/*
*
* Copyright (c) 1994
* Hewlett-Packard Company
*
* Copyright (c) 1996,1997
* Silicon Graphics Computer Systems, Inc.
*
* Copyright (c) 1997
* Moscow Center for SPARC Technology
*
* Copyright (c) 1999
* Boris Fomitchev
*
* This material is provided "as is", with absolutely no warranty expressed
* or implied. Any use is at your own risk.
*
* Permission to use or copy this software for any purpose is hereby granted
* without fee, provided the above notices are retained on all copies.
* Permission to modify the code and to distribute modified code is granted,
* provided the above notices are retained, and a notice that the code was
* modified is included with the above copyright notice.
*
*/
#ifndef _STLP_PTHREAD_ALLOC_H
#define _STLP_PTHREAD_ALLOC_H
// Pthread-specific node allocator.
// This is similar to the default allocator, except that free-list
// information is kept separately for each thread, avoiding locking.
// This should be reasonably fast even in the presence of threads.
// The down side is that storage may not be well-utilized.
// It is not an error to allocate memory in thread A and deallocate
// it in thread B. But this effectively transfers ownership of the memory,
// so that it can only be reallocated by thread B. Thus this can effectively
// result in a storage leak if it's done on a regular basis.
// It can also result in frequent sharing of
// cache lines among processors, with potentially serious performance
// consequences.
#include <pthread.h>
#ifndef _STLP_INTERNAL_ALLOC_H
#include <stl/_alloc.h>
#endif
#ifndef __RESTRICT
# define __RESTRICT
#endif
_STLP_BEGIN_NAMESPACE
#define _STLP_DATA_ALIGNMENT 8
union _Pthread_alloc_obj {
union _Pthread_alloc_obj * __free_list_link;
char __client_data[_STLP_DATA_ALIGNMENT]; /* The client sees this. */
};
// Pthread allocators don't appear to the client to have meaningful
// instances. We do in fact need to associate some state with each
// thread. That state is represented by
// _Pthread_alloc_per_thread_state<_Max_size>.
template<size_t _Max_size>
struct _Pthread_alloc_per_thread_state {
typedef _Pthread_alloc_obj __obj;
enum { _S_NFREELISTS = _Max_size/_STLP_DATA_ALIGNMENT };
// Free list link for list of available per thread structures.
// When one of these becomes available for reuse due to thread
// termination, any objects in its free list remain associated
// with it. The whole structure may then be used by a newly
// created thread.
_Pthread_alloc_per_thread_state() : __next(0)
{
memset((void *)__free_list, 0, (size_t)_S_NFREELISTS * sizeof(__obj *));
}
// Returns an object of size __n, and possibly adds to size n free list.
void *_M_refill(size_t __n);
_Pthread_alloc_obj* volatile __free_list[_S_NFREELISTS];
_Pthread_alloc_per_thread_state<_Max_size> * __next;
// this data member is only to be used by per_thread_allocator, which returns memory to the originating thread.
_STLP_mutex _M_lock;
};
// Pthread-specific allocator.
// The argument specifies the largest object size allocated from per-thread
// free lists. Larger objects are allocated using malloc_alloc.
// Max_size must be a power of 2.
template < __DFL_NON_TYPE_PARAM(size_t, _Max_size, _MAX_BYTES) >
class _Pthread_alloc {
public: // but only for internal use:
typedef _Pthread_alloc_obj __obj;
typedef _Pthread_alloc_per_thread_state<_Max_size> __state_type;
typedef char value_type;
// Allocates a chunk for nobjs of size size. nobjs may be reduced
// if it is inconvenient to allocate the requested number.
static char *_S_chunk_alloc(size_t __size, size_t &__nobjs);
enum {_S_ALIGN = _STLP_DATA_ALIGNMENT};
static size_t _S_round_up(size_t __bytes) {
return (((__bytes) + (int)_S_ALIGN-1) & ~((int)_S_ALIGN - 1));
}
static size_t _S_freelist_index(size_t __bytes) {
return (((__bytes) + (int)_S_ALIGN-1)/(int)_S_ALIGN - 1);
}
private:
// Chunk allocation state. And other shared state.
