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LibJS: Recycle up to 64 HeapBlocks to improve performance :^)

This patch adds a BlockAllocator to the GC heap where we now cache up to
64 HeapBlock-sized mmap's that get recycled when allocating HeapBlocks.

This improves test-js runtime performance by ~35%, pretty cool! :^)
This commit is contained in:
Andreas Kling 2021-05-27 19:01:26 +02:00
parent d2149c153c
commit e9081a2644
6 changed files with 101 additions and 8 deletions

View file

@ -0,0 +1,58 @@
/*
* Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Vector.h>
#include <LibJS/Forward.h>
#include <LibJS/Heap/BlockAllocator.h>
#include <LibJS/Heap/HeapBlock.h>
#include <stdlib.h>
#include <sys/mman.h>
namespace JS {
BlockAllocator::BlockAllocator()
{
}
BlockAllocator::~BlockAllocator()
{
for (auto* block : m_blocks) {
if (munmap(block, HeapBlock::block_size) < 0) {
perror("munmap");
VERIFY_NOT_REACHED();
}
}
}
void* BlockAllocator::allocate_block([[maybe_unused]] char const* name)
{
if (!m_blocks.is_empty())
return m_blocks.take_last();
#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);
#else
auto* block = (HeapBlock*)aligned_alloc(HeapBlock::block_size, HeapBlock::block_size);
#endif
VERIFY(block != MAP_FAILED);
return block;
}
void BlockAllocator::deallocate_block(void* block)
{
VERIFY(block);
if (m_blocks.size() >= max_cached_blocks) {
if (munmap(block, HeapBlock::block_size) < 0) {
perror("munmap");
VERIFY_NOT_REACHED();
}
return;
}
m_blocks.append(block);
}
}