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Kernel: Make purgeable memory a VMObject level concept (again)
This patch changes the semantics of purgeable memory. - AnonymousVMObject now has a "purgeable" flag. It can only be set when constructing the object. (Previously, all anonymous memory was effectively purgeable.) - AnonymousVMObject now has a "volatile" flag. It covers the entire range of physical pages. (Previously, we tracked ranges of volatile pages, effectively making it a page-level concept.) - Non-volatile objects maintain a physical page reservation via the committed pages mechanism, to ensure full coverage for page faults. - When an object is made volatile, it relinquishes any unused committed pages immediately. If later made non-volatile again, we then attempt to make a new committed pages reservation. If this fails, we return ENOMEM to userspace. mmap() now creates purgeable objects if passed the MAP_PURGEABLE option together with MAP_ANONYMOUS. anon_create() memory is always purgeable.
This commit is contained in:
Andreas Kling
parent
6bb53d6a80
commit
2d1a651e0a
Notes:
sideshowbarker
2024-07-18 08:22:06 +09:00
Author: https://github.com/awesomekling Commit: https://github.com/SerenityOS/serenity/commit/2d1a651e0aa
@ -264,7 +264,6 @@ set(KERNEL_SOURCES
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VM/PhysicalZone.cpp
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VM/PrivateInodeVMObject.cpp
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VM/ProcessPagingScope.cpp
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VM/PurgeablePageRanges.cpp
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VM/Range.cpp
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VM/RangeAllocator.cpp
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VM/Region.cpp
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@ -7,6 +7,7 @@
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#pragma once
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#include <Kernel/FileSystem/File.h>
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#include <Kernel/VM/AnonymousVMObject.h>
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namespace Kernel {
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@ -456,7 +456,7 @@ private:
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region_object.add("syscall", region->is_syscall_region());
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region_object.add("purgeable", region->vmobject().is_anonymous());
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if (region->vmobject().is_anonymous()) {
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region_object.add("volatile", static_cast<const AnonymousVMObject&>(region->vmobject()).is_any_volatile());
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region_object.add("volatile", static_cast<AnonymousVMObject const&>(region->vmobject()).is_volatile());
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}
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region_object.add("cacheable", region->is_cacheable());
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region_object.add("address", region->vaddr().get());
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@ -29,7 +29,7 @@ KResultOr<FlatPtr> Process::sys$anon_create(size_t size, int options)
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if (new_fd < 0)
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return new_fd;
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auto vmobject = AnonymousVMObject::try_create_with_size(size, AllocationStrategy::Reserve);
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auto vmobject = AnonymousVMObject::try_create_purgeable_with_size(size, AllocationStrategy::Reserve);
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if (!vmobject)
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return ENOMEM;
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@ -12,6 +12,7 @@
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#include <Kernel/PerformanceEventBuffer.h>
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#include <Kernel/PerformanceManager.h>
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#include <Kernel/Process.h>
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#include <Kernel/VM/AnonymousVMObject.h>
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#include <Kernel/VM/MemoryManager.h>
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#include <Kernel/VM/PageDirectory.h>
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#include <Kernel/VM/PrivateInodeVMObject.h>
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@ -217,7 +218,14 @@ KResultOr<FlatPtr> Process::sys$mmap(Userspace<const Syscall::SC_mmap_params*> u
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if (map_anonymous) {
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auto strategy = map_noreserve ? AllocationStrategy::None : AllocationStrategy::Reserve;
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auto region_or_error = space().allocate_region(range.value(), {}, prot, strategy);
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RefPtr<AnonymousVMObject> vmobject;
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if (flags & MAP_PURGEABLE)
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vmobject = AnonymousVMObject::try_create_purgeable_with_size(page_round_up(size), strategy);
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else
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vmobject = AnonymousVMObject::try_create_with_size(page_round_up(size), strategy);
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if (!vmobject)
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return ENOMEM;
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auto region_or_error = space().allocate_region_with_vmobject(range.value(), vmobject.release_nonnull(), 0, {}, prot, map_shared);
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if (region_or_error.is_error())
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return region_or_error.error().error();
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region = region_or_error.value();
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@ -465,23 +473,17 @@ KResultOr<FlatPtr> Process::sys$madvise(Userspace<void*> address, size_t size, i
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if (set_volatile || set_nonvolatile) {
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if (!region->vmobject().is_anonymous())
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return EPERM;
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auto& vmobject = static_cast<AnonymousVMObject&>(region->vmobject());
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bool was_purged = false;
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switch (region->set_volatile(VirtualAddress(address), size, set_volatile, was_purged)) {
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case Region::SetVolatileError::Success:
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break;
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case Region::SetVolatileError::NotPurgeable:
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return EPERM;
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case Region::SetVolatileError::OutOfMemory:
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return ENOMEM;
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}
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if (set_nonvolatile)
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return was_purged ? 1 : 0;
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return 0;
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auto result = vmobject.set_volatile(set_volatile, was_purged);
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if (result.is_error())
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return result.error();
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return was_purged ? 1 : 0;
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}
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if (advice & MADV_GET_VOLATILE) {
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if (!region->vmobject().is_anonymous())
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return EPERM;
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return region->is_volatile(VirtualAddress(address), size) ? 0 : 1;
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return static_cast<AnonymousVMObject&>(region->vmobject()).is_volatile() ? 0 : 1;
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}
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return EINVAL;
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}
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@ -668,5 +670,4 @@ KResultOr<FlatPtr> Process::sys$msyscall(Userspace<void*> address)
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region->set_syscall_region(true);
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return 0;
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}
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}
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@ -19,7 +19,7 @@ KResultOr<FlatPtr> Process::sys$purge(int mode)
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REQUIRE_NO_PROMISES;
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if (!is_superuser())
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return EPERM;
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int purged_page_count = 0;
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size_t purged_page_count = 0;
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if (mode & PURGE_ALL_VOLATILE) {
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NonnullRefPtrVector<AnonymousVMObject> vmobjects;
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{
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@ -92,6 +92,7 @@ enum {
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#define MAP_STACK 0x40
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#define MAP_NORESERVE 0x80
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#define MAP_RANDOMIZED 0x100
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#define MAP_PURGEABLE 0x200
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#define PROT_READ 0x1
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#define PROT_WRITE 0x2
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@ -22,16 +22,17 @@ RefPtr<VMObject> AnonymousVMObject::try_clone()
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// commit the number of pages that we need to potentially allocate
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// so that the parent is still guaranteed to be able to have all
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// non-volatile memory available.
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size_t need_cow_pages = 0;
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size_t new_cow_pages_needed = 0;
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// We definitely need to commit non-volatile areas
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for_each_nonvolatile_range([&](VolatilePageRange const& nonvolatile_range) {
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need_cow_pages += nonvolatile_range.count;
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});
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if (is_volatile()) {
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// NOTE: If this object is currently volatile, we don't own any committed pages.
