pool_base::_Tune& __tune) 245 : __pool_base(__tune), _M_bin(0), _M_bin_size(1) { } 246 247 private: 248 // An "array" of bin_records each of which represents a specific 249 // power of 2 size. Memory to this "array" is allocated in 250 // _M_initialize(). 251 _Bin_record* _M_bin; 252 253 // Actual value calculated in _M_initialize(). 254 size_t _M_bin_size; 255 256 void 257 _M_initialize(); 258 }; 259 260 #ifdef __GTHREADS 261 /// Specialization for thread enabled, via gthreads.h. 262 template<> 263 class __pool<true> : public __pool_base 264 { 265 public: 266 // Each requesting thread is assigned an id ranging from 1 to 267 // _S_max_threads. Thread id 0 is used as a global memory pool. 268 // In order to get constant performance on the thread assignment 269 // routine, we keep a list of free ids. When a thread first 270 // requests memory we remove the first record in this list and 271 // stores the address in a __gthread_key. When initializing the 272 // __gthread_key we specify a destructor. When this destructor 273 // (i.e. the thread dies) is called, we return the thread id to 274 // the front of this list. 275 struct _Thread_record 276 { 277 // Points to next free thread id record. NULL if last record in list. 278 _Thread_record* _M_next; 279 280 // Thread id ranging from 1 to _S_max_threads. 281 size_t _M_id; 282 }; 283 284 union _Block_record 285 { 286 // Points to the block_record of the next free block. 287 _Block_record* _M_next; 288 289 // The thread id of the thread which has requested this block. 290 size_t _M_thread_id; 291 }; 292 293 struct _Bin_record 294 { 295 // An "array" of pointers to the first free block for each 296 // thread id. Memory to this "array" is allocated in 297 // _S_initialize() for _S_max_threads + global pool 0. 298 _Block_record** _M_first; 299 300 // A list of the initial addresses of all allocated blocks. 301 _Block_address* _M_address; 302 303 // An "array" of counters used to keep track of the amount of 304 // blocks that are on the freelist/used for each thread id. 305 // - Note that the second part of the allocated _M_used "array" 306 // actually hosts (atomic) counters of reclaimed blocks: in 307 // _M_reserve_block and in _M_reclaim_block those numbers are 308 // subtracted from the first ones to obtain the actual size 309 // of the "working set" of the given thread. 310 // - Memory to these "arrays" is allocated in _S_initialize() 311 // for _S_max_threads + global pool 0. 312 size_t* _M_free; 313 size_t* _M_used; 314 315 // Each bin has its own mutex which is used to ensure data 316 // integrity while changing "ownership" on a block. The mutex 317 // is initialized in _S_initialize(). 318 __gthread_mutex_t* _M_mutex; 319 }; 320 321 // XXX GLIBCXX_ABI Deprecated 322 void 323 _M_initialize(__destroy_handler); 324 325 void 326 _M_initialize_once() 327 { 328 if (__builtin_expect(_M_init == false, false)) 329 _M_initialize(); 330 } 331 332 void 333 _M_destroy() throw(); 334 335 char* 336 _M_reserve_block(size_t __bytes, const size_t __thread_id); 337 338 void 339 _M_reclaim_block(char* __p, size_t __bytes) throw (); 340 341 const _Bin_record& 342 _M_get_bin(size_t __which) 343 { return _M_bin[__which]; } 344 345 void 346 _M_adjust_freelist(const _Bin_record& __bin, _Block_record* __block, 347 size_t __thread_id) 348 { 349 if (__gthread_active_p()) 350 { 351 __block->_M_thread_id = __thread_id; 352 --__bin._M_free[__thread_id]; 353 ++__bin._M_used[__thread_id]; 354 } 355 } 356 357 // XXX GLIBCXX_ABI Deprecated 358 _GLIBCXX_CONST void 359 _M_destroy_thread_key(void*) throw (); 360 361 size_t 362 _M_get_thread_id(); 363 364 explicit __pool() 365 : _M_bin(0), _M_bin_size(1), _M_thread_freelist(0) 366 { } 367 368 explicit __pool(const __pool_base::_Tune& __tune) 369 : __pool_base(__tune), _M_bin(0), _M_bin_size(1), 370 _M_thread_freelist(0) 371 { } 372 373 private: 374 // An "array" of bin_records each of which represents a specific 375 // power of 2 size. Memory to this "array" is allocated in 376 // _M_initialize(). 