libstdc++

mt_allocator.h
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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