ladybird/Userland/Libraries/LibC/malloc.cpp
Andreas Kling 5d180d1f99 Everywhere: Rename ASSERT => VERIFY
(...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED)

Since all of these checks are done in release builds as well,
let's rename them to VERIFY to prevent confusion, as everyone is
used to assertions being compiled out in release.

We can introduce a new ASSERT macro that is specifically for debug
checks, but I'm doing this wholesale conversion first since we've
accumulated thousands of these already, and it's not immediately
obvious which ones are suitable for ASSERT.
2021-02-23 20:56:54 +01:00

462 lines
15 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. 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 HOLDER 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.
*/
#include <AK/Debug.h>
#include <AK/InlineLinkedList.h>
#include <AK/LogStream.h>
#include <AK/ScopedValueRollback.h>
#include <AK/Vector.h>
#include <LibELF/AuxiliaryVector.h>
#include <LibThread/Lock.h>
#include <assert.h>
#include <mallocdefs.h>
#include <serenity.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/internals.h>
#include <sys/mman.h>
// FIXME: Thread safety.
#define RECYCLE_BIG_ALLOCATIONS
#define PAGE_ROUND_UP(x) ((((size_t)(x)) + PAGE_SIZE - 1) & (~(PAGE_SIZE - 1)))
ALWAYS_INLINE static void ue_notify_malloc(const void* ptr, size_t size)
{
send_secret_data_to_userspace_emulator(1, size, (FlatPtr)ptr);
}
ALWAYS_INLINE static void ue_notify_free(const void* ptr)
{
send_secret_data_to_userspace_emulator(2, (FlatPtr)ptr, 0);
}
ALWAYS_INLINE static void ue_notify_realloc(const void* ptr, size_t size)
{
send_secret_data_to_userspace_emulator(3, size, (FlatPtr)ptr);
}
static LibThread::Lock& malloc_lock()
{
static u32 lock_storage[sizeof(LibThread::Lock) / sizeof(u32)];
return *reinterpret_cast<LibThread::Lock*>(&lock_storage);
}
constexpr size_t number_of_chunked_blocks_to_keep_around_per_size_class = 4;
constexpr size_t number_of_big_blocks_to_keep_around_per_size_class = 8;
static bool s_log_malloc = false;
static bool s_scrub_malloc = true;
static bool s_scrub_free = true;
static bool s_profiling = false;
struct MallocStats {
size_t number_of_malloc_calls;
size_t number_of_big_allocator_hits;
size_t number_of_big_allocator_purge_hits;
size_t number_of_big_allocs;
size_t number_of_empty_block_hits;
size_t number_of_empty_block_purge_hits;
size_t number_of_block_allocs;
size_t number_of_blocks_full;
size_t number_of_free_calls;
size_t number_of_big_allocator_keeps;
size_t number_of_big_allocator_frees;
size_t number_of_freed_full_blocks;
size_t number_of_keeps;
size_t number_of_frees;
};
static MallocStats g_malloc_stats = {};
struct Allocator {
size_t size { 0 };
size_t block_count { 0 };
size_t empty_block_count { 0 };
ChunkedBlock* empty_blocks[number_of_chunked_blocks_to_keep_around_per_size_class] { nullptr };
InlineLinkedList<ChunkedBlock> usable_blocks;
InlineLinkedList<ChunkedBlock> full_blocks;
};
struct BigAllocator {
Vector<BigAllocationBlock*, number_of_big_blocks_to_keep_around_per_size_class> blocks;
};
// Allocators will be initialized in __malloc_init.
