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Kernel: Move PhysicalPage classes out of the heap into an array

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By moving the PhysicalPage classes out of the kernel heap into a static
array, one for each physical page, we can avoid the added overhead and
easily find them by indexing into an array.

This also wraps the PhysicalPage into a PhysicalPageEntry, which allows
us to re-use each slot with information where to find the next free
page.
This commit is contained in:
Tom 2021-07-07 19:50:05 -06:00 • committed by Andreas Kling
parent ad5d9d648b
commit 87dc4c3d2c
11 changed files with 285 additions and 43 deletions
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19
Kernel/VM/PhysicalRegion.cpp
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@ -44,6 +44,25 @@ unsigned PhysicalRegion::finalize_capacity()
return size();
}
NonnullRefPtr<PhysicalRegion> PhysicalRegion::take_pages_from_beginning(unsigned page_count)
{
VERIFY(m_used == 0);
VERIFY(page_count > 0);
VERIFY(page_count < m_pages);
auto taken_lower = m_lower;
auto taken_upper = taken_lower.offset((PhysicalPtr)page_count * PAGE_SIZE);
m_lower = m_lower.offset((PhysicalPtr)page_count * PAGE_SIZE);
// TODO: find a more elegant way to re-init the existing region
m_pages = 0;
m_bitmap = {}; // FIXME: Kind of wasteful
finalize_capacity();
auto taken_region = create(taken_lower, taken_upper);
taken_region->finalize_capacity();
return taken_region;
}
NonnullRefPtrVector<PhysicalPage> PhysicalRegion::take_contiguous_free_pages(size_t count, bool supervisor, size_t physical_alignment)
{
VERIFY(m_pages);