3edc5c41bb
C/C++ requires the result of malloc/new to be aligned for any primitive type. Change-Id: I715b7679e738f34b3b409993fb3ef242e1321b7f
143 lines
4 KiB
C++
143 lines
4 KiB
C++
/*
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* Copyright (C) 2015 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef __LINKER_ALLOCATOR_H
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#define __LINKER_ALLOCATOR_H
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#include <stdlib.h>
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#include <sys/cdefs.h>
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#include <sys/mman.h>
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#include <stddef.h>
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#include <unistd.h>
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#include <vector>
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#include "private/bionic_prctl.h"
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#include "private/libc_logging.h"
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const uint32_t kSmallObjectMaxSizeLog2 = 10;
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const uint32_t kSmallObjectMinSizeLog2 = 4;
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const uint32_t kSmallObjectAllocatorsCount = kSmallObjectMaxSizeLog2 - kSmallObjectMinSizeLog2 + 1;
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class LinkerSmallObjectAllocator;
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// This structure is placed at the beginning of each addressable page
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// and has all information we need to find the corresponding memory allocator.
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struct page_info {
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char signature[4];
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uint32_t type;
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union {
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// we use allocated_size for large objects allocator
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size_t allocated_size;
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// and allocator_addr for small ones.
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LinkerSmallObjectAllocator* allocator_addr;
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};
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} __attribute__((aligned(16)));
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struct small_object_page_record {
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void* page_addr;
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size_t free_blocks_cnt;
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size_t allocated_blocks_cnt;
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};
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// for lower_bound...
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bool operator<(const small_object_page_record& one, const small_object_page_record& two);
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struct small_object_block_record {
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small_object_block_record* next;
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size_t free_blocks_cnt;
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};
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// This is implementation for std::vector allocator
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template <typename T>
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class linker_vector_allocator {
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public:
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typedef T value_type;
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typedef T* pointer;
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typedef const T* const_pointer;
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typedef T& reference;
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typedef const T& const_reference;
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typedef size_t size_type;
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typedef ptrdiff_t difference_type;
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T* allocate(size_t n, const T* hint = nullptr) {
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size_t size = n * sizeof(T);
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void* ptr = mmap(const_cast<T*>(hint), size,
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PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
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if (ptr == MAP_FAILED) {
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// Spec says we need to throw std::bad_alloc here but because our
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// code does not support exception handling anyways - we are going to abort.
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__libc_fatal("mmap failed");
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}
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prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, ptr, size, "linker_alloc_vector");
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return reinterpret_cast<T*>(ptr);
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}
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void deallocate(T* ptr, size_t n) {
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munmap(ptr, n * sizeof(T));
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}
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};
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typedef
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std::vector<small_object_page_record, linker_vector_allocator<small_object_page_record>>
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linker_vector_t;
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class LinkerSmallObjectAllocator {
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public:
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LinkerSmallObjectAllocator();
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void init(uint32_t type, size_t block_size, const char* name);
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void* alloc();
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void free(void* ptr);
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size_t get_block_size() const { return block_size_; }
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private:
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void alloc_page();
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void free_page(linker_vector_t::iterator page_record);
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linker_vector_t::iterator find_page_record(void* ptr);
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void create_page_record(void* page_addr, size_t free_blocks_cnt);
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uint32_t type_;
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const char* name_;
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size_t block_size_;
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size_t free_pages_cnt_;
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small_object_block_record* free_blocks_list_;
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// sorted vector of page records
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linker_vector_t page_records_;
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};
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class LinkerMemoryAllocator {
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public:
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LinkerMemoryAllocator();
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void* alloc(size_t size);
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// Note that this implementation of realloc never shrinks allocation
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void* realloc(void* ptr, size_t size);
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void free(void* ptr);
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private:
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void* alloc_mmap(size_t size);
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page_info* get_page_info(void* ptr);
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LinkerSmallObjectAllocator* get_small_object_allocator(uint32_t type);
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LinkerSmallObjectAllocator allocators_[kSmallObjectAllocatorsCount];
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};
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#endif /* __LINKER_ALLOCATOR_H */
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