core: hle: kernel: k_memory_block_manager: Update.

This commit is contained in:
bunnei 2022-09-09 21:12:37 -07:00
parent 57a77e9ff4
commit 2bb41cffca
2 changed files with 397 additions and 191 deletions

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@ -2,221 +2,336 @@
// SPDX-License-Identifier: GPL-2.0-or-later // SPDX-License-Identifier: GPL-2.0-or-later
#include "core/hle/kernel/k_memory_block_manager.h" #include "core/hle/kernel/k_memory_block_manager.h"
#include "core/hle/kernel/memory_types.h"
namespace Kernel { namespace Kernel {
KMemoryBlockManager::KMemoryBlockManager(VAddr start_addr_, VAddr end_addr_) KMemoryBlockManager::KMemoryBlockManager() = default;
: start_addr{start_addr_}, end_addr{end_addr_} {
const u64 num_pages{(end_addr - start_addr) / PageSize}; Result KMemoryBlockManager::Initialize(VAddr st, VAddr nd, KMemoryBlockSlabManager* slab_manager) {
memory_block_tree.emplace_back(start_addr, num_pages, KMemoryState::Free, // Allocate a block to encapsulate the address space, insert it into the tree.
KMemoryPermission::None, KMemoryAttribute::None); KMemoryBlock* start_block = slab_manager->Allocate();
R_UNLESS(start_block != nullptr, ResultOutOfResource);
// Set our start and end.
m_start_address = st;
m_end_address = nd;
ASSERT(Common::IsAligned(m_start_address, PageSize));
ASSERT(Common::IsAligned(m_end_address, PageSize));
// Initialize and insert the block.
start_block->Initialize(m_start_address, (m_end_address - m_start_address) / PageSize,
KMemoryState::Free, KMemoryPermission::None, KMemoryAttribute::None);
m_memory_block_tree.insert(*start_block);
return ResultSuccess;
} }
KMemoryBlockManager::iterator KMemoryBlockManager::FindIterator(VAddr addr) { void KMemoryBlockManager::Finalize(KMemoryBlockSlabManager* slab_manager,
auto node{memory_block_tree.begin()}; HostUnmapCallback&& host_unmap_callback) {
while (node != end()) { // Erase every block until we have none left.
const VAddr node_end_addr{node->GetNumPages() * PageSize + node->GetAddress()}; auto it = m_memory_block_tree.begin();
if (node->GetAddress() <= addr && node_end_addr - 1 >= addr) { while (it != m_memory_block_tree.end()) {
return node; KMemoryBlock* block = std::addressof(*it);
} it = m_memory_block_tree.erase(it);
node = std::next(node); slab_manager->Free(block);
} host_unmap_callback(block->GetAddress(), block->GetSize());
return end();
} }
VAddr KMemoryBlockManager::FindFreeArea(VAddr region_start, std::size_t region_num_pages, ASSERT(m_memory_block_tree.empty());
std::size_t num_pages, std::size_t align,
std::size_t offset, std::size_t guard_pages) {
if (num_pages == 0) {
return {};
} }
const VAddr region_end{region_start + region_num_pages * PageSize}; VAddr KMemoryBlockManager::FindFreeArea(VAddr region_start, size_t region_num_pages,
const VAddr region_last{region_end - 1}; size_t num_pages, size_t alignment, size_t offset,
for (auto it{FindIterator(region_start)}; it != memory_block_tree.cend(); it++) { size_t guard_pages) const {
const auto info{it->GetMemoryInfo()}; if (num_pages > 0) {
const VAddr region_end = region_start + region_num_pages * PageSize;
const VAddr region_last = region_end - 1;
for (const_iterator it = this->FindIterator(region_start); it != m_memory_block_tree.cend();
it++) {
const KMemoryInfo info = it->GetMemoryInfo();
if (region_last < info.GetAddress()) { if (region_last < info.GetAddress()) {
break; break;
} }
if (info.m_state != KMemoryState::Free) {
if (info.state != KMemoryState::Free) {
continue; continue;
} }
VAddr area{(info.GetAddress() <= region_start) ? region_start : info.GetAddress()}; VAddr area = (info.GetAddress() <= region_start) ? region_start : info.GetAddress();
area += guard_pages * PageSize; area += guard_pages * PageSize;
const VAddr offset_area{Common::AlignDown(area, align) + offset}; const VAddr offset_area = Common::AlignDown(area, alignment) + offset;
area = (area <= offset_area) ? offset_area : offset_area + align; area = (area <= offset_area) ? offset_area : offset_area + alignment;
const VAddr area_end{area + num_pages * PageSize + guard_pages * PageSize}; const VAddr area_end = area + num_pages * PageSize + guard_pages * PageSize;
const VAddr area_last{area_end - 1}; const VAddr area_last = area_end - 1;
if (info.GetAddress() <= area && area < area_last && area_last <= region_last && if (info.GetAddress() <= area && area < area_last && area_last <= region_last &&
area_last <= info.GetLastAddress()) { area_last <= info.GetLastAddress()) {
return area; return area;
} }
} }
}
return {}; return {};
} }
void KMemoryBlockManager::Update(VAddr addr, std::size_t num_pages, KMemoryState prev_state, void KMemoryBlockManager::CoalesceForUpdate(KMemoryBlockManagerUpdateAllocator* allocator,
KMemoryPermission prev_perm, KMemoryAttribute prev_attribute, VAddr address, size_t num_pages) {
// Find the iterator now that we've updated.
