1
2// Copyright Oliver Kowalke 2014.
3// Distributed under the Boost Software License, Version 1.0.
4// (See accompanying file LICENSE_1_0.txt or copy at
5// http://www.boost.org/LICENSE_1_0.txt)
6
7#ifndef BOOST_CONTEXT_POOLED_pooled_fixedsize_H
8#define BOOST_CONTEXT_POOLED_pooled_fixedsize_H
9
10#include <atomic>
11#include <cstddef>
12#include <cstdlib>
13#include <new>
14
15#include <boost/assert.hpp>
16#include <boost/config.hpp>
17#include <boost/intrusive_ptr.hpp>
18#include <boost/pool/pool.hpp>
19
20#include <boost/context/detail/config.hpp>
21#include <boost/context/stack_context.hpp>
22#include <boost/context/stack_traits.hpp>
23
24#if defined(BOOST_CONTEXT_USE_MAP_STACK)
25extern "C" {
26#include <sys/mman.h>
27#include <stdlib.h>
28}
29#endif
30
31#if defined(BOOST_USE_VALGRIND)
32#include <valgrind/valgrind.h>
33#endif
34
35#ifdef BOOST_HAS_ABI_HEADERS
36# include BOOST_ABI_PREFIX
37#endif
38
39namespace boost {
40namespace context {
41
42#if defined(BOOST_CONTEXT_USE_MAP_STACK)
43namespace detail {
44template< typename traitsT >
45struct map_stack_allocator {
46 typedef std::size_t size_type;
47 typedef std::ptrdiff_t difference_type;
48
49 static char * malloc( const size_type bytes) {
50 void * block;
51 if ( ::posix_memalign( &block, traitsT::page_size(), bytes) != 0) {
52 return 0;
53 }
54 if ( mmap( block, bytes, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON | MAP_FIXED | MAP_STACK, -1, 0) == MAP_FAILED) {
55 std::free( block);
56 return 0;
57 }
58 return reinterpret_cast< char * >( block);
59 }
60 static void free( char * const block) {
61 std::free( block);
62 }
63};
64}
65#endif
66
67template< typename traitsT >
68class basic_pooled_fixedsize_stack {
69private:
70 class storage {
71 private:
72 std::atomic< std::size_t > use_count_;
73 std::size_t stack_size_;
74#if defined(BOOST_CONTEXT_USE_MAP_STACK)
75 boost::pool< detail::map_stack_allocator< traitsT > > storage_;
76#else
77 boost::pool< boost::default_user_allocator_malloc_free > storage_;
78#endif
79
80 public:
81 storage( std::size_t stack_size, std::size_t next_size, std::size_t max_size) :
82 use_count_( 0),
83 stack_size_( stack_size),
84 storage_( stack_size, next_size, max_size) {
85 BOOST_ASSERT( traits_type::is_unbounded() || ( traits_type::maximum_size() >= stack_size_) );
86 }
87
88 stack_context allocate() {
89 void * vp = storage_.malloc();
90 if ( ! vp) {
91 throw std::bad_alloc();
92 }
93 stack_context sctx;
94 sctx.size = stack_size_;
95 sctx.sp = static_cast< char * >( vp) + sctx.size;
96#if defined(BOOST_USE_VALGRIND)
97 sctx.valgrind_stack_id = VALGRIND_STACK_REGISTER( sctx.sp, vp);
98#endif
99 return sctx;
100 }
101
102 void deallocate( stack_context & sctx) BOOST_NOEXCEPT_OR_NOTHROW {
103 BOOST_ASSERT( sctx.sp);
104 BOOST_ASSERT( traits_type::is_unbounded() || ( traits_type::maximum_size() >= sctx.size) );
105
106#if defined(BOOST_USE_VALGRIND)
107 VALGRIND_STACK_DEREGISTER( sctx.valgrind_stack_id);
108#endif
109 void * vp = static_cast< char * >( sctx.sp) - sctx.size;
110 storage_.free( chunk: vp);
111 }
112
113 friend void intrusive_ptr_add_ref( storage * s) noexcept {
114 ++s->use_count_;
115 }
116
117 friend void intrusive_ptr_release( storage * s) noexcept {
118 if ( 0 == --s->use_count_) {
119 delete s;
120 }
121 }
122 };
123
124 intrusive_ptr< storage > storage_;
125
126public:
127 typedef traitsT traits_type;
128
129 basic_pooled_fixedsize_stack( std::size_t stack_size = traits_type::default_size(),
130 std::size_t next_size = 32,
131 std::size_t max_size = 0) BOOST_NOEXCEPT_OR_NOTHROW :
132 storage_( new storage( stack_size, next_size, max_size) ) {
133 }
134
135 stack_context allocate() {
136 return storage_->allocate();
137 }
138
139 void deallocate( stack_context & sctx) BOOST_NOEXCEPT_OR_NOTHROW {
140 storage_->deallocate( sctx);
141 }
142};
143
144typedef basic_pooled_fixedsize_stack< stack_traits > pooled_fixedsize_stack;
145
146}}
147
148#ifdef BOOST_HAS_ABI_HEADERS
149# include BOOST_ABI_SUFFIX
150#endif
151
152#endif // BOOST_CONTEXT_POOLED_pooled_fixedsize_H
153

source code of boost/libs/context/include/boost/context/pooled_fixedsize_stack.hpp