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Kernel: Store AddressSpace memory regions in an IntrusiveRedBlackTree

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This means we never need to allocate when inserting/removing regions
from the address space.
This commit is contained in:
Andreas Kling 2022-04-02 01:28:01 +02:00
parent 7381474835
commit 2617adac52
Notes: sideshowbarker 2024-07-17 14:32:02 +09:00 
Author: https://github.com/awesomekling
Commit: https://github.com/SerenityOS/serenity/commit/2617adac52
7 changed files with 99 additions and 81 deletions
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48
Kernel/Coredump.cpp
View File

@ -48,11 +48,11 @@ Coredump::Coredump(NonnullRefPtr<Process> process, NonnullRefPtr<OpenFileDescrip
m_num_program_headers = 0;
for ([[maybe_unused]] auto& region : m_process->address_space().regions()) {
#if !INCLUDE_USERSPACE_HEAP_MEMORY_IN_COREDUMPS
if (looks_like_userspace_heap_region(*region))
if (looks_like_userspace_heap_region(region))
continue;
#endif
if (region->access() == Memory::Region::Access::None)
if (region.access() == Memory::Region::Access::None)
continue;
++m_num_program_headers;
}
@ -127,28 +127,28 @@ ErrorOr<void> Coredump::write_program_headers(size_t notes_size)
for (auto& region : m_process->address_space().regions()) {
#if !INCLUDE_USERSPACE_HEAP_MEMORY_IN_COREDUMPS
if (looks_like_userspace_heap_region(*region))
if (looks_like_userspace_heap_region(region))
continue;
#endif
if (region->access() == Memory::Region::Access::None)
if (region.access() == Memory::Region::Access::None)
continue;
ElfW(Phdr) phdr {};
phdr.p_type = PT_LOAD;
phdr.p_offset = offset;
phdr.p_vaddr = region->vaddr().get();
phdr.p_vaddr = region.vaddr().get();
phdr.p_paddr = 0;
phdr.p_filesz = region->page_count() * PAGE_SIZE;
phdr.p_memsz = region->page_count() * PAGE_SIZE;
phdr.p_filesz = region.page_count() * PAGE_SIZE;
phdr.p_memsz = region.page_count() * PAGE_SIZE;
phdr.p_align = 0;
phdr.p_flags = region->is_readable() ? PF_R : 0;
if (region->is_writable())
phdr.p_flags = region.is_readable() ? PF_R : 0;
if (region.is_writable())
phdr.p_flags |= PF_W;
if (region->is_executable())
if (region.is_executable())
phdr.p_flags |= PF_X;
offset += phdr.p_filesz;
@ -176,28 +176,28 @@ ErrorOr<void> Coredump::write_regions()
u8 zero_buffer[PAGE_SIZE] = {};
for (auto& region : m_process->address_space().regions()) {
VERIFY(!region->is_kernel());
VERIFY(!region.is_kernel());
#if !INCLUDE_USERSPACE_HEAP_MEMORY_IN_COREDUMPS
if (looks_like_userspace_heap_region(*region))
if (looks_like_userspace_heap_region(region))
continue;
#endif
if (region->access() == Memory::Region::Access::None)
if (region.access() == Memory::Region::Access::None)
continue;
// If we crashed in the middle of mapping in Regions, they do not have a page directory yet, and will crash on a remap() call
if (!region->is_mapped())
if (!region.is_mapped())
continue;
region->set_readable(true);
region->remap();
region.set_readable(true);
region.remap();
for (size_t i = 0; i < region->page_count(); i++) {
auto const* page = region->physical_page(i);
for (size_t i = 0; i < region.page_count(); i++) {
auto const* page = region.physical_page(i);
auto src_buffer = [&]() -> ErrorOr<UserOrKernelBuffer> {
if (page)
return UserOrKernelBuffer::for_user_buffer(reinterpret_cast<uint8_t*>((region->vaddr().as_ptr() + (i * PAGE_SIZE))), PAGE_SIZE);
return UserOrKernelBuffer::for_user_buffer(reinterpret_cast<uint8_t*>((region.vaddr().as_ptr() + (i * PAGE_SIZE))), PAGE_SIZE);
// If the current page is not backed by a physical page, we zero it in the coredump file.
return UserOrKernelBuffer::for_kernel_buffer(zero_buffer);
}();
@ -267,24 +267,24 @@ ErrorOr<void> Coredump::create_notes_regions_data(auto& builder) const
for (auto const& region : m_process->address_space().regions()) {
#if !INCLUDE_USERSPACE_HEAP_MEMORY_IN_COREDUMPS
if (looks_like_userspace_heap_region(*region))
if (looks_like_userspace_heap_region(region))
continue;
#endif
if (region->access() == Memory::Region::Access::None)
if (region.access() == Memory::Region::Access::None)
continue;
ELF::Core::MemoryRegionInfo info {};
info.header.type = ELF::Core::NotesEntryHeader::Type::MemoryRegionInfo;
info.region_start = region->vaddr().get();
info.region_end = region->vaddr().offset(region->size()).get();
info.region_start = region.vaddr().get();
info.region_end = region.vaddr().offset(region.size()).get();
info.program_header_index = region_index++;
TRY(builder.append_bytes(ReadonlyBytes { (void*)&info, sizeof(info) }));
// NOTE: The region name *is* null-terminated, so the following is ok:
auto name = region->name();
auto name = region.name();
if (name.is_empty())
TRY(builder.append('\0'));
else

