Panda3D

deletedBufferChain.cxx
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1 /**
2 * PANDA 3D SOFTWARE
3 * Copyright (c) Carnegie Mellon University. All rights reserved.
4 *
5 * All use of this software is subject to the terms of the revised BSD
6 * license. You should have received a copy of this license along
7 * with this source code in a file named "LICENSE."
8 *
9 * @file deletedBufferChain.cxx
10 * @author drose
11 * @date 2007-07-20
12 */
13
14 #include "deletedBufferChain.h"
15 #include "memoryHook.h"
16
17 /**
18 * Use the global MemoryHook to get a new DeletedBufferChain of the
19 * appropriate size.
20 */
21 DeletedBufferChain::
22 DeletedBufferChain(size_t buffer_size) {
23 _deleted_chain = nullptr;
24 _buffer_size = buffer_size;
25
26 // We must allocate at least this much space for bookkeeping reasons.
27 _buffer_size = std::max(_buffer_size, sizeof(ObjectNode));
28 }
29
30 /**
31 * Allocates the memory for a new buffer of the indicated size (which must be
32 * no greater than the fixed size associated with the DeletedBufferChain).
33 */
34 void *DeletedBufferChain::
35 allocate(size_t size, TypeHandle type_handle) {
36 #ifdef USE_DELETED_CHAIN
37 // TAU_PROFILE("void *DeletedBufferChain::allocate(size_t, TypeHandle)", "
38 // ", TAU_USER);
39 assert(size <= _buffer_size);
40
41 // Determine how much space to allocate.
42 const size_t alloc_size = _buffer_size + flag_reserved_bytes + MEMORY_HOOK_ALIGNMENT - 1;
43
44 ObjectNode *obj;
45
46 _lock.lock();
47 if (_deleted_chain != nullptr) {
48 obj = _deleted_chain;
49 _deleted_chain = _deleted_chain->_next;
50 _lock.unlock();
51
52 #ifdef USE_DELETEDCHAINFLAG
53 assert(obj->_flag == (AtomicAdjust::Integer)DCF_deleted);
54 obj->_flag = DCF_alive;
55 #endif // USE_DELETEDCHAINFLAG
56
57 void *ptr = node_to_buffer(obj);
58
59 #ifdef DO_MEMORY_USAGE
60 // type_handle.dec_memory_usage(TypeHandle::MC_deleted_chain_inactive,
61 // alloc_size);
62 type_handle.inc_memory_usage(TypeHandle::MC_deleted_chain_active, alloc_size);
63 #endif // DO_MEMORY_USAGE
64
65 return ptr;
66 }
67 _lock.unlock();
68
69 // If we get here, the deleted_chain is empty; we have to allocate a new
70 // object from the system pool.
71
72 // Allocate memory, and make sure the object starts at the proper alignment.
73 void *mem = NeverFreeMemory::alloc(alloc_size);
74 uintptr_t aligned = ((uintptr_t)mem + flag_reserved_bytes + MEMORY_HOOK_ALIGNMENT - 1) & ~(MEMORY_HOOK_ALIGNMENT - 1);
75 obj = (ObjectNode *)(aligned - flag_reserved_bytes);
76
77 #ifdef USE_DELETEDCHAINFLAG
78 obj->_flag = DCF_alive;
79 #endif // USE_DELETEDCHAINFLAG
80
81 void *ptr = node_to_buffer(obj);
82
83 #ifndef NDEBUG
84 assert(((uintptr_t)ptr % MEMORY_HOOK_ALIGNMENT) == 0);
85 #endif
86
87 #ifdef DO_MEMORY_USAGE
88 type_handle.inc_memory_usage(TypeHandle::MC_deleted_chain_active, alloc_size);
89 #endif // DO_MEMORY_USAGE
90
91 return ptr;
92
93 #else // USE_DELETED_CHAIN
94 return PANDA_MALLOC_SINGLE(_buffer_size);
95 #endif // USE_DELETED_CHAIN
96 }
97
98 /**
99 * Frees the memory for a buffer previously allocated via allocate().
100 */
101 void DeletedBufferChain::
102 deallocate(void *ptr, TypeHandle type_handle) {
103 #ifdef USE_DELETED_CHAIN
104 // TAU_PROFILE("void DeletedBufferChain::deallocate(void *, TypeHandle)", "
105 // ", TAU_USER);
106 assert(ptr != nullptr);
107
108 #ifdef DO_MEMORY_USAGE
109 const size_t alloc_size = _buffer_size + flag_reserved_bytes + MEMORY_HOOK_ALIGNMENT - 1;
110 type_handle.dec_memory_usage(TypeHandle::MC_deleted_chain_active, alloc_size);
111 // type_handle.inc_memory_usage(TypeHandle::MC_deleted_chain_inactive,
112 // _buffer_size + flag_reserved_bytes);
113
114 #endif // DO_MEMORY_USAGE
115
116 ObjectNode *obj = buffer_to_node(ptr);
117
118 #ifdef USE_DELETEDCHAINFLAG
119 AtomicAdjust::Integer orig_flag = AtomicAdjust::compare_and_exchange(obj->_flag, DCF_alive, DCF_deleted);
120
121 // If this assertion is triggered, you double-deleted an object.
122 assert(orig_flag != (AtomicAdjust::Integer)DCF_deleted);
123
124 // If this assertion is triggered, you tried to delete an object that was
125 // never allocated, or you have heap corruption.
126 assert(orig_flag == (AtomicAdjust::Integer)DCF_alive);
127 #endif // USE_DELETEDCHAINFLAG
128
129 _lock.lock();
130
131 obj->_next = _deleted_chain;
132 _deleted_chain = obj;
133
134 _lock.unlock();
135
136 #else // USE_DELETED_CHAIN
137 PANDA_FREE_SINGLE(ptr);
138 #endif // USE_DELETED_CHAIN
139 }
AtomicAdjustDummyImpl::compare_and_exchange
static Integer compare_and_exchange(Integer &mem, Integer old_value, Integer new_value)
Atomic compare and exchange.
Definition: atomicAdjustDummyImpl.I:93
DeletedBufferChain::deallocate
void deallocate(void *ptr, TypeHandle type_handle)
Frees the memory for a buffer previously allocated via allocate().
Definition: deletedBufferChain.cxx:102
DeletedBufferChain::allocate
void * allocate(size_t size, TypeHandle type_handle)
Allocates the memory for a new buffer of the indicated size (which must be no greater than the fixed ...
Definition: deletedBufferChain.cxx:35
NeverFreeMemory::alloc
static void * alloc(size_t size)
Returns a pointer to a newly-allocated block of memory of the indicated size.
Definition: neverFreeMemory.I:21
TypeHandle
TypeHandle is the identifier used to differentiate C++ class types.
Definition: typeHandle.h:81
TypeHandle::dec_memory_usage
void dec_memory_usage(MemoryClass memory_class, size_t size)
Subtracts the indicated amount from the record for the total allocated memory for objects of this typ...
Definition: typeHandle.cxx:67
TypeHandle::inc_memory_usage
void inc_memory_usage(MemoryClass memory_class, size_t size)
Adds the indicated amount to the record for the total allocated memory for objects of this type.
Definition: typeHandle.cxx:43
deletedBufferChain.h
PANDA 3D SOFTWARE Copyright (c) Carnegie Mellon University.
memoryHook.h
PANDA 3D SOFTWARE Copyright (c) Carnegie Mellon University.