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/*
* Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Platform.h>
#include <AK/Random.h>
#include <AK/Vector.h>
#include <LibJS/Heap/BlockAllocator.h>
#include <LibJS/Heap/HeapBlock.h>
#include <sys/mman.h>
#ifdef HAS_ADDRESS_SANITIZER
# include <sanitizer/asan_interface.h>
#endif
namespace JS {
BlockAllocator::BlockAllocator()
{
}
BlockAllocator::~BlockAllocator()
{
for (auto* block : m_blocks) {
ASAN_UNPOISON_MEMORY_REGION(block, HeapBlock::block_size);
#ifdef __serenity__
if (munmap(block, HeapBlock::block_size) < 0) {
perror("munmap");
VERIFY_NOT_REACHED();
}
#else
free(block);
#endif
}
}
void* BlockAllocator::allocate_block([[maybe_unused]] char const* name)
{
if (!m_blocks.is_empty()) {
// To reduce predictability, take a random block from the cache.
size_t random_index = get_random_uniform(m_blocks.size());
auto* block = m_blocks.unstable_take(random_index);
ASAN_UNPOISON_MEMORY_REGION(block, HeapBlock::block_size);
#ifdef __serenity__
if (set_mmap_name(block, HeapBlock::block_size, name) < 0) {
perror("set_mmap_name");
VERIFY_NOT_REACHED();
}
#endif
return block;
}
#ifdef __serenity__
auto* block = (HeapBlock*)serenity_mmap(nullptr, HeapBlock::block_size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_RANDOMIZED | MAP_PRIVATE, 0, 0, HeapBlock::block_size, name);
VERIFY(block != MAP_FAILED);
#else
auto* block = (HeapBlock*)aligned_alloc(HeapBlock::block_size, HeapBlock::block_size);
VERIFY(block);
#endif
return block;
}
void BlockAllocator::deallocate_block(void* block)
{
VERIFY(block);
if (m_blocks.size() >= max_cached_blocks) {
#ifdef __serenity__
if (munmap(block, HeapBlock::block_size) < 0) {
perror("munmap");
VERIFY_NOT_REACHED();
}
#else
free(block);
#endif
return;
}
ASAN_POISON_MEMORY_REGION(block, HeapBlock::block_size);
m_blocks.append(block);
}
}
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