74
Kernel/Memory/AddressSpace.cpp
View File

@ -30,7 +30,20 @@ AddressSpace::AddressSpace(NonnullRefPtr<PageDirectory> page_directory)
{
}
AddressSpace::~AddressSpace() = default;
AddressSpace::~AddressSpace()
{
delete_all_regions_assuming_they_are_unmapped();
}
void AddressSpace::delete_all_regions_assuming_they_are_unmapped()
{
// FIXME: This could definitely be done in a more efficient manner.
while (!m_regions.is_empty()) {
auto& region = *m_regions.begin();
m_regions.remove(region.vaddr().get());
delete &region;
}
}
ErrorOr<void> AddressSpace::unmap_mmap_range(VirtualAddress addr, size_t size)
{
@ -208,9 +221,9 @@ void AddressSpace::deallocate_region(Region& region)
NonnullOwnPtr<Region> AddressSpace::take_region(Region& region)
{
SpinlockLocker lock(m_lock);
auto found_region = m_regions.unsafe_remove(region.vaddr().get());
VERIFY(found_region.ptr() == &region);
return found_region;
auto did_remove = m_regions.remove(region.vaddr().get());
VERIFY(did_remove);
return NonnullOwnPtr { NonnullOwnPtr<Region>::Adopt, region };
}
Region* AddressSpace::find_region_from_range(VirtualRange const& range)
@ -221,9 +234,9 @@ Region* AddressSpace::find_region_from_range(VirtualRange const& range)
return nullptr;
auto& region = *found_region;
auto rounded_range_size = page_round_up(range.size());
if (rounded_range_size.is_error() || region->size() != rounded_range_size.value())
if (rounded_range_size.is_error() || region.size() != rounded_range_size.value())
return nullptr;
return region;
return &region;
}
Region* AddressSpace::find_region_containing(VirtualRange const& range)
@ -232,7 +245,7 @@ Region* AddressSpace::find_region_containing(VirtualRange const& range)
auto* candidate = m_regions.find_largest_not_above(range.base().get());
if (!candidate)
return nullptr;
return (*candidate)->range().contains(range) ? candidate->ptr() : nullptr;
return (*candidate).range().contains(range) ? candidate : nullptr;
}
ErrorOr<Vector<Region*>> AddressSpace::find_regions_intersecting(VirtualRange const& range)
@ -245,12 +258,12 @@ ErrorOr<Vector<Region*>> AddressSpace::find_regions_intersecting(VirtualRange co
auto* found_region = m_regions.find_largest_not_above(range.base().get());
if (!found_region)
return regions;
for (auto iter = m_regions.begin_from((*found_region)->vaddr().get()); !iter.is_end(); ++iter) {
auto const& iter_range = (*iter)->range();
for (auto iter = m_regions.begin_from((*found_region).vaddr().get()); !iter.is_end(); ++iter) {
auto const& iter_range = (*iter).range();
if (iter_range.base() < range.end() && iter_range.end() > range.base()) {
TRY(regions.try_append(*iter));
TRY(regions.try_append(&*iter));
total_size_collected += (*iter)->size() - iter_range.intersect(range).size();
total_size_collected += (*iter).size() - iter_range.intersect(range).size();
if (total_size_collected == range.size())
break;
}
@ -261,9 +274,10 @@ ErrorOr<Vector<Region*>> AddressSpace::find_regions_intersecting(VirtualRange co
ErrorOr<Region*> AddressSpace::add_region(NonnullOwnPtr<Region> region)
{
auto* ptr = region.ptr();
SpinlockLocker lock(m_lock);
TRY(m_regions.try_insert(region->vaddr().get(), move(region)));
// NOTE: We leak the region into the IRBT here. It must be deleted or readopted when removed from the tree.
auto* ptr = region.leak_ptr();
m_regions.insert(ptr->vaddr().get(), *ptr);
return ptr;
}
@ -300,8 +314,7 @@ void AddressSpace::dump_regions()
SpinlockLocker lock(m_lock);
for (auto const& sorted_region : m_regions) {
auto const& region = *sorted_region;
