// MT-optimized allocator -*- C++ -*-
-// Copyright (C) 2003, 2004 Free Software Foundation, Inc.
+// Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
+// 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 2, or (at your option)
+// 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,
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
-// You should have received a copy of the GNU General Public License along
-// with this library; see the file COPYING. If not, write to the Free
-// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
-// USA.
+// 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.
-// As a special exception, you may use this file as part of a free software
-// library without restriction. Specifically, if other files instantiate
-// templates or use macros or inline functions from this file, or you compile
-// this file and link it with other files to produce an executable, this
-// file does not by itself cause the resulting executable to be covered by
-// the GNU General Public License. This exception does not however
-// invalidate any other reasons why the executable file might be covered by
-// the GNU General Public License.
+// 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
+// <http://www.gnu.org/licenses/>.
/** @file ext/mt_allocator.h
* This file is a GNU extension to the Standard C++ Library.
- * You should only include this header if you are using GCC 3 or later.
*/
#ifndef _MT_ALLOCATOR_H
#include <new>
#include <cstdlib>
#include <bits/functexcept.h>
-#include <bits/gthr.h>
-#include <bits/atomicity.h>
+#include <ext/atomicity.h>
+#include <bits/move.h>
-namespace __gnu_cxx
+namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
{
- /**
- * This is a fixed size (power of 2) allocator which - when
- * compiled with thread support - will maintain one freelist per
- * size per thread plus a "global" one. Steps are taken to limit
- * the per thread freelist sizes (by returning excess back to
- * "global").
- *
- * Further details:
- * http://gcc.gnu.org/onlinedocs/libstdc++/ext/mt_allocator.html
- */
- template<typename _Tp>
- class __mt_alloc
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+ using std::size_t;
+ using std::ptrdiff_t;
+
+ typedef void (*__destroy_handler)(void*);
+
+ /// Base class for pool object.
+ struct __pool_base
+ {
+ // Using short int as type for the binmap implies we are never
+ // caching blocks larger than 32768 with this allocator.
+ typedef unsigned short int _Binmap_type;
+
+ // Variables used to configure the behavior of the allocator,
+ // assigned and explained in detail below.
+ struct _Tune
+ {
+ // Compile time constants for the default _Tune values.
+ enum { _S_align = 8 };
+ enum { _S_max_bytes = 128 };
+ enum { _S_min_bin = 8 };
+ enum { _S_chunk_size = 4096 - 4 * sizeof(void*) };
+ enum { _S_max_threads = 4096 };
+ enum { _S_freelist_headroom = 10 };
+
+ // Alignment needed.
+ // NB: In any case must be >= sizeof(_Block_record), that
+ // is 4 on 32 bit machines and 8 on 64 bit machines.
+ size_t _M_align;
+
+ // Allocation requests (after round-up to power of 2) below
+ // this value will be handled by the allocator. A raw new/
+ // call will be used for requests larger than this value.
+ // NB: Must be much smaller than _M_chunk_size and in any
+ // case <= 32768.
+ size_t _M_max_bytes;
+
+ // Size in bytes of the smallest bin.
+ // NB: Must be a power of 2 and >= _M_align (and of course
+ // much smaller than _M_max_bytes).
+ size_t _M_min_bin;
+
+ // In order to avoid fragmenting and minimize the number of
+ // new() calls we always request new memory using this
+ // value. Based on previous discussions on the libstdc++
+ // mailing list we have chosen the value below.
+ // See http://gcc.gnu.org/ml/libstdc++/2001-07/msg00077.html
+ // NB: At least one order of magnitude > _M_max_bytes.
+ size_t _M_chunk_size;
+
+ // The maximum number of supported threads. For
+ // single-threaded operation, use one. Maximum values will
+ // vary depending on details of the underlying system. (For
+ // instance, Linux 2.4.18 reports 4070 in
+ // /proc/sys/kernel/threads-max, while Linux 2.6.6 reports
+ // 65534)
+ size_t _M_max_threads;
+
+ // Each time a deallocation occurs in a threaded application
+ // we make sure that there are no more than
+ // _M_freelist_headroom % of used memory on the freelist. If
+ // the number of additional records is more than
+ // _M_freelist_headroom % of the freelist, we move these
+ // records back to the global pool.
+ size_t _M_freelist_headroom;
+
+ // Set to true forces all allocations to use new().
