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VM: Refactor free_list to Factor style

db4
Erik Charlebois 2013-05-11 22:01:24 -04:00
parent 83b69d45f8
commit c0aa1c7b3e
2 changed files with 113 additions and 139 deletions
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60
vm/free_list.cpp
View File

@ -1,10 +1,8 @@
#include "master.hpp" #include "master.hpp"
namespace factor namespace factor {
{
void free_list::clear_free_list() void free_list::clear_free_list() {
{
for (cell i = 0; i < free_list_count; i++) for (cell i = 0; i < free_list_count; i++)
small_blocks[i].clear(); small_blocks[i].clear();
large_blocks.clear(); large_blocks.clear();
@ -12,19 +10,16 @@ void free_list::clear_free_list()
free_space = 0; free_space = 0;
} }
void free_list::initial_free_list(cell start, cell end, cell occupied) void free_list::initial_free_list(cell start, cell end, cell occupied) {
{
clear_free_list(); clear_free_list();
if(occupied != end - start) if (occupied != end - start) {
{
free_heap_block* last_block = (free_heap_block*)(start + occupied); free_heap_block* last_block = (free_heap_block*)(start + occupied);
last_block->make_free(end - (cell) last_block); last_block->make_free(end - (cell) last_block);
add_to_free_list(last_block); add_to_free_list(last_block);
} }
} }
void free_list::add_to_free_list(free_heap_block *block) void free_list::add_to_free_list(free_heap_block* block) {
{
cell size = block->size(); cell size = block->size();
free_block_count++; free_block_count++;
@ -36,26 +31,23 @@ void free_list::add_to_free_list(free_heap_block *block)
large_blocks.insert(block); large_blocks.insert(block);
} }
free_heap_block *free_list::find_free_block(cell size) free_heap_block* free_list::find_free_block(cell size) {
{
/* Check small free lists */ /* Check small free lists */
if(size / data_alignment < free_list_count) if (size / data_alignment < free_list_count) {
{
std::vector<free_heap_block*>& blocks = small_blocks[size / data_alignment]; std::vector<free_heap_block*>& blocks = small_blocks[size / data_alignment];
if(blocks.size() == 0) if (blocks.size() == 0) {
{
/* Round up to a multiple of 'size' */ /* Round up to a multiple of 'size' */
cell large_block_size = ((allocation_page_size + size - 1) / size) * size; cell large_block_size = ((allocation_page_size + size - 1) / size) * size;
/* Allocate a block this big */ /* Allocate a block this big */
free_heap_block* large_block = find_free_block(large_block_size); free_heap_block* large_block = find_free_block(large_block_size);
if(!large_block) return NULL; if (!large_block)
return NULL;
large_block = split_free_block(large_block, large_block_size); large_block = split_free_block(large_block, large_block_size);
/* Split it up into pieces and add each piece back to the free list */ /* Split it up into pieces and add each piece back to the free list */
for(cell offset = 0; offset < large_block_size; offset += size) for (cell offset = 0; offset < large_block_size; offset += size) {
{
free_heap_block* small_block = large_block; free_heap_block* small_block = large_block;
large_block = (free_heap_block*)((cell) large_block + size); large_block = (free_heap_block*)((cell) large_block + size);
small_block->make_free(size); small_block->make_free(size);
@ -70,17 +62,14 @@ free_heap_block *free_list::find_free_block(cell size)
free_space -= block->size(); free_space -= block->size();
return block; return block;
} } else {
else
{
/* Check large free list */ /* Check large free list */
free_heap_block key; free_heap_block key;
key.make_free(size); key.make_free(size);
large_block_set::iterator iter = large_blocks.lower_bound(&key); large_block_set::iterator iter = large_blocks.lower_bound(&key);
large_block_set::iterator end = large_blocks.end(); large_block_set::iterator end = large_blocks.end();
if(iter != end) if (iter != end) {
{
free_heap_block* block = *iter; free_heap_block* block = *iter;
large_blocks.erase(iter); large_blocks.erase(iter);
@ -94,10 +83,9 @@ free_heap_block *free_list::find_free_block(cell size)
} }
} }
free_heap_block *free_list::split_free_block(free_heap_block *block, cell size) free_heap_block* free_list::split_free_block(free_heap_block* block,
{ cell size) {
if(block->size() != size) if (block->size() != size) {
{
/* split the block in two */ /* split the block in two */
free_heap_block* split = (free_heap_block*)((cell) block + size); free_heap_block* split = (free_heap_block*)((cell) block + size);
split->make_free(block->size() - size); split->make_free(block->size() - size);
@ -108,22 +96,16 @@ free_heap_block *free_list::split_free_block(free_heap_block *block, cell size)
return block; return block;
} }
bool free_list::can_allot_p(cell size) bool free_list::can_allot_p(cell size) {
{
return largest_free_block() >= std::max(size, allocation_page_size); return largest_free_block() >= std::max(size, allocation_page_size);
} }
cell free_list::largest_free_block() cell free_list::largest_free_block() {
{ if (large_blocks.size()) {
if(large_blocks.size())
{
large_block_set::reverse_iterator last = large_blocks.rbegin(); large_block_set::reverse_iterator last = large_blocks.rbegin();
return (*last)->size(); return (*last)->size();
} } else {
else for (int i = free_list_count - 1; i >= 0; i--) {
{
for(int i = free_list_count - 1; i >= 0; i--)
{
if (small_blocks[i].size()) if (small_blocks[i].size())
return small_blocks[i].back()->size(); return small_blocks[i].back()->size();
} }

20
vm/free_list.hpp
View File

@ -1,35 +1,27 @@
namespace factor namespace factor {
{
static const cell free_list_count = 32; static const cell free_list_count = 32;
static const cell allocation_page_size = 1024; static const cell allocation_page_size = 1024;
struct free_heap_block struct free_heap_block {
{
cell header; cell header;
bool free_p() const bool free_p() const { return (header & 1) == 1; }
{
return (header & 1) == 1;
}
cell size() const cell size() const {
{
cell size = header & ~7; cell size = header & ~7;
FACTOR_ASSERT(size > 0); FACTOR_ASSERT(size > 0);
return size; return size;
} }
void make_free(cell size) void make_free(cell size) {
{
FACTOR_ASSERT(size > 0); FACTOR_ASSERT(size > 0);
header = size | 1; header = size | 1;
} }
}; };
struct block_size_compare { struct block_size_compare {
bool operator()(free_heap_block *a, free_heap_block *b) const bool operator()(free_heap_block* a, free_heap_block* b) const {
{
return a->size() < b->size(); return a->size() < b->size();
} }
}; };