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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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188
vm/free_list.cpp
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@ -1,135 +1,117 @@
#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(); free_block_count = 0;
free_block_count = 0; 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);
{ last_block->make_free(end - (cell) last_block);
free_heap_block *last_block = (free_heap_block *)(start + occupied); add_to_free_list(last_block);
last_block->make_free(end - (cell)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++;
free_space += size; free_space += size;
if(size < free_list_count * data_alignment) if (size < free_list_count * data_alignment)
small_blocks[size / data_alignment].push_back(block); small_blocks[size / data_alignment].push_back(block);
else else
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];
{ if (blocks.size() == 0) {
std::vector<free_heap_block *> &blocks = small_blocks[size / data_alignment]; /* Round up to a multiple of 'size' */
if(blocks.size() == 0) cell large_block_size = ((allocation_page_size + size - 1) / size) * size;
{
/* Round up to a multiple of '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); add_to_free_list(small_block);
add_to_free_list(small_block); }
} }
}
free_heap_block *block = blocks.back(); free_heap_block* block = blocks.back();
blocks.pop_back(); blocks.pop_back();
free_block_count--; free_block_count--;
free_space -= block->size(); free_space -= block->size();
return block; return block;
} } else {
else /* Check large free list */
{ free_heap_block key;
/* Check large free list */ key.make_free(size);
free_heap_block key; large_block_set::iterator iter = large_blocks.lower_bound(&key);
key.make_free(size); large_block_set::iterator end = large_blocks.end();
large_block_set::iterator iter = large_blocks.lower_bound(&key);
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);
free_block_count--; free_block_count--;
free_space -= block->size(); free_space -= block->size();
return block; return block;
} }
return NULL; return NULL;
} }
} }
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); block->make_free(size);
block->make_free(size); add_to_free_list(split);
add_to_free_list(split); }
}
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();
{ return (*last)->size();
large_block_set::reverse_iterator last = large_blocks.rbegin(); } else {
return (*last)->size(); for (int i = free_list_count - 1; i >= 0; i--) {
} if (small_blocks[i].size())
else return small_blocks[i].back()->size();
{ }
for(int i = free_list_count - 1; i >= 0; i--)
{
if(small_blocks[i].size())
return small_blocks[i].back()->size();
}
return 0; return 0;
} }
} }
} }

64
vm/free_list.hpp
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@ -1,54 +1,46 @@
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(); }
}
}; };
typedef std::multiset<free_heap_block *, block_size_compare> large_block_set; typedef std::multiset<free_heap_block*, block_size_compare> large_block_set;
struct free_list { struct free_list {
std::vector<free_heap_block *> small_blocks[free_list_count]; std::vector<free_heap_block*> small_blocks[free_list_count];
large_block_set large_blocks; large_block_set large_blocks;
cell free_block_count; cell free_block_count;
cell free_space; cell free_space;
void clear_free_list(); void clear_free_list();
void initial_free_list(cell start, cell end, cell occupied); void initial_free_list(cell start, cell end, cell occupied);
void add_to_free_list(free_heap_block *block); void add_to_free_list(free_heap_block* block);
free_heap_block *find_free_block(cell size); free_heap_block* find_free_block(cell size);
free_heap_block *split_free_block(free_heap_block *block, cell size); free_heap_block* split_free_block(free_heap_block* block, cell size);
bool can_allot_p(cell size); bool can_allot_p(cell size);
cell largest_free_block(); cell largest_free_block();
}; };
} }