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Revert "[vm, gc] Incremental compaction, take 2."

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This reverts commit 9077bf991f.

Reason for revert: CBuild and TGP crashes in random Dart code which
look a lot like arbitrary memory corruption.

Original change's description:
> [vm, gc] Incremental compaction, take 2.
>
> - Fix missing store buffer flush when --marker_tasks=0.
> - Fix passing untagged pointer to store barrier check on ARM/ARM64 (6bc417dd17).
> - Fix passing uninitialized header to store barrier check on ARM64/RISCV (1447193053).
>
> TEST=ci
> Bug: https://github.com/dart-lang/sdk/issues/52513
> Bug: https://github.com/dart-lang/sdk/issues/55754
> Change-Id: Id2aa95b6d776b82d83464cde0d00e6f3b29b7b77
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/367202
> Commit-Queue: Ryan Macnak <rmacnak@google.com>
> Reviewed-by: Alexander Aprelev <aam@google.com>

Bug: https://github.com/dart-lang/sdk/issues/52513
Bug: https://github.com/dart-lang/sdk/issues/55754
Change-Id: I1d70d33c65fe6bf7089b8c1422d59f9146ae7ebf
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/367962
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Slava Egorov <vegorov@google.com>
Auto-Submit: Daco Harkes <dacoharkes@google.com>
Commit-Queue: Slava Egorov <vegorov@google.com>
This commit is contained in:
Daco Harkes
2024-05-23 19:00:50 +00:00
committed by Commit Queue
parent b2a27cbf90
commit b732c96e8a
42 changed files with 144 additions and 1696 deletions
Download Patch File Download Diff File Expand all files Collapse all files
runtime/docs/gc.md
+7 -6
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@@ -95,18 +95,18 @@ But we combine the generational and incremental checks with a shift-and-mask.
```c++
enum HeaderBits {
...
kNotMarkedBit, // Incremental barrier target.
kNewOrEvacuationCandidateBit, // Generational barrier target.
kAlwaysSetBit, // Incremental barrier source.
kOldAndNotRememberedBit, // Generational barrier source.
kNotMarkedBit, // Incremental barrier target.
kNewBit, // Generational barrier target.
kAlwaysSetBit, // Incremental barrier source.
kOldAndNotRememberedBit, // Generational barrier source.
...
};
static constexpr intptr_t kGenerationalBarrierMask = 1 << kNewOrEvacuationCandidateBit;
static constexpr intptr_t kGenerationalBarrierMask = 1 << kNewBit;
static constexpr intptr_t kIncrementalBarrierMask = 1 << kNotMarkedBit;
static constexpr intptr_t kBarrierOverlapShift = 2;
COMPILE_ASSERT(kNotMarkedBit + kBarrierOverlapShift == kAlwaysSetBit);
COMPILE_ASSERT(kNewOrEvacuationCandidateBit + kBarrierOverlapShift == kOldAndNotRememberedBit);
COMPILE_ASSERT(kNewBit + kBarrierOverlapShift == kOldAndNotRememberedBit);
StorePointer(ObjectPtr source, ObjectPtr* slot, ObjectPtr target) {
*slot = target;
@@ -178,6 +178,7 @@ We can eliminate these checks when the compiler can prove these cases cannot hap
* `value` is a constant. Constants are always old, and they will be marked via the constant pools even if we fail to mark them via `container`.
* `value` has the static type bool. All possible values of the bool type (null, false, true) are constants.
* `value` is known to be a Smi. Smis are not heap objects.
* `container` is the same object as `value`. The GC never needs to retain an additional object if it sees a self-reference, so ignoring a self-reference cannot cause us to free a reachable object.
* `container` is known to be a new object or known to be an old object that is in the remembered set and is marked if marking is in progress.
We can know that `container` meets the last property if `container` is the result of an allocation (instead of a heap load), and there is no instruction that can trigger a GC between the allocation and the store. This is because the allocation stubs ensure the result of AllocateObject is either a new-space object (common case, bump pointer allocation succeeds), or has been preemptively added to the remembered set and marking worklist (uncommon case, entered runtime to allocate object, possibly triggering GC).
runtime/platform/atomic.h
+2 -2
View File
@@ -80,8 +80,8 @@ class RelaxedAtomic {
}
T operator+=(T arg) { return fetch_add(arg) + arg; }
T operator-=(T arg) { return fetch_sub(arg) - arg; }
T operator++() { return fetch_add(1) + 1; }
T operator--() { return fetch_sub(1) - 1; }
T& operator++() { return fetch_add(1) + 1; }
T& operator--() { return fetch_sub(1) - 1; }
T operator++(int) { return fetch_add(1); }
T operator--(int) { return fetch_sub(1); }
runtime/vm/app_snapshot.cc
+1 -1
View File
@@ -893,7 +893,7 @@ void Deserializer::InitializeHeader(ObjectPtr raw,
tags = UntaggedObject::AlwaysSetBit::update(true, tags);
tags = UntaggedObject::NotMarkedBit::update(true, tags);
tags = UntaggedObject::OldAndNotRememberedBit::update(true, tags);
tags = UntaggedObject::NewOrEvacuationCandidateBit::update(false, tags);
tags = UntaggedObject::NewBit::update(false, tags);
tags = UntaggedObject::ImmutableBit::update(is_immutable, tags);
raw->untag()->tags_ = tags;
}
runtime/vm/bitfield.h
+5 -3
View File
@@ -36,9 +36,6 @@ class AtomicBitFieldContainer : AtomicBitFieldContainerBase {
}
T load(std::memory_order order) const { return field_.load(order); }
NO_SANITIZE_THREAD T load_ignore_race() const {
return *reinterpret_cast<const T*>(&field_);
}
void store(T value, std::memory_order order) { field_.store(value, order); }
bool compare_exchange_weak(T old_tags, T new_tags, std::memory_order order) {
@@ -51,6 +48,11 @@ class AtomicBitFieldContainer : AtomicBitFieldContainerBase {
return TargetBitField::decode(field_.load(order));
}
template <class TargetBitField>
NO_SANITIZE_THREAD typename TargetBitField::Type ReadIgnoreRace() const {
return TargetBitField::decode(*reinterpret_cast<const T*>(&field_));
}
template <class TargetBitField,
std::memory_order order = std::memory_order_relaxed>
void UpdateBool(bool value) {
runtime/vm/compiler/assembler/assembler_arm.cc
+1 -1
View File
@@ -1933,7 +1933,7 @@ void Assembler::VerifyStoreNeedsNoWriteBarrier(Register object,
Label done;
BranchIfSmi(value, &done, kNearJump);
ldrb(TMP, FieldAddress(value, target::Object::tags_offset()));
tst(TMP, Operand(1 << target::UntaggedObject::kNewOrEvacuationCandidateBit));
tst(TMP, Operand(1 << target::UntaggedObject::kNewBit));
b(&done, ZERO);
ldrb(TMP, FieldAddress(object, target::Object::tags_offset()));
tst(TMP, Operand(1 << target::UntaggedObject::kOldAndNotRememberedBit));
runtime/vm/compiler/assembler/assembler_arm64.cc
+1 -1
View File
@@ -1231,7 +1231,7 @@ void Assembler::VerifyStoreNeedsNoWriteBarrier(Register object,
Label done;
BranchIfSmi(value, &done, kNearJump);
ldr(TMP, FieldAddress(value, target::Object::tags_offset()), kUnsignedByte);
tbz(&done, TMP, target::UntaggedObject::kNewOrEvacuationCandidateBit);
tbz(&done, TMP, target::UntaggedObject::kNewBit);
ldr(TMP, FieldAddress(object, target::Object::tags_offset()), kUnsignedByte);
tbz(&done, TMP, target::UntaggedObject::kOldAndNotRememberedBit);
Stop("Write barrier is required");
runtime/vm/compiler/assembler/assembler_ia32.cc
+1 -1
View File
@@ -2207,7 +2207,7 @@ void Assembler::VerifyStoreNeedsNoWriteBarrier(Register object,
Label done;
BranchIfSmi(value, &done, kNearJump);
testb(FieldAddress(value, target::Object::tags_offset()),
