129 lines
4.4 KiB
C++
129 lines
4.4 KiB
C++
/*
|
|
* Copyright (C) 2015 The Android Open Source Project
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* * Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* * Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in
|
|
* the documentation and/or other materials provided with the
|
|
* distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
|
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
|
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
|
|
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
|
|
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
|
|
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
|
|
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
|
|
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <errno.h>
|
|
#include <stdlib.h>
|
|
#include <sys/cdefs.h>
|
|
#include <sys/mman.h>
|
|
#include <sys/prctl.h>
|
|
#include <stddef.h>
|
|
#include <unistd.h>
|
|
|
|
const uint32_t kSmallObjectMaxSizeLog2 = 10;
|
|
const uint32_t kSmallObjectMinSizeLog2 = 4;
|
|
const uint32_t kSmallObjectAllocatorsCount = kSmallObjectMaxSizeLog2 - kSmallObjectMinSizeLog2 + 1;
|
|
|
|
class BionicSmallObjectAllocator;
|
|
|
|
// This structure is placed at the beginning of each addressable page
|
|
// and has all information we need to find the corresponding memory allocator.
|
|
struct page_info {
|
|
char signature[4];
|
|
uint32_t type;
|
|
union {
|
|
// we use allocated_size for large objects allocator
|
|
size_t allocated_size;
|
|
// and allocator_addr for small ones.
|
|
BionicSmallObjectAllocator* allocator_addr;
|
|
};
|
|
};
|
|
|
|
struct small_object_block_record {
|
|
small_object_block_record* next;
|
|
size_t free_blocks_cnt;
|
|
};
|
|
|
|
// This structure is placed at the beginning of each page managed by
|
|
// BionicSmallObjectAllocator. Note that a page_info struct is expected at the
|
|
// beginning of each page as well, and therefore this structure contains a
|
|
// page_info as its *first* field.
|
|
struct small_object_page_info {
|
|
page_info info; // Must be the first field.
|
|
|
|
// Doubly linked list for traversing all pages allocated by a
|
|
// BionicSmallObjectAllocator.
|
|
small_object_page_info* next_page;
|
|
small_object_page_info* prev_page;
|
|
|
|
// Linked list containing all free blocks in this page.
|
|
small_object_block_record* free_block_list;
|
|
|
|
// Free blocks counter.
|
|
size_t free_blocks_cnt;
|
|
};
|
|
|
|
class BionicSmallObjectAllocator {
|
|
public:
|
|
BionicSmallObjectAllocator(uint32_t type, size_t block_size);
|
|
void* alloc();
|
|
void free(void* ptr);
|
|
|
|
size_t get_block_size() const { return block_size_; }
|
|
private:
|
|
void alloc_page();
|
|
void free_page(small_object_page_info* page);
|
|
void add_to_page_list(small_object_page_info* page);
|
|
void remove_from_page_list(small_object_page_info* page);
|
|
|
|
const uint32_t type_;
|
|
const size_t block_size_;
|
|
const size_t blocks_per_page_;
|
|
|
|
size_t free_pages_cnt_;
|
|
|
|
small_object_page_info* page_list_;
|
|
};
|
|
|
|
class BionicAllocator {
|
|
public:
|
|
constexpr BionicAllocator() : allocators_(nullptr), allocators_buf_() {}
|
|
void* alloc(size_t size);
|
|
void* memalign(size_t align, size_t size);
|
|
|
|
// Note that this implementation of realloc never shrinks allocation
|
|
void* realloc(void* ptr, size_t size);
|
|
void free(void* ptr);
|
|
|
|
// Returns the size of the given allocated heap chunk, if it is valid.
|
|
// Otherwise, this may return 0 or cause a segfault if the pointer is invalid.
|
|
size_t get_chunk_size(void* ptr);
|
|
|
|
private:
|
|
void* alloc_mmap(size_t align, size_t size);
|
|
inline void* alloc_impl(size_t align, size_t size);
|
|
inline page_info* get_page_info_unchecked(void* ptr);
|
|
inline page_info* get_page_info(void* ptr);
|
|
BionicSmallObjectAllocator* get_small_object_allocator(uint32_t type);
|
|
void initialize_allocators();
|
|
|
|
BionicSmallObjectAllocator* allocators_;
|
|
uint8_t allocators_buf_[sizeof(BionicSmallObjectAllocator)*kSmallObjectAllocatorsCount];
|
|
};
|