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/*
* 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.
*/
#ifndef __LINKER_ALLOCATOR_H
#define __LINKER_ALLOCATOR_H
#include <stdlib.h>
#include <sys/cdefs.h>
#include <sys/mman.h>
#include <stddef.h>
#include <unistd.h>
#include <vector>
#include <async_safe/log.h>
#include "private/bionic_prctl.h"
const uint32_t kSmallObjectMaxSizeLog2 = 10;
const uint32_t kSmallObjectMinSizeLog2 = 4;
const uint32_t kSmallObjectAllocatorsCount = kSmallObjectMaxSizeLog2 - kSmallObjectMinSizeLog2 + 1;
class LinkerSmallObjectAllocator;
// 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.
LinkerSmallObjectAllocator* allocator_addr;
};
} __attribute__((aligned(16)));
struct small_object_page_record {
void* page_addr;
size_t free_blocks_cnt;
size_t allocated_blocks_cnt;
};
// for lower_bound...
bool operator<(const small_object_page_record& one, const small_object_page_record& two);
struct small_object_block_record {
small_object_block_record* next;
size_t free_blocks_cnt;
};
// This is implementation for std::vector allocator
template <typename T>
class linker_vector_allocator {
public:
typedef T value_type;
typedef T* pointer;
typedef const T* const_pointer;
typedef T& reference;
typedef const T& const_reference;
typedef size_t size_type;
typedef ptrdiff_t difference_type;
T* allocate(size_t n, const T* hint = nullptr) {
size_t size = n * sizeof(T);
void* ptr = mmap(const_cast<T*>(hint), size,
PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
if (ptr == MAP_FAILED) {
// Spec says we need to throw std::bad_alloc here but because our
// code does not support exception handling anyways - we are going to abort.
async_safe_fatal("mmap failed");
}
prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, ptr, size, "linker_alloc_vector");
return reinterpret_cast<T*>(ptr);
}
void deallocate(T* ptr, size_t n) {
munmap(ptr, n * sizeof(T));
}
};
typedef
std::vector<small_object_page_record, linker_vector_allocator<small_object_page_record>>
linker_vector_t;
class LinkerSmallObjectAllocator {
public:
LinkerSmallObjectAllocator(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(linker_vector_t::iterator page_record);
linker_vector_t::iterator find_page_record(void* ptr);
void create_page_record(void* page_addr, size_t free_blocks_cnt);
uint32_t type_;
size_t block_size_;
size_t free_pages_cnt_;
small_object_block_record* free_blocks_list_;
// sorted vector of page records
linker_vector_t page_records_;
};
class LinkerMemoryAllocator {
public:
constexpr LinkerMemoryAllocator() : allocators_(nullptr), allocators_buf_() {}
void* alloc(size_t size);
// Note that this implementation of realloc never shrinks allocation
void* realloc(void* ptr, size_t size);
void free(void* ptr);
private:
void* alloc_mmap(size_t size);
page_info* get_page_info(void* ptr);
LinkerSmallObjectAllocator* get_small_object_allocator(uint32_t type);
void initialize_allocators();
LinkerSmallObjectAllocator* allocators_;
uint8_t allocators_buf_[sizeof(LinkerSmallObjectAllocator)*kSmallObjectAllocatorsCount];
};
#endif /* __LINKER_ALLOCATOR_H */
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