Immediate(1 << target::UntaggedObject::kNewOrEvacuationCandidateBit));
Immediate(1 << target::UntaggedObject::kNewBit));
j(ZERO, &done, Assembler::kNearJump);
testb(FieldAddress(object, target::Object::tags_offset()),
Immediate(1 << target::UntaggedObject::kOldAndNotRememberedBit));
runtime/vm/compiler/assembler/assembler_riscv.cc
+1 -1
View File
@@ -3518,7 +3518,7 @@ void Assembler::VerifyStoreNeedsNoWriteBarrier(Register object,
Label done;
BranchIfSmi(value, &done, kNearJump);
lbu(TMP2, FieldAddress(value, target::Object::tags_offset()));
andi(TMP2, TMP2, 1 << target::UntaggedObject::kNewOrEvacuationCandidateBit);
andi(TMP2, TMP2, 1 << target::UntaggedObject::kNewBit);
beqz(TMP2, &done, kNearJump);
lbu(TMP2, FieldAddress(object, target::Object::tags_offset()));
andi(TMP2, TMP2, 1 << target::UntaggedObject::kOldAndNotRememberedBit);
runtime/vm/compiler/assembler/assembler_x64.cc
+1 -1
View File
@@ -1684,7 +1684,7 @@ void Assembler::VerifyStoreNeedsNoWriteBarrier(Register object,
Label done;
BranchIfSmi(value, &done, kNearJump);
testb(FieldAddress(value, target::Object::tags_offset()),
Immediate(1 << target::UntaggedObject::kNewOrEvacuationCandidateBit));
Immediate(1 << target::UntaggedObject::kNewBit));
j(ZERO, &done, Assembler::kNearJump);
testb(FieldAddress(object, target::Object::tags_offset()),
Immediate(1 << target::UntaggedObject::kOldAndNotRememberedBit));
runtime/vm/compiler/backend/il.cc
+3 -10
View File
@@ -1392,17 +1392,10 @@ bool Value::NeedsWriteBarrier() {
// Strictly speaking, the incremental barrier can only be skipped for
// immediate objects (Smis) or permanent objects (vm-isolate heap or
// image pages). For AOT, we choose to skip the barrier for any constant on
// the assumptions it will remain reachable through the object pool and it
// is on a page created by snapshot loading that is marked so as to never be
// evacuated.
// image pages). Here we choose to skip the barrier for any constant on
// the assumption it will remain reachable through the object pool.
if (value->BindsToConstant()) {
if (FLAG_precompiled_mode) {
return false;
} else {
const Object& constant = value->BoundConstant();
return constant.ptr()->IsHeapObject() && !constant.InVMIsolateHeap();
}
return false;
}
// Follow the chain of redefinitions as redefined value could have a more
runtime/vm/compiler/backend/il.h
+11
View File
@@ -6417,6 +6417,11 @@ class StoreFieldInstr : public TemplateInstruction<2, NoThrow> {
// The target field is native and unboxed, so not traversed by the GC.
return false;
}
if (instance()->definition() == value()->definition()) {
// `x.slot = x` cannot create an old->new or old&marked->old&unmarked
// reference.
return false;
}
if (value()->definition()->Type()->IsBool()) {
return false;
@@ -7069,6 +7074,12 @@ class StoreIndexedInstr : public TemplateInstruction<3, NoThrow> {
bool aligned() const { return alignment_ == kAlignedAccess; }
bool ShouldEmitStoreBarrier() const {
if (array()->definition() == value()->definition()) {
// `x[slot] = x` cannot create an old->new or old&marked->old&unmarked
// reference.
return false;
}
if (value()->definition()->Type()->IsBool()) {
return false;
}
runtime/vm/compiler/frontend/base_flow_graph_builder.cc
+4 -2
View File
@@ -522,9 +522,11 @@ Fragment BaseFlowGraphBuilder::StoreNativeField(
StoreBarrierType emit_store_barrier /* = kEmitStoreBarrier */,
compiler::Assembler::MemoryOrder memory_order /* = kRelaxed */) {
Value* value = Pop();
Value* instance = Pop();
if (value->BindsToConstant()) {
emit_store_barrier = kNoStoreBarrier;
}
StoreFieldInstr* store = new (Z)
StoreFieldInstr(slot, instance, value, emit_store_barrier,
StoreFieldInstr(slot, Pop(), value, emit_store_barrier,
stores_inner_pointer, InstructionSource(position), kind);
return Fragment(store);
}
runtime/vm/compiler/runtime_api.cc
+2 -3
View File
@@ -361,7 +361,7 @@ uword MakeTagWordForNewSpaceObject(classid_t cid, uword instance_size) {
return dart::UntaggedObject::SizeTag::encode(
TranslateOffsetInWordsToHost(instance_size)) |
dart::UntaggedObject::ClassIdTag::encode(cid) |
dart::UntaggedObject::NewOrEvacuationCandidateBit::encode(true) |
dart::UntaggedObject::NewBit::encode(true) |
dart::UntaggedObject::AlwaysSetBit::encode(true) |
dart::UntaggedObject::NotMarkedBit::encode(true) |
dart::UntaggedObject::ImmutableBit::encode(
@@ -377,8 +377,7 @@ const word UntaggedObject::kCardRememberedBit =
const word UntaggedObject::kCanonicalBit = dart::UntaggedObject::kCanonicalBit;
const word UntaggedObject::kNewOrEvacuationCandidateBit =
dart::UntaggedObject::kNewOrEvacuationCandidateBit;
const word UntaggedObject::kNewBit = dart::UntaggedObject::kNewBit;
const word UntaggedObject::kOldAndNotRememberedBit =
dart::UntaggedObject::kOldAndNotRememberedBit;
runtime/vm/compiler/runtime_api.h
+1 -1
View File
@@ -418,7 +418,7 @@ class UntaggedObject : public AllStatic {
public:
static const word kCardRememberedBit;
static const word kCanonicalBit;
static const word kNewOrEvacuationCandidateBit;
static const word kNewBit;
static const word kOldAndNotRememberedBit;
static const word kNotMarkedBit;
static const word kImmutableBit;
runtime/vm/flag_list.h
+2 -4
View File
@@ -127,8 +127,8 @@ constexpr bool FLAG_support_il_printer = false;
R(log_marker_tasks, false, bool, false, \
"Log debugging information for old gen GC marking tasks.") \
P(scavenger_tasks, int, 2, \
"The number of tasks to spawn during scavenging and incremental " \
"compaction (0 means perform all work on the main thread).") \
"The number of tasks to spawn during scavenging (0 means " \
"perform all marking on main thread).") \
P(mark_when_idle, bool, false, \
"The Dart thread will assist in concurrent marking during idle time and " \
"is counted as one marker task") \
@@ -216,8 +216,6 @@ constexpr bool FLAG_support_il_printer = false;
P(truncating_left_shift, bool, true, \
"Optimize left shift to truncate if possible") \
P(use_compactor, bool, false, "Compact the heap during old-space GC.") \
P(use_incremental_compactor, bool, true, \
"Compact the heap during old-space GC.") \
P(use_cha_deopt, bool, true, \
"Use class hierarchy analysis even if it can cause deoptimization.") \
P(use_field_guards, bool, true, "Use field guards and track field types") \
runtime/vm/heap/become.cc
+1 -1
View File
@@ -29,7 +29,7 @@ ForwardingCorpse* ForwardingCorpse::AsForwarder(uword addr, intptr_t size) {
bool is_old = (addr & kNewObjectAlignmentOffset) == kOldObjectAlignmentOffset;
tags = UntaggedObject::NotMarkedBit::update(true, tags);
tags = UntaggedObject::OldAndNotRememberedBit::update(is_old, tags);
tags = UntaggedObject::NewOrEvacuationCandidateBit::update(!is_old, tags);
tags = UntaggedObject::NewBit::update(!is_old, tags);
result->tags_ = tags;
if (size > UntaggedObject::SizeTag::kMaxSizeTag) {
runtime/vm/heap/compactor.cc
+4 -75
View File
@@ -6,9 +6,9 @@
#include "platform/atomic.h"
#include "vm/globals.h"
#include "vm/heap/become.h"
#include "vm/heap/heap.h"
#include "vm/heap/pages.h"
#include "vm/heap/sweeper.h"
#include "vm/thread_barrier.h"
#include "vm/timeline.h"
@@ -184,52 +184,18 @@ class CompactorTask : public ThreadPool::Task {
void GCCompactor::Compact(Page* pages, FreeList* freelist, Mutex* pages_lock) {
SetupImagePageBoundaries();
Page* fixed_head = nullptr;
Page* fixed_tail = nullptr;
// Divide the heap, and set aside never-evacuate pages.