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} else {
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new_cow_pages_needed = page_count();
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}
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dbgln_if(COMMIT_DEBUG, "Cloning {:p}, need {} committed cow pages", this, need_cow_pages);
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dbgln_if(COMMIT_DEBUG, "Cloning {:p}, need {} committed cow pages", this, new_cow_pages_needed);
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if (!MM.commit_user_physical_pages(need_cow_pages))
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if (!MM.commit_user_physical_pages(new_cow_pages_needed))
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return {};
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// Create or replace the committed cow pages. When cloning a previously
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@ -40,10 +41,10 @@ RefPtr<VMObject> AnonymousVMObject::try_clone()
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// one would keep the one it still has. This ensures that the original
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// one and this one, as well as the clone have sufficient resources
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// to cow all pages as needed
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m_shared_committed_cow_pages = try_create<CommittedCowPages>(need_cow_pages);
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m_shared_committed_cow_pages = try_create<CommittedCowPages>(new_cow_pages_needed);
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if (!m_shared_committed_cow_pages) {
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MM.uncommit_user_physical_pages(need_cow_pages);
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MM.uncommit_user_physical_pages(new_cow_pages_needed);
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return {};
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}
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@ -65,6 +66,20 @@ RefPtr<AnonymousVMObject> AnonymousVMObject::try_create_with_size(size_t size, A
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return adopt_ref_if_nonnull(new (nothrow) AnonymousVMObject(size, commit));
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}
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RefPtr<AnonymousVMObject> AnonymousVMObject::try_create_purgeable_with_size(size_t size, AllocationStrategy commit)
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{
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if (commit == AllocationStrategy::Reserve || commit == AllocationStrategy::AllocateNow) {
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// We need to attempt to commit before actually creating the object
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if (!MM.commit_user_physical_pages(ceil_div(size, static_cast<size_t>(PAGE_SIZE))))
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return {};
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}
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auto vmobject = adopt_ref_if_nonnull(new (nothrow) AnonymousVMObject(size, commit));
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if (!vmobject)
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return {};
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vmobject->m_purgeable = true;
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return vmobject;
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}
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RefPtr<AnonymousVMObject> AnonymousVMObject::try_create_with_physical_pages(Span<NonnullRefPtr<PhysicalPage>> physical_pages)
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{
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return adopt_ref_if_nonnull(new (nothrow) AnonymousVMObject(physical_pages));
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@ -81,7 +96,6 @@ RefPtr<AnonymousVMObject> AnonymousVMObject::try_create_for_physical_range(Physi
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AnonymousVMObject::AnonymousVMObject(size_t size, AllocationStrategy strategy)
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: VMObject(size)
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, m_volatile_ranges_cache({ 0, page_count() })
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, m_unused_committed_pages(strategy == AllocationStrategy::Reserve ? page_count() : 0)
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{
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if (strategy == AllocationStrategy::AllocateNow) {
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@ -97,7 +111,6 @@ AnonymousVMObject::AnonymousVMObject(size_t size, AllocationStrategy strategy)
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AnonymousVMObject::AnonymousVMObject(PhysicalAddress paddr, size_t size)
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: VMObject(size)
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, m_volatile_ranges_cache({ 0, page_count() })
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{
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VERIFY(paddr.page_base() == paddr);
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for (size_t i = 0; i < page_count(); ++i)
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@ -106,7 +119,6 @@ AnonymousVMObject::AnonymousVMObject(PhysicalAddress paddr, size_t size)
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AnonymousVMObject::AnonymousVMObject(Span<NonnullRefPtr<PhysicalPage>> physical_pages)
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: VMObject(physical_pages.size() * PAGE_SIZE)
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, m_volatile_ranges_cache({ 0, page_count() })
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{
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for (size_t i = 0; i < physical_pages.size(); ++i) {
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m_physical_pages[i] = physical_pages[i];
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@ -115,9 +127,6 @@ AnonymousVMObject::AnonymousVMObject(Span<NonnullRefPtr<PhysicalPage>> physical_
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AnonymousVMObject::AnonymousVMObject(AnonymousVMObject const& other)
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: VMObject(other)
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, m_volatile_ranges_cache({ 0, page_count() }) // do *not* clone this
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, m_volatile_ranges_cache_dirty(true) // do *not* clone this
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, m_purgeable_ranges() // do *not* clone this
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, m_unused_committed_pages(other.m_unused_committed_pages)
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, m_cow_map() // do *not* clone this
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, m_shared_committed_cow_pages(other.m_shared_committed_cow_pages) // share the pool
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@ -152,217 +161,94 @@ AnonymousVMObject::~AnonymousVMObject()
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MM.uncommit_user_physical_pages(m_unused_committed_pages);
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}
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int AnonymousVMObject::purge()
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{
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int purged_page_count = 0;
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ScopedSpinLock lock(m_lock);
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for_each_volatile_range([&](auto const& range) {
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int purged_in_range = 0;
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auto range_end = range.base + range.count;
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for (size_t i = range.base; i < range_end; i++) {
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auto& phys_page = m_physical_pages[i];
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if (phys_page && !phys_page->is_shared_zero_page()) {
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VERIFY(!phys_page->is_lazy_committed_page());
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++purged_in_range;
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}
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phys_page = MM.shared_zero_page();
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}
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if (purged_in_range > 0) {
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purged_page_count += purged_in_range;
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set_was_purged(range);
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for_each_region([&](auto& region) {
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if (auto owner = region.get_owner()) {
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// we need to hold a reference the process here (if there is one) as we may not own this region
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dmesgln("Purged {} pages from region {} owned by {} at {} - {}",
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purged_in_range,
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region.name(),
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*owner,
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region.vaddr_from_page_index(range.base),
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region.vaddr_from_page_index(range.base + range.count));
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} else {
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dmesgln("Purged {} pages from region {} (no ownership) at {} - {}",
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purged_in_range,
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region.name(),
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region.vaddr_from_page_index(range.base),
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region.vaddr_from_page_index(range.base + range.count));
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}
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region.remap_vmobject_page_range(range.base, range.count);
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});
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}
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});
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return purged_page_count;
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}
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void AnonymousVMObject::set_was_purged(VolatilePageRange const& range)
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{
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VERIFY(m_lock.is_locked());
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for (auto* purgeable_ranges : m_purgeable_ranges)
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purgeable_ranges->set_was_purged(range);
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}
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void AnonymousVMObject::register_purgeable_page_ranges(PurgeablePageRanges& purgeable_page_ranges)
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size_t AnonymousVMObject::purge()
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{
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ScopedSpinLock lock(m_lock);
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purgeable_page_ranges.set_vmobject(this);
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VERIFY(!m_purgeable_ranges.contains_slow(&purgeable_page_ranges));
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m_purgeable_ranges.append(&purgeable_page_ranges);
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}
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void AnonymousVMObject::unregister_purgeable_page_ranges(PurgeablePageRanges& purgeable_page_ranges)
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{
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ScopedSpinLock lock(m_lock);
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for (size_t i = 0; i < m_purgeable_ranges.size(); i++) {
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if (m_purgeable_ranges[i] != &purgeable_page_ranges)
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if (!is_purgeable() || !is_volatile())
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return 0;
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size_t total_pages_purged = 0;
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for (auto& page : m_physical_pages) {
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VERIFY(page);
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if (page->is_shared_zero_page())
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continue;
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purgeable_page_ranges.set_vmobject(nullptr);
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m_purgeable_ranges.remove(i);
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return;
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page = MM.shared_zero_page();
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++total_pages_purged;
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}
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VERIFY_NOT_REACHED();
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}
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bool AnonymousVMObject::is_any_volatile() const
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{
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ScopedSpinLock lock(m_lock);
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for (auto& volatile_ranges : m_purgeable_ranges) {
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ScopedSpinLock lock(volatile_ranges->m_volatile_ranges_lock);
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if (!volatile_ranges->is_empty())
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return true;
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}
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return false;
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}
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m_was_purged = true;
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size_t AnonymousVMObject::remove_lazy_commit_pages(VolatilePageRange const& range)
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{
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VERIFY(m_lock.is_locked());
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size_t removed_count = 0;
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auto range_end = range.base + range.count;
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for (size_t i = range.base; i < range_end; i++) {
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auto& phys_page = m_physical_pages[i];
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if (phys_page && phys_page->is_lazy_committed_page()) {
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phys_page = MM.shared_zero_page();
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removed_count++;
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VERIFY(m_unused_committed_pages > 0);
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if (--m_unused_committed_pages == 0)
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break;
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}
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}
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return removed_count;
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}
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void AnonymousVMObject::update_volatile_cache()
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{
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VERIFY(m_lock.is_locked());
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VERIFY(m_volatile_ranges_cache_dirty);
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m_volatile_ranges_cache.clear();
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for_each_nonvolatile_range([&](VolatilePageRange const& range) {
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m_volatile_ranges_cache.add_unchecked(range);
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for_each_region([](Region& region) {
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region.remap();
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});
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m_volatile_ranges_cache_dirty = false;
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return total_pages_purged;
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}
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void AnonymousVMObject::range_made_volatile(VolatilePageRange const& range)
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KResult AnonymousVMObject::set_volatile(bool is_volatile, bool& was_purged)
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{
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VERIFY(m_lock.is_locked());
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VERIFY(is_purgeable());
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if (m_unused_committed_pages == 0)
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return;
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ScopedSpinLock locker(m_lock);
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// We need to check this range for any pages that are marked for
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// lazy committed allocation and turn them into shared zero pages
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// and also adjust the m_unused_committed_pages for each such page.
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// Take into account all the other views as well.
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size_t uncommit_page_count = 0;
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for_each_volatile_range([&](auto const& r) {
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auto intersected = range.intersected(r);
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if (!intersected.is_empty()) {
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uncommit_page_count += remove_lazy_commit_pages(intersected);
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if (m_unused_committed_pages == 0)
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return IterationDecision::Break;
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was_purged = m_was_purged;
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if (m_volatile == is_volatile)
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return KSuccess;
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if (is_volatile) {
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// When a VMObject is made volatile, it gives up all of its committed memory.
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// Any physical pages already allocated remain in the VMObject for now, but the kernel is free to take them at any moment.