377 _Bin_record* _M_bin; 378 379 // Actual value calculated in _M_initialize(). 380 size_t _M_bin_size; 381 382 _Thread_record* _M_thread_freelist; 383 void* _M_thread_freelist_initial; 384 385 void 386 _M_initialize(); 387 }; 388 #endif 389 390 template<template <bool> class _PoolTp, bool _Thread> 391 struct __common_pool 392 { 393 typedef _PoolTp<_Thread> pool_type; 394 395 static pool_type& 396 _S_get_pool() 397 { 398 static pool_type _S_pool; 399 return _S_pool; 400 } 401 }; 402 403 template<template <bool> class _PoolTp, bool _Thread> 404 struct __common_pool_base; 405 406 template<template <bool> class _PoolTp> 407 struct __common_pool_base<_PoolTp, false> 408 : public __common_pool<_PoolTp, false> 409 { 410 using __common_pool<_PoolTp, false>::_S_get_pool; 411 412 static void 413 _S_initialize_once() 414 { 415 static bool __init; 416 if (__builtin_expect(__init == false, false)) 417 { 418 _S_get_pool()._M_initialize_once(); 419 __init = true; 420 } 421 } 422 }; 423 424 #ifdef __GTHREADS 425 template<template <bool> class _PoolTp> 426 struct __common_pool_base<_PoolTp, true> 427 : public __common_pool<_PoolTp, true> 428 { 429 using __common_pool<_PoolTp, true>::_S_get_pool; 430 431 static void 432 _S_initialize() 433 { _S_get_pool()._M_initialize_once(); } 434 435 static void 436 _S_initialize_once() 437 { 438 static bool __init; 439 if (__builtin_expect(__init == false, false)) 440 { 441 if (__gthread_active_p()) 442 { 443 // On some platforms, __gthread_once_t is an aggregate. 444 static __gthread_once_t __once = __GTHREAD_ONCE_INIT; 445 __gthread_once(&__once, _S_initialize); 446 } 447 448 // Double check initialization. May be necessary on some 449 // systems for proper construction when not compiling with 450 // thread flags. 451 _S_get_pool()._M_initialize_once(); 452 __init = true; 453 } 454 } 455 }; 456 #endif 457 458 /// Policy for shared __pool objects. 459 template<template <bool> class _PoolTp, bool _Thread> 460 struct __common_pool_policy : public __common_pool_base<_PoolTp, _Thread> 461 { 462 template<typename _Tp1, template <bool> class _PoolTp1 = _PoolTp, 463 bool _Thread1 = _Thread> 464 struct _M_rebind 465 { typedef __common_pool_policy<_PoolTp1, _Thread1> other; }; 466 467 using __common_pool_base<_PoolTp, _Thread>::_S_get_pool; 468 using __common_pool_base<_PoolTp, _Thread>::_S_initialize_once; 469 }; 470 471 472 template<typename _Tp, template <bool> class _PoolTp, bool _Thread> 473 struct __per_type_pool 474 { 475 typedef _Tp value_type; 476 typedef _PoolTp<_Thread> pool_type; 477 478 static pool_type& 479 _S_get_pool() 480 { 481 // Sane defaults for the _PoolTp. 482 typedef typename pool_type::_Block_record _Block_record; 483 const static size_t __a = (__alignof__(_Tp) >= sizeof(_Block_record) 484 ? __alignof__(_Tp) : sizeof(_Block_record)); 485 486 typedef typename __pool_base::_Tune _Tune; 487 static _Tune _S_tune(__a, sizeof(_Tp) * 64, 488 sizeof(_Tp) * 2 >= __a ? sizeof(_Tp) * 2 : __a, 489 sizeof(_Tp) * size_t(_Tune::_S_chunk_size), 490 _Tune::_S_max_threads, 491 _Tune::_S_freelist_headroom, 492 std::getenv("GLIBCXX_FORCE_NEW") ? true : false); 493 static pool_type _S_pool(_S_tune); 494 return _S_pool; 495 } 496 }; 497 498 template<typename _Tp, template <bool> class _PoolTp, bool _Thread> 499 struct __per_type_pool_base; 500 501 template<typename _Tp, template <bool> class _PoolTp> 502 struct __per_type_pool_base<_Tp, _PoolTp, false> 503 : public __per_type_pool<_Tp, _PoolTp, false> 504 { 505 using __per_type_pool<_Tp, _PoolTp, false>::_S_get_pool; 506 507 static void 508 _S_initialize_once() 