// Protected by _S_chunk_allocator_lock.
static _STLP_mutex_base _S_chunk_allocator_lock;
static char *_S_start_free;
static char *_S_end_free;
static size_t _S_heap_size;
static _Pthread_alloc_per_thread_state<_Max_size>* _S_free_per_thread_states;
static pthread_key_t _S_key;
static bool _S_key_initialized;
// Pthread key under which per thread state is stored.
// Allocator instances that are currently unclaimed by any thread.
static void _S_destructor(void *instance);
// Function to be called on thread exit to reclaim per thread
// state.
static _Pthread_alloc_per_thread_state<_Max_size> *_S_new_per_thread_state();
public:
// Return a recycled or new per thread state.
static _Pthread_alloc_per_thread_state<_Max_size> *_S_get_per_thread_state();
private:
// ensure that the current thread has an associated
// per thread state.
class _M_lock;
friend class _M_lock;
class _M_lock {
public:
_M_lock () { _S_chunk_allocator_lock._M_acquire_lock(); }
~_M_lock () { _S_chunk_allocator_lock._M_release_lock(); }
};
public:
/* n must be > 0 */
static void * allocate(size_t __n)
{
__obj * volatile * __my_free_list;
__obj * __RESTRICT __result;
__state_type* __a;
if (__n > _Max_size) {
return(__malloc_alloc<0>::allocate(__n));
}
__a = _S_get_per_thread_state();
__my_free_list = __a -> __free_list + _S_freelist_index(__n);
__result = *__my_free_list;
if (__result == 0) {
void *__r = __a -> _M_refill(_S_round_up(__n));
return __r;
}
*__my_free_list = __result -> __free_list_link;
return (__result);
};
/* p may not be 0 */
static void deallocate(void *__p, size_t __n)
{
__obj *__q = (__obj *)__p;
__obj * volatile * __my_free_list;
__state_type* __a;
if (__n > _Max_size) {
__malloc_alloc<0>::deallocate(__p, __n);
return;
}
__a = _S_get_per_thread_state();
__my_free_list = __a->__free_list + _S_freelist_index(__n);
__q -> __free_list_link = *__my_free_list;
*__my_free_list = __q;
}
// boris : versions for per_thread_allocator
/* n must be > 0 */
static void * allocate(size_t __n, __state_type* __a)
{
__obj * volatile * __my_free_list;
__obj * __RESTRICT __result;
if (__n > _Max_size) {
return(__malloc_alloc<0>::allocate(__n));
}
// boris : here, we have to lock per thread state, as we may be getting memory from
// different thread pool.
_STLP_mutex_lock __lock(__a->_M_lock);
__my_free_list = __a -> __free_list + _S_freelist_index(__n);
__result = *__my_free_list;
if (__result == 0) {
void *__r = __a -> _M_refill(_S_round_up(__n));
return __r;
}
*__my_free_list = __result -> __free_list_link;
return (__result);
};
/* p may not be 0 */
static void deallocate(void *__p, size_t __n, __state_type* __a)
{
__obj *__q = (__obj *)__p;
__obj * volatile * __my_free_list;
if (__n > _Max_size) {
__malloc_alloc<0>::deallocate(__p, __n);
return;
}
// boris : here, we have to lock per thread state, as we may be returning memory from
// different thread.
_STLP_mutex_lock __lock(__a->_M_lock);
__my_free_list = __a->__free_list + _S_freelist_index(__n);
__q -> __free_list_link = *__my_free_list;
*__my_free_list = __q;
}
static void * reallocate(void *__p, size_t __old_sz, size_t __new_sz);
} ;
# if defined (_STLP_USE_TEMPLATE_EXPORT)
_STLP_EXPORT_TEMPLATE_CLASS _Pthread_alloc<_MAX_BYTES>;
# endif
typedef _Pthread_alloc<_MAX_BYTES> __pthread_alloc;
typedef __pthread_alloc pthread_alloc;
template <class _Tp>
class pthread_allocator {
typedef pthread_alloc _S_Alloc; // The underlying allocator.