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for (auto& page : m_physical_pages) {
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if (page && page->is_lazy_committed_page())
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page = MM.shared_zero_page();
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}
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return IterationDecision::Continue;
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});
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// Return those committed pages back to the system
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if (uncommit_page_count > 0) {
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dbgln_if(COMMIT_DEBUG, "Uncommit {} lazy-commit pages from {:p}", uncommit_page_count, this);
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MM.uncommit_user_physical_pages(uncommit_page_count);
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}
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m_volatile_ranges_cache_dirty = true;
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}
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void AnonymousVMObject::range_made_nonvolatile(VolatilePageRange const&)
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{
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VERIFY(m_lock.is_locked());
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m_volatile_ranges_cache_dirty = true;
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}
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size_t AnonymousVMObject::count_needed_commit_pages_for_nonvolatile_range(VolatilePageRange const& range)
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{
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VERIFY(m_lock.is_locked());
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VERIFY(!range.is_empty());
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size_t need_commit_pages = 0;
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auto range_end = range.base + range.count;
|
||||
for (size_t page_index = range.base; page_index < range_end; page_index++) {
|
||||
// COW pages are accounted for in m_shared_committed_cow_pages
|
||||
if (!m_cow_map.is_null() && m_cow_map.get(page_index))
|
||||
continue;
|
||||
auto& phys_page = m_physical_pages[page_index];
|
||||
if (phys_page && phys_page->is_shared_zero_page())
|
||||
need_commit_pages++;
|
||||
}
|
||||
return need_commit_pages;
|
||||
}
|
||||
|
||||
size_t AnonymousVMObject::mark_committed_pages_for_nonvolatile_range(VolatilePageRange const& range, size_t mark_total)
|
||||
{
|
||||
VERIFY(m_lock.is_locked());
|
||||
VERIFY(!range.is_empty());
|
||||
VERIFY(mark_total > 0);
|
||||
|
||||
size_t pages_updated = 0;
|
||||
auto range_end = range.base + range.count;
|
||||
for (size_t page_index = range.base; page_index < range_end; page_index++) {
|
||||
// COW pages are accounted for in m_shared_committed_cow_pages
|
||||
if (!m_cow_map.is_null() && m_cow_map.get(page_index))
|
||||
continue;
|
||||
auto& phys_page = m_physical_pages[page_index];
|
||||
if (phys_page && phys_page->is_shared_zero_page()) {
|
||||
phys_page = MM.lazy_committed_page();
|
||||
if (++pages_updated == mark_total)
|
||||
break;
|
||||
if (m_unused_committed_pages) {
|
||||
MM.uncommit_user_physical_pages(m_unused_committed_pages);
|
||||
m_unused_committed_pages = 0;
|
||||
}
|
||||
|
||||
m_volatile = true;
|
||||
m_was_purged = false;
|
||||
return KSuccess;
|
||||
}
|
||||
// When a VMObject is made non-volatile, we try to commit however many pages are not currently available.
|
||||
// If that fails, we return false to indicate that memory allocation failed.
|
||||
size_t committed_pages_needed = 0;
|
||||
for (auto& page : m_physical_pages) {
|
||||
VERIFY(page);
|
||||
if (page->is_shared_zero_page())
|
||||
++committed_pages_needed;
|
||||
}
|
||||
|
||||
dbgln_if(COMMIT_DEBUG, "Added {} lazy-commit pages to {:p}", pages_updated, this);
|
||||
if (!committed_pages_needed) {
|
||||
m_volatile = false;
|
||||
return KSuccess;
|
||||
}
|
||||
|
||||
m_unused_committed_pages += pages_updated;
|
||||
return pages_updated;
|
||||
if (!MM.commit_user_physical_pages(committed_pages_needed))
|
||||
return ENOMEM;
|
||||
|
||||
m_unused_committed_pages = committed_pages_needed;
|
||||
|
||||
for (auto& page : m_physical_pages) {
|
||||
if (page->is_shared_zero_page())
|
||||
page = MM.lazy_committed_page();
|
||||
}
|
||||
|
||||
m_volatile = false;
|
||||
m_was_purged = false;
|
||||
return KSuccess;
|
||||
}
|
||||
|
||||
NonnullRefPtr<PhysicalPage> AnonymousVMObject::allocate_committed_page(Badge<Region>, size_t page_index)
|
||||
NonnullRefPtr<PhysicalPage> AnonymousVMObject::allocate_committed_page(Badge<Region>)
|
||||
{
|
||||
{
|
||||
ScopedSpinLock lock(m_lock);
|
||||
|
||||
VERIFY(m_unused_committed_pages > 0);
|
||||
|
||||
// We shouldn't have any committed page tags in volatile regions
|
||||
VERIFY([&]() {
|
||||
for (auto* purgeable_ranges : m_purgeable_ranges) {
|
||||
if (purgeable_ranges->is_volatile(page_index))
|
||||
return false;
|
||||
}
|
||||
return true;
|
||||
}());
|
||||
|
||||
m_unused_committed_pages--;
|
||||
--m_unused_committed_pages;
|
||||
}
|
||||
return MM.allocate_committed_user_physical_page(MemoryManager::ShouldZeroFill::Yes);
|
||||
}
|
||||
@ -404,19 +290,20 @@ size_t AnonymousVMObject::cow_pages() const
|
||||
return m_cow_map.count_slow(true);
|
||||
}
|
||||
|
||||
bool AnonymousVMObject::is_nonvolatile(size_t page_index)
|
||||
{
|
||||
if (m_volatile_ranges_cache_dirty)
|
||||
update_volatile_cache();
|
||||
return !m_volatile_ranges_cache.contains(page_index);
|
||||
}
|
||||
|
||||
PageFaultResponse AnonymousVMObject::handle_cow_fault(size_t page_index, VirtualAddress vaddr)
|
||||
{
|
||||
VERIFY_INTERRUPTS_DISABLED();
|
||||
ScopedSpinLock lock(m_lock);
|
||||
|
||||
if (is_volatile()) {
|
||||
// A COW fault in a volatile region? Userspace is writing to volatile memory, this is a bug. Crash.
|
||||
dbgln("COW fault in volatile region, will crash.");
|
||||
return PageFaultResponse::ShouldCrash;
|
||||
}
|
||||
|
||||
auto& page_slot = physical_pages()[page_index];
|
||||
bool have_committed = m_shared_committed_cow_pages && is_nonvolatile(page_index);
|
||||
bool have_committed = m_shared_committed_cow_pages;
|
||||
|
||||
if (page_slot->ref_count() == 1) {
|
||||
dbgln_if(PAGE_FAULT_DEBUG, " >> It's a COW page but nobody is sharing it anymore. Remap r/w");
|
||||
set_should_cow(page_index, false);
|
||||
@ -462,4 +349,33 @@ PageFaultResponse AnonymousVMObject::handle_cow_fault(size_t page_index, Virtual
|
||||
return PageFaultResponse::Continue;
|
||||
}
|
||||
|
||||
CommittedCowPages::CommittedCowPages(size_t committed_pages)
|
||||
: m_committed_pages(committed_pages)
|
||||
{
|
||||
}
|
||||
|
||||
CommittedCowPages::~CommittedCowPages()
|
||||
{
|
||||
// Return unused committed pages
|
||||
if (m_committed_pages > 0)
|
||||
MM.uncommit_user_physical_pages(m_committed_pages);
|
||||
}
|
||||
|
||||
NonnullRefPtr<PhysicalPage> CommittedCowPages::allocate_one()
|
||||
{
|
||||
VERIFY(m_committed_pages > 0);
|
||||
m_committed_pages--;
|
||||
|
||||
return MM.allocate_committed_user_physical_page(MemoryManager::ShouldZeroFill::Yes);
|
||||
}
|
||||
|
||||
bool CommittedCowPages::return_one()
|
||||
{
|
||||
VERIFY(m_committed_pages > 0);
|
||||
m_committed_pages--;
|
||||
|
||||
MM.uncommit_user_physical_pages(1);
|
||||
return m_committed_pages == 0;
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
@ -10,108 +10,48 @@
|
||||
#include <Kernel/VM/AllocationStrategy.h>
|
||||
#include <Kernel/VM/MemoryManager.h>
|
||||
#include <Kernel/VM/PageFaultResponse.h>
|
||||
#include <Kernel/VM/PurgeablePageRanges.h>
|
||||
#include <Kernel/VM/VMObject.h>
|
||||
|
||||
namespace Kernel {
|
||||
|
||||
class AnonymousVMObject final : public VMObject {
|
||||
friend class PurgeablePageRanges;
|
||||
class CommittedCowPages : public RefCounted<CommittedCowPages> {
|
||||
AK_MAKE_NONCOPYABLE(CommittedCowPages);
|
||||
|
||||
public:
|
||||
CommittedCowPages() = delete;
|
||||
|
||||
CommittedCowPages(size_t);
|
||||
~CommittedCowPages();
|
||||
|
||||
NonnullRefPtr<PhysicalPage> allocate_one();
|
||||
bool return_one();
|
||||
|
||||
private:
|
||||
size_t m_committed_pages;
|
||||
};
|
||||
|
||||
class AnonymousVMObject final : public VMObject {
|
||||
public:
|
||||
virtual ~AnonymousVMObject() override;
|
||||
|
||||
static RefPtr<AnonymousVMObject> try_create_with_size(size_t, AllocationStrategy);
|
||||
static RefPtr<AnonymousVMObject> try_create_for_physical_range(PhysicalAddress paddr, size_t size);
|
||||
static RefPtr<AnonymousVMObject> try_create_with_physical_pages(Span<NonnullRefPtr<PhysicalPage>>);
|
||||
static RefPtr<AnonymousVMObject> try_create_purgeable_with_size(size_t, AllocationStrategy);
|
||||
virtual RefPtr<VMObject> try_clone() override;
|
||||
|