+ bool _M_force_new;
+
+ explicit
+ _Tune()
+ : _M_align(_S_align), _M_max_bytes(_S_max_bytes), _M_min_bin(_S_min_bin),
+ _M_chunk_size(_S_chunk_size), _M_max_threads(_S_max_threads),
+ _M_freelist_headroom(_S_freelist_headroom),
+ _M_force_new(std::getenv("GLIBCXX_FORCE_NEW") ? true : false)
+ { }
+
+ explicit
+ _Tune(size_t __align, size_t __maxb, size_t __minbin, size_t __chunk,
+ size_t __maxthreads, size_t __headroom, bool __force)
+ : _M_align(__align), _M_max_bytes(__maxb), _M_min_bin(__minbin),
+ _M_chunk_size(__chunk), _M_max_threads(__maxthreads),
+ _M_freelist_headroom(__headroom), _M_force_new(__force)
+ { }
+ };
+
+ struct _Block_address
{
- public:
- typedef size_t size_type;
- typedef ptrdiff_t difference_type;
- typedef _Tp* pointer;
- typedef const _Tp* const_pointer;
- typedef _Tp& reference;
- typedef const _Tp& const_reference;
- typedef _Tp value_type;
+ void* _M_initial;
+ _Block_address* _M_next;
+ };
+
+ const _Tune&
+ _M_get_options() const
+ { return _M_options; }
- template<typename _Tp1>
- struct rebind
- { typedef __mt_alloc<_Tp1> other; };
+ void
+ _M_set_options(_Tune __t)
+ {
+ if (!_M_init)
+ _M_options = __t;
+ }
- __mt_alloc() throw()
- {
- // XXX
- }
+ bool
+ _M_check_threshold(size_t __bytes)
+ { return __bytes > _M_options._M_max_bytes || _M_options._M_force_new; }
- __mt_alloc(const __mt_alloc&) throw()
- {
- // XXX
- }
+ size_t
+ _M_get_binmap(size_t __bytes)
+ { return _M_binmap[__bytes]; }
- template<typename _Tp1>
- __mt_alloc(const __mt_alloc<_Tp1>& obj) throw()
- {
- // XXX
- }
+ size_t
+ _M_get_align()
+ { return _M_options._M_align; }
- ~__mt_alloc() throw() { }
+ explicit
+ __pool_base()
+ : _M_options(_Tune()), _M_binmap(0), _M_init(false) { }
- pointer
- address(reference __x) const
- { return &__x; }
+ explicit
+ __pool_base(const _Tune& __options)
+ : _M_options(__options), _M_binmap(0), _M_init(false) { }
- const_pointer
- address(const_reference __x) const
- { return &__x; }
+ private:
+ explicit
+ __pool_base(const __pool_base&);
- size_type
- max_size() const throw()
- { return size_t(-1) / sizeof(_Tp); }
+ __pool_base&
+ operator=(const __pool_base&);
- // _GLIBCXX_RESOLVE_LIB_DEFECTS
- // 402. wrong new expression in [some_] allocator::construct
- void
- construct(pointer __p, const _Tp& __val)
- { ::new(__p) _Tp(__val); }
+ protected:
+ // Configuration options.
+ _Tune _M_options;
+
+ _Binmap_type* _M_binmap;
- void
- destroy(pointer __p) { __p->~_Tp(); }
+ // Configuration of the pool object via _M_options can happen
+ // after construction but before initialization. After
+ // initialization is complete, this variable is set to true.
+ bool _M_init;
+ };
- pointer
- allocate(size_type __n, const void* = 0);
- void
- deallocate(pointer __p, size_type __n);
+ /**
+ * @brief Data describing the underlying memory pool, parameterized on
+ * threading support.
+ */
+ template<bool _Thread>
+ class __pool;
- // Variables used to configure the behavior of the allocator,
- // assigned and explained in detail below.
- struct _Tune
+ /// Specialization for single thread.
+ template<>
+ class __pool<false> : public __pool_base
+ {
+ public:
+ union _Block_record
{
- // Alignment needed.
- // NB: In any case must be >= sizeof(_Block_record), that
- // is 4 on 32 bit machines and 8 on 64 bit machines.
- size_t _M_align;
-
- // Allocation requests (after round-up to power of 2) below
- // this value will be handled by the allocator. A raw new/
- // call will be used for requests larger than this value.
- size_t _M_max_bytes;
-
- // Size in bytes of the smallest bin.
- // NB: Must be a power of 2 and >= _M_align.
- size_t _M_min_bin;
-
- // In order to avoid fragmenting and minimize the number of
- // new() calls we always request new memory using this
- // value. Based on previous discussions on the libstdc++
- // mailing list we have choosen the value below.
- // See http://gcc.gnu.org/ml/libstdc++/2001-07/msg00077.html
- size_t _M_chunk_size;
-
- // The maximum number of supported threads. For
- // single-threaded operation, use one. Maximum values will
- // vary depending on details of the underlying system. (For
- // instance, Linux 2.4.18 reports 4070 in
- // /proc/sys/kernel/threads-max, while Linux 2.6.6 reports
- // 65534)
- size_t _M_max_threads;
-
- // Each time a deallocation occurs in a threaded application
- // we make sure that there are no more than
- // _M_freelist_headroom % of used memory on the freelist. If
- // the number of additional records is more than
- // _M_freelist_headroom % of the freelist, we move these
- // records back to the global pool.
- size_t _M_freelist_headroom;
-
- // Set to true forces all allocations to use new().
- bool _M_force_new;
-
- explicit
- _Tune()
- : _M_align(8), _M_max_bytes(128), _M_min_bin(8),
- _M_chunk_size(4096 - 4 * sizeof(void*)),
- _M_max_threads(4096), _M_freelist_headroom(10),
- _M_force_new(getenv("GLIBCXX_FORCE_NEW") ? true : false)
- { }
-
- explicit
- _Tune(size_t __align, size_t __maxb, size_t __minbin,
- size_t __chunk, size_t __maxthreads, size_t __headroom,
- bool __force)
- : _M_align(__align), _M_max_bytes(__maxb), _M_min_bin(__minbin),
- _M_chunk_size(__chunk), _M_max_threads(__maxthreads),
- _M_freelist_headroom(__headroom), _M_force_new(__force)
- { }
+ // Points to the block_record of the next free block.
+ _Block_record* _M_next;
};
- static const _Tune
- _S_get_options()
- { return _S_options; }
+ struct _Bin_record
+ {
+ // An "array" of pointers to the first free block.
+ _Block_record** _M_first;
- static void
- _S_set_options(_Tune __t)
- {
- if (!_S_init)
- _S_options = __t;
+ // A list of the initial addresses of all allocated blocks.
+ _Block_address* _M_address;
+ };
+
+ void
+ _M_initialize_once()
+ {
+ if (__builtin_expect(_M_init == false, false))
+ _M_initialize();
}
- private:
- // We need to create the initial lists and set up some variables
- // before we can answer to the first request for memory.