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;
#ifdef _STLP_MEMBER_TEMPLATE_CLASSES
template <class _NewType> struct rebind {
typedef pthread_allocator<_NewType> other;
};
#endif
pthread_allocator() _STLP_NOTHROW {}
pthread_allocator(const pthread_allocator<_Tp>& a) _STLP_NOTHROW {}
#if defined (_STLP_MEMBER_TEMPLATES) /* && defined (_STLP_FUNCTION_PARTIAL_ORDER) */
template <class _OtherType> pthread_allocator(const pthread_allocator<_OtherType>&)
_STLP_NOTHROW {}
#endif
~pthread_allocator() _STLP_NOTHROW {}
pointer address(reference __x) const { return &__x; }
const_pointer address(const_reference __x) const { return &__x; }
// __n is permitted to be 0. The C++ standard says nothing about what
// the return value is when __n == 0.
_Tp* allocate(size_type __n, const void* = 0) {
return __n != 0 ? __STATIC_CAST(_Tp*,_S_Alloc::allocate(__n * sizeof(_Tp)))
: 0;
}
// p is not permitted to be a null pointer.
void deallocate(pointer __p, size_type __n)
{ _S_Alloc::deallocate(__p, __n * sizeof(_Tp)); }
size_type max_size() const _STLP_NOTHROW
{ return size_t(-1) / sizeof(_Tp); }
void construct(pointer __p, const _Tp& __val) { _STLP_PLACEMENT_NEW (__p) _Tp(__val); }
void destroy(pointer _p) { _p->~_Tp(); }
};
_STLP_TEMPLATE_NULL
class _STLP_CLASS_DECLSPEC pthread_allocator<void> {
public:
typedef size_t size_type;
typedef ptrdiff_t difference_type;
typedef void* pointer;
typedef const void* const_pointer;
typedef void value_type;
#ifdef _STLP_MEMBER_TEMPLATE_CLASSES
template <class _NewType> struct rebind {
typedef pthread_allocator<_NewType> other;
};
#endif
};
template <class _T1, class _T2>
inline bool operator==(const pthread_allocator<_T1>&,
const pthread_allocator<_T2>& a2)
{
return true;
}
#ifdef _STLP_FUNCTION_TMPL_PARTIAL_ORDER
template <class _T1, class _T2>
inline bool operator!=(const pthread_allocator<_T1>&,
const pthread_allocator<_T2>&)
{
return false;
}
#endif
#ifdef _STLP_CLASS_PARTIAL_SPECIALIZATION
# ifdef _STLP_USE_RAW_SGI_ALLOCATORS
template <class _Tp, size_t _Max_size>
struct _Alloc_traits<_Tp, _Pthread_alloc<_Max_size> >
{
typedef __allocator<_Tp, _Pthread_alloc<_Max_size> >
allocator_type;
};
# endif
template <class _Tp, class _Atype>
struct _Alloc_traits<_Tp, pthread_allocator<_Atype> >
{
typedef pthread_allocator<_Tp> allocator_type;
};
#endif
#if !defined (_STLP_USE_NESTED_TCLASS_THROUGHT_TPARAM)
template <class _Tp1, class _Tp2>
inline pthread_allocator<_Tp2>&
__stl_alloc_rebind(pthread_allocator<_Tp1>& __x, const _Tp2*) {
return (pthread_allocator<_Tp2>&)__x;
}
template <class _Tp1, class _Tp2>
inline pthread_allocator<_Tp2>
__stl_alloc_create(pthread_allocator<_Tp1>&, const _Tp2*) {
return pthread_allocator<_Tp2>();
}
#endif /* _STLP_USE_NESTED_TCLASS_THROUGHT_TPARAM */
//
// per_thread_allocator<> : this allocator always return memory to the same thread
// it was allocated from.
