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Kernel: Heap implementation can now give free pages from all of RAM

This commit is contained in:
Bananymous 2023-04-14 23:23:31 +03:00
parent a4568f9263
commit 1aac3a0425
2 changed files with 74 additions and 24 deletions
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19
kernel/include/kernel/Memory/Heap.h
View File

@ -22,12 +22,19 @@ namespace Kernel::Memory
paddr_t reserve_page();
void release_page(paddr_t);
paddr_t start() const { return m_start + m_list_pages * PAGE_SIZE; }
paddr_t end() const { return m_start + m_total_pages * PAGE_SIZE; }
uint64_t pages() const { return m_reservable_pages; }
paddr_t usable_start() const { return m_start + m_list_pages * PAGE_SIZE; }
paddr_t usable_end() const { return m_start + m_total_pages * PAGE_SIZE; }
uint64_t usable_pages() const { return m_reservable_pages; }
private:
paddr_t page_address(uint64_t) const;
struct node
{
node* next;
node* prev;
};
paddr_t page_address(const node*) const;
node* node_address(paddr_t) const;
private:
paddr_t m_start { 0 };
@ -37,8 +44,8 @@ namespace Kernel::Memory
uint64_t m_reservable_pages { 0 };
uint64_t m_list_pages { 0 };
uint64_t* m_free_list { nullptr };
uint64_t* m_used_list { nullptr };
node* m_free_list { nullptr };
node* m_used_list { nullptr };
};
class Heap

79
kernel/kernel/Memory/Heap.cpp
View File

@ -21,44 +21,84 @@ namespace Kernel::Memory
if (auto rem = m_size % PAGE_SIZE)
m_size -= rem;
// FIXME: if total pages is just over multiple of (4096/sizeof(uint64_t)) we might make
// FIXME: if total pages is just over multiple of (PAGE_SIZE / sizeof(node)) we might make
// couple of pages unallocatable
m_total_pages = m_size / PAGE_SIZE;
m_list_pages = BAN::Math::div_round_up<uint64_t>(m_total_pages * sizeof(uint64_t), PAGE_SIZE);
m_list_pages = BAN::Math::div_round_up<uint64_t>(m_total_pages * sizeof(node), PAGE_SIZE);
m_reservable_pages = m_total_pages - m_list_pages;
MMU::get().allocate_range(m_start, m_list_pages * PAGE_SIZE, MMU::Flags::Present);
// Initialize free list with every page pointing to the next one
uint64_t* list_ptr = (uint64_t*)m_start;
for (uint64_t i = 0; i < m_reservable_pages - 1; i++)
{
*list_ptr++ = i + 1;
//dprintln("{}/{}", i, m_reservable_pages);
}
*list_ptr = invalid;
m_free_list = (uint64_t*)m_start;
// Initialize page list so that every page points to the next one
node* page_list = (node*)m_start;
for (uint64_t i = 0; i < m_reservable_pages; i++)
page_list[i] = { page_list + i - 1, page_list + i + 1 };
page_list[ 0 ].next = nullptr;
page_list[m_reservable_pages - 1].prev = nullptr;
m_free_list = page_list;
m_used_list = nullptr;
}
paddr_t PhysicalRange::reserve_page()
{
ASSERT_NOT_REACHED();
if (m_free_list == nullptr)
return invalid;
node* page = m_free_list;
ASSERT(page->next == nullptr);
// Detatch page from top of the free list
m_free_list = m_free_list->prev ? m_free_list->prev : nullptr;
if (m_free_list)
m_free_list->next = nullptr;
// Add page to used list
if (m_used_list)
m_used_list->next = page;
page->prev = m_used_list;
m_used_list = page;
return page_address(page);
}
void PhysicalRange::release_page(paddr_t)
void PhysicalRange::release_page(paddr_t page_address)
{
ASSERT_NOT_REACHED();
ASSERT(m_used_list);
node* page = node_address(page_address);
// Detach page from used list
if (page->prev)
page->prev->next = page->next;
if (page->next)
page->next->prev = page->prev;
if (m_used_list == page)
m_used_list = page->prev;
// Add page to the top of free list
page->prev = m_free_list;
page->next = nullptr;
if (m_free_list)
m_free_list->next = page;
m_free_list = page;
}
paddr_t PhysicalRange::page_address(uint64_t page_index) const
paddr_t PhysicalRange::page_address(const node* page) const
{
ASSERT(page_index < m_reservable_pages);
ASSERT((paddr_t)page <= m_start + m_reservable_pages * sizeof(node));
uint64_t page_index = page - (node*)m_start;
return m_start + (page_index + m_list_pages) * PAGE_SIZE;
}
PhysicalRange::node* PhysicalRange::node_address(paddr_t page_address) const
{
ASSERT(page_address % PAGE_SIZE == 0);
ASSERT(m_start + m_list_pages * PAGE_SIZE <= page_address && page_address < m_start + m_size);
uint64_t page_offset = page_address - (m_start + m_list_pages * PAGE_SIZE);
return (node*)m_start + page_offset / PAGE_SIZE;
}
static Heap* s_instance = nullptr;
@ -97,7 +137,10 @@ namespace Kernel::Memory
}
for (auto& range : m_physical_ranges)
dprintln("RAM {8H}->{8H}, {} pages ({}.{} MB)", range.start(), range.end(), range.pages(), range.pages() * PAGE_SIZE / (1 << 20), range.pages() * PAGE_SIZE % (1 << 20) * 100 / (1 << 20));
{
size_t bytes = range.usable_pages() * PAGE_SIZE;
dprintln("RAM {8H}->{8H}, {} pages ({}.{} MB)", range.usable_start(), range.usable_end(), range.usable_pages(), bytes / (1 << 20), bytes % (1 << 20) * 1000 / (1 << 20));
}
}
}