-#ifdef __GTHREADS
- static __gthread_once_t _S_once;
-#endif
- static bool _S_init;
+ void
+ _M_destroy() throw();
- static void
- _S_initialize();
+ char*
+ _M_reserve_block(size_t __bytes, const size_t __thread_id);
+
+ void
+ _M_reclaim_block(char* __p, size_t __bytes) throw ();
+
+ size_t
+ _M_get_thread_id() { return 0; }
+
+ const _Bin_record&
+ _M_get_bin(size_t __which)
+ { return _M_bin[__which]; }
+
+ void
+ _M_adjust_freelist(const _Bin_record&, _Block_record*, size_t)
+ { }
- // Configuration options.
- static _Tune _S_options;
+ explicit __pool()
+ : _M_bin(0), _M_bin_size(1) { }
- // Using short int as type for the binmap implies we are never
- // caching blocks larger than 65535 with this allocator
- typedef unsigned short int _Binmap_type;
- static _Binmap_type* _S_binmap;
+ explicit __pool(const __pool_base::_Tune& __tune)
+ : __pool_base(__tune), _M_bin(0), _M_bin_size(1) { }
+ private:
+ // An "array" of bin_records each of which represents a specific
+ // power of 2 size. Memory to this "array" is allocated in
+ // _M_initialize().
+ _Bin_record* _M_bin;
+
+ // Actual value calculated in _M_initialize().
+ size_t _M_bin_size;
+
+ void
+ _M_initialize();
+ };
+
+#ifdef __GTHREADS
+ /// Specialization for thread enabled, via gthreads.h.
+ template<>
+ class __pool<true> : public __pool_base
+ {
+ public:
// Each requesting thread is assigned an id ranging from 1 to
// _S_max_threads. Thread id 0 is used as a global memory pool.
// In order to get constant performance on the thread assignment
// __gthread_key we specify a destructor. When this destructor
// (i.e. the thread dies) is called, we return the thread id to
// the front of this list.
-#ifdef __GTHREADS
struct _Thread_record
{
- // Points to next free thread id record. NULL if last record in list.
- _Thread_record* volatile _M_next;
-
+ // Points to next free thread id record. NULL if last record in list.
+ _Thread_record* _M_next;
+
// Thread id ranging from 1 to _S_max_threads.
- size_t _M_id;
+ size_t _M_id;
};
-
- static _Thread_record* volatile _S_thread_freelist_first;
- static __gthread_mutex_t _S_thread_freelist_mutex;
- static __gthread_key_t _S_thread_key;
-
- static void
- _S_destroy_thread_key(void* __freelist_pos);
-#endif
-
- static size_t
- _S_get_thread_id();
-
+
union _Block_record
{
// Points to the block_record of the next free block.
- _Block_record* volatile _M_next;
-
-#ifdef __GTHREADS
+ _Block_record* _M_next;
+
// The thread id of the thread which has requested this block.
- size_t _M_thread_id;
-#endif
+ size_t _M_thread_id;
};
-
+
struct _Bin_record
{
// An "array" of pointers to the first free block for each
- // thread id. Memory to this "array" is allocated in _S_initialize()
- // for _S_max_threads + global pool 0.
- _Block_record** volatile _M_first;
+ // thread id. Memory to this "array" is allocated in
+ // _S_initialize() for _S_max_threads + global pool 0.
+ _Block_record** _M_first;
+
+ // A list of the initial addresses of all allocated blocks.
+ _Block_address* _M_address;
-#ifdef __GTHREADS
// An "array" of counters used to keep track of the amount of
// blocks that are on the freelist/used for each thread id.
- // Memory to these "arrays" is allocated in _S_initialize() for
- // _S_max_threads + global pool 0.
- size_t* volatile _M_free;
- size_t* volatile _M_used;
-
+ // - Note that the second part of the allocated _M_used "array"
+ // actually hosts (atomic) counters of reclaimed blocks: in
+ // _M_reserve_block and in _M_reclaim_block those numbers are
+ // subtracted from the first ones to obtain the actual size
+ // of the "working set" of the given thread.
+ // - Memory to these "arrays" is allocated in _S_initialize()
+ // for _S_max_threads + global pool 0.
+ size_t* _M_free;
+ size_t* _M_used;
+
// Each bin has its own mutex which is used to ensure data
// integrity while changing "ownership" on a block. The mutex
// is initialized in _S_initialize().
- __gthread_mutex_t* _M_mutex;
-#endif
+ __gthread_mutex_t* _M_mutex;
};
+
+ // XXX GLIBCXX_ABI Deprecated
+ void
+ _M_initialize(__destroy_handler);
+
+ void
+ _M_initialize_once()
+ {
+ if (__builtin_expect(_M_init == false, false))
+ _M_initialize();
+ }
+
+ void
+ _M_destroy() throw();
+
+ char*
+ _M_reserve_block(size_t __bytes, const size_t __thread_id);
+
+ void
+ _M_reclaim_block(char* __p, size_t __bytes) throw ();
+
+ const _Bin_record&
+ _M_get_bin(size_t __which)
+ { return _M_bin[__which]; }
+
+ void
+ _M_adjust_freelist(const _Bin_record& __bin, _Block_record* __block,
+ size_t __thread_id)
+ {
+ if (__gthread_active_p())
+ {
+ __block->_M_thread_id = __thread_id;
+ --__bin._M_free[__thread_id];
+ ++__bin._M_used[__thread_id];
+ }
+ }
+
+ // XXX GLIBCXX_ABI Deprecated
+ _GLIBCXX_CONST void
+ _M_destroy_thread_key(void*) throw ();
+
+ size_t
+ _M_get_thread_id();
+
+ explicit __pool()
+ : _M_bin(0), _M_bin_size(1), _M_thread_freelist(0)
+ { }
+
+ explicit __pool(const __pool_base::_Tune& __tune)
+ : __pool_base(__tune), _M_bin(0), _M_bin_size(1),
+ _M_thread_freelist(0)
+ { }
+ private:
// An "array" of bin_records each of which represents a specific
// power of 2 size. Memory to this "array" is allocated in
- // _S_initialize().
