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malloc: Make it possible to recycle big allocation blocks as well.

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This patch makes us recycle up to 8 blocks of 4KB size. This should
probably be extended to handle other sizes.
This commit is contained in:
Andreas Kling 2019-05-14 16:38:06 +02:00
parent 1e0f9d325c
commit 5f7bb9d072
1 changed files with 29 additions and 2 deletions
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31
LibC/malloc.cpp
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@ -1,5 +1,6 @@
#include <AK/Bitmap.h>
#include <AK/InlineLinkedList.h>
#include <AK/Vector.h>
#include <sys/mman.h>
#include <stdlib.h>
#include <assert.h>
@ -16,6 +17,7 @@
#define PAGE_ROUND_UP(x) ((((size_t)(x)) + PAGE_SIZE-1) & (~(PAGE_SIZE-1)))
static const size_t number_of_chunked_blocks_to_keep_around_per_size_class = 32;
static const 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;
@ -82,7 +84,12 @@ struct Allocator {
InlineLinkedList<ChunkedBlock> full_blocks;
};
struct BigAllocator {
Vector<BigAllocationBlock*> blocks;
};
static Allocator g_allocators[num_size_classes];
static BigAllocator g_big_allocators[1];
static Allocator* allocator_for_size(size_t size, size_t& good_size)
{
@ -96,6 +103,14 @@ static Allocator* allocator_for_size(size_t size, size_t& good_size)
return nullptr;
}
static BigAllocator* big_allocator_for_size(size_t size)
{
if (size == 4096)
return &g_big_allocators[0];
return nullptr;
}
extern "C" {
size_t malloc_good_size(size_t size)
@ -130,10 +145,16 @@ void* malloc(size_t size)
auto* allocator = allocator_for_size(size, good_size);
if (!allocator) {
size_t real_size = sizeof(BigAllocationBlock) + size;
size_t real_size = PAGE_ROUND_UP(sizeof(BigAllocationBlock) + size);
if (auto* allocator = big_allocator_for_size(real_size)) {
if (!allocator->blocks.is_empty()) {
auto* block = allocator->blocks.take_last();
return &block->m_slot[0];
}
}
auto* block = (BigAllocationBlock*)os_alloc(real_size);
char buffer[64];
snprintf(buffer, sizeof(buffer), "malloc: BigAllocationBlock(%u)", good_size);
snprintf(buffer, sizeof(buffer), "malloc: BigAllocationBlock(%u)", real_size);
set_mmap_name(block, PAGE_SIZE, buffer);
new (block) BigAllocationBlock(real_size);
return &block->m_slot[0];
@ -184,6 +205,12 @@ void free(void* ptr)
if (magic == MAGIC_BIGALLOC_HEADER) {
auto* block = (BigAllocationBlock*)page_base;
if (auto* allocator = big_allocator_for_size(block->m_size)) {
if (allocator->blocks.size() < number_of_big_blocks_to_keep_around_per_size_class) {
allocator->blocks.append(block);
return;
}
}
os_free(block, block->m_size);
return;
}