for (auto const& region : m_regions) {
dbgln("{:p} -- {:p} {:p} {:c}{:c}{:c}{:c}{:c}{:c} {}", region.vaddr().get(), region.vaddr().offset(region.size() - 1).get(), region.size(),
region.is_readable() ? 'R' : ' ',
region.is_writable() ? 'W' : ' ',
@ -322,9 +335,10 @@ void AddressSpace::remove_all_regions(Badge<Process>)
SpinlockLocker pd_locker(m_page_directory->get_lock());
SpinlockLocker mm_locker(s_mm_lock);
for (auto& region : m_regions)
(*region).unmap_with_locks_held(Region::ShouldDeallocateVirtualRange::No, ShouldFlushTLB::No, pd_locker, mm_locker);
region.unmap_with_locks_held(Region::ShouldDeallocateVirtualRange::No, ShouldFlushTLB::No, pd_locker, mm_locker);
}
m_regions.clear();
delete_all_regions_assuming_they_are_unmapped();
}
size_t AddressSpace::amount_dirty_private() const
@ -335,8 +349,8 @@ size_t AddressSpace::amount_dirty_private() const
// That's probably a situation that needs to be looked at in general.
size_t amount = 0;
for (auto const& region : m_regions) {
if (!region->is_shared())
amount += region->amount_dirty();
if (!region.is_shared())
amount += region.amount_dirty();
}
return amount;
}
@ -346,8 +360,8 @@ ErrorOr<size_t> AddressSpace::amount_clean_inode() const
SpinlockLocker lock(m_lock);
HashTable<InodeVMObject const*> vmobjects;
for (auto const& region : m_regions) {
if (region->vmobject().is_inode())
TRY(vmobjects.try_set(&static_cast<InodeVMObject const&>(region->vmobject())));
if (region.vmobject().is_inode())
TRY(vmobjects.try_set(&static_cast<InodeVMObject const&>(region.vmobject())));
}
size_t amount = 0;
for (auto& vmobject : vmobjects)
@ -360,7 +374,7 @@ size_t AddressSpace::amount_virtual() const
SpinlockLocker lock(m_lock);
size_t amount = 0;
for (auto const& region : m_regions) {
amount += region->size();
amount += region.size();
}
return amount;
}
@ -371,7 +385,7 @@ size_t AddressSpace::amount_resident() const
// FIXME: This will double count if multiple regions use the same physical page.
size_t amount = 0;
for (auto const& region : m_regions) {
amount += region->amount_resident();
amount += region.amount_resident();
}
return amount;
}
@ -385,7 +399,7 @@ size_t AddressSpace::amount_shared() const
// so that every Region contributes +1 ref to each of its PhysicalPages.
size_t amount = 0;
for (auto const& region : m_regions) {
amount += region->amount_shared();
amount += region.amount_shared();
}
return amount;
}
@ -395,11 +409,11 @@ size_t AddressSpace::amount_purgeable_volatile() const
SpinlockLocker lock(m_lock);
size_t amount = 0;
for (auto const& region : m_regions) {
if (!region->vmobject().is_anonymous())
if (!region.vmobject().is_anonymous())
continue;
auto const& vmobject = static_cast<AnonymousVMObject const&>(region->vmobject());
auto const& vmobject = static_cast<AnonymousVMObject const&>(region.vmobject());
if (vmobject.is_purgeable() && vmobject.is_volatile())
amount += region->amount_resident();
amount += region.amount_resident();
}
return amount;
}
@ -409,11 +423,11 @@ size_t AddressSpace::amount_purgeable_nonvolatile() const
SpinlockLocker lock(m_lock);
size_t amount = 0;
for (auto const& region : m_regions) {
if (!region->vmobject().is_anonymous())
if (!region.vmobject().is_anonymous())
continue;
auto const& vmobject = static_cast<AnonymousVMObject const&>(region->vmobject());
auto const& vmobject = static_cast<AnonymousVMObject const&>(region.vmobject());
if (vmobject.is_purgeable() && !vmobject.is_volatile())
amount += region->amount_resident();
amount += region.amount_resident();
}
return amount;
}