- static _Bin_record* volatile _S_bin;
+ // _M_initialize().
+ _Bin_record* _M_bin;
+
+ // Actual value calculated in _M_initialize().
+ size_t _M_bin_size;
+
+ _Thread_record* _M_thread_freelist;
+ void* _M_thread_freelist_initial;
+
+ void
+ _M_initialize();
+ };
+#endif
- // Actual value calculated in _S_initialize().
- static size_t _S_bin_size;
+ template<template <bool> class _PoolTp, bool _Thread>
+ struct __common_pool
+ {
+ typedef _PoolTp<_Thread> pool_type;
+
+ static pool_type&
+ _S_get_pool()
+ {
+ static pool_type _S_pool;
+ return _S_pool;
+ }
};
- template<typename _Tp>
- typename __mt_alloc<_Tp>::pointer
- __mt_alloc<_Tp>::
- allocate(size_type __n, const void*)
+ template<template <bool> class _PoolTp, bool _Thread>
+ struct __common_pool_base;
+
+ template<template <bool> class _PoolTp>
+ struct __common_pool_base<_PoolTp, false>
+ : public __common_pool<_PoolTp, false>
{
- // Although the test in __gthread_once() would suffice, we wrap
- // test of the once condition in our own unlocked check. This
- // saves one function call to pthread_once() (which itself only
- // tests for the once value unlocked anyway and immediately
- // returns if set)
- if (!_S_init)
- {
+ using __common_pool<_PoolTp, false>::_S_get_pool;
+
+ static void
+ _S_initialize_once()
+ {
+ static bool __init;
+ if (__builtin_expect(__init == false, false))
+ {
+ _S_get_pool()._M_initialize_once();
+ __init = true;
+ }
+ }
+ };
+
#ifdef __GTHREADS
- if (__gthread_active_p())
- __gthread_once(&_S_once, _S_initialize);
-#endif
- if (!_S_init)
- _S_initialize();
- }
+ template<template <bool> class _PoolTp>
+ struct __common_pool_base<_PoolTp, true>
+ : public __common_pool<_PoolTp, true>
+ {
+ using __common_pool<_PoolTp, true>::_S_get_pool;
- // Requests larger than _M_max_bytes are handled by new/delete
- // directly.
- const size_t __bytes = __n * sizeof(_Tp);
- if (__bytes > _S_options._M_max_bytes || _S_options._M_force_new)
- {
- void* __ret = ::operator new(__bytes);
- return static_cast<_Tp*>(__ret);
- }
+ static void
+ _S_initialize()
+ { _S_get_pool()._M_initialize_once(); }
- // Round up to power of 2 and figure out which bin to use.
- const size_t __which = _S_binmap[__bytes];
- const size_t __thread_id = _S_get_thread_id();
+ static void
+ _S_initialize_once()
+ {
+ static bool __init;
+ if (__builtin_expect(__init == false, false))
+ {
+ if (__gthread_active_p())
+ {
+ // On some platforms, __gthread_once_t is an aggregate.
+ static __gthread_once_t __once = __GTHREAD_ONCE_INIT;
+ __gthread_once(&__once, _S_initialize);
+ }
+
+ // Double check initialization. May be necessary on some
+ // systems for proper construction when not compiling with
+ // thread flags.
+ _S_get_pool()._M_initialize_once();
+ __init = true;
+ }
+ }
+ };
+#endif
+
+ /// Policy for shared __pool objects.
+ template<template <bool> class _PoolTp, bool _Thread>
+ struct __common_pool_policy : public __common_pool_base<_PoolTp, _Thread>
+ {
+ template<typename _Tp1, template <bool> class _PoolTp1 = _PoolTp,
+ bool _Thread1 = _Thread>
+ struct _M_rebind
+ { typedef __common_pool_policy<_PoolTp1, _Thread1> other; };
+
+ using __common_pool_base<_PoolTp, _Thread>::_S_get_pool;
+ using __common_pool_base<_PoolTp, _Thread>::_S_initialize_once;
+ };
+
+
+ template<typename _Tp, template <bool> class _PoolTp, bool _Thread>
+ struct __per_type_pool
+ {
+ typedef _Tp value_type;
+ typedef _PoolTp<_Thread> pool_type;
- // Find out if we have blocks on our freelist. If so, go ahead
- // and use them directly without having to lock anything.
- const _Bin_record& __bin = _S_bin[__which];
- _Block_record* __block = NULL;
- if (__bin._M_first[__thread_id] == NULL)
- {
- // NB: For alignment reasons, we can't use the first _M_align
- // bytes, even when sizeof(_Block_record) < _M_align.
- const size_t __bin_size = ((_S_options._M_min_bin << __which)
- + _S_options._M_align);
- size_t __block_count = _S_options._M_chunk_size / __bin_size;
-
- // Are we using threads?
- // - Yes, check if there are free blocks on the global
- // list. If so, grab up to __block_count blocks in one
- // lock and change ownership. If the global list is
- // empty, we allocate a new chunk and add those blocks
- // directly to our own freelist (with us as owner).
- // - No, all operations are made directly to global pool 0
- // no need to lock or change ownership but check for free
- // blocks on global list (and if not add new ones) and
- // get the first one.
-#ifdef __GTHREADS
- if (__gthread_active_p())
- {
- __gthread_mutex_lock(__bin._M_mutex);
- if (__bin._M_first[0] == NULL)
- {
- // No need to hold the lock when we are adding a
- // whole chunk to our own list.