||||
[[nodiscard]] NonnullRefPtr<PhysicalPage> allocate_committed_page(Badge<Region>, size_t);
|
||||
[[nodiscard]] NonnullRefPtr<PhysicalPage> allocate_committed_page(Badge<Region>);
|
||||
PageFaultResponse handle_cow_fault(size_t, VirtualAddress);
|
||||
size_t cow_pages() const;
|
||||
bool should_cow(size_t page_index, bool) const;
|
||||
void set_should_cow(size_t page_index, bool);
|
||||
|
||||
void register_purgeable_page_ranges(PurgeablePageRanges&);
|
||||
void unregister_purgeable_page_ranges(PurgeablePageRanges&);
|
||||
bool is_purgeable() const { return m_purgeable; }
|
||||
bool is_volatile() const { return m_volatile; }
|
||||
|
||||
int purge();
|
||||
KResult set_volatile(bool is_volatile, bool& was_purged);
|
||||
|
||||
bool is_any_volatile() const;
|
||||
|
||||
template<IteratorFunction<VolatilePageRange const&> F>
|
||||
IterationDecision for_each_volatile_range(F f) const
|
||||
{
|
||||
VERIFY(m_lock.is_locked());
|
||||
// This is a little ugly. Basically, we're trying to find the
|
||||
// volatile ranges that all share, because those are the only
|
||||
// pages we can actually purge
|
||||
for (auto* purgeable_range : m_purgeable_ranges) {
|
||||
ScopedSpinLock purgeable_lock(purgeable_range->m_volatile_ranges_lock);
|
||||
for (auto& r1 : purgeable_range->volatile_ranges().ranges()) {
|
||||
VolatilePageRange range(r1);
|
||||
for (auto* purgeable_range2 : m_purgeable_ranges) {
|
||||
if (purgeable_range2 == purgeable_range)
|
||||
continue;
|
||||
ScopedSpinLock purgeable2_lock(purgeable_range2->m_volatile_ranges_lock);
|
||||
if (purgeable_range2->is_empty()) {
|
||||
// If just one doesn't allow any purging, we can
|
||||
// immediately bail
|
||||
return IterationDecision::Continue;
|
||||
}
|
||||
for (auto const& r2 : purgeable_range2->volatile_ranges().ranges()) {
|
||||
range = range.intersected(r2);
|
||||
if (range.is_empty())
|
||||
break;
|
||||
}
|
||||
if (range.is_empty())
|
||||
break;
|
||||
}
|
||||
if (range.is_empty())
|
||||
continue;
|
||||
IterationDecision decision = f(range);
|
||||
if (decision != IterationDecision::Continue)
|
||||
return decision;
|
||||
}
|
||||
}
|
||||
return IterationDecision::Continue;
|
||||
}
|
||||
|
||||
template<IteratorFunction<VolatilePageRange const&> F>
|
||||
IterationDecision for_each_nonvolatile_range(F f) const
|
||||
{
|
||||
size_t base = 0;
|
||||
for_each_volatile_range([&](VolatilePageRange const& volatile_range) {
|
||||
if (volatile_range.base == base)
|
||||
return IterationDecision::Continue;
|
||||
IterationDecision decision = f(VolatilePageRange { base, volatile_range.base - base });
|
||||
if (decision != IterationDecision::Continue)
|
||||
return decision;
|
||||
base = volatile_range.base + volatile_range.count;
|
||||
return IterationDecision::Continue;
|
||||
});
|
||||
if (base < page_count())
|
||||
return f(VolatilePageRange { base, page_count() - base });
|
||||
return IterationDecision::Continue;
|
||||
}
|
||||
|
||||
template<VoidFunction<VolatilePageRange const&> F>
|
||||
IterationDecision for_each_volatile_range(F f) const
|
||||
{
|
||||
return for_each_volatile_range([&](auto& range) {
|
||||
f(range);
|
||||
return IterationDecision::Continue;
|
||||
});
|
||||
}
|
||||
|
||||
template<VoidFunction<VolatilePageRange const&> F>
|
||||
IterationDecision for_each_nonvolatile_range(F f) const
|
||||
{
|
||||
return for_each_nonvolatile_range([&](auto range) {
|
||||
f(move(range));
|
||||
return IterationDecision::Continue;
|
||||
});
|
||||
}
|
||||
size_t purge();
|
||||
|
||||
private:
|
||||
explicit AnonymousVMObject(size_t, AllocationStrategy);
|
||||
@ -121,15 +61,6 @@ private:
|
||||
|
||||
virtual StringView class_name() const override { return "AnonymousVMObject"sv; }
|
||||
|
||||
void update_volatile_cache();
|
||||
void set_was_purged(VolatilePageRange const&);
|
||||
size_t remove_lazy_commit_pages(VolatilePageRange const&);
|
||||
void range_made_volatile(VolatilePageRange const&);
|
||||
void range_made_nonvolatile(VolatilePageRange const&);
|
||||
size_t count_needed_commit_pages_for_nonvolatile_range(VolatilePageRange const&);
|
||||
size_t mark_committed_pages_for_nonvolatile_range(VolatilePageRange const&, size_t);
|
||||
bool is_nonvolatile(size_t page_index);
|
||||
|
||||
AnonymousVMObject& operator=(AnonymousVMObject const&) = delete;
|
||||
AnonymousVMObject& operator=(AnonymousVMObject&&) = delete;
|
||||
AnonymousVMObject(AnonymousVMObject&&) = delete;
|
||||
@ -139,15 +70,15 @@ private:
|
||||
Bitmap& ensure_cow_map();
|
||||
void ensure_or_reset_cow_map();
|
||||
|
||||
VolatilePageRanges m_volatile_ranges_cache;
|
||||
bool m_volatile_ranges_cache_dirty { true };
|
||||
Vector<PurgeablePageRanges*> m_purgeable_ranges;
|
||||
size_t m_unused_committed_pages { 0 };
|
||||
|
||||
Bitmap m_cow_map;
|
||||
|
||||
// We share a pool of committed cow-pages with clones
|
||||
RefPtr<CommittedCowPages> m_shared_committed_cow_pages;
|
||||
|
||||
bool m_purgeable { false };
|
||||
bool m_volatile { false };
|
||||
bool m_was_purged { false };
|
||||
};
|
||||
|
||||
}
|
||||
|
||||
@ -1,310 +0,0 @@
|
||||
/*
|
||||
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
|
||||
*
|
||||
* SPDX-License-Identifier: BSD-2-Clause
|
||||
*/
|
||||
|
||||
#include <AK/BinarySearch.h>
|
||||
#include <AK/ScopeGuard.h>
|
||||
#include <Kernel/Debug.h>
|
||||
#include <Kernel/Process.h>
|
||||
#include <Kernel/VM/AnonymousVMObject.h>
|
||||
#include <Kernel/VM/MemoryManager.h>
|
||||
#include <Kernel/VM/PhysicalPage.h>
|
||||
#include <Kernel/VM/PurgeablePageRanges.h>
|
||||
|
||||
namespace AK {
|
||||
template<>
|
||||
struct Formatter<Kernel::VolatilePageRange> : Formatter<String> {
|
||||
void format(FormatBuilder& builder, const Kernel::VolatilePageRange& value)
|
||||
{
|
||||
return Formatter<String>::format(builder, String::formatted("{{{} ({}) purged: {}}}", value.base, value.count, value.was_purged));
|
||||
}
|
||||
};
|
||||
}
|
||||
|
||||
namespace Kernel {
|
||||
|
||||
static void dump_volatile_page_ranges(const Vector<VolatilePageRange>& ranges)
|
||||
{
|
||||
if constexpr (VOLATILE_PAGE_RANGES_DEBUG) {
|
||||
for (size_t i = 0; i < ranges.size(); i++) {
|
||||
dbgln("[{}] {}", i, ranges[i]);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
void VolatilePageRanges::add_unchecked(const VolatilePageRange& range)
|
||||
{
|
||||
auto add_range = m_total_range.intersected(range);
|
||||
if (add_range.is_empty())
|
||||
return;
|
||||
m_ranges.append(range);
|
||||
}
|
||||
|
||||
bool VolatilePageRanges::add(const VolatilePageRange& range)
|
||||
{
|
||||
auto add_range = m_total_range.intersected(range);
|
||||
if (add_range.is_empty())
|
||||
return false;
|
||||
add_range.was_purged = range.was_purged;
|
||||
|
||||
if constexpr (VOLATILE_PAGE_RANGES_DEBUG) {
|
||||
dbgln("ADD {} (total range: {}) -->", range, m_total_range);
|
||||
dump_volatile_page_ranges(m_ranges);
|
||||
ScopeGuard debug_guard([&]() {
|
||||
dbgln("After adding {} (total range: {})", range, m_total_range);
|
||||
dump_volatile_page_ranges(m_ranges);
|
||||
dbgln("<-- ADD {} (total range: {})", range, m_total_range);
|
||||
});
|
||||
}
|
||||
|
||||
size_t nearby_index = 0;
|
||||
auto* existing_range = binary_search(
|
||||
m_ranges.span(), add_range, &nearby_index, [](auto& a, auto& b) {
|
||||
if (a.intersects_or_adjacent(b))
|
||||
return 0;
|
||||
return (signed)(a.base - (b.base + b.count - 1));
|
||||
});
|
||||
|
||||
size_t inserted_index = 0;
|
||||
if (existing_range) {
|
||||
if (*existing_range == add_range)
|
||||
return false;
|
||||
|
||||
if (existing_range->was_purged != add_range.was_purged) {
|
||||
// Found an intersecting or adjacent range, but the purge flag
|
||||
// doesn't match. Subtract what we're adding from it, and
|
||||
existing_range->subtract_intersecting(add_range);
|
||||
if (existing_range->is_empty()) {
|
||||
*existing_range = add_range;
|
||||
} else {
|
||||
m_ranges.insert(++nearby_index, add_range);
|
||||
existing_range = &m_ranges[nearby_index];
|
||||
}
|
||||
} else {
|
||||
// Found an intersecting or adjacent range that can be merged
|
||||
existing_range->combine_intersecting_or_adjacent(add_range);
|
||||
}
|
||||
inserted_index = nearby_index;
|
||||
} else {
|
||||
// Insert into the sorted list
|
||||
m_ranges.insert_before_matching(
|
||||
VolatilePageRange(add_range), [&](auto& entry) {
|
||||
return entry.base >= add_range.base + add_range.count;
|
||||
},
|
||||
nearby_index, &inserted_index);
|
||||
existing_range = &m_ranges[inserted_index];
|
||||
}
|
||||
|
||||
// See if we can merge any of the following ranges
|
||||
inserted_index++;
|
||||
while (inserted_index < m_ranges.size()) {
|
||||
auto& next_range = m_ranges[inserted_index];
|
||||
if (!next_range.intersects_or_adjacent(*existing_range))
|
||||
break;
|
||||
if (next_range.was_purged != existing_range->was_purged) {
|
||||
// The purged flag of following range is not the same.