// Divide the heap.
// TODO(30978): Try to divide based on live bytes or with work stealing.
intptr_t num_pages = 0;
Page* page = pages;
Page* prev = nullptr;
while (page != nullptr) {
Page* next = page->next();
if (page->is_never_evacuate()) {
if (prev != nullptr) {
prev->set_next(next);
} else {
pages = next;
}
if (fixed_tail == nullptr) {
fixed_tail = page;
}
page->set_next(fixed_head);
fixed_head = page;
} else {
prev = page;
num_pages++;
}
page = next;
for (Page* page = pages; page != nullptr; page = page->next()) {
num_pages++;
}
fixed_pages_ = fixed_head;
intptr_t num_tasks = FLAG_compactor_tasks;
RELEASE_ASSERT(num_tasks >= 1);
if (num_pages < num_tasks) {
num_tasks = num_pages;
}
if (num_tasks == 0) {
ASSERT(pages == nullptr);
// Move pages to sweeper work lists.
heap_->old_space()->pages_ = nullptr;
heap_->old_space()->pages_tail_ = nullptr;
heap_->old_space()->sweep_regular_ = fixed_head;
heap_->old_space()->Sweep(/*exclusive*/ true);
heap_->old_space()->SweepLarge();
return;
}
Partition* partitions = new Partition[num_tasks];
@@ -240,7 +206,6 @@ void GCCompactor::Compact(Page* pages, FreeList* freelist, Mutex* pages_lock) {
Page* page = pages;
Page* prev = nullptr;
while (task_index < num_tasks) {
ASSERT(!page->is_never_evacuate());
if (page_index % pages_per_task == 0) {
partitions[task_index].head = page;
partitions[task_index].tail = nullptr;
@@ -387,12 +352,6 @@ void GCCompactor::Compact(Page* pages, FreeList* freelist, Mutex* pages_lock) {
partitions[num_tasks - 1].tail->set_next(nullptr);
heap_->old_space()->pages_ = pages = partitions[0].head;
heap_->old_space()->pages_tail_ = partitions[num_tasks - 1].tail;
if (fixed_head != nullptr) {
fixed_tail->set_next(heap_->old_space()->pages_);
heap_->old_space()->pages_ = fixed_head;
ASSERT(heap_->old_space()->pages_tail_ != nullptr);
}
delete[] partitions;
}
@@ -527,7 +486,6 @@ void CompactorTask::RunEnteredIsolateGroup() {
}
void CompactorTask::PlanPage(Page* page) {
ASSERT(!page->is_never_evacuate());
uword current = page->object_start();
uword end = page->object_end();
@@ -540,7 +498,6 @@ void CompactorTask::PlanPage(Page* page) {
}
void CompactorTask::SlidePage(Page* page) {
ASSERT(!page->is_never_evacuate());
uword current = page->object_start();
uword end = page->object_end();
@@ -710,11 +667,6 @@ void GCCompactor::ForwardPointer(ObjectPtr* ptr) {
if (forwarding_page == nullptr) {
return; // Not moved (VM isolate, large page, code page).
}
if (page->is_never_evacuate()) {
// Forwarding page is non-NULL since one is still reserved for use as a
// counting page, but it doesn't have forwarding information.
return;
}
ObjectPtr new_target =
UntaggedObject::FromAddr(forwarding_page->Lookup(old_addr));
@@ -751,11 +703,6 @@ void GCCompactor::ForwardCompressedPointer(uword heap_base,
if (forwarding_page == nullptr) {
return; // Not moved (VM isolate, large page, code page).
}
if (page->is_never_evacuate()) {
// Forwarding page is non-NULL since one is still reserved for use as a
// counting page, but it doesn't have forwarding information.
return;
}
ObjectPtr new_target =
UntaggedObject::FromAddr(forwarding_page->Lookup(old_addr));
@@ -849,24 +796,6 @@ void GCCompactor::ForwardLargePages() {
page->VisitObjectPointers(this);
ml.Lock();
}
while (fixed_pages_ != nullptr) {
Page* page = fixed_pages_;
fixed_pages_ = page->next();
ml.Unlock();
GCSweeper sweeper;
FreeList* freelist = heap_->old_space()->DataFreeList(0);
bool page_in_use;
{
MutexLocker ml(freelist->mutex());
page_in_use = sweeper.SweepPage(page, freelist);
}
ASSERT(page_in_use);
page->VisitObjectPointers(this);
ml.Lock();
}
}
void GCCompactor::ForwardStackPointers() {
runtime/vm/heap/compactor.h
-1
View File
@@ -74,7 +74,6 @@ class GCCompactor : public ValueObject,
Mutex large_pages_mutex_;
Page* large_pages_ = nullptr;
Page* fixed_pages_ = nullptr;
// The typed data views whose inner pointer must be updated after sliding is
// complete.
runtime/vm/heap/freelist.cc
+2 -2
View File
@@ -28,7 +28,7 @@ FreeListElement* FreeListElement::AsElement(uword addr, intptr_t size) {
tags = UntaggedObject::AlwaysSetBit::update(true, tags);
tags = UntaggedObject::NotMarkedBit::update(true, tags);
tags = UntaggedObject::OldAndNotRememberedBit::update(true, tags);
tags = UntaggedObject::NewOrEvacuationCandidateBit::update(false, tags);
tags = UntaggedObject::NewBit::update(false, tags);
result->tags_ = tags;
if (size > UntaggedObject::SizeTag::kMaxSizeTag) {
@@ -53,7 +53,7 @@ FreeListElement* FreeListElement::AsElementNew(uword addr, intptr_t size) {
tags = UntaggedObject::AlwaysSetBit::update(true, tags);
tags = UntaggedObject::NotMarkedBit::update(true, tags);
tags = UntaggedObject::OldAndNotRememberedBit::update(false, tags);
tags = UntaggedObject::NewOrEvacuationCandidateBit::update(true, tags);
tags = UntaggedObject::NewBit::update(true, tags);
result->tags_ = tags;
if (size > UntaggedObject::SizeTag::kMaxSizeTag) {
runtime/vm/heap/freelist.h
-3
View File
@@ -224,9 +224,6 @@ class FreeList {
// The largest available small size in bytes, or negative if there is none.
intptr_t last_free_small_size_;
friend class GCIncrementalCompactor;
friend class PrologueTask;
DISALLOW_COPY_AND_ASSIGN(FreeList);
};
runtime/vm/heap/heap.cc
-11
View File
@@ -12,7 +12,6 @@
#include "vm/compiler/jit/compiler.h"
#include "vm/dart.h"
#include "vm/flags.h"
#include "vm/heap/incremental_compactor.h"
#include "vm/heap/pages.h"
#include "vm/heap/safepoint.h"
#include "vm/heap/scavenger.h"
@@ -468,16 +467,6 @@ void Heap::CollectNewSpaceGarbage(Thread* thread,
VMTagScope tagScope(thread, reason == GCReason::kIdle
? VMTag::kGCIdleTagId
: VMTag::kGCNewSpaceTagId);
if (reason == GCReason::kStoreBuffer) {
// The remembered set may become too full, increasing the time of
// stop-the-world phases, if new-space or to-be-evacuated objects are
// pointed to by too many objects. This is resolved by evacuating
// new-space (so there are no old->new pointers) and aborting an
// incremental compaction (so there are no old->to-be-evacuated
// pointers). If we had separate remembered sets, would could do these
// actions separately.
