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LibJS: Use IntrusiveList for Allocator's block lists

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This way we don't need to deal with shifting vector storage, and most
operations are upgraded from O(n) to O(1) :^)
This commit is contained in:
Andreas Kling 2020-10-07 14:04:52 +02:00
parent eeffd5be07
commit c541310e19
Notes: sideshowbarker 2024-07-19 01:59:46 +09:00
3 changed files with 17 additions and 18 deletions
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21
Libraries/LibJS/Heap/Allocator.cpp
View file

@ -42,35 +42,28 @@ Allocator::~Allocator()
Cell* Allocator::allocate_cell(Heap& heap) Cell* Allocator::allocate_cell(Heap& heap)
{ {
if (m_usable_blocks.is_empty()) { if (m_usable_blocks.is_empty()) {
m_usable_blocks.append(HeapBlock::create_with_cell_size(heap, m_cell_size)); auto block = HeapBlock::create_with_cell_size(heap, m_cell_size);
m_usable_blocks.append(*block.leak_ptr());
} }
auto& block = *m_usable_blocks.last(); auto& block = *m_usable_blocks.last();
auto* cell = block.allocate(); auto* cell = block.allocate();
ASSERT(cell); ASSERT(cell);
if (block.is_full()) { if (block.is_full())
m_full_blocks.append(m_usable_blocks.take_last()); m_full_blocks.append(*m_usable_blocks.last());
}
return cell; return cell;
} }
void Allocator::block_did_become_empty(Badge<Heap>, HeapBlock& block) void Allocator::block_did_become_empty(Badge<Heap>, HeapBlock& block)
{ {
bool removed_something = false; block.m_list_node.remove();
removed_something |= m_full_blocks.remove_first_matching([&block](auto& entry) { return entry == &block; }); delete &block;
removed_something |= m_usable_blocks.remove_first_matching([&block](auto& entry) { return entry == &block; });
ASSERT(removed_something);
} }
void Allocator::block_did_become_usable(Badge<Heap>, HeapBlock& block) void Allocator::block_did_become_usable(Badge<Heap>, HeapBlock& block)
{ {
ASSERT(!block.is_full()); ASSERT(!block.is_full());
auto it = m_full_blocks.find([&](auto& entry) { m_usable_blocks.append(block);
return entry == &block;
});
ASSERT(it != m_full_blocks.end());
auto owned_block = m_full_blocks.take(it.index());
m_usable_blocks.append(move(owned_block));
} }
} }

11
Libraries/LibJS/Heap/Allocator.h
View file

@ -26,9 +26,11 @@
#pragma once #pragma once
#include <AK/IntrusiveList.h>
#include <AK/NonnullOwnPtr.h> #include <AK/NonnullOwnPtr.h>
#include <AK/Vector.h> #include <AK/Vector.h>
#include <LibJS/Forward.h> #include <LibJS/Forward.h>
#include <LibJS/Heap/HeapBlock.h>
namespace JS { namespace JS {
@ -45,11 +47,11 @@ public:
IterationDecision for_each_block(Callback callback) IterationDecision for_each_block(Callback callback)
{ {
for (auto& block : m_full_blocks) { for (auto& block : m_full_blocks) {
if (callback(*block) == IterationDecision::Break) if (callback(block) == IterationDecision::Break)
return IterationDecision::Break; return IterationDecision::Break;
} }
for (auto& block : m_usable_blocks) { for (auto& block : m_usable_blocks) {
if (callback(*block) == IterationDecision::Break) if (callback(block) == IterationDecision::Break)
return IterationDecision::Break; return IterationDecision::Break;
} }
return IterationDecision::Continue; return IterationDecision::Continue;
@ -61,8 +63,9 @@ public:
private: private:
const size_t m_cell_size; const size_t m_cell_size;
Vector<NonnullOwnPtr<HeapBlock>> m_full_blocks; typedef IntrusiveList<HeapBlock, &HeapBlock::m_list_node> BlockList;
Vector<NonnullOwnPtr<HeapBlock>> m_usable_blocks; BlockList m_full_blocks;
BlockList m_usable_blocks;
}; };
} }

3
Libraries/LibJS/Heap/HeapBlock.h
View file

@ -26,6 +26,7 @@
#pragma once #pragma once
#include <AK/IntrusiveList.h>
#include <AK/Types.h> #include <AK/Types.h>
#include <LibJS/Forward.h> #include <LibJS/Forward.h>
#include <LibJS/Runtime/Cell.h> #include <LibJS/Runtime/Cell.h>
@ -79,6 +80,8 @@ public:
return cell(cell_index); return cell(cell_index);
} }
IntrusiveListNode m_list_node;
private: private:
HeapBlock(Heap&, size_t cell_size); HeapBlock(Heap&, size_t cell_size);