9
Kernel/Memory/AddressSpace.h
View File

@ -12,6 +12,7 @@
#include <AK/WeakPtr.h>
#include <Kernel/Memory/AllocationStrategy.h>
#include <Kernel/Memory/PageDirectory.h>
#include <Kernel/Memory/Region.h>
#include <Kernel/UnixTypes.h>
namespace Kernel::Memory {
@ -28,8 +29,8 @@ public:
size_t region_count() const { return m_regions.size(); }
RedBlackTree<FlatPtr, NonnullOwnPtr<Region>>& regions() { return m_regions; }
RedBlackTree<FlatPtr, NonnullOwnPtr<Region>> const& regions() const { return m_regions; }
auto& regions() { return m_regions; }
auto const& regions() const { return m_regions; }
void dump_regions();
@ -68,11 +69,13 @@ public:
private:
explicit AddressSpace(NonnullRefPtr<PageDirectory>);
void delete_all_regions_assuming_they_are_unmapped();
mutable RecursiveSpinlock m_lock;
RefPtr<PageDirectory> m_page_directory;
RedBlackTree<FlatPtr, NonnullOwnPtr<Region>> m_regions;
IntrusiveRedBlackTree<&Region::m_tree_node> m_regions;
bool m_enforces_syscall_regions { false };
};

1
Kernel/Memory/Region.h
View File

@ -31,6 +31,7 @@ enum class ShouldFlushTLB {
class Region final
: public Weakable<Region> {
friend class AddressSpace;
friend class MemoryManager;
public:

2
Kernel/PerformanceEventBuffer.cpp
View File

@ -362,7 +362,7 @@ ErrorOr<void> PerformanceEventBuffer::add_process(Process const& process, Proces
for (auto const& region : process.address_space().regions()) {
TRY(append_with_ip_and_bp(process.pid(), 0,
0, 0, PERF_EVENT_MMAP, 0, region->range().base().get(), region->range().size(), region->name()));
0, 0, PERF_EVENT_MMAP, 0, region.range().base().get(), region.range().size(), region.name()));
}
return {};