GCIncrementalCompactor::Abort(old_space());
}
TIMELINE_FUNCTION_GC_DURATION(thread, "CollectNewGeneration");
new_space_.Scavenge(thread, type, reason);
RecordAfterGC(type);
runtime/vm/heap/heap.h
-1
View File
@@ -387,7 +387,6 @@ class Heap {
friend class Serializer; // VisitObjectsImagePages
friend class HeapTestHelper;
friend class GCTestHelper;
friend class GCIncrementalCompactor;
DISALLOW_COPY_AND_ASSIGN(Heap);
};
runtime/vm/heap/heap_sources.gni
-2
View File
@@ -13,8 +13,6 @@ heap_sources = [
"gc_shared.h",
"heap.cc",
"heap.h",
"incremental_compactor.cc",
"incremental_compactor.h",
"marker.cc",
"marker.h",
"page.cc",
runtime/vm/heap/incremental_compactor.cc
-1013
View File
File diff suppressed because it is too large Load Diff
runtime/vm/heap/incremental_compactor.h
-40
View File
@@ -1,40 +0,0 @@
// Copyright (c) 2024, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#ifndef RUNTIME_VM_HEAP_INCREMENTAL_COMPACTOR_H_
#define RUNTIME_VM_HEAP_INCREMENTAL_COMPACTOR_H_
#include "vm/allocation.h"
namespace dart {
// Forward declarations.
class PageSpace;
class ObjectVisitor;
class IncrementalForwardingVisitor;
// An evacuating compactor that is incremental in the sense that building the
// remembered set is interleaved with the mutator. The evacuation and forwarding
// is not interleaved with the mutator, which would require a read barrier.
class GCIncrementalCompactor : public AllStatic {
public:
static void Prologue(PageSpace* old_space);
static bool Epilogue(PageSpace* old_space);
static void Abort(PageSpace* old_space);
private:
static bool SelectEvacuationCandidates(PageSpace* old_space);
static void CheckFreeLists(PageSpace* old_space);
static bool HasEvacuationCandidates(PageSpace* old_space);
static void CheckPreEvacuate(PageSpace* old_space);
static void Evacuate(PageSpace* old_space);
static void CheckPostEvacuate(PageSpace* old_space);
static void FreeEvacuatedPages(PageSpace* old_space);
static void VerifyAfterIncrementalCompaction(PageSpace* old_space);
};
} // namespace dart
#endif // RUNTIME_VM_HEAP_INCREMENTAL_COMPACTOR_H_
runtime/vm/heap/marker.cc
+34 -163
View File
@@ -39,8 +39,7 @@ class MarkingVisitorBase : public ObjectPointerVisitor {
deferred_work_list_(deferred_marking_stack),
marked_bytes_(0),
marked_micros_(0),
concurrent_(true),
has_evacuation_candidate_(false) {}
concurrent_(true) {}
~MarkingVisitorBase() { ASSERT(delayed_.IsEmpty()); }
uintptr_t marked_bytes() const { return marked_bytes_; }
@@ -57,11 +56,6 @@ class MarkingVisitorBase : public ObjectPointerVisitor {
return raw->untag()->IsMarked();
}
void FinishedRoots() {
// Nothing to remember for roots. Don't carry over to objects.
has_evacuation_candidate_ = false;
}
bool ProcessPendingWeakProperties() {
bool more_to_mark = false;
WeakPropertyPtr cur_weak = delayed_.weak_properties.Release();
@@ -80,15 +74,6 @@ class MarkingVisitorBase : public ObjectPointerVisitor {
// The key is marked so we make sure to properly visit all pointers
// originating from this weak property.
cur_weak->untag()->VisitPointersNonvirtual(this);
if (has_evacuation_candidate_) {
has_evacuation_candidate_ = false;
if (!cur_weak->untag()->IsCardRemembered()) {
if (cur_weak->untag()->TryAcquireRememberedBit()) {
Thread::Current()->StoreBufferAddObjectGC(cur_weak);
}
}
}
} else {
// Requeue this weak property to be handled later.
ASSERT(IsMarked(cur_weak));
@@ -100,24 +85,10 @@ class MarkingVisitorBase : public ObjectPointerVisitor {
return more_to_mark;
}
DART_NOINLINE
void YieldConcurrentMarking() {
work_list_.Flush();
new_work_list_.Flush();
deferred_work_list_.Flush();
Thread* thread = Thread::Current();
thread->StoreBufferReleaseGC();
page_space_->YieldConcurrentMarking();
thread->StoreBufferAcquireGC();
}
void DrainMarkingStackWithPauseChecks() {
Thread* thread = Thread::Current();
do {
ObjectPtr obj;
while (work_list_.Pop(&obj)) {
ASSERT(!has_evacuation_candidate_);
if (obj->IsNewObject()) {
Page* page = Page::Of(obj);
uword top = page->original_top();
@@ -126,7 +97,10 @@ class MarkingVisitorBase : public ObjectPointerVisitor {
if (top <= addr && addr < end) {
new_work_list_.Push(obj);
if (UNLIKELY(page_space_->pause_concurrent_marking())) {
YieldConcurrentMarking();
work_list_.Flush();
new_work_list_.Flush();
deferred_work_list_.Flush();
page_space_->YieldConcurrentMarking();
}
continue;
}
@@ -150,26 +124,18 @@ class MarkingVisitorBase : public ObjectPointerVisitor {
// Shape changing is not compatible with concurrent marking.
deferred_work_list_.Push(obj);
size = obj->untag()->HeapSize();
} else if (obj->untag()->IsCardRemembered()) {
ASSERT((class_id == kArrayCid) || (class_id == kImmutableArrayCid));
size = VisitCards(static_cast<ArrayPtr>(obj));
} else {
size = obj->untag()->VisitPointersNonvirtual(this);
}
if (has_evacuation_candidate_) {
has_evacuation_candidate_ = false;
if (!obj->untag()->IsCardRemembered()) {
if (obj->untag()->TryAcquireRememberedBit()) {
thread->StoreBufferAddObjectGC(obj);
}
}
}
if (!obj->IsNewObject()) {
marked_bytes_ += size;
}
if (UNLIKELY(page_space_->pause_concurrent_marking())) {
YieldConcurrentMarking();
work_list_.Flush();
new_work_list_.Flush();
deferred_work_list_.Flush();
page_space_->YieldConcurrentMarking();
}
}
} while (ProcessPendingWeakProperties());
@@ -180,44 +146,6 @@ class MarkingVisitorBase : public ObjectPointerVisitor {
deferred_work_list_.Flush();
}
intptr_t VisitCards(ArrayPtr obj) {
ASSERT(obj->IsArray() || obj->IsImmutableArray());
ASSERT(obj->untag()->IsCardRemembered());
CompressedObjectPtr* obj_from = obj->untag()->from();
CompressedObjectPtr* obj_to =
obj->untag()->to(Smi::Value(obj->untag()->length()));
uword heap_base = obj.heap_base();
Page* page = Page::Of(obj);
for (intptr_t i = 0, n = page->card_table_size(); i < n; i++) {
CompressedObjectPtr* card_from =
reinterpret_cast<CompressedObjectPtr*>(page) +
(i << Page::kSlotsPerCardLog2);
CompressedObjectPtr* card_to =
reinterpret_cast<CompressedObjectPtr*>(card_from) +
(1 << Page::kSlotsPerCardLog2) - 1;
// Minus 1 because to is inclusive.
if (card_from < obj_from) {
// First card overlaps with header.
card_from = obj_from;
}
if (card_to > obj_to) {
// Last card(s) may extend past the object. Array truncation can make
// this happen for more than one card.
card_to = obj_to;
}
VisitCompressedPointers(heap_base, card_from, card_to);
if (has_evacuation_candidate_) {
has_evacuation_candidate_ = false;
page->RememberCard(card_from);
}
}
return obj->untag()->HeapSize();
}
void DrainMarkingStack() {
while (ProcessMarkingStack(kIntptrMax)) {
}
@@ -242,13 +170,10 @@ class MarkingVisitorBase : public ObjectPointerVisitor {
}
bool ProcessMarkingStack(intptr_t remaining_budget) {
Thread* thread = Thread::Current();
do {
// First drain the marking stacks.
