}
};
-typedef std::multiset<free_heap_block*, block_size_compare> large_block_set;
-
-struct free_list {
- std::vector<free_heap_block*> small_blocks[free_list_count];
- large_block_set large_blocks;
- cell free_block_count;
- cell free_space;
-
- void clear_free_list();
- void initial_free_list(cell start, cell end, cell occupied);
- void add_to_free_list(free_heap_block* block);
- free_heap_block* find_free_block(cell size);
- free_heap_block* split_free_block(free_heap_block* block, cell size);
- bool can_allot_p(cell size);
- cell largest_free_block();
-};
-
struct allocator_room {
cell size;
cell occupied_space;
};
template <typename Block> struct free_list_allocator {
- cell size;
+ // Region of memory managed by this free list allocator.
cell start;
cell end;
- free_list free_blocks;
+ cell size;
+
+ // Stores the free blocks
+ std::vector<free_heap_block*> small_blocks[free_list_count];
+ std::multiset<free_heap_block*, block_size_compare> large_blocks;
+ cell free_block_count;
+ cell free_space;
+
mark_bits state;
+ // Initializing & freeing
free_list_allocator(cell size, cell start);
void initial_free_list(cell occupied);
+ void clear_free_list();
+ void add_to_free_list(free_heap_block* block);
+ void free(Block* block);
+
+ // Allocating
+ free_heap_block* find_free_block(cell size);
+ free_heap_block* split_free_block(free_heap_block* block, cell size);
+ Block* allot(cell size);
+
+ // Data
bool contains_p(Block* block);
bool can_allot_p(cell size);
- Block* allot(cell size);
- void free(Block* block);
cell occupied_space();
- cell free_space();
cell largest_free_block();
- cell free_block_count();
+ allocator_room as_allocator_room();
+
+ // Iteration
void sweep();
template <typename Iterator> void sweep(Iterator& iter);
template <typename Iterator, typename Fixup>
void compact(Iterator& iter, Fixup fixup, const Block** finger);
template <typename Iterator, typename Fixup>
void iterate(Iterator& iter, Fixup fixup);
- template <typename Iterator> void iterate(Iterator& iter);
- allocator_room as_allocator_room();
};
template <typename Block>
-free_list_allocator<Block>::free_list_allocator(cell size, cell start)
- : size(size),
- start(start),
- end(start + size),
- state(mark_bits(size, start)) {
- initial_free_list(0);
+void free_list_allocator<Block>::clear_free_list() {
+ for (cell i = 0; i < free_list_count; i++)
+ small_blocks[i].clear();
+ large_blocks.clear();
+ free_block_count = 0;
+ free_space = 0;
+}
+
+template <typename Block>
+void free_list_allocator<Block>::add_to_free_list(free_heap_block* block) {
+ cell size = block->size();
+
+ free_block_count++;
+ free_space += size;
+
+ if (size < free_list_count * data_alignment)
+ small_blocks[size / data_alignment].push_back(block);
+ else
+ large_blocks.insert(block);
}
template <typename Block>
void free_list_allocator<Block>::initial_free_list(cell occupied) {
- free_blocks.initial_free_list(start, end, occupied);
+ clear_free_list();
+ if (occupied != end - start) {
+ free_heap_block* last_block = (free_heap_block*)(start + occupied);
+ last_block->make_free(end - (cell)last_block);
+ add_to_free_list(last_block);
+ }
+}
+
+template <typename Block>
+free_list_allocator<Block>::free_list_allocator(cell size, cell start)
+ : start(start),
+ end(start + size),
+ size(size),
+ state(mark_bits(size, start)) {
+ initial_free_list(0);
}
template <typename Block>
template <typename Block>
bool free_list_allocator<Block>::can_allot_p(cell size) {
- return free_blocks.can_allot_p(size);
+ return largest_free_block() >= std::max(size, allocation_page_size);
+}
+
+template <typename Block>
+free_heap_block* free_list_allocator<Block>::split_free_block(
+ free_heap_block* block,
+ cell size) {
+ if (block->size() != size) {
+ // split the block in two
+ free_heap_block* split = (free_heap_block*)((cell)block + size);
+ split->make_free(block->size() - size);
+ block->make_free(size);
+ add_to_free_list(split);
+ }
+
+ return block;
}
-template <typename Block> Block* free_list_allocator<Block>::allot(cell size) {