|
||||
// Subtract the added/combined range from it
|
||||
next_range.subtract_intersecting(*existing_range);
|
||||
if (next_range.is_empty())
|
||||
m_ranges.remove(inserted_index);
|
||||
} else {
|
||||
existing_range->combine_intersecting_or_adjacent(next_range);
|
||||
m_ranges.remove(inserted_index);
|
||||
}
|
||||
}
|
||||
return true;
|
||||
}
|
||||
|
||||
bool VolatilePageRanges::remove(const VolatilePageRange& range, bool& was_purged)
|
||||
{
|
||||
auto remove_range = m_total_range.intersected(range);
|
||||
if (remove_range.is_empty())
|
||||
return false;
|
||||
|
||||
if constexpr (VOLATILE_PAGE_RANGES_DEBUG) {
|
||||
dbgln("REMOVE {} (total range: {}) -->", range, m_total_range);
|
||||
dump_volatile_page_ranges(m_ranges);
|
||||
ScopeGuard debug_guard([&]() {
|
||||
dbgln("After removing {} (total range: {})", range, m_total_range);
|
||||
dump_volatile_page_ranges(m_ranges);
|
||||
dbgln("<-- REMOVE {} (total range: {}) was_purged: {}", range, m_total_range, was_purged);
|
||||
});
|
||||
}
|
||||
|
||||
size_t nearby_index = 0;
|
||||
auto* existing_range = binary_search(
|
||||
m_ranges.span(), remove_range, &nearby_index, [](auto& a, auto& b) {
|
||||
if (a.intersects(b))
|
||||
return 0;
|
||||
return (signed)(a.base - (b.base + b.count - 1));
|
||||
});
|
||||
if (!existing_range)
|
||||
return false;
|
||||
|
||||
was_purged = existing_range->was_purged;
|
||||
if (existing_range->range_equals(remove_range)) {
|
||||
m_ranges.remove(nearby_index);
|
||||
} else {
|
||||
// See if we need to remove any of the following ranges
|
||||
VERIFY(existing_range == &m_ranges[nearby_index]); // sanity check
|
||||
while (nearby_index < m_ranges.size()) {
|
||||
existing_range = &m_ranges[nearby_index];
|
||||
if (!existing_range->intersects(range))
|
||||
break;
|
||||
was_purged |= existing_range->was_purged;
|
||||
existing_range->subtract_intersecting(remove_range);
|
||||
if (existing_range->is_empty()) {
|
||||
m_ranges.remove(nearby_index);
|
||||
break;
|
||||
}
|
||||
}
|
||||
}
|
||||
return true;
|
||||
}
|
||||
|
||||
bool VolatilePageRanges::intersects(const VolatilePageRange& range) const
|
||||
{
|
||||
auto* existing_range = binary_search(
|
||||
m_ranges.span(), range, nullptr, [](auto& a, auto& b) {
|
||||
if (a.intersects(b))
|
||||
return 0;
|
||||
return (signed)(a.base - (b.base + b.count - 1));
|
||||
});
|
||||
return existing_range != nullptr;
|
||||
}
|
||||
|
||||
PurgeablePageRanges::PurgeablePageRanges(const VMObject& vmobject)
|
||||
: m_volatile_ranges({ 0, vmobject.is_anonymous() ? vmobject.page_count() : 0 })
|
||||
{
|
||||
}
|
||||
|
||||
bool PurgeablePageRanges::add_volatile_range(const VolatilePageRange& range)
|
||||
{
|
||||
if (range.is_empty())
|
||||
return false;
|
||||
|
||||
// Since we may need to call into AnonymousVMObject we need to acquire
|
||||
// its lock as well, and acquire it first. This is important so that
|
||||
// we don't deadlock when a page fault (e.g. on another processor)
|
||||
// happens that is meant to lazy-allocate a committed page. It would
|
||||
// call into AnonymousVMObject::range_made_volatile, which then would
|
||||
// also call into this object and need to acquire m_lock. By acquiring
|
||||
// the vmobject lock first in both cases, we avoid deadlocking.
|
||||
// We can access m_vmobject without any locks for that purpose because
|
||||
// add_volatile_range and remove_volatile_range can only be called
|
||||
// by same object that calls set_vmobject.
|
||||
ScopedSpinLock vmobject_lock(m_vmobject->m_lock);
|
||||
ScopedSpinLock lock(m_volatile_ranges_lock);
|
||||
bool added = m_volatile_ranges.add(range);
|
||||
if (added)
|
||||
m_vmobject->range_made_volatile(range);
|
||||
return added;
|
||||
}
|
||||
|
||||
auto PurgeablePageRanges::remove_volatile_range(const VolatilePageRange& range, bool& was_purged) -> RemoveVolatileError
|
||||
{
|
||||
if (range.is_empty()) {
|
||||
was_purged = false;
|
||||
return RemoveVolatileError::Success;
|
||||
}
|
||||
ScopedSpinLock vmobject_lock(m_vmobject->m_lock); // see comment in add_volatile_range
|
||||
ScopedSpinLock lock(m_volatile_ranges_lock);
|
||||
VERIFY(m_vmobject);
|
||||
|
||||
// Before we actually remove this range, we need to check if we need
|
||||
// to commit any pages, which may fail. If it fails, we don't actually
|
||||
// want to make any modifications. COW pages are already accounted for
|
||||
// in m_shared_committed_cow_pages
|
||||
size_t need_commit_pages = 0;
|
||||
m_volatile_ranges.for_each_intersecting_range(range, [&](const VolatilePageRange& intersected_range) {
|
||||
need_commit_pages += m_vmobject->count_needed_commit_pages_for_nonvolatile_range(intersected_range);
|
||||
return IterationDecision::Continue;
|
||||
});
|
||||
if (need_commit_pages > 0) {
|
||||
// See if we can grab enough pages for what we're marking non-volatile
|
||||
if (!MM.commit_user_physical_pages(need_commit_pages))
|
||||
return RemoveVolatileError::OutOfMemory;
|
||||
|
||||
// Now that we are committed to these pages, mark them for lazy-commit allocation
|
||||
auto pages_to_mark = need_commit_pages;
|
||||
m_volatile_ranges.for_each_intersecting_range(range, [&](const VolatilePageRange& intersected_range) {
|
||||
auto pages_marked = m_vmobject->mark_committed_pages_for_nonvolatile_range(intersected_range, pages_to_mark);
|
||||
pages_to_mark -= pages_marked;
|
||||
return IterationDecision::Continue;
|
||||
});
|
||||
}
|
||||
|
||||
// Now actually remove the range
|
||||
if (m_volatile_ranges.remove(range, was_purged)) {
|
||||
m_vmobject->range_made_nonvolatile(range);
|
||||
return RemoveVolatileError::Success;
|
||||
}
|
||||
|
||||
VERIFY(need_commit_pages == 0); // We should have not touched anything
|
||||
return RemoveVolatileError::SuccessNoChange;
|
||||
}
|
||||
|
||||
bool PurgeablePageRanges::is_volatile_range(const VolatilePageRange& range) const
|
||||
{
|
||||
if (range.is_empty())
|
||||
return false;
|
||||
ScopedSpinLock lock(m_volatile_ranges_lock);
|
||||
return m_volatile_ranges.intersects(range);
|
||||
}
|
||||
|
||||
bool PurgeablePageRanges::is_volatile(size_t index) const
|
||||
{
|
||||
ScopedSpinLock lock(m_volatile_ranges_lock);
|
||||
return m_volatile_ranges.contains(index);
|
||||
}
|
||||
|
||||
void PurgeablePageRanges::set_was_purged(const VolatilePageRange& range)
|
||||
{
|
||||
ScopedSpinLock lock(m_volatile_ranges_lock);
|
||||
m_volatile_ranges.add({ range.base, range.count, true });
|
||||
}
|
||||
|
||||
