File size: 10,423 Bytes
2fbb123 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 | #pragma once
#include <atomic> // Atomic operations library for lock-free programming
#include <cstddef> // Standard definitions, including size_t
#include <cstdint> // Standard integer types
#include <memory> // Memory management
#include <type_traits> // Type traits
#include <iostream> // Input/output stream
#include <vector>
#include <stdexcept>
#ifdef _WIN32
#include <Windows.h> // Windows system calls
#else
#include <sys/mman.h> // Linux memory mapping
#include <unistd.h> // Linux system calls
#endif
namespace hhb {
namespace core {
// Object pool configuration
template <typename T>
struct ObjectPoolConfig {
static constexpr size_t DEFAULT_BLOCK_SIZE = 1024 * 1024; // 1MB block size
static constexpr size_t DEFAULT_OBJECTS_PER_BLOCK = 1024; // Default objects per block
};
// Memory block header structure
// alignas(64): Force alignment to 64 bytes, the size of a cache line
struct alignas(64) BlockHeader {
std::atomic<BlockHeader*> next; // Atomic pointer to next block
std::atomic<size_t> used; // Number of used objects
size_t capacity; // Block capacity
char data[]; // Flexible array for actual objects
};
// Free object node
struct FreeNode {
std::atomic<FreeNode*> next; // Atomic pointer to next free node
};
// High-performance object pool
template <typename T>
class ObjectPool {
public:
// Constructor: Initialize object pool
// objects_per_block: Number of objects per block
ObjectPool(size_t objects_per_block = ObjectPoolConfig<T>::DEFAULT_OBJECTS_PER_BLOCK)
: objects_per_block_(objects_per_block),
// Calculate block size: block header size + object size * object count
block_size_(sizeof(BlockHeader) + sizeof(T) * objects_per_block),
head_block_(nullptr),
free_list_(nullptr) {
try {
// Pre-allocate first block
allocate_block();
} catch (const std::exception& e) {
std::cerr << "Exception in ObjectPool constructor: " << e.what() << std::endl;
throw;
}
}
// Destructor: Release all blocks
~ObjectPool() {
// Release all blocks
BlockHeader* block = head_block_;
while (block) {
BlockHeader* next = block->next;
deallocate_block(block);
block = next;
}
}
// Disable copy and move
ObjectPool(const ObjectPool&) = delete;
ObjectPool& operator=(const ObjectPool&) = delete;
ObjectPool(ObjectPool&&) = delete;
ObjectPool& operator=(ObjectPool&&) = delete;
// Allocate object
T* allocate() {
// Try to get from free list
FreeNode* node = free_list_.load(std::memory_order_acquire);
while (node) {
// Load next node with acquire memory order
FreeNode* next = node->next.load(std::memory_order_acquire);
// Compare-exchange weak: lock-free CAS operation
if (free_list_.compare_exchange_weak(node, next, std::memory_order_acq_rel, std::memory_order_acquire)) {
// Reinterpret cast: convert FreeNode* to T*
return reinterpret_cast<T*>(node);
}
}
// Free list is empty, try to allocate in existing blocks
BlockHeader* block = head_block_.load(std::memory_order_acquire);
while (block) {
size_t used = block->used.load(std::memory_order_acquire);
while (used < block->capacity) {
if (block->used.compare_exchange_weak(
used, used + 1,
std::memory_order_acq_rel,
std::memory_order_acquire)) {
return reinterpret_cast<T*>(
reinterpret_cast<char*>(block) + sizeof(BlockHeader) + sizeof(T) * used);
}
}
block = block->next.load(std::memory_order_acquire);
}
// All blocks are full, allocate new block and retry on head
allocate_block();
BlockHeader* head = head_block_.load(std::memory_order_acquire);
while (true) {
size_t used = head->used.load(std::memory_order_acquire);
if (used >= head->capacity) {
allocate_block();
head = head_block_.load(std::memory_order_acquire);
continue;
}
if (head->used.compare_exchange_weak(
used, used + 1,
std::memory_order_acq_rel,
std::memory_order_acquire)) {
return reinterpret_cast<T*>(
reinterpret_cast<char*>(head) + sizeof(BlockHeader) + sizeof(T) * used);
}
}
}
// Deallocate object
void deallocate(T* ptr) {
// Convert object to free node
FreeNode* node = reinterpret_cast<FreeNode*>(ptr);
// Load free list head with acquire memory order