ObjectPtr obj;
while (work_list_.Pop(&obj)) {
ASSERT(!has_evacuation_candidate_);
if (sync && concurrent_ && obj->IsNewObject()) {
Page* page = Page::Of(obj);
uword top = page->original_top();
@@ -293,19 +218,7 @@ class MarkingVisitorBase : public ObjectPointerVisitor {
return true; // More to mark.
}
}
if (obj->untag()->IsCardRemembered()) {
ASSERT((class_id == kArrayCid) || (class_id == kImmutableArrayCid));
size = VisitCards(static_cast<ArrayPtr>(obj));
} else {
size = obj->untag()->VisitPointersNonvirtual(this);
}
}
if (has_evacuation_candidate_) {
has_evacuation_candidate_ = false;
if (!obj->untag()->IsCardRemembered() &&
obj->untag()->TryAcquireRememberedBit()) {
thread->StoreBufferAddObjectGC(obj);
}
size = obj->untag()->VisitPointersNonvirtual(this);
}
if (!obj->IsNewObject()) {
marked_bytes_ += size;
@@ -341,23 +254,19 @@ class MarkingVisitorBase : public ObjectPointerVisitor {
}
void VisitPointers(ObjectPtr* first, ObjectPtr* last) override {
bool has_evacuation_candidate = false;
for (ObjectPtr* current = first; current <= last; current++) {
has_evacuation_candidate |= MarkObject(LoadPointerIgnoreRace(current));
MarkObject(LoadPointerIgnoreRace(current));
}
has_evacuation_candidate_ |= has_evacuation_candidate;
}
#if defined(DART_COMPRESSED_POINTERS)
void VisitCompressedPointers(uword heap_base,
CompressedObjectPtr* first,
CompressedObjectPtr* last) override {
bool has_evacuation_candidate = false;
for (CompressedObjectPtr* current = first; current <= last; current++) {
has_evacuation_candidate |= MarkObject(
MarkObject(
LoadCompressedPointerIgnoreRace(current).Decompress(heap_base));
}
has_evacuation_candidate_ |= has_evacuation_candidate;
}
#endif
@@ -382,25 +291,17 @@ class MarkingVisitorBase : public ObjectPointerVisitor {
ObjectPtr raw_target =
LoadCompressedPointerIgnoreRace(&raw_weak->untag()->target_)
.Decompress(raw_weak->heap_base());
if (raw_target->IsHeapObject()) {
if (!raw_target->untag()->IsMarked()) {
// Target was white. Enqueue the weak reference. It is potentially dead.
// It might still be made alive by weak properties in next rounds.
ASSERT(IsMarked(raw_weak));
delayed_.weak_references.Enqueue(raw_weak);
} else {
if (raw_target->untag()->IsEvacuationCandidate()) {
has_evacuation_candidate_ = true;
}
}
if (raw_target->IsHeapObject() && !raw_target->untag()->IsMarked()) {
// Target was white. Enqueue the weak reference. It is potentially dead.
// It might still be made alive by weak properties in next rounds.
ASSERT(IsMarked(raw_weak));
delayed_.weak_references.Enqueue(raw_weak);
}
// Always visit the type argument.
ObjectPtr raw_type_arguments =
LoadCompressedPointerIgnoreRace(&raw_weak->untag()->type_arguments_)
.Decompress(raw_weak->heap_base());
if (MarkObject(raw_type_arguments)) {
has_evacuation_candidate_ = true;
}
MarkObject(raw_type_arguments);
return raw_weak->untag()->HeapSize();
}
@@ -413,24 +314,18 @@ class MarkingVisitorBase : public ObjectPointerVisitor {
ASSERT(IsMarked(raw_entry));
delayed_.finalizer_entries.Enqueue(raw_entry);
// Only visit token and next.
if (MarkObject(LoadCompressedPointerIgnoreRace(&raw_entry->untag()->token_)
.Decompress(raw_entry->heap_base()))) {
has_evacuation_candidate_ = true;
}
if (MarkObject(LoadCompressedPointerIgnoreRace(&raw_entry->untag()->next_)
.Decompress(raw_entry->heap_base()))) {
has_evacuation_candidate_ = true;
}
MarkObject(LoadCompressedPointerIgnoreRace(&raw_entry->untag()->token_)
.Decompress(raw_entry->heap_base()));
MarkObject(LoadCompressedPointerIgnoreRace(&raw_entry->untag()->next_)
.Decompress(raw_entry->heap_base()));
return raw_entry->untag()->HeapSize();
}
void ProcessDeferredMarking() {
Thread* thread = Thread::Current();
TIMELINE_FUNCTION_GC_DURATION(thread, "ProcessDeferredMarking");
TIMELINE_FUNCTION_GC_DURATION(Thread::Current(), "ProcessDeferredMarking");
ObjectPtr obj;
while (deferred_work_list_.Pop(&obj)) {
ASSERT(!has_evacuation_candidate_);
ASSERT(obj->IsHeapObject());
// We need to scan objects even if they were already scanned via ordinary
// marking. An object may have changed since its ordinary scan and been
@@ -456,13 +351,6 @@ class MarkingVisitorBase : public ObjectPointerVisitor {
marked_bytes_ += size;
}
}
if (has_evacuation_candidate_) {
has_evacuation_candidate_ = false;
if (!obj->untag()->IsCardRemembered() &&
obj->untag()->TryAcquireRememberedBit()) {
thread->StoreBufferAddObjectGC(obj);
}
}
}
}
@@ -537,15 +425,6 @@ class MarkingVisitorBase : public ObjectPointerVisitor {
if (target->untag()->IsMarked()) {
// Object already null (which is permanently marked) or has survived this
// GC.
if (target->untag()->IsEvacuationCandidate()) {
if (parent->untag()->IsCardRemembered()) {
Page::Of(parent)->RememberCard(slot);
} else {
if (parent->untag()->TryAcquireRememberedBit()) {
Thread::Current()->StoreBufferAddObjectGC(parent);
}
}
}
return false;
}
*slot = Object::null();
@@ -606,16 +485,16 @@ class MarkingVisitorBase : public ObjectPointerVisitor {
}
DART_FORCE_INLINE
bool MarkObject(ObjectPtr obj) {
void MarkObject(ObjectPtr obj) {
if (obj->IsImmediateObject()) {
return false;
return;
}
if (sync && concurrent_ && obj->IsNewObject()) {
if (TryAcquireMarkBit(obj)) {
PushMarked(obj);
}
return false;
return;
}
// While it might seem this is redundant with TryAcquireMarkBit, we must
@@ -628,26 +507,26 @@ class MarkingVisitorBase : public ObjectPointerVisitor {
// was allocated after the concurrent marker started. It can read either a
// zero or the header of an object allocated black, both of which appear
// marked.