void PurgeablePageRanges::set_vmobject(AnonymousVMObject* vmobject)
|
||||
{
|
||||
// No lock needed here
|
||||
if (vmobject) {
|
||||
VERIFY(!m_vmobject);
|
||||
m_vmobject = vmobject;
|
||||
} else {
|
||||
VERIFY(m_vmobject);
|
||||
m_vmobject = nullptr;
|
||||
}
|
||||
}
|
||||
|
||||
CommittedCowPages::CommittedCowPages(size_t committed_pages)
|
||||
: m_committed_pages(committed_pages)
|
||||
{
|
||||
}
|
||||
|
||||
CommittedCowPages::~CommittedCowPages()
|
||||
{
|
||||
// Return unused committed pages
|
||||
if (m_committed_pages > 0)
|
||||
MM.uncommit_user_physical_pages(m_committed_pages);
|
||||
}
|
||||
|
||||
NonnullRefPtr<PhysicalPage> CommittedCowPages::allocate_one()
|
||||
{
|
||||
VERIFY(m_committed_pages > 0);
|
||||
m_committed_pages--;
|
||||
|
||||
return MM.allocate_committed_user_physical_page(MemoryManager::ShouldZeroFill::Yes);
|
||||
}
|
||||
|
||||
bool CommittedCowPages::return_one()
|
||||
{
|
||||
VERIFY(m_committed_pages > 0);
|
||||
m_committed_pages--;
|
||||
|
||||
MM.uncommit_user_physical_pages(1);
|
||||
return m_committed_pages == 0;
|
||||
}
|
||||
|
||||
}
|
||||
@ -1,245 +0,0 @@
|
||||
/*
|
||||
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
|
||||
*
|
||||
* SPDX-License-Identifier: BSD-2-Clause
|
||||
*/
|
||||
|
||||
#pragma once
|
||||
|
||||
#include <AK/Bitmap.h>
|
||||
#include <AK/RefCounted.h>
|
||||
#include <Kernel/SpinLock.h>
|
||||
|
||||
namespace Kernel {
|
||||
|
||||
struct VolatilePageRange {
|
||||
size_t base { 0 };
|
||||
size_t count { 0 };
|
||||
bool was_purged { false };
|
||||
|
||||
bool is_empty() const { return count == 0; }
|
||||
|
||||
bool intersects(const VolatilePageRange& other) const
|
||||
{
|
||||
return other.base < base + count || other.base + other.count > base;
|
||||
}
|
||||
|
||||
bool intersects_or_adjacent(const VolatilePageRange& other) const
|
||||
{
|
||||
return other.base <= base + count || other.base + other.count >= base;
|
||||
}
|
||||
|
||||
bool contains(const VolatilePageRange& other) const
|
||||
{
|
||||
return base <= other.base && base + count >= other.base + other.count;
|
||||
}
|
||||
|
||||
VolatilePageRange intersected(const VolatilePageRange& other) const
|
||||
{
|
||||
auto b = max(base, other.base);
|
||||
auto e = min(base + count, other.base + other.count);
|
||||
if (b >= e)
|
||||
return {};
|
||||
return { b, e - b, was_purged };
|
||||
}
|
||||
|
||||
void combine_intersecting_or_adjacent(const VolatilePageRange& other)
|
||||
{
|
||||
VERIFY(intersects_or_adjacent(other));
|
||||
if (base <= other.base) {
|
||||
count = (other.base - base) + other.count;
|
||||
} else {
|
||||
count = (base - other.base) + count;
|
||||
base = other.base;
|
||||
}
|
||||
was_purged |= other.was_purged;
|
||||
}
|
||||
|
||||
void subtract_intersecting(const VolatilePageRange& other)
|
||||
{
|
||||
if (!intersects(other))
|
||||
return;
|
||||
if (other.contains(*this)) {
|
||||
count = 0;
|
||||
return;
|
||||
}
|
||||
if (base <= other.base) {
|
||||
count = (other.base - base);
|
||||
} else {
|
||||
auto new_base = other.base + other.count;
|
||||
count = (base + count) - new_base;
|
||||
base = new_base;
|
||||
}
|
||||
}
|
||||
|
||||
bool range_equals(const VolatilePageRange& other) const
|
||||
{
|
||||
return base == other.base && count == other.count;
|
||||
}
|
||||
bool operator==(const VolatilePageRange& other) const
|
||||
{
|
||||
return base == other.base && count == other.count && was_purged == other.was_purged;
|
||||
}
|
||||
bool operator!=(const VolatilePageRange& other) const
|
||||
{
|
||||
return base != other.base || count != other.count || was_purged != other.was_purged;
|
||||
}
|
||||
};
|
||||
|
||||
class VolatilePageRanges {
|
||||
public:
|
||||
VolatilePageRanges(const VolatilePageRange& total_range)
|
||||
: m_total_range(total_range)
|
||||
{
|
||||
}
|
||||
VolatilePageRanges(const VolatilePageRanges& other)
|
||||
: m_ranges(other.m_ranges)
|
||||
, m_total_range(other.m_total_range)
|
||||
{
|
||||
}
|
||||
|
||||
bool is_empty() const { return m_ranges.is_empty(); }
|
||||
void clear() { m_ranges.clear_with_capacity(); }
|
||||
|
||||
bool is_all() const
|
||||
{
|
||||
if (m_ranges.size() != 1)
|
||||
return false;
|
||||
return m_ranges[0] == m_total_range;
|
||||
}
|
||||
|
||||
void set_all()
|
||||
{
|
||||
if (m_ranges.size() != 1)
|
||||
m_ranges = { m_total_range };
|
||||
else
|
||||
m_ranges[0] = m_total_range;
|
||||
}
|
||||
|
||||
bool intersects(const VolatilePageRange&) const;
|
||||
bool contains(size_t index) const
|
||||
{
|
||||
return intersects({ index, 1 });
|
||||
}
|
||||
|
||||
bool add(const VolatilePageRange&);
|
||||
void add_unchecked(const VolatilePageRange&);
|
||||
bool remove(const VolatilePageRange&, bool&);
|
||||
|
||||
template<typename F>
|
||||
IterationDecision for_each_intersecting_range(const VolatilePageRange& range, F f)
|
||||
{
|
||||
auto r = m_total_range.intersected(range);
|
||||
if (r.is_empty())
|
||||
return IterationDecision::Continue;
|
||||
|
||||
size_t nearby_index = 0;
|
||||
auto* existing_range = binary_search(
|
||||
m_ranges.span(), r, &nearby_index, [](auto& a, auto& b) {
|
||||
if (a.intersects(b))
|
||||
return 0;
|
||||
return (signed)(a.base - (b.base + b.count - 1));
|
||||
});
|
||||
if (!existing_range)
|
||||
return IterationDecision::Continue;
|
||||
|
||||
if (existing_range->range_equals(r))
|
||||
return f(r);
|
||||
VERIFY(existing_range == &m_ranges[nearby_index]); // sanity check
|
||||
while (nearby_index < m_ranges.size()) {
|
||||
existing_range = &m_ranges[nearby_index];
|
||||
if (!existing_range->intersects(range))
|
||||
break;
|
||||
|
||||
IterationDecision decision = f(existing_range->intersected(r));
|
||||
if (decision != IterationDecision::Continue)
|
||||
return decision;
|
||||
|
||||
nearby_index++;
|
||||
}
|
||||
return IterationDecision::Continue;
|
||||
}
|
||||
|
||||
template<typename F>
|
||||
IterationDecision for_each_nonvolatile_range(F f) const
|
||||
{
|
||||
size_t base = m_total_range.base;
|
||||
for (const auto& volatile_range : m_ranges) {
|
||||
if (volatile_range.base == base)
|
||||
continue;
|
||||
IterationDecision decision = f({ base, volatile_range.base - base });
|
||||
if (decision != IterationDecision::Continue)
|
||||
return decision;
|
||||
base = volatile_range.base + volatile_range.count;
|
||||
}
|
||||
if (base < m_total_range.base + m_total_range.count)
|
||||
return f({ base, (m_total_range.base + m_total_range.count) - base });
|
||||
return IterationDecision::Continue;
|