- __gthread_mutex_unlock(__bin._M_mutex);
-
- void* __v = ::operator new(_S_options._M_chunk_size);
- __bin._M_first[__thread_id] = static_cast<_Block_record*>(__v);
- __bin._M_free[__thread_id] = __block_count;
-
- --__block_count;
- __block = __bin._M_first[__thread_id];
- while (__block_count-- > 0)
- {
- char* __c = reinterpret_cast<char*>(__block) + __bin_size;
- __block->_M_next = reinterpret_cast<_Block_record*>(__c);
- __block = __block->_M_next;
- }
- __block->_M_next = NULL;
- }
- else
- {
- // Is the number of required blocks greater than or
- // equal to the number that can be provided by the
- // global free list?
- __bin._M_first[__thread_id] = __bin._M_first[0];
- if (__block_count >= __bin._M_free[0])
- {
- __bin._M_free[__thread_id] = __bin._M_free[0];
- __bin._M_free[0] = 0;
- __bin._M_first[0] = NULL;
- }
- else
- {
- __bin._M_free[__thread_id] = __block_count;
- __bin._M_free[0] -= __block_count;
- --__block_count;
- __block = __bin._M_first[0];
- while (__block_count-- > 0)
- __block = __block->_M_next;
- __bin._M_first[0] = __block->_M_next;
- __block->_M_next = NULL;
- }
- __gthread_mutex_unlock(__bin._M_mutex);
- }
- }
- else
+ static pool_type&
+ _S_get_pool()
+ {
+ // Sane defaults for the _PoolTp.
+ typedef typename pool_type::_Block_record _Block_record;
+ const static size_t __a = (__alignof__(_Tp) >= sizeof(_Block_record)
+ ? __alignof__(_Tp) : sizeof(_Block_record));
+
+ typedef typename __pool_base::_Tune _Tune;
+ static _Tune _S_tune(__a, sizeof(_Tp) * 64,
+ sizeof(_Tp) * 2 >= __a ? sizeof(_Tp) * 2 : __a,
+ sizeof(_Tp) * size_t(_Tune::_S_chunk_size),
+ _Tune::_S_max_threads,
+ _Tune::_S_freelist_headroom,
+ std::getenv("GLIBCXX_FORCE_NEW") ? true : false);
+ static pool_type _S_pool(_S_tune);
+ return _S_pool;
+ }
+ };
+
+ template<typename _Tp, template <bool> class _PoolTp, bool _Thread>
+ struct __per_type_pool_base;
+
+ template<typename _Tp, template <bool> class _PoolTp>
+ struct __per_type_pool_base<_Tp, _PoolTp, false>
+ : public __per_type_pool<_Tp, _PoolTp, false>
+ {
+ using __per_type_pool<_Tp, _PoolTp, false>::_S_get_pool;
+
+ static void
+ _S_initialize_once()
+ {
+ static bool __init;
+ if (__builtin_expect(__init == false, false))
+ {
+ _S_get_pool()._M_initialize_once();
+ __init = true;
+ }
+ }
+ };
+
+ #ifdef __GTHREADS
+ template<typename _Tp, template <bool> class _PoolTp>
+ struct __per_type_pool_base<_Tp, _PoolTp, true>
+ : public __per_type_pool<_Tp, _PoolTp, true>
+ {
+ using __per_type_pool<_Tp, _PoolTp, true>::_S_get_pool;
+
+ static void
+ _S_initialize()
+ { _S_get_pool()._M_initialize_once(); }
+
+ static void
+ _S_initialize_once()
+ {
+ static bool __init;
+ if (__builtin_expect(__init == false, false))
+ {
+ if (__gthread_active_p())
+ {
+ // On some platforms, __gthread_once_t is an aggregate.
+ static __gthread_once_t __once = __GTHREAD_ONCE_INIT;
+ __gthread_once(&__once, _S_initialize);
+ }
+
+ // Double check initialization. May be necessary on some
+ // systems for proper construction when not compiling with
+ // thread flags.
+ _S_get_pool()._M_initialize_once();
+ __init = true;
+ }
+ }
+ };
#endif
- {
- void* __v = ::operator new(_S_options._M_chunk_size);
- __bin._M_first[0] = static_cast<_Block_record*>(__v);
-
- --__block_count;
- __block = __bin._M_first[0];
- while (__block_count-- > 0)
- {
- char* __c = reinterpret_cast<char*>(__block) + __bin_size;
- __block->_M_next = reinterpret_cast<_Block_record*>(__c);
- __block = __block->_M_next;
- }
- __block->_M_next = NULL;
- }
- }
- __block = __bin._M_first[__thread_id];
- __bin._M_first[__thread_id] = __bin._M_first[__thread_id]->_M_next;
+ /// Policy for individual __pool objects.
+ template<typename _Tp, template <bool> class _PoolTp, bool _Thread>
+ struct __per_type_pool_policy
+ : public __per_type_pool_base<_Tp, _PoolTp, _Thread>
+ {
+ template<typename _Tp1, template <bool> class _PoolTp1 = _PoolTp,
+ bool _Thread1 = _Thread>
+ struct _M_rebind
+ { typedef __per_type_pool_policy<_Tp1, _PoolTp1, _Thread1> other; };
+
+ using __per_type_pool_base<_Tp, _PoolTp, _Thread>::_S_get_pool;
+ using __per_type_pool_base<_Tp, _PoolTp, _Thread>::_S_initialize_once;
+ };
+
+
+ /// Base class for _Tp dependent member functions.