iterator it = this->FindIterator(address);
if (address != m_start_address) {
it--;
}
// Coalesce blocks that we can.
while (true) {
iterator prev = it++;
if (it == m_memory_block_tree.end()) {
break;
}
if (prev->CanMergeWith(*it)) {
KMemoryBlock* block = std::addressof(*it);
m_memory_block_tree.erase(it);
prev->Add(*block);
allocator->Free(block);
it = prev;
}
if (address + num_pages * PageSize < it->GetMemoryInfo().GetEndAddress()) {
break;
}
}
}
void KMemoryBlockManager::Update(KMemoryBlockManagerUpdateAllocator* allocator, VAddr address,
size_t num_pages, KMemoryState state, KMemoryPermission perm,
KMemoryAttribute attr,
KMemoryBlockDisableMergeAttribute set_disable_attr,
KMemoryBlockDisableMergeAttribute clear_disable_attr) {
// Ensure for auditing that we never end up with an invalid tree.
KScopedMemoryBlockManagerAuditor auditor(this);
ASSERT(Common::IsAligned(address, PageSize));
ASSERT((attr & (KMemoryAttribute::IpcLocked | KMemoryAttribute::DeviceShared)) ==
KMemoryAttribute::None);
VAddr cur_address = address;
size_t remaining_pages = num_pages;
iterator it = this->FindIterator(address);
while (remaining_pages > 0) {
const size_t remaining_size = remaining_pages * PageSize;
KMemoryInfo cur_info = it->GetMemoryInfo();
if (it->HasProperties(state, perm, attr)) {
// If we already have the right properties, just advance.
if (cur_address + remaining_size < cur_info.GetEndAddress()) {
remaining_pages = 0;
cur_address += remaining_size;
} else {
remaining_pages =
(cur_address + remaining_size - cur_info.GetEndAddress()) / PageSize;
cur_address = cur_info.GetEndAddress();
}
} else {
// If we need to, create a new block before and insert it.
if (cur_info.GetAddress() != cur_address) {
KMemoryBlock* new_block = allocator->Allocate();
it->Split(new_block, cur_address);
it = m_memory_block_tree.insert(*new_block);
it++;
cur_info = it->GetMemoryInfo();
cur_address = cur_info.GetAddress();
}
// If we need to, create a new block after and insert it.
if (cur_info.GetSize() > remaining_size) {
KMemoryBlock* new_block = allocator->Allocate();
it->Split(new_block, cur_address + remaining_size);
it = m_memory_block_tree.insert(*new_block);
cur_info = it->GetMemoryInfo();
}
// Update block state.
it->Update(state, perm, attr, cur_address == address, static_cast<u8>(set_disable_attr),
static_cast<u8>(clear_disable_attr));
cur_address += cur_info.GetSize();
remaining_pages -= cur_info.GetNumPages();
}
it++;
}
this->CoalesceForUpdate(allocator, address, num_pages);
}
void KMemoryBlockManager::UpdateIfMatch(KMemoryBlockManagerUpdateAllocator* allocator,
VAddr address, size_t num_pages, KMemoryState test_state,
KMemoryPermission test_perm, KMemoryAttribute test_attr,
KMemoryState state, KMemoryPermission perm, KMemoryState state, KMemoryPermission perm,
KMemoryAttribute attribute) { KMemoryAttribute attr) {
const VAddr update_end_addr{addr + num_pages * PageSize}; // Ensure for auditing that we never end up with an invalid tree.