||||
}
|
||||
|
||||
Vector<VolatilePageRange>& ranges() { return m_ranges; }
|
||||
const Vector<VolatilePageRange>& ranges() const { return m_ranges; }
|
||||
|
||||
private:
|
||||
Vector<VolatilePageRange> m_ranges;
|
||||
VolatilePageRange m_total_range;
|
||||
};
|
||||
|
||||
class AnonymousVMObject;
|
||||
|
||||
class PurgeablePageRanges {
|
||||
friend class AnonymousVMObject;
|
||||
|
||||
public:
|
||||
PurgeablePageRanges(const VMObject&);
|
||||
|
||||
void copy_purgeable_page_ranges(const PurgeablePageRanges& other)
|
||||
{
|
||||
if (this == &other)
|
||||
return;
|
||||
ScopedSpinLock lock(m_volatile_ranges_lock);
|
||||
ScopedSpinLock other_lock(other.m_volatile_ranges_lock);
|
||||
m_volatile_ranges = other.m_volatile_ranges;
|
||||
}
|
||||
|
||||
bool add_volatile_range(const VolatilePageRange& range);
|
||||
enum class RemoveVolatileError {
|
||||
Success = 0,
|
||||
SuccessNoChange,
|
||||
OutOfMemory
|
||||
};
|
||||
RemoveVolatileError remove_volatile_range(const VolatilePageRange& range, bool& was_purged);
|
||||
bool is_volatile_range(const VolatilePageRange& range) const;
|
||||
bool is_volatile(size_t) const;
|
||||
|
||||
bool is_empty() const { return m_volatile_ranges.is_empty(); }
|
||||
|
||||
void set_was_purged(const VolatilePageRange&);
|
||||
|
||||
const VolatilePageRanges& volatile_ranges() const { return m_volatile_ranges; }
|
||||
|
||||
protected:
|
||||
void set_vmobject(AnonymousVMObject*);
|
||||
|
||||
VolatilePageRanges m_volatile_ranges;
|
||||
mutable RecursiveSpinLock m_volatile_ranges_lock;
|
||||
AnonymousVMObject* m_vmobject { nullptr };
|
||||
};
|
||||
|
||||
class CommittedCowPages : public RefCounted<CommittedCowPages> {
|
||||
AK_MAKE_NONCOPYABLE(CommittedCowPages);
|
||||
|
||||
public:
|
||||
CommittedCowPages() = delete;
|
||||
|
||||
CommittedCowPages(size_t);
|
||||
~CommittedCowPages();
|
||||
|
||||
NonnullRefPtr<PhysicalPage> allocate_one();
|
||||
bool return_one();
|
||||
|
||||
private:
|
||||
size_t m_committed_pages;
|
||||
};
|
||||
|
||||
}
|
||||
@ -20,8 +20,7 @@
|
||||
namespace Kernel {
|
||||
|
||||
Region::Region(Range const& range, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, OwnPtr<KString> name, Region::Access access, Cacheable cacheable, bool shared)
|
||||
: PurgeablePageRanges(vmobject)
|
||||
, m_range(range)
|
||||
: m_range(range)
|
||||
, m_offset_in_vmobject(offset_in_vmobject)
|
||||
, m_vmobject(move(vmobject))
|
||||
, m_name(move(name))
|
||||
@ -34,14 +33,12 @@ Region::Region(Range const& range, NonnullRefPtr<VMObject> vmobject, size_t offs
|
||||
VERIFY((m_range.size() % PAGE_SIZE) == 0);
|
||||
|
||||
m_vmobject->add_region(*this);
|
||||
register_purgeable_page_ranges();
|
||||
MM.register_region(*this);
|
||||
}
|
||||
|
||||
Region::~Region()
|
||||
{
|
||||
m_vmobject->remove_region(*this);
|
||||
unregister_purgeable_page_ranges();
|
||||
|
||||
// Make sure we disable interrupts so we don't get interrupted between unmapping and unregistering.
|
||||
// Unmapping the region will give the VM back to the RangeAllocator, so an interrupt handler would
|
||||
@ -55,22 +52,6 @@ Region::~Region()
|
||||
MM.unregister_region(*this);
|
||||
}
|
||||
|
||||
void Region::register_purgeable_page_ranges()
|
||||
{
|
||||
if (m_vmobject->is_anonymous()) {
|
||||
auto& vmobject = static_cast<AnonymousVMObject&>(*m_vmobject);
|
||||
vmobject.register_purgeable_page_ranges(*this);
|
||||
}
|
||||
}
|
||||
|
||||
void Region::unregister_purgeable_page_ranges()
|
||||
{
|
||||
if (m_vmobject->is_anonymous()) {
|
||||
auto& vmobject = static_cast<AnonymousVMObject&>(*m_vmobject);
|
||||
vmobject.unregister_purgeable_page_ranges(*this);
|
||||
}
|
||||
}
|
||||
|
||||
OwnPtr<Region> Region::clone(Process& new_owner)
|
||||
{
|
||||
VERIFY(Process::current());
|
||||
@ -89,8 +70,6 @@ OwnPtr<Region> Region::clone(Process& new_owner)
|
||||
dbgln("Region::clone: Unable to allocate new Region");
|
||||
return nullptr;
|
||||
}
|
||||
if (m_vmobject->is_anonymous())
|
||||
region->copy_purgeable_page_ranges(*this);
|
||||
region->set_mmap(m_mmap);
|
||||
region->set_shared(m_shared);
|
||||
region->set_syscall_region(is_syscall_region());
|
||||
@ -112,8 +91,6 @@ OwnPtr<Region> Region::clone(Process& new_owner)
|
||||
dbgln("Region::clone: Unable to allocate new Region for COW");
|
||||
return nullptr;
|
||||
}
|
||||
if (m_vmobject->is_anonymous())
|
||||
clone_region->copy_purgeable_page_ranges(*this);
|
||||
if (m_stack) {
|
||||
VERIFY(is_readable());
|
||||
VERIFY(is_writable());
|
||||
@ -129,55 +106,9 @@ void Region::set_vmobject(NonnullRefPtr<VMObject>&& obj)
|
||||
{
|
||||
if (m_vmobject.ptr() == obj.ptr())
|
||||
return;
|
||||
unregister_purgeable_page_ranges();
|
||||
m_vmobject->remove_region(*this);
|
||||
m_vmobject = move(obj);
|
||||
m_vmobject->add_region(*this);
|
||||
register_purgeable_page_ranges();
|
||||
}
|
||||
|
||||
bool Region::is_volatile(VirtualAddress vaddr, size_t size) const
|
||||
{
|
||||
if (!m_vmobject->is_anonymous())
|
||||
return false;
|
||||
|
||||
auto offset_in_vmobject = vaddr.get() - (this->vaddr().get() - m_offset_in_vmobject);
|
||||
size_t first_page_index = page_round_down(offset_in_vmobject) / PAGE_SIZE;
|
||||
size_t last_page_index = page_round_up(offset_in_vmobject + size) / PAGE_SIZE;
|
||||
return is_volatile_range({ first_page_index, last_page_index - first_page_index });
|
||||
}
|
||||
|
||||
auto Region::set_volatile(VirtualAddress vaddr, size_t size, bool is_volatile, bool& was_purged) -> SetVolatileError
|
||||
{
|
||||
was_purged = false;
|
||||
if (!m_vmobject->is_anonymous())
|
||||
return SetVolatileError::NotPurgeable;
|
||||
|
||||
auto offset_in_vmobject = vaddr.get() - (this->vaddr().get() - m_offset_in_vmobject);
|
||||
if (is_volatile) {
|
||||
// If marking pages as volatile, be prudent by not marking
|
||||
// partial pages volatile to prevent potentially non-volatile
|
||||
// data to be discarded. So rund up the first page and round
|
||||
// down the last page.
|
||||
size_t first_page_index = page_round_up(offset_in_vmobject) / PAGE_SIZE;
|
||||
size_t last_page_index = page_round_down(offset_in_vmobject + size) / PAGE_SIZE;
|
||||
if (first_page_index != last_page_index)
|
||||
add_volatile_range({ first_page_index, last_page_index - first_page_index });
|
||||
} else {
|
||||
// If marking pages as non-volatile, round down the first page
|
||||
// and round up the last page to make sure the beginning and
|
||||
// end of the range doesn't inadvertedly get discarded.
