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Kernel: Don't clone entire kernel stack on fork

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We only need to copy area between [ret_sp, stack_end]. This range is
always very small compared to the whole stack (64 KiB).
This commit is contained in:
Bananymous
2026-04-04 23:26:39 +03:00
parent 9d83424346
commit 9fce114e8e
3 changed files with 26 additions and 41 deletions
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30
kernel/kernel/Memory/VirtualRange.cpp
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@@ -110,36 +110,6 @@ namespace Kernel
return {};
}
BAN::ErrorOr<BAN::UniqPtr<VirtualRange>> VirtualRange::clone(PageTable& page_table)
{
ASSERT(&PageTable::current() == &m_page_table);
ASSERT(&m_page_table != &page_table);
SpinLockGuard _(m_lock);
auto result = TRY(create_to_vaddr(page_table, vaddr(), size(), m_flags, m_preallocated, m_has_guard_pages));
const size_t page_count = size() / PAGE_SIZE;
for (size_t i = 0; i < page_count; i++)
{
if (m_paddrs[i] == 0)
continue;
if (!result->m_preallocated)
{
result->m_paddrs[i] = Heap::get().take_free_page();
if (result->m_paddrs[i] == 0)
return BAN::Error::from_errno(ENOMEM);
result->m_page_table.map_page_at(result->m_paddrs[i], vaddr() + i * PAGE_SIZE, m_flags);
}
PageTable::with_fast_page(result->m_paddrs[i], [&] {
memcpy(PageTable::fast_page_as_ptr(), reinterpret_cast<void*>(vaddr() + i * PAGE_SIZE), PAGE_SIZE);
});
}
return result;
}
BAN::ErrorOr<bool> VirtualRange::allocate_page_for_demand_paging(vaddr_t vaddr)
{
ASSERT(contains(vaddr));