//
template <class _Tp>
class per_thread_allocator {
typedef pthread_alloc _S_Alloc; // The underlying allocator.
typedef pthread_alloc::__state_type __state_type;
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;
#ifdef _STLP_MEMBER_TEMPLATE_CLASSES
template <class _NewType> struct rebind {
typedef per_thread_allocator<_NewType> other;
};
#endif
per_thread_allocator() _STLP_NOTHROW {
_M_state = _S_Alloc::_S_get_per_thread_state();
}
per_thread_allocator(const per_thread_allocator<_Tp>& __a) _STLP_NOTHROW : _M_state(__a._M_state){}
#if defined (_STLP_MEMBER_TEMPLATES) /* && defined (_STLP_FUNCTION_PARTIAL_ORDER) */
template <class _OtherType> per_thread_allocator(const per_thread_allocator<_OtherType>& __a)
_STLP_NOTHROW : _M_state(__a._M_state) {}
#endif
~per_thread_allocator() _STLP_NOTHROW {}
pointer address(reference __x) const { return &__x; }
const_pointer address(const_reference __x) const { return &__x; }
// __n is permitted to be 0. The C++ standard says nothing about what
// the return value is when __n == 0.
_Tp* allocate(size_type __n, const void* = 0) {
return __n != 0 ? __STATIC_CAST(_Tp*,_S_Alloc::allocate(__n * sizeof(_Tp), _M_state)): 0;
}
// p is not permitted to be a null pointer.
void deallocate(pointer __p, size_type __n)
{ _S_Alloc::deallocate(__p, __n * sizeof(_Tp), _M_state); }
size_type max_size() const _STLP_NOTHROW
{ return size_t(-1) / sizeof(_Tp); }
void construct(pointer __p, const _Tp& __val) { _STLP_PLACEMENT_NEW (__p) _Tp(__val); }
void destroy(pointer _p) { _p->~_Tp(); }
// state is being kept here
__state_type* _M_state;
};
_STLP_TEMPLATE_NULL
class _STLP_CLASS_DECLSPEC per_thread_allocator<void> {
public:
typedef size_t size_type;
typedef ptrdiff_t difference_type;
typedef void* pointer;
typedef const void* const_pointer;
typedef void value_type;
#ifdef _STLP_MEMBER_TEMPLATE_CLASSES
template <class _NewType> struct rebind {
typedef per_thread_allocator<_NewType> other;
};
#endif
};
template <class _T1, class _T2>
inline bool operator==(const per_thread_allocator<_T1>& __a1,
const per_thread_allocator<_T2>& __a2)
{
return __a1._M_state == __a2._M_state;
}
#ifdef _STLP_FUNCTION_TMPL_PARTIAL_ORDER
template <class _T1, class _T2>
inline bool operator!=(const per_thread_allocator<_T1>& __a1,
const per_thread_allocator<_T2>& __a2)
{
return __a1._M_state != __a2._M_state;
}
#endif
#ifdef _STLP_CLASS_PARTIAL_SPECIALIZATION
template <class _Tp, class _Atype>
struct _Alloc_traits<_Tp, per_thread_allocator<_Atype> >
{
typedef per_thread_allocator<_Tp> allocator_type;
};
#endif
#if !defined (_STLP_USE_NESTED_TCLASS_THROUGHT_TPARAM)
template <class _Tp1, class _Tp2>
inline per_thread_allocator<_Tp2>&
__stl_alloc_rebind(per_thread_allocator<_Tp1>& __x, const _Tp2*) {
return (per_thread_allocator<_Tp2>&)__x;
}
template <class _Tp1, class _Tp2>
inline per_thread_allocator<_Tp2>
__stl_alloc_create(per_thread_allocator<_Tp1>&, const _Tp2*) {
return per_thread_allocator<_Tp2>();
}
#endif /* _STLP_USE_NESTED_TCLASS_THROUGHT_TPARAM */
_STLP_END_NAMESPACE
# if defined (_STLP_EXPOSE_GLOBALS_IMPLEMENTATION) && !defined (_STLP_LINK_TIME_INSTANTIATION)
# include <stl/_pthread_alloc.c>
# endif
#endif /* _STLP_PTHREAD_ALLOC */
// Local Variables:
// mode:C++
// End:
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