uword tags = obj->untag()->tags_ignore_race();
if (UntaggedObject::IsMarked(tags)) {
return UntaggedObject::IsEvacuationCandidate(tags);
if (obj->untag()->IsMarkedIgnoreRace()) {
return;
}
intptr_t class_id = UntaggedObject::ClassIdTag::decode(tags);
intptr_t class_id = obj->GetClassId();
ASSERT(class_id != kFreeListElement);
if (sync && UNLIKELY(class_id == kInstructionsCid)) {
// If this is the concurrent marker, this object may be non-writable due
// to W^X (--write-protect-code).
deferred_work_list_.Push(obj);
return false;
return;
}
if (TryAcquireMarkBit(obj)) {
PushMarked(obj);
if (!TryAcquireMarkBit(obj)) {
// Already marked.
return;
}
return UntaggedObject::IsEvacuationCandidate(tags);
PushMarked(obj);
}
PageSpace* page_space_;
@@ -658,7 +537,6 @@ class MarkingVisitorBase : public ObjectPointerVisitor {
uintptr_t marked_bytes_;
int64_t marked_micros_;
bool concurrent_;
bool has_evacuation_candidate_;
DISALLOW_IMPLICIT_CONSTRUCTORS(MarkingVisitorBase);
};
@@ -897,7 +775,6 @@ class ParallelMarkTask : public ThreadPool::Task {
num_busy_->fetch_add(1u);
visitor_->set_concurrent(false);
marker_->IterateRoots(visitor_);
visitor_->FinishedRoots();
visitor_->ProcessDeferredMarking();
@@ -948,8 +825,6 @@ class ParallelMarkTask : public ThreadPool::Task {
// Don't MournFinalizerEntries here, do it on main thread, so that we
// don't have to coordinate workers.
thread->ReleaseStoreBuffer(); // Ahead of IterateWeak
barrier_->Sync();
marker_->IterateWeakRoots(thread);
int64_t stop = OS::GetCurrentMonotonicMicros();
visitor_->AddMicros(stop - start);
@@ -996,7 +871,6 @@ class ConcurrentMarkTask : public ThreadPool::Task {
int64_t start = OS::GetCurrentMonotonicMicros();
marker_->IterateRoots(visitor_);
visitor_->FinishedRoots();
visitor_->DrainMarkingStackWithPauseChecks();
int64_t stop = OS::GetCurrentMonotonicMicros();
@@ -1119,7 +993,6 @@ void GCMarker::StartConcurrentMark(PageSpace* page_space) {
TIMELINE_FUNCTION_GC_DURATION(Thread::Current(), "ConcurrentMark");
int64_t start = OS::GetCurrentMonotonicMicros();
IterateRoots(visitor);
visitor->FinishedRoots();
int64_t stop = OS::GetCurrentMonotonicMicros();
visitor->AddMicros(stop - start);
if (FLAG_log_marker_tasks) {
@@ -1270,7 +1143,6 @@ void GCMarker::MarkObjects(PageSpace* page_space) {
visitor.set_concurrent(false);
ResetSlices();
IterateRoots(&visitor);
visitor.FinishedRoots();
visitor.ProcessDeferredMarking();
visitor.DrainMarkingStack();
visitor.ProcessDeferredMarking();
@@ -1279,7 +1151,6 @@ void GCMarker::MarkObjects(PageSpace* page_space) {
visitor.MournWeakReferences();
visitor.MournWeakArrays();
visitor.MournFinalizerEntries();
thread->ReleaseStoreBuffer(); // Ahead of IterateWeak
IterateWeakRoots(thread);
// All marking done; detach code, etc.
int64_t stop = OS::GetCurrentMonotonicMicros();
runtime/vm/heap/page.cc
+3 -8
View File
@@ -114,7 +114,6 @@ Page* Page::Allocate(intptr_t size, uword flags) {
result->end_ = 0;
result->survivor_end_ = 0;
result->resolved_top_ = 0;
result->live_bytes_ = 0;
if ((flags & kNew) != 0) {
uword top = result->object_start();
@@ -172,8 +171,7 @@ void Page::Deallocate() {
}
void Page::VisitObjects(ObjectVisitor* visitor) const {
ASSERT(Thread::Current()->OwnsGCSafepoint() ||
(Thread::Current()->task_kind() == Thread::kIncrementalCompactorTask));
ASSERT(Thread::Current()->OwnsGCSafepoint());
NoSafepointScope no_safepoint;
uword obj_addr = object_start();
uword end_addr = object_end();
@@ -209,11 +207,9 @@ void Page::VisitObjectPointers(ObjectPointerVisitor* visitor) const {
ASSERT(obj_addr == end_addr);
}
void Page::VisitRememberedCards(PredicateObjectPointerVisitor* visitor,
bool only_marked) {
void Page::VisitRememberedCards(PredicateObjectPointerVisitor* visitor) {
ASSERT(Thread::Current()->OwnsGCSafepoint() ||
(Thread::Current()->task_kind() == Thread::kScavengerTask) ||
(Thread::Current()->task_kind() == Thread::kIncrementalCompactorTask));
(Thread::Current()->task_kind() == Thread::kScavengerTask));
NoSafepointScope no_safepoint;
if (card_table_ == nullptr) {
@@ -224,7 +220,6 @@ void Page::VisitRememberedCards(PredicateObjectPointerVisitor* visitor,
static_cast<ArrayPtr>(UntaggedObject::FromAddr(object_start()));
ASSERT(obj->IsArray() || obj->IsImmutableArray());
ASSERT(obj->untag()->IsCardRemembered());
if (only_marked && !obj->untag()->IsMarked()) return;
CompressedObjectPtr* obj_from = obj->untag()->from();
CompressedObjectPtr* obj_to =
obj->untag()->to(Smi::Value(obj->untag()->length()));
runtime/vm/heap/page.h
+5 -32
View File
@@ -72,7 +72,6 @@ class Page {
kVMIsolate = 1 << 3,
kNew = 1 << 4,
kEvacuationCandidate = 1 << 5,
kNeverEvacuate = 1 << 6,
};
bool is_executable() const { return (flags_ & kExecutable) != 0; }
bool is_large() const { return (flags_ & kLarge) != 0; }
@@ -83,21 +82,6 @@ class Page {
bool is_evacuation_candidate() const {
return (flags_ & kEvacuationCandidate) != 0;
}
void set_evacuation_candidate(bool value) {
if (value) {
flags_ |= kEvacuationCandidate;
} else {
flags_ &= ~kEvacuationCandidate;
}
}
bool is_never_evacuate() const { return (flags_ & kNeverEvacuate) != 0; }
void set_never_evacuate(bool value) {
if (value) {
flags_ |= kNeverEvacuate;
} else {
flags_ &= ~kNeverEvacuate;
}
}
Page* next() const { return next_; }
void set_next(Page* next) { next_ = next; }
@@ -121,11 +105,6 @@ class Page {
}
intptr_t used() const { return object_end() - object_start(); }
intptr_t live_bytes() const { return live_bytes_; }
void set_live_bytes(intptr_t value) { live_bytes_ = value; }
void add_live_bytes(intptr_t value) { live_bytes_ += value; }
void sub_live_bytes(intptr_t value) { live_bytes_ -= value; }
ForwardingPage* forwarding_page() const { return forwarding_page_; }
void RegisterUnwindingRecords();
void UnregisterUnwindingRecords();
@@ -163,12 +142,11 @@ class Page {
ASSERT(obj->IsHeapObject());
return reinterpret_cast<Page*>(static_cast<uword>(obj) & kPageMask);
}
// Warning: This does not work for addresses on image pages or on large pages.
static Page* Of(uword addr) {
return reinterpret_cast<Page*>(addr & kPageMask);
}
static Page* Of(void* addr) {
return reinterpret_cast<Page*>(reinterpret_cast<uword>(addr) & kPageMask);
}
// 1 card = 32 slots.
