ladybird/Kernel/Memory/PhysicalRegion.h
Andreas Kling ac7ce12123 Kernel: Remove the kmalloc_eternal heap :^)
This was a premature optimization from the early days of SerenityOS.
The eternal heap was a simple bump pointer allocator over a static
byte array. My original idea was to avoid heap fragmentation and improve
data locality, but both ideas were rooted in cargo culting, not data.

We would reserve 4 MiB at boot and only ended up using ~256 KiB, wasting
the rest.

This patch replaces all kmalloc_eternal() usage by regular kmalloc().
2021-12-28 21:02:38 +01:00

58 lines
1.5 KiB
C++

/*
* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/OwnPtr.h>
#include <Kernel/Memory/PhysicalPage.h>
#include <Kernel/Memory/PhysicalZone.h>
namespace Kernel::Memory {
class PhysicalRegion {
AK_MAKE_NONCOPYABLE(PhysicalRegion);
AK_MAKE_NONMOVABLE(PhysicalRegion);
public:
static OwnPtr<PhysicalRegion> try_create(PhysicalAddress lower, PhysicalAddress upper)
{
return adopt_own_if_nonnull(new PhysicalRegion { lower, upper });
}
~PhysicalRegion();
void initialize_zones();
PhysicalAddress lower() const { return m_lower; }
PhysicalAddress upper() const { return m_upper; }
unsigned size() const { return m_pages; }
bool contains(PhysicalAddress paddr) const { return paddr >= m_lower && paddr < m_upper; }
OwnPtr<PhysicalRegion> try_take_pages_from_beginning(unsigned);
RefPtr<PhysicalPage> take_free_page();
NonnullRefPtrVector<PhysicalPage> take_contiguous_free_pages(size_t count);
void return_page(PhysicalAddress);
private:
PhysicalRegion(PhysicalAddress lower, PhysicalAddress upper);
static constexpr size_t large_zone_size = 16 * MiB;
static constexpr size_t small_zone_size = 1 * MiB;
NonnullOwnPtrVector<PhysicalZone> m_zones;
size_t m_large_zones { 0 };
PhysicalZone::List m_usable_zones;
PhysicalZone::List m_full_zones;
PhysicalAddress m_lower;
PhysicalAddress m_upper;
unsigned m_pages { 0 };
};
}