+template <typename Block>
+free_heap_block* free_list_allocator<Block>::find_free_block(cell size) {
+ // Check small free lists
+ cell bucket = size / data_alignment;
+ if (bucket < free_list_count) {
+ std::vector<free_heap_block*>& blocks = small_blocks[bucket];
+ if (blocks.size() == 0) {
+ // Round up to a multiple of 'size'
+ cell large_block_size = ((allocation_page_size + size - 1) / size) * size;
+
+ // Allocate a block this big
+ free_heap_block* large_block = find_free_block(large_block_size);
+ if (!large_block)
+ return NULL;
+
+ large_block = split_free_block(large_block, large_block_size);
+
+ // Split it up into pieces and add each piece back to the free list
+ for (cell offset = 0; offset < large_block_size; offset += size) {
+ free_heap_block* small_block = large_block;
+ large_block = (free_heap_block*)((cell)large_block + size);
+ small_block->make_free(size);
+ add_to_free_list(small_block);
+ }
+ }
+
+ free_heap_block* block = blocks.back();
+ blocks.pop_back();
+
+ free_block_count--;
+ free_space -= block->size();
+
+ return block;
+ } else {
+ // Check large free list
+ free_heap_block key;
+ key.make_free(size);
+ auto iter = large_blocks.lower_bound(&key);
+ auto end = large_blocks.end();
+
+ if (iter != end) {
+ free_heap_block* block = *iter;
+ large_blocks.erase(iter);
+
+ free_block_count--;
+ free_space -= block->size();
+
+ return block;
+ }
+
+ return NULL;
+ }
+}
+
+
+template <typename Block>
+Block* free_list_allocator<Block>::allot(cell size) {
size = align(size, data_alignment);
- free_heap_block* block = free_blocks.find_free_block(size);
+ free_heap_block* block = find_free_block(size);
if (block) {
- block = free_blocks.split_free_block(block, size);
+ block = split_free_block(block, size);
return (Block*)block;
}
return NULL;
}
-template <typename Block> void free_list_allocator<Block>::free(Block* block) {
+template <typename Block>
+void free_list_allocator<Block>::free(Block* block) {
free_heap_block* free_block = (free_heap_block*)block;
free_block->make_free(block->size());
- free_blocks.add_to_free_list(free_block);
+ add_to_free_list(free_block);
}
-template <typename Block> cell free_list_allocator<Block>::free_space() {
- return free_blocks.free_space;
-}
-
-template <typename Block> cell free_list_allocator<Block>::occupied_space() {
- return size - free_blocks.free_space;
+template <typename Block>
+cell free_list_allocator<Block>::occupied_space() {
+ return size - free_space;
}
template <typename Block>
cell free_list_allocator<Block>::largest_free_block() {
- return free_blocks.largest_free_block();
-}
-
-template <typename Block> cell free_list_allocator<Block>::free_block_count() {
- return free_blocks.free_block_count;
+ if (large_blocks.size()) {
+ auto last = large_blocks.rbegin();
+ return (*last)->size();
+ } else {
+ for (int i = free_list_count - 1; i >= 0; i--) {
+ if (small_blocks[i].size())
+ return small_blocks[i].back()->size();
+ }
+ return 0;
+ }
}
template <typename Block>
template <typename Iterator>
void free_list_allocator<Block>::sweep(Iterator& iter) {
- free_blocks.clear_free_list();
+ clear_free_list();
cell start = this->start;
cell end = this->end;
free_heap_block* free_block = (free_heap_block*)start;
free_block->make_free(size);
- free_blocks.add_to_free_list(free_block);
+ add_to_free_list(free_block);
iter((Block*)start, size);
start = start + size;
// Now update the free list; there will be a single free block at
// the end
- free_blocks.initial_free_list(start, end, dest_addr - start);
+ initial_free_list(dest_addr - start);
}
// During compaction we have to be careful and measure object sizes
allocator_room room;
room.size = size;
room.occupied_space = occupied_space();
- room.total_free = free_space();
+ room.total_free = free_space;
room.contiguous_free = largest_free_block();
- room.free_block_count = free_block_count();
+ room.free_block_count = free_block_count;
return room;
}
projects / factor.git / blobdiff