static constexpr intptr_t kSlotsPerCardLog2 = 5;
@@ -195,8 +173,7 @@ class Page {
return IsCardRemembered(reinterpret_cast<uword>(slot));
}
#endif
void VisitRememberedCards(PredicateObjectPointerVisitor* visitor,
bool only_marked = false);
void VisitRememberedCards(PredicateObjectPointerVisitor* visitor);
void ResetProgressBar();
Thread* owner() const { return owner_; }
@@ -286,8 +263,7 @@ class Page {
intptr_t word_offset = index >> kBitsPerWordLog2;
intptr_t bit_offset = index & (kBitsPerWord - 1);
uword bit_mask = static_cast<uword>(1) << bit_offset;
reinterpret_cast<std::atomic<uword>*>(&card_table_[word_offset])
->fetch_or(bit_mask, std::memory_order_relaxed);
card_table_[word_offset] |= bit_mask;
}
bool IsCardRemembered(uword slot) {
ASSERT(Contains(slot));
@@ -340,10 +316,7 @@ class Page {
// value meets the allocation top. Called "SCAN" in the original Cheney paper.
uword resolved_top_;
RelaxedAtomic<intptr_t> live_bytes_;
friend class CheckStoreBufferScavengeVisitor;
friend class CheckStoreBufferEvacuateVisitor;
friend class CheckStoreBufferVisitor;
friend class GCCompactor;
friend class PageSpace;
template <bool>
runtime/vm/heap/pages.cc
+11 -191
View File
@@ -10,7 +10,6 @@
#include "vm/dart.h"
#include "vm/heap/become.h"
#include "vm/heap/compactor.h"
#include "vm/heap/incremental_compactor.h"
#include "vm/heap/marker.h"
#include "vm/heap/safepoint.h"
#include "vm/heap/sweeper.h"
@@ -347,7 +346,6 @@ uword PageSpace::TryAllocateInFreshPage(intptr_t size,
// Start of the newly allocated page is the allocated object.
result = page->object_start();
// Note: usage_.capacity_in_words is increased by AllocatePage.
Page::Of(result)->add_live_bytes(size);
usage_.used_in_words += (size >> kWordSizeLog2);
// Enqueue the remainder in the free list.
uword free_start = result + size;
@@ -389,7 +387,6 @@ uword PageSpace::TryAllocateInFreshLargePage(intptr_t size,
if (page != nullptr) {
result = page->object_start();
// Note: usage_.capacity_in_words is increased by AllocateLargePage.
Page::Of(result)->add_live_bytes(size);
usage_.used_in_words += (size >> kWordSizeLog2);
}
}
@@ -416,9 +413,6 @@ uword PageSpace::TryAllocateInternal(intptr_t size,
is_locked);
// usage_ is updated by the call above.
} else {
if (!is_protected) {
Page::Of(result)->add_live_bytes(size);
}
usage_.used_in_words += (size >> kWordSizeLog2);
}
} else {
@@ -1045,9 +1039,6 @@ void PageSpace::CollectGarbageHelper(Thread* thread,
if (marker_ == nullptr) {
ASSERT(phase() == kDone);
marker_ = new GCMarker(isolate_group, heap_);
if (FLAG_use_incremental_compactor) {
GCIncrementalCompactor::Prologue(this);
}
} else {
ASSERT(phase() == kAwaitingFinalization);
}
@@ -1068,26 +1059,15 @@ void PageSpace::CollectGarbageHelper(Thread* thread,
delete marker_;
marker_ = nullptr;
if (FLAG_verify_store_buffer) {
VerifyStoreBuffers("Verifying remembered set after marking");
// Reset the freelists and setup sweeping.
for (intptr_t i = 0; i < num_freelists_; i++) {
freelists_[i].Reset();
}
if (FLAG_verify_before_gc) {
heap_->VerifyGC("Verifying before sweeping", kAllowMarked);
}
bool has_reservation = MarkReservation();
bool new_space_is_swept = false;
if (FLAG_use_incremental_compactor) {
new_space_is_swept = GCIncrementalCompactor::Epilogue(this);
}
// Reset the freelists and setup sweeping.
for (intptr_t i = 0; i < num_freelists_; i++) {
freelists_[i].Reset();
}
{
// Executable pages are always swept immediately to simplify
// code protection.
@@ -1110,6 +1090,8 @@ void PageSpace::CollectGarbageHelper(Thread* thread,
}
}
bool has_reservation = MarkReservation();
{
// Move pages to sweeper work lists.
MutexLocker ml(&pages_lock_);
@@ -1123,24 +1105,23 @@ void PageSpace::CollectGarbageHelper(Thread* thread,
}
}
if (!new_space_is_swept) {
SweepNew();
}
bool is_concurrent_sweep_running = false;
bool can_verify;
SweepNew();
if (compact) {
Compact(thread);
set_phase(kDone);
is_concurrent_sweep_running = true;
can_verify = true;
} else if (FLAG_concurrent_sweep && has_reservation) {
ConcurrentSweep(isolate_group);
is_concurrent_sweep_running = true;
can_verify = false;
} else {
SweepLarge();
Sweep(/*exclusive*/ true);
set_phase(kDone);
can_verify = true;
}
if (FLAG_verify_after_gc && !is_concurrent_sweep_running) {
if (FLAG_verify_after_gc && can_verify) {
heap_->VerifyGC("Verifying after sweeping", kForbidMarked);
}
@@ -1168,163 +1149,6 @@ void PageSpace::CollectGarbageHelper(Thread* thread,
}
}
class CollectStoreBufferEvacuateVisitor : public ObjectPointerVisitor {
public:
CollectStoreBufferEvacuateVisitor(ObjectSet* in_store_buffer, const char* msg)
: ObjectPointerVisitor(IsolateGroup::Current()),
in_store_buffer_(in_store_buffer),
msg_(msg) {}
void VisitPointers(ObjectPtr* from, ObjectPtr* to) override {
for (ObjectPtr* ptr = from; ptr <= to; ptr++) {
ObjectPtr obj = *ptr;
RELEASE_ASSERT_WITH_MSG(obj->untag()->IsRemembered(), msg_);
RELEASE_ASSERT_WITH_MSG(obj->IsOldObject(), msg_);
RELEASE_ASSERT_WITH_MSG(!obj->untag()->IsCardRemembered(), msg_);
if (obj.GetClassId() == kArrayCid) {
const uword length =
Smi::Value(static_cast<UntaggedArray*>(obj.untag())->length());
RELEASE_ASSERT_WITH_MSG(!Array::UseCardMarkingForAllocation(length),
msg_);
}
in_store_buffer_->Add(obj);
}
}
#if defined(DART_COMPRESSED_POINTERS)
void VisitCompressedPointers(uword heap_base,
CompressedObjectPtr* from,
CompressedObjectPtr* to) override {
UNREACHABLE(); // Store buffer blocks are not compressed.
