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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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18
Kernel/VM/PhysicalPage.h
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@ -18,11 +18,8 @@ class PhysicalPage {
friend class PageDirectory;
friend class VMObject;
MAKE_SLAB_ALLOCATED(PhysicalPage);
AK_MAKE_NONMOVABLE(PhysicalPage);
public:
PhysicalAddress paddr() const { return m_paddr; }
PhysicalAddress paddr() const;
void ref()
{
@ -34,7 +31,7 @@ public:
if (m_ref_count.fetch_sub(1, AK::memory_order_acq_rel) == 1) {
if (m_may_return_to_freelist)
return_to_freelist();
delete this;
this->~PhysicalPage(); // delete in place
}
}
@ -46,7 +43,7 @@ public:
bool is_lazy_committed_page() const;
private:
PhysicalPage(PhysicalAddress paddr, bool supervisor, bool may_return_to_freelist = true);
PhysicalPage(bool supervisor, bool may_return_to_freelist = true);
~PhysicalPage() = default;
void return_to_freelist() const;
@ -54,7 +51,14 @@ private:
Atomic<u32> m_ref_count { 1 };
bool m_may_return_to_freelist { true };
bool m_supervisor { false };
PhysicalAddress m_paddr;
};
struct PhysicalPageEntry {
// This structure either holds a valid PhysicalPage
// or a PhysicalAllocator's free list information!
union {
PhysicalPage physical_page;
};
};
}