+ template<typename _Tp>
+ class __mt_alloc_base
+ {
+ public:
+ typedef size_t size_type;
+ typedef ptrdiff_t difference_type;
+ typedef _Tp* pointer;
+ typedef const _Tp* const_pointer;
+ typedef _Tp& reference;
+ typedef const _Tp& const_reference;
+ typedef _Tp value_type;
+
+ pointer
+ address(reference __x) const
+ { return std::__addressof(__x); }
+
+ const_pointer
+ address(const_reference __x) const
+ { return std::__addressof(__x); }
+
+ size_type
+ max_size() const throw()
+ { return size_t(-1) / sizeof(_Tp); }
+
+ // _GLIBCXX_RESOLVE_LIB_DEFECTS
+ // 402. wrong new expression in [some_] allocator::construct
+ void
+ construct(pointer __p, const _Tp& __val)
+ { ::new((void *)__p) _Tp(__val); }
+
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+ template<typename... _Args>
+ void
+ construct(pointer __p, _Args&&... __args)
+ { ::new((void *)__p) _Tp(std::forward<_Args>(__args)...); }
+#endif
+
+ void
+ destroy(pointer __p) { __p->~_Tp(); }
+ };
+
#ifdef __GTHREADS
- if (__gthread_active_p())
- {
- __block->_M_thread_id = __thread_id;
- --__bin._M_free[__thread_id];
- ++__bin._M_used[__thread_id];
- }
+#define __thread_default true
+#else
+#define __thread_default false
#endif
- char* __c = reinterpret_cast<char*>(__block) + _S_options._M_align;
- return static_cast<_Tp*>(static_cast<void*>(__c));
- }
-
- template<typename _Tp>
- void
- __mt_alloc<_Tp>::
- deallocate(pointer __p, size_type __n)
+ /**
+ * @brief This is a fixed size (power of 2) allocator which - when
+ * compiled with thread support - will maintain one freelist per
+ * size per thread plus a @a global one. Steps are taken to limit
+ * the per thread freelist sizes (by returning excess back to
+ * the @a global list).
+ * @ingroup allocators
+ *
+ * Further details:
+ * http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt12ch32.html
+ */
+ template<typename _Tp,
+ typename _Poolp = __common_pool_policy<__pool, __thread_default> >
+ class __mt_alloc : public __mt_alloc_base<_Tp>
{
- // Requests larger than _M_max_bytes are handled by operators
+ public:
+ typedef size_t size_type;
+ typedef ptrdiff_t difference_type;
+ typedef _Tp* pointer;
+ typedef const _Tp* const_pointer;
+ typedef _Tp& reference;
+ typedef const _Tp& const_reference;
+ typedef _Tp value_type;
+ typedef _Poolp __policy_type;
+ typedef typename _Poolp::pool_type __pool_type;
+
+ template<typename _Tp1, typename _Poolp1 = _Poolp>
+ struct rebind
+ {
+ typedef typename _Poolp1::template _M_rebind<_Tp1>::other pol_type;
+ typedef __mt_alloc<_Tp1, pol_type> other;
+ };
+
+ __mt_alloc() throw() { }
+
+ __mt_alloc(const __mt_alloc&) throw() { }
+
+ template<typename _Tp1, typename _Poolp1>
+ __mt_alloc(const __mt_alloc<_Tp1, _Poolp1>&) throw() { }
+
+ ~__mt_alloc() throw() { }
+
+ pointer
+ allocate(size_type __n, const void* = 0);
+
+ void
+ deallocate(pointer __p, size_type __n);
+
+ const __pool_base::_Tune
+ _M_get_options()
+ {
+ // Return a copy, not a reference, for external consumption.
+ return __policy_type::_S_get_pool()._M_get_options();
+ }
+
+ void
+ _M_set_options(__pool_base::_Tune __t)
+ { __policy_type::_S_get_pool()._M_set_options(__t); }
+ };
+
+ template<typename _Tp, typename _Poolp>
+ typename __mt_alloc<_Tp, _Poolp>::pointer
+ __mt_alloc<_Tp, _Poolp>::
+ allocate(size_type __n, const void*)
+ {
+ if (__n > this->max_size())
+ std::__throw_bad_alloc();
+
+ __policy_type::_S_initialize_once();
+
+ // Requests larger than _M_max_bytes are handled by operator
// new/delete directly.
+ __pool_type& __pool = __policy_type::_S_get_pool();
const size_t __bytes = __n * sizeof(_Tp);
- if (__bytes > _S_options._M_max_bytes || _S_options._M_force_new)
+ if (__pool._M_check_threshold(__bytes))
{
- ::operator delete(__p);
- return;
+ void* __ret = ::operator new(__bytes);
+ return static_cast<_Tp*>(__ret);
}
// Round up to power of 2 and figure out which bin to use.
- const size_t __which = _S_binmap[__bytes];
- const _Bin_record& __bin = _S_bin[__which];
-
- char* __c = reinterpret_cast<char*>(__p) - _S_options._M_align;
- _Block_record* __block = reinterpret_cast<_Block_record*>(__c);
+ const size_t __which = __pool._M_get_binmap(__bytes);
+ const size_t __thread_id = __pool._M_get_thread_id();
-#ifdef __GTHREADS
- if (__gthread_active_p())
+ // Find out if we have blocks on our freelist. If so, go ahead
+ // and use them directly without having to lock anything.
+ char* __c;
+ typedef typename __pool_type::_Bin_record _Bin_record;
+ const _Bin_record& __bin = __pool._M_get_bin(__which);
+ if (__bin._M_first[__thread_id])
{
- // Calculate the number of records to remove from our freelist:
- // in order to avoid too much contention we wait until the
- // number of records is "high enough".