// We can not rely on global constructors to initialize them,
// because they must be initialized before other global constructors
// are run. Similarly, we can not allow global destructors to destruct
// them. We could have used AK::NeverDestoyed to prevent the latter,
// but it would have not helped with the former.
static u8 g_allocators_storage[sizeof(Allocator) * num_size_classes];
static u8 g_big_allocators_storage[sizeof(BigAllocator)];
static inline Allocator (&allocators())[num_size_classes]
{
return reinterpret_cast<Allocator(&)[num_size_classes]>(g_allocators_storage);
}
static inline BigAllocator (&big_allocators())[1]
{
return reinterpret_cast<BigAllocator(&)[1]>(g_big_allocators_storage);
}
static Allocator* allocator_for_size(size_t size, size_t& good_size)
{
for (size_t i = 0; size_classes[i]; ++i) {
if (size <= size_classes[i]) {
good_size = size_classes[i];
return &allocators()[i];
}
}
good_size = PAGE_ROUND_UP(size);
return nullptr;
}
#ifdef RECYCLE_BIG_ALLOCATIONS
static BigAllocator* big_allocator_for_size(size_t size)
{
if (size == 65536)
return &big_allocators()[0];
return nullptr;
}
#endif
extern "C" {
static void* os_alloc(size_t size, const char* name)
{
auto* ptr = serenity_mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0, ChunkedBlock::block_size, name);
VERIFY(ptr != MAP_FAILED);
return ptr;
}
static void os_free(void* ptr, size_t size)
{
int rc = munmap(ptr, size);
assert(rc == 0);
}
static void* malloc_impl(size_t size)
{
LOCKER(malloc_lock());
if (s_log_malloc)
dbgln("LibC: malloc({})", size);
if (!size)
return nullptr;
g_malloc_stats.number_of_malloc_calls++;
size_t good_size;
auto* allocator = allocator_for_size(size, good_size);
if (!allocator) {
size_t real_size = round_up_to_power_of_two(sizeof(BigAllocationBlock) + size, ChunkedBlock::block_size);
#ifdef RECYCLE_BIG_ALLOCATIONS
if (auto* allocator = big_allocator_for_size(real_size)) {
if (!allocator->blocks.is_empty()) {
g_malloc_stats.number_of_big_allocator_hits++;
auto* block = allocator->blocks.take_last();
int rc = madvise(block, real_size, MADV_SET_NONVOLATILE);
bool this_block_was_purged = rc == 1;
if (rc < 0) {
perror("madvise");
VERIFY_NOT_REACHED();
}
if (mprotect(block, real_size, PROT_READ | PROT_WRITE) < 0) {
perror("mprotect");
VERIFY_NOT_REACHED();
}
if (this_block_was_purged) {
g_malloc_stats.number_of_big_allocator_purge_hits++;
new (block) BigAllocationBlock(real_size);
}
ue_notify_malloc(&block->m_slot[0], size);
return &block->m_slot[0];
}
}
#endif
g_malloc_stats.number_of_big_allocs++;
auto* block = (BigAllocationBlock*)os_alloc(real_size, "malloc: BigAllocationBlock");
new (block) BigAllocationBlock(real_size);
ue_notify_malloc(&block->m_slot[0], size);
return &block->m_slot[0];
}
ChunkedBlock* block = nullptr;
for (block = allocator->usable_blocks.head(); block; block = block->next()) {
if (block->free_chunks())
break;
}
if (!block && allocator->empty_block_count) {
g_malloc_stats.number_of_empty_block_hits++;
block = allocator->empty_blocks[--allocator->empty_block_count];
int rc = madvise(block, ChunkedBlock::block_size, MADV_SET_NONVOLATILE);
bool this_block_was_purged = rc == 1;
if (rc < 0) {
perror("madvise");
VERIFY_NOT_REACHED();
}