iterator node{memory_block_tree.begin()}; KScopedMemoryBlockManagerAuditor auditor(this);
ASSERT(Common::IsAligned(address, PageSize));
ASSERT((attr & (KMemoryAttribute::IpcLocked | KMemoryAttribute::DeviceShared)) ==
KMemoryAttribute::None);
prev_attribute |= KMemoryAttribute::IpcAndDeviceMapped; VAddr cur_address = address;
size_t remaining_pages = num_pages;
iterator it = this->FindIterator(address);
while (node != memory_block_tree.end()) { while (remaining_pages > 0) {
KMemoryBlock* block{&(*node)}; const size_t remaining_size = remaining_pages * PageSize;
iterator next_node{std::next(node)}; KMemoryInfo cur_info = it->GetMemoryInfo();
const VAddr cur_addr{block->GetAddress()}; if (it->HasProperties(test_state, test_perm, test_attr) &&
const VAddr cur_end_addr{block->GetNumPages() * PageSize + cur_addr}; !it->HasProperties(state, perm, attr)) {
// If we need to, create a new block before and insert it.
if (cur_info.GetAddress() != cur_address) {
KMemoryBlock* new_block = allocator->Allocate();
if (addr < cur_end_addr && cur_addr < update_end_addr) { it->Split(new_block, cur_address);
if (!block->HasProperties(prev_state, prev_perm, prev_attribute)) { it = m_memory_block_tree.insert(*new_block);
node = next_node; it++;
continue;
cur_info = it->GetMemoryInfo();
cur_address = cur_info.GetAddress();
} }
iterator new_node{node}; // If we need to, create a new block after and insert it.
if (addr > cur_addr) { if (cur_info.GetSize() > remaining_size) {
memory_block_tree.insert(node, block->Split(addr)); KMemoryBlock* new_block = allocator->Allocate();
it->Split(new_block, cur_address + remaining_size);
it = m_memory_block_tree.insert(*new_block);
cur_info = it->GetMemoryInfo();
} }
if (update_end_addr < cur_end_addr) { // Update block state.
new_node = memory_block_tree.insert(node, block->Split(update_end_addr)); it->Update(state, perm, attr, false, 0, 0);
} cur_address += cur_info.GetSize();
remaining_pages -= cur_info.GetNumPages();
new_node->Update(state, perm, attribute); } else {
// If we already have the right properties, just advance.
MergeAdjacent(new_node, next_node); if (cur_address + remaining_size < cur_info.GetEndAddress()) {
} remaining_pages = 0;
cur_address += remaining_size;
if (cur_end_addr - 1 >= update_end_addr - 1) { } else {
break; remaining_pages =
} (cur_address + remaining_size - cur_info.GetEndAddress()) / PageSize;
cur_address = cur_info.GetEndAddress();
node = next_node;
} }
} }
it++;
void KMemoryBlockManager::Update(VAddr addr, std::size_t num_pages, KMemoryState state,
KMemoryPermission perm, KMemoryAttribute attribute) {
const VAddr update_end_addr{addr + num_pages * PageSize};
iterator node{memory_block_tree.begin()};
while (node != memory_block_tree.end()) {
KMemoryBlock* block{&(*node)};
iterator next_node{std::next(node)};
const VAddr cur_addr{block->GetAddress()};
const VAddr cur_end_addr{block->GetNumPages() * PageSize + cur_addr};
if (addr < cur_end_addr && cur_addr < update_end_addr) {
iterator new_node{node};
if (addr > cur_addr) {
memory_block_tree.insert(node, block->Split(addr));
} }
if (update_end_addr < cur_end_addr) { this->CoalesceForUpdate(allocator, address, num_pages);
new_node = memory_block_tree.insert(node, block->Split(update_end_addr));
} }
new_node->Update(state, perm, attribute); void KMemoryBlockManager::UpdateLock(KMemoryBlockManagerUpdateAllocator* allocator, VAddr address,
size_t num_pages, MemoryBlockLockFunction lock_func,
MergeAdjacent(new_node, next_node);
}
if (cur_end_addr - 1 >= update_end_addr - 1) {
break;
}
node = next_node;
}
}
void KMemoryBlockManager::UpdateLock(VAddr addr, std::size_t num_pages, LockFunc&& lock_func,
KMemoryPermission perm) { KMemoryPermission perm) {
const VAddr update_end_addr{addr + num_pages * PageSize}; // Ensure for auditing that we never end up with an invalid tree.
