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Kernel: Minor MM optimization for SMP

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MemoryManager::quickmap_pd and MemoryManager::quickmap_pt can only
be called by one processor at the time anyway, since anything using
these must have the MM lock held. So, no need to inform the other
CPUs to flush their TLBs, we can just flush our own.
This commit is contained in:
Tom 2020-07-06 09:11:52 -06:00 • committed by Andreas Kling
parent bc107d0b33
commit 655f4daeb1
2 changed files with 18 additions and 12 deletions
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7
Kernel/VM/PageDirectory.cpp
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@ -48,7 +48,7 @@ static HashMap<u32, PageDirectory*>& cr3_map()
RefPtr<PageDirectory> PageDirectory::find_by_cr3(u32 cr3)
{
InterruptDisabler disabler;
ScopedSpinLock lock(s_mm_lock);
return cr3_map().get(cr3).value_or({});
}
@ -76,6 +76,7 @@ PageDirectory::PageDirectory()
PageDirectory::PageDirectory(Process& process, const RangeAllocator* parent_range_allocator)
: m_process(&process)
{
ScopedSpinLock lock(s_mm_lock);
if (parent_range_allocator) {
m_range_allocator.initialize_from_parent(*parent_range_allocator);
} else {
@ -93,7 +94,6 @@ PageDirectory::PageDirectory(Process& process, const RangeAllocator* parent_rang
m_directory_pages[3] = MM.kernel_page_directory().m_directory_pages[3];
{
InterruptDisabler disabler;
auto& table = *(PageDirectoryPointerTable*)MM.quickmap_page(*m_directory_table);
table.raw[0] = (u64)m_directory_pages[0]->paddr().as_ptr() | 1;
table.raw[1] = (u64)m_directory_pages[1]->paddr().as_ptr() | 1;
@ -109,7 +109,6 @@ PageDirectory::PageDirectory(Process& process, const RangeAllocator* parent_rang
auto* new_pd = MM.quickmap_pd(*this, 0);
memcpy(new_pd, &buffer, sizeof(PageDirectoryEntry));
InterruptDisabler disabler;
cr3_map().set(cr3(), this);
}
@ -118,7 +117,7 @@ PageDirectory::~PageDirectory()
#ifdef MM_DEBUG
dbg() << "MM: ~PageDirectory K" << this;
#endif
InterruptDisabler disabler;
ScopedSpinLock lock(s_mm_lock);
cr3_map().remove(cr3());
}