|
||||
size_t first_page_index = page_round_down(offset_in_vmobject) / PAGE_SIZE;
|
||||
size_t last_page_index = page_round_up(offset_in_vmobject + size) / PAGE_SIZE;
|
||||
switch (remove_volatile_range({ first_page_index, last_page_index - first_page_index }, was_purged)) {
|
||||
case PurgeablePageRanges::RemoveVolatileError::Success:
|
||||
case PurgeablePageRanges::RemoveVolatileError::SuccessNoChange:
|
||||
break;
|
||||
case PurgeablePageRanges::RemoveVolatileError::OutOfMemory:
|
||||
return SetVolatileError::OutOfMemory;
|
||||
}
|
||||
}
|
||||
return SetVolatileError::Success;
|
||||
}
|
||||
|
||||
size_t Region::cow_pages() const
|
||||
@ -279,43 +210,6 @@ bool Region::map_individual_page_impl(size_t page_index)
|
||||
return true;
|
||||
}
|
||||
|
||||
bool Region::do_remap_vmobject_page_range(size_t page_index, size_t page_count)
|
||||
{
|
||||
bool success = true;
|
||||
if (!m_page_directory)
|
||||
return success; // not an error, region may have not yet mapped it
|
||||
if (!translate_vmobject_page_range(page_index, page_count))
|
||||
return success; // not an error, region doesn't map this page range
|
||||
ScopedSpinLock page_lock(m_page_directory->get_lock());
|
||||
size_t index = page_index;
|
||||
while (index < page_index + page_count) {
|
||||
if (!map_individual_page_impl(index)) {
|
||||
success = false;
|
||||
break;
|
||||
}
|
||||
index++;
|
||||
}
|
||||
if (index > page_index)
|
||||
MM.flush_tlb(m_page_directory, vaddr_from_page_index(page_index), index - page_index);
|
||||
return success;
|
||||
}
|
||||
|
||||
bool Region::remap_vmobject_page_range(size_t page_index, size_t page_count)
|
||||
{
|
||||
bool success = true;
|
||||
auto& vmobject = this->vmobject();
|
||||
if (vmobject.is_shared_by_multiple_regions()) {
|
||||
vmobject.for_each_region([&](auto& region) {
|
||||
if (!region.do_remap_vmobject_page_range(page_index, page_count))
|
||||
success = false;
|
||||
});
|
||||
} else {
|
||||
if (!do_remap_vmobject_page_range(page_index, page_count))
|
||||
success = false;
|
||||
}
|
||||
return success;
|
||||
}
|
||||
|
||||
bool Region::do_remap_vmobject_page(size_t page_index, bool with_flush)
|
||||
{
|
||||
ScopedSpinLock lock(vmobject().m_lock);
|
||||
@ -428,7 +322,7 @@ PageFaultResponse Region::handle_fault(PageFault const& fault)
|
||||
if (page_slot->is_lazy_committed_page()) {
|
||||
auto page_index_in_vmobject = translate_to_vmobject_page(page_index_in_region);
|
||||
VERIFY(m_vmobject->is_anonymous());
|
||||
page_slot = static_cast<AnonymousVMObject&>(*m_vmobject).allocate_committed_page({}, page_index_in_vmobject);
|
||||
page_slot = static_cast<AnonymousVMObject&>(*m_vmobject).allocate_committed_page({});
|
||||
remap_vmobject_page(page_index_in_vmobject);
|
||||
return PageFaultResponse::Continue;
|
||||
}
|
||||
@ -472,7 +366,7 @@ PageFaultResponse Region::handle_zero_fault(size_t page_index_in_region)
|
||||
|
||||
if (page_slot->is_lazy_committed_page()) {
|
||||
VERIFY(m_vmobject->is_anonymous());
|
||||
page_slot = static_cast<AnonymousVMObject&>(*m_vmobject).allocate_committed_page({}, page_index_in_vmobject);
|
||||
page_slot = static_cast<AnonymousVMObject&>(*m_vmobject).allocate_committed_page({});
|
||||
dbgln_if(PAGE_FAULT_DEBUG, " >> ALLOCATED COMMITTED {}", page_slot->paddr());
|
||||
} else {
|
||||
page_slot = MM.allocate_user_physical_page(MemoryManager::ShouldZeroFill::Yes);
|
||||
|
||||
@ -17,7 +17,6 @@
|
||||
#include <Kernel/Sections.h>
|
||||
#include <Kernel/UnixTypes.h>
|
||||
#include <Kernel/VM/PageFaultResponse.h>
|
||||
#include <Kernel/VM/PurgeablePageRanges.h>
|
||||
#include <Kernel/VM/RangeAllocator.h>
|
||||
|
||||
namespace Kernel {
|
||||
@ -28,8 +27,7 @@ enum class ShouldFlushTLB {
|
||||
};
|
||||
|
||||
class Region final
|
||||
: public Weakable<Region>
|
||||
, public PurgeablePageRanges {
|
||||
: public Weakable<Region> {
|
||||
friend class MemoryManager;
|
||||
|
||||
MAKE_SLAB_ALLOCATED(Region)
|
||||
@ -201,15 +199,11 @@ public:
|
||||
|
||||
void remap();
|
||||
|
||||
bool remap_vmobject_page_range(size_t page_index, size_t page_count);
|
||||
|
||||
bool is_volatile(VirtualAddress vaddr, size_t size) const;
|
||||
enum class SetVolatileError {
|
||||
Success = 0,
|
||||
NotPurgeable,
|
||||
OutOfMemory
|
||||
};
|
||||
SetVolatileError set_volatile(VirtualAddress vaddr, size_t size, bool is_volatile, bool& was_purged);
|
||||
|
||||
RefPtr<Process> get_owner();
|
||||
|
||||
@ -219,7 +213,8 @@ public:
|
||||
private:
|
||||
Region(Range const&, NonnullRefPtr<VMObject>, size_t offset_in_vmobject, OwnPtr<KString>, Region::Access access, Cacheable, bool shared);
|
||||
|
||||
bool do_remap_vmobject_page_range(size_t page_index, size_t page_count);
|
||||
bool remap_vmobject_page(size_t page_index, bool with_flush = true);
|
||||
bool do_remap_vmobject_page(size_t page_index, bool with_flush = true);
|
||||
|
||||
void set_access_bit(Access access, bool b)
|
||||
{
|
||||
@ -229,18 +224,12 @@ private:
|
||||
m_access &= ~access;
|
||||
}
|
||||
|
||||
bool do_remap_vmobject_page(size_t index, bool with_flush = true);
|
||||
bool remap_vmobject_page(size_t index, bool with_flush = true);
|
||||
|
||||
PageFaultResponse handle_cow_fault(size_t page_index);
|
||||
PageFaultResponse handle_inode_fault(size_t page_index);
|
||||
PageFaultResponse handle_zero_fault(size_t page_index);
|
||||
|
||||
bool map_individual_page_impl(size_t page_index);
|
||||
|
||||
void register_purgeable_page_ranges();
|
||||
void unregister_purgeable_page_ranges();
|
||||
|
||||
RefPtr<PageDirectory> m_page_directory;
|
||||
Range m_range;
|
||||
size_t m_offset_in_vmobject { 0 };
|
||||
|
||||
@ -414,7 +414,10 @@ size_t Space::amount_purgeable_volatile() const
|
||||
ScopedSpinLock lock(m_lock);
|
||||
size_t amount = 0;
|
||||
for (auto& region : m_regions) {
|
||||
if (region->vmobject().is_anonymous() && static_cast<const AnonymousVMObject&>(region->vmobject()).is_any_volatile())
|
||||
if (!region->vmobject().is_anonymous())
|
||||
continue;
|
||||
auto const& vmobject = static_cast<AnonymousVMObject const&>(region->vmobject());
|
||||
if (vmobject.is_purgeable() && vmobject.is_volatile())
|
||||
amount += region->amount_resident();
|
||||
}
|
||||
return amount;
|
||||
@ -425,7 +428,10 @@ size_t Space::amount_purgeable_nonvolatile() const
|
||||
ScopedSpinLock lock(m_lock);
|
||||
size_t amount = 0;
|
||||
for (auto& region : m_regions) {
|
||||
if (region->vmobject().is_anonymous() && !static_cast<const AnonymousVMObject&>(region->vmobject()).is_any_volatile())
|
||||
if (!region->vmobject().is_anonymous())
|
||||
continue;
|
||||
auto const& vmobject = static_cast<AnonymousVMObject const&>(region->vmobject());
|
||||
if (vmobject.is_purgeable() && !vmobject.is_volatile())
|
||||
amount += region->amount_resident();
|
||||
}
|
||||
return amount;
|
||||
|
||||
@ -158,7 +158,7 @@ extern "C" {
|
||||
|
||||
static void* os_alloc(size_t size, const char* name)
|
||||
{
|
||||
auto* ptr = serenity_mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0, ChunkedBlock::block_size, name);
|
||||
auto* ptr = serenity_mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE | MAP_PURGEABLE, 0, 0, ChunkedBlock::block_size, name);
|
||||
VERIFY(ptr != MAP_FAILED);
|
||||
return ptr;
|
||||
}
|
||||
|
||||
@ -18,6 +18,7 @@
|
||||
#define MAP_STACK 0x40
|
||||
#define MAP_NORESERVE 0x80
|
||||
#define MAP_RANDOMIZED 0x100
|
||||
#define MAP_PURGEABLE 0x200
|
||||
|
||||
#define PROT_READ 0x1
|
||||
#define PROT_WRITE 0x2
|
||||
|
||||
@ -544,11 +544,11 @@ void Bitmap::set_volatile()
|
||||
int rc = madvise(m_data, size_in_bytes(), MADV_SET_NONVOLATILE);
|
||||
if (rc < 0) {
|
||||
if (errno == ENOMEM) {
|
||||
was_purged = was_purged_int;
|
||||
was_purged = true;
|
||||
return false;
|
||||
}
|
||||
|
||||
perror("madvise(MADV_SET_NONVOLATILE)");
|
||||
VERIFY_NOT_REACHED();
|
||||
}
|
||||
was_purged = rc != 0;
|
||||
#endif
|
||||
@ -574,6 +574,7 @@ Optional<BackingStore> Bitmap::try_allocate_backing_store(BitmapFormat format, I
|
||||
|
||||
int map_flags = MAP_ANONYMOUS | MAP_PRIVATE;
|
||||
#ifdef __serenity__
|
||||
map_flags |= MAP_PURGEABLE;
|
||||
void* data = mmap_with_name(nullptr, data_size_in_bytes, PROT_READ | PROT_WRITE, map_flags, 0, 0, String::formatted("GraphicsBitmap [{}]", size).characters());
|
||||
#else
|
||||
void* data = mmap(nullptr, data_size_in_bytes, PROT_READ | PROT_WRITE, map_flags, 0, 0);
|
||||
|
||||
Loading…
Reference in New Issue
Block a user