FreeNode* old_head = free_list_.load(std::memory_order_acquire);
do {
// Set new node's next pointer to old head
node->next.store(old_head, std::memory_order_release);
// CAS operation: try to set new node as list head
} while (!free_list_.compare_exchange_weak(old_head, node, std::memory_order_acq_rel, std::memory_order_acquire));
}
// Get number of allocated objects
size_t size() const {
size_t total = 0;
BlockHeader* block = head_block_.load(std::memory_order_acquire);
while (block) {
total += block->used.load(std::memory_order_acquire);
block = block->next.load(std::memory_order_acquire);
}
return total;
}
// Iterate all objects and execute callback
template <typename Func>
void for_each(Func func) {
BlockHeader* block = head_block_.load(std::memory_order_acquire);
while (block) {
size_t used = block->used.load(std::memory_order_acquire);
for (size_t i = 0; i < used; ++i) {
T* obj = reinterpret_cast<T*>(
reinterpret_cast<char*>(block) + sizeof(BlockHeader) + sizeof(T) * i);
func(obj);
}
block = block->next.load(std::memory_order_acquire);
}
}
// Access object by index
T& operator[](size_t index) {
size_t current_index = 0;
BlockHeader* block = head_block_.load(std::memory_order_acquire);
// Reverse traversal since blocks are linked in reverse order
std::vector<BlockHeader*> blocks;
while (block) {
blocks.push_back(block);
block = block->next.load(std::memory_order_acquire);
}
// Traverse in reverse order (oldest first)
for (auto it = blocks.rbegin(); it != blocks.rend(); ++it) {
BlockHeader* b = *it;
size_t used = b->used.load(std::memory_order_acquire);
if (index < current_index + used) {
size_t offset = index - current_index;
return *reinterpret_cast<T*>(
reinterpret_cast<char*>(b) + sizeof(BlockHeader) + sizeof(T) * offset);
}
current_index += used;
}
throw std::out_of_range("Index out of range");
}
// Const access
const T& operator[](size_t index) const {
return const_cast<ObjectPool*>(this)->operator[](index);
}
private:
// Allocate new memory block
void allocate_block() {
try {
// Calculate block size
size_t actual_block_size = block_size_;
std::cout << "Allocating block with size: " << actual_block_size << " bytes" << std::endl;
// Allocate memory
void* memory = nullptr;
#ifdef _WIN32
// Windows: Use VirtualAlloc to allocate virtual memory
// MEM_COMMIT | MEM_RESERVE: Reserve and commit memory
// PAGE_READWRITE: Readable and writable
std::cout << "Calling VirtualAlloc" << std::endl;
memory = VirtualAlloc(nullptr, actual_block_size, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
std::cout << "VirtualAlloc returned: " << memory << std::endl;
#else
// Linux: Use mmap to allocate memory
// MAP_PRIVATE | MAP_ANONYMOUS: Private, anonymous mapping
// PROT_READ | PROT_WRITE: Readable and writable
memory = mmap(nullptr, actual_block_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
#endif
if (!memory) {
std::cerr << "Failed to allocate memory" << std::endl;
throw std::bad_alloc();
}
// Initialize block header
BlockHeader* block = reinterpret_cast<BlockHeader*>(memory);
block->used.store(0, std::memory_order_release);
block->capacity = objects_per_block_;
BlockHeader* old_head = head_block_.load(std::memory_order_acquire);
do {
block->next.store(old_head, std::memory_order_release);
} while (!head_block_.compare_exchange_weak(old_head, block, std::memory_order_acq_rel, std::memory_order_acquire));
std::cout << "Block allocated successfully" << std::endl;
} catch (const std::exception& e) {
std::cerr << "Exception in allocate_block: " << e.what() << std::endl;
throw;
}
}
// Release memory block
void deallocate_block(BlockHeader* block) {
#ifdef _WIN32
// Windows: Use VirtualFree to release memory
// MEM_RELEASE: Release entire memory block
VirtualFree(block, 0, MEM_RELEASE);
#else
// Linux: Use munmap to release memory
munmap(block, block_size_);
#endif
}
size_t objects_per_block_; // Number of objects per block
size_t block_size_; // Size of each block
std::atomic<BlockHeader*> head_block_; // Head block pointer
std::atomic<FreeNode*> free_list_; // Free list (atomic pointer)
};
} // namespace core
} // namespace hhb
|