rc = mprotect(block, ChunkedBlock::block_size, PROT_READ | PROT_WRITE);
if (rc < 0) {
perror("mprotect");
VERIFY_NOT_REACHED();
}
if (this_block_was_purged) {
g_malloc_stats.number_of_empty_block_purge_hits++;
new (block) ChunkedBlock(good_size);
}
allocator->usable_blocks.append(block);
}
if (!block) {
g_malloc_stats.number_of_block_allocs++;
char buffer[64];
snprintf(buffer, sizeof(buffer), "malloc: ChunkedBlock(%zu)", good_size);
block = (ChunkedBlock*)os_alloc(ChunkedBlock::block_size, buffer);
new (block) ChunkedBlock(good_size);
allocator->usable_blocks.append(block);
++allocator->block_count;
}
--block->m_free_chunks;
void* ptr = block->m_freelist;
VERIFY(ptr);
block->m_freelist = block->m_freelist->next;
if (block->is_full()) {
g_malloc_stats.number_of_blocks_full++;
dbgln_if(MALLOC_DEBUG, "Block {:p} is now full in size class {}", block, good_size);
allocator->usable_blocks.remove(block);
allocator->full_blocks.append(block);
}
dbgln_if(MALLOC_DEBUG, "LibC: allocated {:p} (chunk in block {:p}, size {})", ptr, block, block->bytes_per_chunk());
if (s_scrub_malloc)
memset(ptr, MALLOC_SCRUB_BYTE, block->m_size);
ue_notify_malloc(ptr, size);
return ptr;
}
static void free_impl(void* ptr)
{
ScopedValueRollback rollback(errno);
if (!ptr)
return;
g_malloc_stats.number_of_free_calls++;
LOCKER(malloc_lock());
void* block_base = (void*)((FlatPtr)ptr & ChunkedBlock::ChunkedBlock::block_mask);
size_t magic = *(size_t*)block_base;
if (magic == MAGIC_BIGALLOC_HEADER) {
auto* block = (BigAllocationBlock*)block_base;
#ifdef RECYCLE_BIG_ALLOCATIONS
if (auto* allocator = big_allocator_for_size(block->m_size)) {
if (allocator->blocks.size() < number_of_big_blocks_to_keep_around_per_size_class) {
g_malloc_stats.number_of_big_allocator_keeps++;
allocator->blocks.append(block);
size_t this_block_size = block->m_size;
if (mprotect(block, this_block_size, PROT_NONE) < 0) {
perror("mprotect");
VERIFY_NOT_REACHED();
}
if (madvise(block, this_block_size, MADV_SET_VOLATILE) != 0) {
perror("madvise");
VERIFY_NOT_REACHED();
}
return;
}
}
#endif
g_malloc_stats.number_of_big_allocator_frees++;
os_free(block, block->m_size);
return;
}
assert(magic == MAGIC_PAGE_HEADER);
auto* block = (ChunkedBlock*)block_base;
dbgln_if(MALLOC_DEBUG, "LibC: freeing {:p} in allocator {:p} (size={}, used={})", ptr, block, block->bytes_per_chunk(), block->used_chunks());
if (s_scrub_free)
memset(ptr, FREE_SCRUB_BYTE, block->bytes_per_chunk());
auto* entry = (FreelistEntry*)ptr;
entry->next = block->m_freelist;
block->m_freelist = entry;
if (block->is_full()) {
size_t good_size;
auto* allocator = allocator_for_size(block->m_size, good_size);
dbgln_if(MALLOC_DEBUG, "Block {:p} no longer full in size class {}", block, good_size);
g_malloc_stats.number_of_freed_full_blocks++;
allocator->full_blocks.remove(block);
allocator->usable_blocks.prepend(block);
}
++block->m_free_chunks;
if (!block->used_chunks()) {
size_t good_size;
auto* allocator = allocator_for_size(block->m_size, good_size);
if (allocator->block_count < number_of_chunked_blocks_to_keep_around_per_size_class) {
dbgln_if(MALLOC_DEBUG, "Keeping block {:p} around for size class {}", block, good_size);
g_malloc_stats.number_of_keeps++;
allocator->usable_blocks.remove(block);