iterator node{memory_block_tree.begin()}; KScopedMemoryBlockManagerAuditor auditor(this);
ASSERT(Common::IsAligned(address, PageSize));
while (node != memory_block_tree.end()) { VAddr cur_address = address;
KMemoryBlock* block{&(*node)}; size_t remaining_pages = num_pages;
iterator next_node{std::next(node)}; iterator it = this->FindIterator(address);
const VAddr cur_addr{block->GetAddress()};
const VAddr cur_end_addr{block->GetNumPages() * PageSize + cur_addr};
if (addr < cur_end_addr && cur_addr < update_end_addr) { const VAddr end_address = address + (num_pages * PageSize);
iterator new_node{node};
if (addr > cur_addr) { while (remaining_pages > 0) {
memory_block_tree.insert(node, block->Split(addr)); const size_t remaining_size = remaining_pages * PageSize;
KMemoryInfo cur_info = it->GetMemoryInfo();
// If we need to, create a new block before and insert it.
if (cur_info.m_address != cur_address) {
KMemoryBlock* new_block = allocator->Allocate();
it->Split(new_block, cur_address);
it = m_memory_block_tree.insert(*new_block);
it++;
cur_info = it->GetMemoryInfo();
cur_address = cur_info.GetAddress();
} }
if (update_end_addr < cur_end_addr) { if (cur_info.GetSize() > remaining_size) {
new_node = memory_block_tree.insert(node, block->Split(update_end_addr)); // If we need to, create a new block after and insert it.
KMemoryBlock* new_block = allocator->Allocate();
it->Split(new_block, cur_address + remaining_size);
it = m_memory_block_tree.insert(*new_block);
cur_info = it->GetMemoryInfo();
} }
lock_func(new_node, perm); // Call the locked update function.
(std::addressof(*it)->*lock_func)(perm, cur_info.GetAddress() == address,
MergeAdjacent(new_node, next_node); cur_info.GetEndAddress() == end_address);
cur_address += cur_info.GetSize();
remaining_pages -= cur_info.GetNumPages();
it++;
} }
if (cur_end_addr - 1 >= update_end_addr - 1) { this->CoalesceForUpdate(allocator, address, num_pages);
break;
} }
node = next_node; // Debug.
bool KMemoryBlockManager::CheckState() const {
// Loop over every block, ensuring that we are sorted and coalesced.
auto it = m_memory_block_tree.cbegin();
auto prev = it++;
while (it != m_memory_block_tree.cend()) {
const KMemoryInfo prev_info = prev->GetMemoryInfo();
const KMemoryInfo cur_info = it->GetMemoryInfo();
// Sequential blocks which can be merged should be merged.
if (prev->CanMergeWith(*it)) {
return false;
}
// Sequential blocks should be sequential.
if (prev_info.GetEndAddress() != cur_info.GetAddress()) {
return false;
}
// If the block is ipc locked, it must have a count.
if ((cur_info.m_attribute & KMemoryAttribute::IpcLocked) != KMemoryAttribute::None &&
cur_info.m_ipc_lock_count == 0) {
return false;
}
// If the block is device shared, it must have a count.
if ((cur_info.m_attribute & KMemoryAttribute::DeviceShared) != KMemoryAttribute::None &&
cur_info.m_device_use_count == 0) {
return false;
}
// Advance the iterator.
prev = it++;
}
// Our loop will miss checking the last block, potentially, so check it.
if (prev != m_memory_block_tree.cend()) {
const KMemoryInfo prev_info = prev->GetMemoryInfo();
// If the block is ipc locked, it must have a count.
if ((prev_info.m_attribute & KMemoryAttribute::IpcLocked) != KMemoryAttribute::None &&
prev_info.m_ipc_lock_count == 0) {
return false;
}
// If the block is device shared, it must have a count.
