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Kernel: Optimize PageTable::unmap_range on x86_64

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Bananymous
2026-05-20 16:16:44 +03:00
parent 45e55d8907
commit 6045726e41
1 changed files with 62 additions and 4 deletions
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66
kernel/arch/x86_64/PageTable.cpp
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@@ -564,12 +564,70 @@ namespace Kernel
{
ASSERT(vaddr % PAGE_SIZE == 0);
const size_t page_count = range_page_count(vaddr, size);
ASSERT(is_canonical(vaddr));
ASSERT(is_canonical(vaddr + size - 1));
const vaddr_t uc_vaddr_start = uncanonicalize(vaddr);
const vaddr_t uc_vaddr_end = uncanonicalize(vaddr + size - 1);
uint16_t pml4e = (uc_vaddr_start >> 39) & 0x1FF;
uint16_t pdpte = (uc_vaddr_start >> 30) & 0x1FF;
uint16_t pde = (uc_vaddr_start >> 21) & 0x1FF;
uint16_t pte = (uc_vaddr_start >> 12) & 0x1FF;
const uint16_t e_pml4e = (uc_vaddr_end >> 39) & 0x1FF;
const uint16_t e_pdpte = (uc_vaddr_end >> 30) & 0x1FF;
const uint16_t e_pde = (uc_vaddr_end >> 21) & 0x1FF;
const uint16_t e_pte = (uc_vaddr_end >> 12) & 0x1FF;
SpinLockGuard _(m_lock);
for (vaddr_t page = 0; page < page_count; page++)
unmap_page(vaddr + page * PAGE_SIZE, false);
invalidate_range(vaddr, page_count, true);
uint64_t* pml4 = P2V(m_highest_paging_struct);
for (; pml4e <= e_pml4e; pml4e++)
{
#define UNALLOCATE_TABLE_IF_EMPTY(outer, inner) \
if (old_##inner##e == 0 && inner##e == 512) { \
unallocate_page(outer[outer##e] & s_page_addr_mask); \
outer[outer##e] = 0; \
}
if (!(pml4[pml4e] & Flags::Present))
continue;
const uint16_t old_pdpte = pdpte;
uint64_t* pdpt = P2V(pml4[pml4e] & s_page_addr_mask);
for (; pdpte < 512; pdpte++)
{
if (pml4e == e_pml4e && pdpte > e_pdpte)
break;
if (!(pdpt[pdpte] & Flags::Present))
continue;
const uint16_t old_pde = pde;
uint64_t* pd = P2V(pdpt[pdpte] & s_page_addr_mask);
for (; pde < 512; pde++)
{
if (pml4e == e_pml4e && pdpte == e_pdpte && pde > e_pde)
break;
if (!(pd[pde] & Flags::Present))
continue;
const uint16_t old_pte = pte;
uint64_t* pt = P2V(pd[pde] & s_page_addr_mask);
for (; pte < 512; pte++)
{
if (pml4e == e_pml4e && pdpte == e_pdpte && pde == e_pde && pte > e_pte)
break;
pt[pte] = 0;
}
UNALLOCATE_TABLE_IF_EMPTY(pd, pt);
pte = 0;
}
UNALLOCATE_TABLE_IF_EMPTY(pdpt, pd);
pde = 0;
}
UNALLOCATE_TABLE_IF_EMPTY(pml4, pdpt);
pdpte = 0;
#undef UNALLOCATE_TABLE_IF_EMPTY
}
invalidate_range(vaddr, range_page_count(vaddr, size), true);
}
void PageTable::map_page_at(paddr_t paddr, vaddr_t vaddr, flags_t flags, MemoryType memory_type, bool invalidate)