509 { 510 static bool __init; 511 if (__builtin_expect(__init == false, false)) 512 { 513 _S_get_pool()._M_initialize_once(); 514 __init = true; 515 } 516 } 517 }; 518 519 #ifdef __GTHREADS 520 template<typename _Tp, template <bool> class _PoolTp> 521 struct __per_type_pool_base<_Tp, _PoolTp, true> 522 : public __per_type_pool<_Tp, _PoolTp, true> 523 { 524 using __per_type_pool<_Tp, _PoolTp, true>::_S_get_pool; 525 526 static void 527 _S_initialize() 528 { _S_get_pool()._M_initialize_once(); } 529 530 static void 531 _S_initialize_once() 532 { 533 static bool __init; 534 if (__builtin_expect(__init == false, false)) 535 { 536 if (__gthread_active_p()) 537 { 538 // On some platforms, __gthread_once_t is an aggregate. 539 static __gthread_once_t __once = __GTHREAD_ONCE_INIT; 540 __gthread_once(&__once, _S_initialize); 541 } 542 543 // Double check initialization. May be necessary on some 544 // systems for proper construction when not compiling with 545 // thread flags. 546 _S_get_pool()._M_initialize_once(); 547 __init = true; 548 } 549 } 550 }; 551 #endif 552 553 /// Policy for individual __pool objects. 554 template<typename _Tp, template <bool> class _PoolTp, bool _Thread> 555 struct __per_type_pool_policy 556 : public __per_type_pool_base<_Tp, _PoolTp, _Thread> 557 { 558 template<typename _Tp1, template <bool> class _PoolTp1 = _PoolTp, 559 bool _Thread1 = _Thread> 560 struct _M_rebind 561 { typedef __per_type_pool_policy<_Tp1, _PoolTp1, _Thread1> other; }; 562 563 using __per_type_pool_base<_Tp, _PoolTp, _Thread>::_S_get_pool; 564 using __per_type_pool_base<_Tp, _PoolTp, _Thread>::_S_initialize_once; 565 }; 566 567 568 /// Base class for _Tp dependent member functions. 569 template<typename _Tp> 570 class __mt_alloc_base 571 { 572 public: 573 typedef size_t size_type; 574 typedef ptrdiff_t difference_type; 575 typedef _Tp* pointer; 576 typedef const _Tp* const_pointer; 577 typedef _Tp& reference; 578 typedef const _Tp& const_reference; 579 typedef _Tp value_type; 580 581 #if __cplusplus >= 201103L 582 // _GLIBCXX_RESOLVE_LIB_DEFECTS 583 // 2103. propagate_on_container_move_assignment 584 typedef std::true_type propagate_on_container_move_assignment; 585 #endif 586 587 pointer 588 address(reference __x) const _GLIBCXX_NOEXCEPT 589 { return std::__addressof(__x); } 590 591 const_pointer 592 address(const_reference __x) const _GLIBCXX_NOEXCEPT 593 { return std::__addressof(__x); } 594 595 size_type 596 max_size() const _GLIBCXX_USE_NOEXCEPT 597 { return size_t(-1) / sizeof(_Tp); } 598 599 #if __cplusplus >= 201103L 600 template<typename _Up, typename... _Args> 601 void 602 construct(_Up* __p, _Args&&... __args) 603 { ::new((void *)__p) _Up(std::forward<_Args>(__args)...); } 604 605 template<typename _Up> 606 void 607 destroy(_Up* __p) { __p->~_Up(); } 608 #else 609 // _GLIBCXX_RESOLVE_LIB_DEFECTS 610 // 402. wrong new expression in [some_] allocator::construct 611 void 612 construct(pointer __p, const _Tp& __val) 613 { ::new((void *)__p) _Tp(__val); } 614 615 void 616 destroy(pointer __p) { __p->~_Tp(); } 617 #endif 618 }; 619 620 #ifdef __GTHREADS 621 #define __thread_default true 622 #else 623 #define __thread_default false 624 #endif 625 626 /** 627 * @brief This is a fixed size (power of 2) allocator which - when 628 * compiled with thread support - will maintain one freelist per 629 * size per thread plus a @a global one. Steps are taken to limit 630 * the per thread freelist sizes (by returning excess back to 631 * the @a global list). 