if ((prev_info.m_attribute & KMemoryAttribute::DeviceShared) != KMemoryAttribute::None &&
prev_info.m_device_use_count == 0) {
return false;
} }
} }
void KMemoryBlockManager::IterateForRange(VAddr start, VAddr end, IterateFunc&& func) { return true;
const_iterator it{FindIterator(start)};
KMemoryInfo info{};
do {
info = it->GetMemoryInfo();
func(info);
it = std::next(it);
} while (info.addr + info.size - 1 < end - 1 && it != cend());
}
void KMemoryBlockManager::MergeAdjacent(iterator it, iterator& next_it) {
KMemoryBlock* block{&(*it)};
auto EraseIt = [&](const iterator it_to_erase) {
if (next_it == it_to_erase) {
next_it = std::next(next_it);
}
memory_block_tree.erase(it_to_erase);
};
if (it != memory_block_tree.begin()) {
KMemoryBlock* prev{&(*std::prev(it))};
if (block->HasSameProperties(*prev)) {
const iterator prev_it{std::prev(it)};
prev->Add(block->GetNumPages());
EraseIt(it);
it = prev_it;
block = prev;
}
}
if (it != cend()) {
const KMemoryBlock* const next{&(*std::next(it))};
if (block->HasSameProperties(*next)) {
block->Add(next->GetNumPages());
EraseIt(std::next(it));
}
}
} }
} // namespace Kernel } // namespace Kernel

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@ -4,63 +4,154 @@
#pragma once #pragma once
#include <functional> #include <functional>
#include <list>
#include "common/common_funcs.h"
#include "common/common_types.h" #include "common/common_types.h"
#include "core/hle/kernel/k_dynamic_resource_manager.h"
#include "core/hle/kernel/k_memory_block.h" #include "core/hle/kernel/k_memory_block.h"
namespace Kernel { namespace Kernel {
class KMemoryBlockManagerUpdateAllocator {
public:
static constexpr size_t MaxBlocks = 2;
private:
KMemoryBlock* m_blocks[MaxBlocks];
size_t m_index;
KMemoryBlockSlabManager* m_slab_manager;
private:
Result Initialize(size_t num_blocks) {
// Check num blocks.
ASSERT(num_blocks <= MaxBlocks);
// Set index.
m_index = MaxBlocks - num_blocks;
// Allocate the blocks.
for (size_t i = 0; i < num_blocks && i < MaxBlocks; ++i) {
m_blocks[m_index + i] = m_slab_manager->Allocate();
R_UNLESS(m_blocks[m_index + i] != nullptr, ResultOutOfResource);
}
return ResultSuccess;
}
public:
KMemoryBlockManagerUpdateAllocator(Result* out_result, KMemoryBlockSlabManager* sm,
size_t num_blocks = MaxBlocks)
: m_blocks(), m_index(MaxBlocks), m_slab_manager(sm) {
*out_result = this->Initialize(num_blocks);
}
~KMemoryBlockManagerUpdateAllocator() {
for (const auto& block : m_blocks) {
if (block != nullptr) {
m_slab_manager->Free(block);
}
}
}
KMemoryBlock* Allocate() {
ASSERT(m_index < MaxBlocks);
ASSERT(m_blocks[m_index] != nullptr);
KMemoryBlock* block = nullptr;
std::swap(block, m_blocks[m_index++]);
return block;
}
void Free(KMemoryBlock* block) {
ASSERT(m_index <= MaxBlocks);
ASSERT(block != nullptr);
if (m_index == 0) {
m_slab_manager->Free(block);
} else {
m_blocks[--m_index] = block;
}
}
};
class KMemoryBlockManager final { class KMemoryBlockManager final {
public: public:
using MemoryBlockTree = std::list<KMemoryBlock>; using MemoryBlockTree =
Common::IntrusiveRedBlackTreeBaseTraits<KMemoryBlock>::TreeType<KMemoryBlock>;
using MemoryBlockLockFunction = void (KMemoryBlock::*)(KMemoryPermission new_perm, bool left,
bool right);
using iterator = MemoryBlockTree::iterator; using iterator = MemoryBlockTree::iterator;
using const_iterator = MemoryBlockTree::const_iterator; using const_iterator = MemoryBlockTree::const_iterator;
public: public:
KMemoryBlockManager(VAddr start_addr_, VAddr end_addr_); KMemoryBlockManager();
