1 /* 2 * Copyright (C) 2015 The Android Open Source Project 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #ifndef __LINKER_ALLOCATOR_H 30 #define __LINKER_ALLOCATOR_H 31 32 #include <stdlib.h> 33 #include <sys/cdefs.h> 34 #include <sys/mman.h> 35 #include <stddef.h> 36 #include <unistd.h> 37 38 #include <vector> 39 40 #include "private/bionic_prctl.h" 41 #include "private/libc_logging.h" 42 43 const uint32_t kSmallObjectMaxSizeLog2 = 10; 44 const uint32_t kSmallObjectMinSizeLog2 = 4; 45 const uint32_t kSmallObjectAllocatorsCount = kSmallObjectMaxSizeLog2 - kSmallObjectMinSizeLog2 + 1; 46 47 class LinkerSmallObjectAllocator; 48 49 // This structure is placed at the beginning of each addressable page 50 // and has all information we need to find the corresponding memory allocator. 51 struct page_info { 52 char signature[4]; 53 uint32_t type; 54 union { 55 // we use allocated_size for large objects allocator 56 size_t allocated_size; 57 // and allocator_addr for small ones. 58 LinkerSmallObjectAllocator* allocator_addr; 59 }; 60 } __attribute__((aligned(16))); 61 62 struct small_object_page_record { 63 void* page_addr; 64 size_t free_blocks_cnt; 65 size_t allocated_blocks_cnt; 66 }; 67 68 // for lower_bound... 69 bool operator<(const small_object_page_record& one, const small_object_page_record& two); 70 71 struct small_object_block_record { 72 small_object_block_record* next; 73 size_t free_blocks_cnt; 74 }; 75 76 // This is implementation for std::vector allocator 77 template <typename T> 78 class linker_vector_allocator { 79 public: 80 typedef T value_type; 81 typedef T* pointer; 82 typedef const T* const_pointer; 83 typedef T& reference; 84 typedef const T& const_reference; 85 typedef size_t size_type; 86 typedef ptrdiff_t difference_type; 87 88 T* allocate(size_t n, const T* hint = nullptr) { 89 size_t size = n * sizeof(T); 90 void* ptr = mmap(const_cast<T*>(hint), size, 91 PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, 0, 0); 92 if (ptr == MAP_FAILED) { 93 // Spec says we need to throw std::bad_alloc here but because our 94 // code does not support exception handling anyways - we are going to abort. 95 __libc_fatal("mmap failed"); 96 } 97 98 prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, ptr, size, "linker_alloc_vector"); 99 100 return reinterpret_cast<T*>(ptr); 101 } 102 103 void deallocate(T* ptr, size_t n) { 104 munmap(ptr, n * sizeof(T)); 105 } 106 }; 107 108 typedef 109 std::vector<small_object_page_record, linker_vector_allocator<small_object_page_record>> 110 linker_vector_t; 111 112 113 class LinkerSmallObjectAllocator { 114 public: 115 LinkerSmallObjectAllocator(uint32_t type, size_t block_size); 116 void* alloc(); 117 void free(void* ptr); 118 119 size_t get_block_size() const { return block_size_; } 120 private: 121 void alloc_page(); 122 void free_page(linker_vector_t::iterator page_record); 123 linker_vector_t::iterator find_page_record(void* ptr); 124 void create_page_record(void* page_addr, size_t free_blocks_cnt); 125 126 uint32_t type_; 127 size_t block_size_; 128 129 size_t free_pages_cnt_; 130 small_object_block_record* free_blocks_list_; 131 132 // sorted vector of page records 133 linker_vector_t page_records_; 134 }; 135 136 class LinkerMemoryAllocator { 137 public: 138 constexpr LinkerMemoryAllocator() : allocators_(nullptr), allocators_buf_() {} 139 void* alloc(size_t size); 140 141 // Note that this implementation of realloc never shrinks allocation 142 void* realloc(void* ptr, size_t size); 143 void free(void* ptr); 144 private: 145 void* alloc_mmap(size_t size); 146 page_info* get_page_info(void* ptr); 147 LinkerSmallObjectAllocator* get_small_object_allocator(uint32_t type); 148 void initialize_allocators(); 149 150 LinkerSmallObjectAllocator* allocators_; 151 uint8_t allocators_buf_[sizeof(LinkerSmallObjectAllocator)*kSmallObjectAllocatorsCount]; 152 }; 153 154 155 #endif /* __LINKER_ALLOCATOR_H */ 156