- const size_t __thread_id = _S_get_thread_id();
-
- long __remove = ((__bin._M_free[__thread_id]
- * _S_options._M_freelist_headroom)
- - __bin._M_used[__thread_id]);
- if (__remove > static_cast<long>(100 * (_S_bin_size - __which)
- * _S_options._M_freelist_headroom)
- && __remove > static_cast<long>(__bin._M_free[__thread_id]))
- {
- _Block_record* __tmp = __bin._M_first[__thread_id];
- _Block_record* __first = __tmp;
- __remove /= _S_options._M_freelist_headroom;
- const long __removed = __remove;
- --__remove;
- while (__remove-- > 0)
- __tmp = __tmp->_M_next;
- __bin._M_first[__thread_id] = __tmp->_M_next;
- __bin._M_free[__thread_id] -= __removed;
-
- __gthread_mutex_lock(__bin._M_mutex);
- __tmp->_M_next = __bin._M_first[0];
- __bin._M_first[0] = __first;
- __bin._M_free[0] += __removed;
- __gthread_mutex_unlock(__bin._M_mutex);
- }
-
- // Return this block to our list and update counters and
- // owner id as needed.
- --__bin._M_used[__block->_M_thread_id];
-
- __block->_M_next = __bin._M_first[__thread_id];
- __bin._M_first[__thread_id] = __block;
+ // Already reserved.
+ typedef typename __pool_type::_Block_record _Block_record;
+ _Block_record* __block = __bin._M_first[__thread_id];
+ __bin._M_first[__thread_id] = __block->_M_next;
- ++__bin._M_free[__thread_id];
+ __pool._M_adjust_freelist(__bin, __block, __thread_id);
+ __c = reinterpret_cast<char*>(__block) + __pool._M_get_align();
}
else
-#endif
{
- // Single threaded application - return to global pool.
- __block->_M_next = __bin._M_first[0];
- __bin._M_first[0] = __block;
+ // Null, reserve.
+ __c = __pool._M_reserve_block(__bytes, __thread_id);
}
+ return static_cast<_Tp*>(static_cast<void*>(__c));
}
- template<typename _Tp>
+ template<typename _Tp, typename _Poolp>
void
- __mt_alloc<_Tp>::
- _S_initialize()
+ __mt_alloc<_Tp, _Poolp>::
+ deallocate(pointer __p, size_type __n)
{
- // This method is called on the first allocation (when _S_init is still
- // false) to create the bins.
-
- // Ensure that the static initialization of _S_options has
- // happened. This depends on (a) _M_align == 0 being an invalid
- // value that is only present at startup, and (b) the real
- // static initialization that happens later not actually
- // changing anything.
- if (_S_options._M_align == 0)
- new (&_S_options) _Tune;
-
- // _M_force_new must not change after the first allocate(),
- // which in turn calls this method, so if it's false, it's false
- // forever and we don't need to return here ever again.
- if (_S_options._M_force_new)
+ if (__builtin_expect(__p != 0, true))
{
- _S_init = true;
- return;
- }
-
- // Calculate the number of bins required based on _M_max_bytes.
- // _S_bin_size is statically-initialized to one.
- size_t __bin_size = _S_options._M_min_bin;
- while (_S_options._M_max_bytes > __bin_size)
- {
- __bin_size <<= 1;
- ++_S_bin_size;
- }
-
- // Setup the bin map for quick lookup of the relevant bin.
- const size_t __j = (_S_options._M_max_bytes + 1) * sizeof(_Binmap_type);
- _S_binmap = static_cast<_Binmap_type*>(::operator new(__j));
-
- _Binmap_type* __bp = _S_binmap;
- _Binmap_type __bin_max = _S_options._M_min_bin;
- _Binmap_type __bint = 0;
- for (_Binmap_type __ct = 0; __ct <= _S_options._M_max_bytes; ++__ct)
- {
- if (__ct > __bin_max)
- {
- __bin_max <<= 1;
- ++__bint;
- }
- *__bp++ = __bint;
- }
-
- // Initialize _S_bin and its members.
- void* __v = ::operator new(sizeof(_Bin_record) * _S_bin_size);
- _S_bin = static_cast<_Bin_record*>(__v);
-
- // If __gthread_active_p() create and initialize the list of
- // free thread ids. Single threaded applications use thread id 0
- // directly and have no need for this.
-#ifdef __GTHREADS
- if (__gthread_active_p())
- {
- const size_t __k = sizeof(_Thread_record) * _S_options._M_max_threads;
- __v = ::operator new(__k);
- _S_thread_freelist_first = static_cast<_Thread_record*>(__v);
-
- // NOTE! The first assignable thread id is 1 since the
- // global pool uses id 0
- size_t __i;
- for (__i = 1; __i < _S_options._M_max_threads; ++__i)
- {
- _Thread_record& __tr = _S_thread_freelist_first[__i - 1];
- __tr._M_next = &_S_thread_freelist_first[__i];
- __tr._M_id = __i;
- }
-
- // Set last record.
- _S_thread_freelist_first[__i - 1]._M_next = NULL;
- _S_thread_freelist_first[__i - 1]._M_id = __i;
-
- // Make sure this is initialized.
-#ifndef __GTHREAD_MUTEX_INIT
- __GTHREAD_MUTEX_INIT_FUNCTION(&_S_thread_freelist_mutex);
-#endif
- // Initialize per thread key to hold pointer to
- // _S_thread_freelist.
- __gthread_key_create(&_S_thread_key, _S_destroy_thread_key);
-
- const size_t __max_threads = _S_options._M_max_threads + 1;
- for (size_t __n = 0; __n < _S_bin_size; ++__n)
- {
- _Bin_record& __bin = _S_bin[__n];
- __v = ::operator new(sizeof(_Block_record*) * __max_threads);
- __bin._M_first = static_cast<_Block_record**>(__v);
-
- __v = ::operator new(sizeof(size_t) * __max_threads);
- __bin._M_free = static_cast<size_t*>(__v);
-
- __v = ::operator new(sizeof(size_t) * __max_threads);
- __bin._M_used = static_cast<size_t*>(__v);
-
- __v = ::operator new(sizeof(__gthread_mutex_t));
- __bin._M_mutex = static_cast<__gthread_mutex_t*>(__v);
-
-#ifdef __GTHREAD_MUTEX_INIT
- {
- // Do not copy a POSIX/gthr mutex once in use.
