ladybird/Kernel/Memory/VirtualRangeAllocator.h
Idan Horowitz 4174fe0156 Kernel: Use find_largest_not_above in VirtualRangeAllocator
Instead of iterating over the regions in the tree which is O(n), we can
just use RedBlackTree's find_largest_not_above method, which is O(logn)
2021-10-07 22:10:45 +02:00

49 lines
1.3 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/RedBlackTree.h>
#include <AK/Traits.h>
#include <Kernel/Locking/Spinlock.h>
#include <Kernel/Memory/VirtualRange.h>
namespace Kernel::Memory {
class VirtualRangeAllocator {
public:
VirtualRangeAllocator();
~VirtualRangeAllocator() = default;
void initialize_with_range(VirtualAddress, size_t);
void initialize_from_parent(VirtualRangeAllocator const&);
KResultOr<VirtualRange> try_allocate_anywhere(size_t, size_t alignment = PAGE_SIZE);
KResultOr<VirtualRange> try_allocate_specific(VirtualAddress, size_t);
KResultOr<VirtualRange> try_allocate_randomized(size_t, size_t alignment);
void deallocate(VirtualRange const&);
void dump() const;
bool contains(VirtualRange const& range) const { return m_total_range.contains(range); }
private:
void carve_from_region(VirtualRange const& from, VirtualRange const&);
RedBlackTree<FlatPtr, VirtualRange> m_available_ranges;
VirtualRange m_total_range;
mutable Spinlock m_lock;
};
}
namespace AK {
template<>
struct Traits<Kernel::Memory::VirtualRange> : public GenericTraits<Kernel::Memory::VirtualRange> {
static constexpr bool is_trivial() { return true; }
};
}