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Make PageDirectory store physical pages in a HashMap.

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This container is really just there to keep a retain on the individual
PhysicalPages for each page table. A HashMap does the job with far greater
space efficiency.
This commit is contained in:
Andreas Kling 2018-12-31 15:10:12 +01:00
parent 193ead94f8
commit edac1d6748
3 changed files with 23 additions and 16 deletions
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13
AK/HashMap.h
View file

@ -70,6 +70,19 @@ public:
void dump() const { m_table.dump(); }
V get(const K& key) const
{
auto it = find(key);
if (it == end())
return V();
return (*it).value;
}
bool contains(const K& key) const
{
return find(key) != end();
}
private:
HashTable<Entry, EntryTraits> m_table;
};

24
Kernel/MemoryManager.cpp
View file

@ -95,29 +95,23 @@ void MemoryManager::initialize_paging()
RetainPtr<PhysicalPage> MemoryManager::allocate_page_table(PageDirectory& page_directory, unsigned index)
{
auto& page_directory_physical_ptr = page_directory.m_physical_pages[index];
ASSERT(!page_directory_physical_ptr);
ASSERT(!page_directory.m_physical_pages.contains(index));
auto physical_page = allocate_physical_page();
if (!physical_page)
return nullptr;
dword address = physical_page->paddr().get();
create_identity_mapping(LinearAddress(address), PAGE_SIZE);
memset((void*)address, 0, PAGE_SIZE);
page_directory.m_physical_pages[index] = move(physical_page);
return page_directory.m_physical_pages[index];
page_directory.m_physical_pages.set(index, physical_page.copyRef());
return physical_page;
}
void MemoryManager::deallocate_page_table(PageDirectory& page_directory, unsigned index)
{
auto& physical_page = page_directory.m_physical_pages[index];
ASSERT(physical_page);
//FIXME: This line is buggy and effectful somehow :(
//ASSERT(!m_free_physical_pages.contains_slow(physical_page));
for (size_t i = 0; i < MM.m_free_physical_pages.size(); ++i) {
ASSERT(MM.m_free_physical_pages[i].ptr() != physical_page.ptr());
}
remove_identity_mapping(LinearAddress(physical_page->paddr().get()), PAGE_SIZE);
page_directory.m_physical_pages[index] = nullptr;
auto it = page_directory.m_physical_pages.find(index);
ASSERT(it != page_directory.m_physical_pages.end());
remove_identity_mapping(LinearAddress((*it).value->paddr().get()), PAGE_SIZE);
page_directory.m_physical_pages.set(index, nullptr);
}
void MemoryManager::remove_identity_mapping(LinearAddress laddr, size_t size)
@ -173,7 +167,7 @@ auto MemoryManager::ensure_pte(PageDirectory& page_directory, LinearAddress ladd
pde.set_user_allowed(true);
pde.set_present(true);
pde.set_writable(true);
page_directory.m_physical_pages[page_directory_index] = move(page_table);
page_directory.m_physical_pages.set(page_directory_index, move(page_table));
}
}
return PageTableEntry(&pde.pageTableBase()[page_table_index]);
@ -803,7 +797,7 @@ PageDirectory::~PageDirectory()
dbgprintf("MM: ~PageDirectory K%x\n", this);
#endif
for (size_t i = 0; i < 1024; ++i) {
auto& page_table = m_physical_pages[i];
auto page_table = m_physical_pages.get(i);
if (!page_table.is_null()) {
#ifdef MM_DEBUG
dbgprintf("MM: deallocating user page table P%x\n", page_table->paddr().get());

2
Kernel/MemoryManager.h
View file

@ -67,7 +67,7 @@ public:
private:
RetainPtr<PhysicalPage> m_directory_page;
RetainPtr<PhysicalPage> m_physical_pages[1024];
HashMap<unsigned, RetainPtr<PhysicalPage>> m_physical_pages;
};
class VMObject : public Retainable<VMObject> {