- __gthread_mutex_t __tmp = __GTHREAD_MUTEX_INIT;
- *__bin._M_mutex = __tmp;
- }
-#else
- { __GTHREAD_MUTEX_INIT_FUNCTION(__bin._M_mutex); }
-#endif
-
- for (size_t __threadn = 0; __threadn < __max_threads;
- ++__threadn)
- {
- __bin._M_first[__threadn] = NULL;
- __bin._M_free[__threadn] = 0;
- __bin._M_used[__threadn] = 0;
- }
- }
+ // Requests larger than _M_max_bytes are handled by
+ // operators new/delete directly.
+ __pool_type& __pool = __policy_type::_S_get_pool();
+ const size_t __bytes = __n * sizeof(_Tp);
+ if (__pool._M_check_threshold(__bytes))
+ ::operator delete(__p);
+ else
+ __pool._M_reclaim_block(reinterpret_cast<char*>(__p), __bytes);
}
- else
-#endif
- for (size_t __n = 0; __n < _S_bin_size; ++__n)
- {
- _Bin_record& __bin = _S_bin[__n];
- __v = ::operator new(sizeof(_Block_record*));
- __bin._M_first = static_cast<_Block_record**>(__v);
- __bin._M_first[0] = NULL;
- }
-
- _S_init = true;
- }
-
- template<typename _Tp>
- size_t
- __mt_alloc<_Tp>::
- _S_get_thread_id()
- {
-#ifdef __GTHREADS
- // If we have thread support and it's active we check the thread
- // key value and return its id or if it's not set we take the
- // first record from _S_thread_freelist and sets the key and
- // returns it's id.
- if (__gthread_active_p())
- {
- _Thread_record* __freelist_pos =
- static_cast<_Thread_record*>(__gthread_getspecific(_S_thread_key));
- if (__freelist_pos == NULL)
- {
- // Since _S_options._M_max_threads must be larger than
- // the theoretical max number of threads of the OS the
- // list can never be empty.
- __gthread_mutex_lock(&_S_thread_freelist_mutex);
- __freelist_pos = _S_thread_freelist_first;
- _S_thread_freelist_first = _S_thread_freelist_first->_M_next;
- __gthread_mutex_unlock(&_S_thread_freelist_mutex);
-
- __gthread_setspecific(_S_thread_key,
- static_cast<void*>(__freelist_pos));
- }
- return __freelist_pos->_M_id;
- }
-#endif
- // Otherwise (no thread support or inactive) all requests are
- // served from the global pool 0.
- return 0;
- }
-
-#ifdef __GTHREADS
- template<typename _Tp>
- void
- __mt_alloc<_Tp>::
- _S_destroy_thread_key(void* __freelist_pos)
- {
- // Return this thread id record to front of thread_freelist.
- __gthread_mutex_lock(&_S_thread_freelist_mutex);
- _Thread_record* __tr = static_cast<_Thread_record*>(__freelist_pos);
- __tr->_M_next = _S_thread_freelist_first;
- _S_thread_freelist_first = __tr;
- __gthread_mutex_unlock(&_S_thread_freelist_mutex);
}
-#endif
-
- template<typename _Tp>
+
+ template<typename _Tp, typename _Poolp>
inline bool
- operator==(const __mt_alloc<_Tp>&, const __mt_alloc<_Tp>&)
+ operator==(const __mt_alloc<_Tp, _Poolp>&, const __mt_alloc<_Tp, _Poolp>&)
{ return true; }
- template<typename _Tp>
+ template<typename _Tp, typename _Poolp>
inline bool
- operator!=(const __mt_alloc<_Tp>&, const __mt_alloc<_Tp>&)
+ operator!=(const __mt_alloc<_Tp, _Poolp>&, const __mt_alloc<_Tp, _Poolp>&)
{ return false; }
- template<typename _Tp>
- bool __mt_alloc<_Tp>::_S_init = false;
-
- template<typename _Tp>
- typename __mt_alloc<_Tp>::_Tune __mt_alloc<_Tp>::_S_options;
+#undef __thread_default
- template<typename _Tp>
- typename __mt_alloc<_Tp>::_Binmap_type* __mt_alloc<_Tp>::_S_binmap;
-
- template<typename _Tp>
- typename __mt_alloc<_Tp>::_Bin_record* volatile __mt_alloc<_Tp>::_S_bin;
-
- template<typename _Tp>
- size_t __mt_alloc<_Tp>::_S_bin_size = 1;
-
- // Actual initialization in _S_initialize().
-#ifdef __GTHREADS
- template<typename _Tp>
- __gthread_once_t __mt_alloc<_Tp>::_S_once = __GTHREAD_ONCE_INIT;
-
- template<typename _Tp>
- typename __mt_alloc<_Tp>::_Thread_record*
- volatile __mt_alloc<_Tp>::_S_thread_freelist_first = NULL;
-
- template<typename _Tp>
- __gthread_key_t __mt_alloc<_Tp>::_S_thread_key;
-
- template<typename _Tp>
- __gthread_mutex_t
-#ifdef __GTHREAD_MUTEX_INIT
- __mt_alloc<_Tp>::_S_thread_freelist_mutex = __GTHREAD_MUTEX_INIT;
-#else
- __mt_alloc<_Tp>::_S_thread_freelist_mutex;
-#endif
-#endif
-} // namespace __gnu_cxx
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
#endif
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