632 * @ingroup allocators 633 * 634 * Further details: 635 * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt12ch32.html 636 */ 637 template<typename _Tp, 638 typename _Poolp = __common_pool_policy<__pool, __thread_default> > 639 class __mt_alloc : public __mt_alloc_base<_Tp> 640 { 641 public: 642 typedef size_t size_type; 643 typedef ptrdiff_t difference_type; 644 typedef _Tp* pointer; 645 typedef const _Tp* const_pointer; 646 typedef _Tp& reference; 647 typedef const _Tp& const_reference; 648 typedef _Tp value_type; 649 typedef _Poolp __policy_type; 650 typedef typename _Poolp::pool_type __pool_type; 651 652 template<typename _Tp1, typename _Poolp1 = _Poolp> 653 struct rebind 654 { 655 typedef typename _Poolp1::template _M_rebind<_Tp1>::other pol_type; 656 typedef __mt_alloc<_Tp1, pol_type> other; 657 }; 658 659 __mt_alloc() _GLIBCXX_USE_NOEXCEPT { } 660 661 __mt_alloc(const __mt_alloc&) _GLIBCXX_USE_NOEXCEPT { } 662 663 template<typename _Tp1, typename _Poolp1> 664 __mt_alloc(const __mt_alloc<_Tp1, _Poolp1>&) _GLIBCXX_USE_NOEXCEPT { } 665 666 ~__mt_alloc() _GLIBCXX_USE_NOEXCEPT { } 667 668 pointer 669 allocate(size_type __n, const void* = 0); 670 671 void 672 deallocate(pointer __p, size_type __n); 673 674 const __pool_base::_Tune 675 _M_get_options() 676 { 677 // Return a copy, not a reference, for external consumption. 678 return __policy_type::_S_get_pool()._M_get_options(); 679 } 680 681 void 682 _M_set_options(__pool_base::_Tune __t) 683 { __policy_type::_S_get_pool()._M_set_options(__t); } 684 }; 685 686 template<typename _Tp, typename _Poolp> 687 typename __mt_alloc<_Tp, _Poolp>::pointer 688 __mt_alloc<_Tp, _Poolp>:: 689 allocate(size_type __n, const void*) 690 { 691 if (__n > this->max_size()) 692 std::__throw_bad_alloc(); 693 694 __policy_type::_S_initialize_once(); 695 696 // Requests larger than _M_max_bytes are handled by operator 697 // new/delete directly. 698 __pool_type& __pool = __policy_type::_S_get_pool(); 699 const size_t __bytes = __n * sizeof(_Tp); 700 if (__pool._M_check_threshold(__bytes)) 701 { 702 void* __ret = ::operator new(__bytes); 703 return static_cast<_Tp*>(__ret); 704 } 705 706 // Round up to power of 2 and figure out which bin to use. 707 const size_t __which = __pool._M_get_binmap(__bytes); 708 const size_t __thread_id = __pool._M_get_thread_id(); 709 710 // Find out if we have blocks on our freelist. If so, go ahead 711 // and use them directly without having to lock anything. 712 char* __c; 713 typedef typename __pool_type::_Bin_record _Bin_record; 714 const _Bin_record& __bin = __pool._M_get_bin(__which); 715 if (__bin._M_first[__thread_id]) 716 { 717 // Already reserved. 718 typedef typename __pool_type::_Block_record _Block_record; 719 _Block_record* __block = __bin._M_first[__thread_id]; 720 __bin._M_first[__thread_id] = __block->_M_next; 721 722 __pool._M_adjust_freelist(__bin, __block, __thread_id); 723 __c = reinterpret_cast<char*>(__block) + __pool._M_get_align(); 724 } 725 else 726 { 727 // Null, reserve. 728 __c = __pool._M_reserve_block(__bytes, __thread_id); 729 } 730 return static_cast<_Tp*>(static_cast<void*>(__c)); 731 } 732 733 template<typename _Tp, typename _Poolp> 734 void 735 __mt_alloc<_Tp, _Poolp>:: 736 deallocate(pointer __p, size_type __n) 737 { 738 if (__builtin_expect(__p != 0, true)) 739 { 740 // Requests larger than _M_max_bytes are handled by 741 // operators new/delete directly. 742 __pool_type& __pool = __policy_type::_S_get_pool(); 743 const size_t __bytes = __n * sizeof(_Tp); 744 if (__pool._M_check_threshold(__bytes)) 745 ::operator delete(__p); 746 else 747 __pool._M_reclaim_block(reinterpret_cast<char*>(__p), __bytes); 748 } 749 } 750 751 template<typename _Tp, typename _Poolp> 752 inline bool 753 operator==(const __mt_alloc<_Tp, _Poolp>&, const __mt_alloc<_Tp, _Poolp>&) 754 { return true; } 755 756 template<typename _Tp, typename _Poolp> 757 inline bool 758 operator!=(const __mt_alloc<_Tp, _Poolp>&, const __mt_alloc<_Tp, _Poolp>&) 759 { return false; } 760 761 #undef __thread_default 762 763 _GLIBCXX_END_NAMESPACE_VERSION 764 } // namespace 765 766 #endif 767