using HostUnmapCallback = std::function<void(VAddr, u64)>;
Result Initialize(VAddr st, VAddr nd, KMemoryBlockSlabManager* slab_manager);
void Finalize(KMemoryBlockSlabManager* slab_manager, HostUnmapCallback&& host_unmap_callback);
iterator end() { iterator end() {
return memory_block_tree.end(); return m_memory_block_tree.end();
} }
const_iterator end() const { const_iterator end() const {
return memory_block_tree.end(); return m_memory_block_tree.end();
} }
const_iterator cend() const { const_iterator cend() const {
return memory_block_tree.cend(); return m_memory_block_tree.cend();
} }
iterator FindIterator(VAddr addr); VAddr FindFreeArea(VAddr region_start, size_t region_num_pages, size_t num_pages,
size_t alignment, size_t offset, size_t guard_pages) const;
VAddr FindFreeArea(VAddr region_start, std::size_t region_num_pages, std::size_t num_pages, void Update(KMemoryBlockManagerUpdateAllocator* allocator, VAddr address, size_t num_pages,
std::size_t align, std::size_t offset, std::size_t guard_pages); KMemoryState state, KMemoryPermission perm, KMemoryAttribute attr,
KMemoryBlockDisableMergeAttribute set_disable_attr,
KMemoryBlockDisableMergeAttribute clear_disable_attr);
void UpdateLock(KMemoryBlockManagerUpdateAllocator* allocator, VAddr address, size_t num_pages,
MemoryBlockLockFunction lock_func, KMemoryPermission perm);
void Update(VAddr addr, std::size_t num_pages, KMemoryState prev_state, void UpdateIfMatch(KMemoryBlockManagerUpdateAllocator* allocator, VAddr address,
KMemoryPermission prev_perm, KMemoryAttribute prev_attribute, KMemoryState state, size_t num_pages, KMemoryState test_state, KMemoryPermission test_perm,
KMemoryPermission perm, KMemoryAttribute attribute); KMemoryAttribute test_attr, KMemoryState state, KMemoryPermission perm,
KMemoryAttribute attr);
void Update(VAddr addr, std::size_t num_pages, KMemoryState state, iterator FindIterator(VAddr address) const {
KMemoryPermission perm = KMemoryPermission::None, return m_memory_block_tree.find(KMemoryBlock(
KMemoryAttribute attribute = KMemoryAttribute::None); address, 1, KMemoryState::Free, KMemoryPermission::None, KMemoryAttribute::None));
}
using LockFunc = std::function<void(iterator, KMemoryPermission)>; const KMemoryBlock* FindBlock(VAddr address) const {
void UpdateLock(VAddr addr, std::size_t num_pages, LockFunc&& lock_func, if (const_iterator it = this->FindIterator(address); it != m_memory_block_tree.end()) {
KMemoryPermission perm); return std::addressof(*it);
}
using IterateFunc = std::function<void(const KMemoryInfo&)>; return nullptr;
void IterateForRange(VAddr start, VAddr end, IterateFunc&& func); }
KMemoryBlock& FindBlock(VAddr addr) { // Debug.
return *FindIterator(addr); bool CheckState() const;
private:
void CoalesceForUpdate(KMemoryBlockManagerUpdateAllocator* allocator, VAddr address,
size_t num_pages);
MemoryBlockTree m_memory_block_tree;
VAddr m_start_address{};
VAddr m_end_address{};
};
class KScopedMemoryBlockManagerAuditor {
public:
explicit KScopedMemoryBlockManagerAuditor(KMemoryBlockManager* m) : m_manager(m) {
ASSERT(m_manager->CheckState());
}
explicit KScopedMemoryBlockManagerAuditor(KMemoryBlockManager& m)
: KScopedMemoryBlockManagerAuditor(std::addressof(m)) {}
~KScopedMemoryBlockManagerAuditor() {
ASSERT(m_manager->CheckState());
} }
private: private:
void MergeAdjacent(iterator it, iterator& next_it); KMemoryBlockManager* m_manager;
[[maybe_unused]] const VAddr start_addr;
[[maybe_unused]] const VAddr end_addr;
MemoryBlockTree memory_block_tree;
}; };
} // namespace Kernel } // namespace Kernel