40
Kernel/ProcessSpecificExposed.cpp
View File

@ -234,31 +234,31 @@ ErrorOr<void> Process::procfs_get_virtual_memory_stats(KBufferBuilder& builder)
{
SpinlockLocker lock(address_space().get_lock());
for (auto const& region : address_space().regions()) {
if (!region->is_user() && !Process::current().is_superuser())
if (!region.is_user() && !Process::current().is_superuser())
continue;
auto region_object = TRY(array.add_object());
TRY(region_object.add("readable", region->is_readable()));
TRY(region_object.add("writable", region->is_writable()));
TRY(region_object.add("executable", region->is_executable()));
TRY(region_object.add("stack", region->is_stack()));
TRY(region_object.add("shared", region->is_shared()));
TRY(region_object.add("syscall", region->is_syscall_region()));
TRY(region_object.add("purgeable", region->vmobject().is_anonymous()));
if (region->vmobject().is_anonymous()) {
TRY(region_object.add("volatile", static_cast<Memory::AnonymousVMObject const&>(region->vmobject()).is_volatile()));
TRY(region_object.add("readable", region.is_readable()));
TRY(region_object.add("writable", region.is_writable()));
TRY(region_object.add("executable", region.is_executable()));
TRY(region_object.add("stack", region.is_stack()));
TRY(region_object.add("shared", region.is_shared()));
TRY(region_object.add("syscall", region.is_syscall_region()));
TRY(region_object.add("purgeable", region.vmobject().is_anonymous()));
if (region.vmobject().is_anonymous()) {
TRY(region_object.add("volatile", static_cast<Memory::AnonymousVMObject const&>(region.vmobject()).is_volatile()));
}
TRY(region_object.add("cacheable", region->is_cacheable()));
TRY(region_object.add("address", region->vaddr().get()));
TRY(region_object.add("size", region->size()));
TRY(region_object.add("amount_resident", region->amount_resident()));
TRY(region_object.add("amount_dirty", region->amount_dirty()));
TRY(region_object.add("cow_pages", region->cow_pages()));
TRY(region_object.add("name", region->name()));
TRY(region_object.add("vmobject", region->vmobject().class_name()));
TRY(region_object.add("cacheable", region.is_cacheable()));
TRY(region_object.add("address", region.vaddr().get()));
TRY(region_object.add("size", region.size()));
TRY(region_object.add("amount_resident", region.amount_resident()));
TRY(region_object.add("amount_dirty", region.amount_dirty()));
TRY(region_object.add("cow_pages", region.cow_pages()));
TRY(region_object.add("name", region.name()));
TRY(region_object.add("vmobject", region.vmobject().class_name()));
StringBuilder pagemap_builder;
for (size_t i = 0; i < region->page_count(); ++i) {
auto const* page = region->physical_page(i);
for (size_t i = 0; i < region.page_count(); ++i) {
auto const* page = region.physical_page(i);
if (!page)
pagemap_builder.append('N');
else if (page->is_shared_zero_page() || page->is_lazy_committed_page())

6
Kernel/Syscalls/fork.cpp
View File

@ -109,12 +109,12 @@ ErrorOr<FlatPtr> Process::sys$fork(RegisterState& regs)
{
SpinlockLocker lock(address_space().get_lock());
for (auto& region : address_space().regions()) {
dbgln_if(FORK_DEBUG, "fork: cloning Region({}) '{}' @ {}", region, region->name(), region->vaddr());
auto region_clone = TRY(region->try_clone());
dbgln_if(FORK_DEBUG, "fork: cloning Region({}) '{}' @ {}", region, region.name(), region.vaddr());
auto region_clone = TRY(region.try_clone());
TRY(region_clone->map(child->address_space().page_directory(), Memory::ShouldFlushTLB::No));
auto* child_region = TRY(child->address_space().add_region(move(region_clone)));
if (region == m_master_tls_region.unsafe_ptr())
if (&region == m_master_tls_region.unsafe_ptr())
child->m_master_tls_region = TRY(child_region->try_make_weak_ptr());
}
}