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Kernel: Aggregate TLB flush requests for Regions for SMP

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Rather than sending one TLB flush request for each page,
aggregate them so that we're not spamming the other
processors with FlushTLB IPIs.
This commit is contained in:
Tom 2020-07-06 12:47:08 -06:00 • committed by Andreas Kling
parent 56126d7a45
commit 06d50f64b0
3 changed files with 28 additions and 13 deletions
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29
Kernel/VM/Region.cpp
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@ -69,6 +69,7 @@ NonnullOwnPtr<Region> Region::clone()
{
ASSERT(Process::current());
ScopedSpinLock lock(s_mm_lock);
if (m_inherit_mode == InheritMode::ZeroedOnFork) {
ASSERT(m_mmap);
ASSERT(!m_shared);
@ -122,16 +123,21 @@ bool Region::commit()
dbg() << "MM: Commit " << page_count() << " pages in Region " << this << " (VMO=" << &vmobject() << ") at " << vaddr();
#endif
for (size_t i = 0; i < page_count(); ++i) {
if (!commit(i))
if (!commit(i)) {
// Flush what we did commit
if (i > 0)
MM.flush_tlb(vaddr(), i + 1);
return false;
}
}
MM.flush_tlb(vaddr(), page_count());
return true;
}
bool Region::commit(size_t page_index)
{
ASSERT(vmobject().is_anonymous() || vmobject().is_purgeable());
ScopedSpinLock lock(s_mm_lock);
ASSERT(s_mm_lock.own_lock());
auto& vmobject_physical_page_entry = physical_page_slot(page_index);
if (!vmobject_physical_page_entry.is_null() && !vmobject_physical_page_entry->is_shared_zero_page())
return true;
@ -142,7 +148,7 @@ bool Region::commit(size_t page_index)
return false;
}
vmobject_physical_page_entry = move(physical_page);
remap_page(page_index);
remap_page(page_index, false); // caller is in charge of flushing tlb
return true;
}
@ -224,7 +230,7 @@ Bitmap& Region::ensure_cow_map() const
void Region::map_individual_page_impl(size_t page_index)
{
auto page_vaddr = vaddr().offset(page_index * PAGE_SIZE);
auto page_vaddr = vaddr_from_page_index(page_index);
auto& pte = MM.ensure_pte(*m_page_directory, page_vaddr);
auto* page = physical_page(page_index);
if (!page || (!is_readable() && !is_writable())) {
@ -244,15 +250,16 @@ void Region::map_individual_page_impl(size_t page_index)
dbg() << "MM: >> region map (PD=" << m_page_directory->cr3() << ", PTE=" << (void*)pte.raw() << "{" << &pte << "}) " << name() << " " << page_vaddr << " => " << page->paddr() << " (@" << page << ")";
#endif
}
MM.flush_tlb(page_vaddr);
}
void Region::remap_page(size_t page_index)
void Region::remap_page(size_t page_index, bool with_flush)
{
ASSERT(m_page_directory);
ScopedSpinLock lock(s_mm_lock);
ASSERT(physical_page(page_index));
map_individual_page_impl(page_index);
if (with_flush)
MM.flush_tlb(vaddr_from_page_index(page_index));
}
void Region::unmap(ShouldDeallocateVirtualMemoryRange deallocate_range)
@ -260,15 +267,15 @@ void Region::unmap(ShouldDeallocateVirtualMemoryRange deallocate_range)
ScopedSpinLock lock(s_mm_lock);
ASSERT(m_page_directory);
for (size_t i = 0; i < page_count(); ++i) {
auto vaddr = this->vaddr().offset(i * PAGE_SIZE);
auto vaddr = vaddr_from_page_index(i);
auto& pte = MM.ensure_pte(*m_page_directory, vaddr);
pte.clear();
MM.flush_tlb(vaddr);
#ifdef MM_DEBUG
auto* page = physical_page(i);
dbg() << "MM: >> Unmapped " << vaddr << " => P" << String::format("%p", page ? page->paddr().get() : 0) << " <<";
#endif
}
MM.flush_tlb(vaddr(), page_count());
if (deallocate_range == ShouldDeallocateVirtualMemoryRange::Yes) {
if (m_page_directory->range_allocator().contains(range()))
m_page_directory->range_allocator().deallocate(range());
@ -281,18 +288,20 @@ void Region::unmap(ShouldDeallocateVirtualMemoryRange deallocate_range)
void Region::set_page_directory(PageDirectory& page_directory)
{
ASSERT(!m_page_directory || m_page_directory == &page_directory);
ScopedSpinLock lock(s_mm_lock);
ASSERT(s_mm_lock.own_lock());
m_page_directory = page_directory;
}
void Region::map(PageDirectory& page_directory)
{
set_page_directory(page_directory);
ScopedSpinLock lock(s_mm_lock);
set_page_directory(page_directory);
#ifdef MM_DEBUG
dbg() << "MM: Region::map() will map VMO pages " << first_page_index() << " - " << last_page_index() << " (VMO page count: " << vmobject().page_count() << ")";
#endif
for (size_t page_index = 0; page_index < page_count(); ++page_index)
map_individual_page_impl(page_index);
MM.flush_tlb(vaddr(), page_count());
}
void Region::remap()