allocator->empty_blocks[allocator->empty_block_count++] = block;
mprotect(block, ChunkedBlock::block_size, PROT_NONE);
madvise(block, ChunkedBlock::block_size, MADV_SET_VOLATILE);
return;
}
dbgln_if(MALLOC_DEBUG, "Releasing block {:p} for size class {}", block, good_size);
g_malloc_stats.number_of_frees++;
allocator->usable_blocks.remove(block);
--allocator->block_count;
os_free(block, ChunkedBlock::block_size);
}
}
[[gnu::flatten]] void* malloc(size_t size)
{
void* ptr = malloc_impl(size);
if (s_profiling)
perf_event(PERF_EVENT_MALLOC, size, reinterpret_cast<FlatPtr>(ptr));
return ptr;
}
[[gnu::flatten]] void free(void* ptr)
{
if (s_profiling)
perf_event(PERF_EVENT_FREE, reinterpret_cast<FlatPtr>(ptr), 0);
ue_notify_free(ptr);
free_impl(ptr);
}
void* calloc(size_t count, size_t size)
{
size_t new_size = count * size;
auto* ptr = malloc(new_size);
if (ptr)
memset(ptr, 0, new_size);
return ptr;
}
size_t malloc_size(void* ptr)
{
if (!ptr)
return 0;
LOCKER(malloc_lock());
void* page_base = (void*)((FlatPtr)ptr & ChunkedBlock::block_mask);
auto* header = (const CommonHeader*)page_base;
auto size = header->m_size;
if (header->m_magic == MAGIC_BIGALLOC_HEADER)
size -= sizeof(CommonHeader);
else
VERIFY(header->m_magic == MAGIC_PAGE_HEADER);
return size;
}
void* realloc(void* ptr, size_t size)
{
if (!ptr)
return malloc(size);
if (!size)
return nullptr;
LOCKER(malloc_lock());
auto existing_allocation_size = malloc_size(ptr);
if (size <= existing_allocation_size) {
ue_notify_realloc(ptr, size);
return ptr;
}
auto* new_ptr = malloc(size);
if (new_ptr) {
memcpy(new_ptr, ptr, min(existing_allocation_size, size));
free(ptr);
}
return new_ptr;
}
void __malloc_init()
{
new (&malloc_lock()) LibThread::Lock();
if (secure_getenv("LIBC_NOSCRUB_MALLOC"))
s_scrub_malloc = false;
if (secure_getenv("LIBC_NOSCRUB_FREE"))
s_scrub_free = false;
if (secure_getenv("LIBC_LOG_MALLOC"))
s_log_malloc = true;
if (secure_getenv("LIBC_PROFILE_MALLOC"))
s_profiling = true;
for (size_t i = 0; i < num_size_classes; ++i) {
new (&allocators()[i]) Allocator();
allocators()[i].size = size_classes[i];
}
new (&big_allocators()[0])(BigAllocator);
}
void serenity_dump_malloc_stats()
{
dbgln("# malloc() calls: {}", g_malloc_stats.number_of_malloc_calls);
dbgln();
dbgln("big alloc hits: {}", g_malloc_stats.number_of_big_allocator_hits);
dbgln("big alloc hits that were purged: {}", g_malloc_stats.number_of_big_allocator_purge_hits);
dbgln("big allocs: {}", g_malloc_stats.number_of_big_allocs);
dbgln();
dbgln("empty block hits: {}", g_malloc_stats.number_of_empty_block_hits);
dbgln("empty block hits that were purged: {}", g_malloc_stats.number_of_empty_block_purge_hits);
dbgln("block allocs: {}", g_malloc_stats.number_of_block_allocs);
dbgln("filled blocks: {}", g_malloc_stats.number_of_blocks_full);
dbgln();
dbgln("# free() calls: {}", g_malloc_stats.number_of_free_calls);
dbgln();
dbgln("big alloc keeps: {}", g_malloc_stats.number_of_big_allocator_keeps);
dbgln("big alloc frees: {}", g_malloc_stats.number_of_big_allocator_frees);
dbgln();
dbgln("full block frees: {}", g_malloc_stats.number_of_freed_full_blocks);
dbgln("number of keeps: {}", g_malloc_stats.number_of_keeps);
dbgln("number of frees: {}", g_malloc_stats.number_of_frees);
}
}