}
#endif
private:
ObjectSet* const in_store_buffer_;
const char* msg_;
DISALLOW_COPY_AND_ASSIGN(CollectStoreBufferEvacuateVisitor);
};
class CheckStoreBufferEvacuateVisitor : public ObjectVisitor,
public ObjectPointerVisitor {
public:
CheckStoreBufferEvacuateVisitor(ObjectSet* in_store_buffer, const char* msg)
: ObjectVisitor(),
ObjectPointerVisitor(IsolateGroup::Current()),
in_store_buffer_(in_store_buffer),
msg_(msg) {}
void VisitObject(ObjectPtr obj) override {
if (obj->IsPseudoObject()) return;
RELEASE_ASSERT_WITH_MSG(obj->IsOldObject(), msg_);
if (!obj->untag()->IsMarked()) return;
if (obj->untag()->IsRemembered()) {
RELEASE_ASSERT_WITH_MSG(in_store_buffer_->Contains(obj), msg_);
} else {
RELEASE_ASSERT_WITH_MSG(!in_store_buffer_->Contains(obj), msg_);
}
visiting_ = obj;
is_remembered_ = obj->untag()->IsRemembered();
is_card_remembered_ = obj->untag()->IsCardRemembered();
if (is_card_remembered_) {
RELEASE_ASSERT_WITH_MSG(!is_remembered_, msg_);
RELEASE_ASSERT_WITH_MSG(Page::Of(obj)->progress_bar_ == 0, msg_);
}
obj->untag()->VisitPointers(this);
}
void VisitPointers(ObjectPtr* from, ObjectPtr* to) override {
for (ObjectPtr* ptr = from; ptr <= to; ptr++) {
ObjectPtr obj = *ptr;
if (obj->IsHeapObject() && obj->untag()->IsEvacuationCandidate()) {
if (is_card_remembered_) {
if (!Page::Of(visiting_)->IsCardRemembered(ptr)) {
FATAL(
"%s: Old object %#" Px " references new object %#" Px
", but the "
"slot's card is not remembered. Consider using rr to watch the "
"slot %p and reverse-continue to find the store with a missing "
"barrier.\n",
msg_, static_cast<uword>(visiting_), static_cast<uword>(obj),
ptr);
}
} else if (!is_remembered_) {
FATAL("%s: Old object %#" Px " references new object %#" Px
", but it is "
"not in any store buffer. Consider using rr to watch the "
"slot %p and reverse-continue to find the store with a missing "
"barrier.\n",
msg_, static_cast<uword>(visiting_), static_cast<uword>(obj),
ptr);
}
}
}
}
#if defined(DART_COMPRESSED_POINTERS)
void VisitCompressedPointers(uword heap_base,
CompressedObjectPtr* from,
CompressedObjectPtr* to) override {
for (CompressedObjectPtr* ptr = from; ptr <= to; ptr++) {
ObjectPtr obj = ptr->Decompress(heap_base);
if (obj->IsHeapObject() && obj->IsNewObject()) {
if (is_card_remembered_) {
if (!Page::Of(visiting_)->IsCardRemembered(ptr)) {
FATAL(
"%s: Old object %#" Px " references new object %#" Px
", but the "
"slot's card is not remembered. Consider using rr to watch the "
"slot %p and reverse-continue to find the store with a missing "
"barrier.\n",
msg_, static_cast<uword>(visiting_), static_cast<uword>(obj),
ptr);
}
} else if (!is_remembered_) {
FATAL("%s: Old object %#" Px " references new object %#" Px
", but it is "
"not in any store buffer. Consider using rr to watch the "
"slot %p and reverse-continue to find the store with a missing "
"barrier.\n",
msg_, static_cast<uword>(visiting_), static_cast<uword>(obj),
ptr);
}
}
}
}
#endif
private:
const ObjectSet* const in_store_buffer_;
ObjectPtr visiting_;
bool is_remembered_;
bool is_card_remembered_;
const char* msg_;
};
void PageSpace::VerifyStoreBuffers(const char* msg) {
ASSERT(msg != nullptr);
Thread* thread = Thread::Current();
StackZone stack_zone(thread);
Zone* zone = stack_zone.GetZone();
ObjectSet* in_store_buffer = new (zone) ObjectSet(zone);
heap_->AddRegionsToObjectSet(in_store_buffer);
{
CollectStoreBufferEvacuateVisitor visitor(in_store_buffer, msg);
heap_->isolate_group()->store_buffer()->VisitObjectPointers(&visitor);
}
{
CheckStoreBufferEvacuateVisitor visitor(in_store_buffer, msg);
heap_->old_space()->VisitObjects(&visitor);
}
}
void PageSpace::SweepNew() {
// TODO(rmacnak): Run in parallel with SweepExecutable.
TIMELINE_FUNCTION_GC_DURATION(Thread::Current(), "SweepNew");
@@ -1455,7 +1279,6 @@ uword PageSpace::TryAllocateDataBumpLocked(FreeList* freelist, intptr_t size) {
intptr_t block_size = block->HeapSize();
if (remaining > 0) {
usage_.used_in_words -= (remaining >> kWordSizeLog2);
Page::Of(freelist->top())->add_live_bytes(remaining);
freelist->FreeLocked(freelist->top(), remaining);
}
freelist->set_top(reinterpret_cast<uword>(block));
@@ -1464,7 +1287,6 @@ uword PageSpace::TryAllocateDataBumpLocked(FreeList* freelist, intptr_t size) {
// the size of the whole bump area here and subtract the remaining size
// when switching to a new area.
usage_.used_in_words += (block_size >> kWordSizeLog2);
Page::Of(block)->add_live_bytes(block_size);
remaining = block_size;
}
ASSERT(remaining >= size);
@@ -1485,7 +1307,6 @@ uword PageSpace::TryAllocateDataBumpLocked(FreeList* freelist, intptr_t size) {
uword PageSpace::TryAllocatePromoLockedSlow(FreeList* freelist, intptr_t size) {
uword result = freelist->TryAllocateSmallLocked(size);
if (result != 0) {
Page::Of(result)->add_live_bytes(size);
freelist->AddUnaccountedSize(size);
return result;
}
@@ -1528,7 +1349,6 @@ void PageSpace::SetupImagePage(void* pointer, uword size, bool is_executable) {
page->end_ = memory->end();
page->survivor_end_ = 0;
page->resolved_top_ = 0;
page->live_bytes_ = 0;
MutexLocker ml(&pages_lock_);
page->next_ = image_pages_;
runtime/vm/heap/pages.h
-9
View File
@@ -184,11 +184,6 @@ class PageSpace {
}
void EvaluateAfterLoading() {
page_space_controller_.EvaluateAfterLoading(usage_);
MutexLocker ml(&pages_lock_);
for (Page* page = pages_; page != nullptr; page = page->next()) {
page->set_never_evacuate(true);
}
}
intptr_t UsedInWords() const { return usage_.used_in_words; }
@@ -417,7 +412,6 @@ class PageSpace {
void FreePages(Page* pages);
void CollectGarbageHelper(Thread* thread, bool compact, bool finalize);
void VerifyStoreBuffers(const char* msg);
void SweepNew();
void SweepLarge();
void Sweep(bool exclusive);
@@ -502,9 +496,6 @@ class PageSpace {
friend class PageSpaceController;
friend class ConcurrentSweeperTask;
friend class GCCompactor;
friend class GCIncrementalCompactor;
friend class PrologueTask;
friend class EpilogueTask;
friend class CompactorTask;
friend class Code;
runtime/vm/heap/pointer_block.cc
-3
View File
@@ -266,9 +266,6 @@ void BlockStack<BlockSize>::TrimGlobalEmpty() {
}
}
template class PointerBlock<kStoreBufferBlockSize>;
template class PointerBlock<kMarkingStackBlockSize>;
template class BlockStack<kStoreBufferBlockSize>;
template class BlockStack<kMarkingStackBlockSize>;
runtime/vm/heap/pointer_block.h
+1 -1
View File
@@ -129,7 +129,7 @@ class BlockStack {
private:
Block* head_;
RelaxedAtomic<intptr_t> length_;
intptr_t length_;
DISALLOW_COPY_AND_ASSIGN(List);
};
runtime/vm/heap/scavenger.cc
+19 -47
View File
@@ -220,11 +220,8 @@ class ScavengerVisitorBase : public ObjectPointerVisitor,
}
void VisitPointers(ObjectPtr* first, ObjectPtr* last) override {
#if !defined(TARGET_ARCH_IA32)
// Pointers embedded in Instructions are not aligned.
ASSERT(Utils::IsAligned(first, sizeof(*first)));
ASSERT(Utils::IsAligned(last, sizeof(*last)));
#endif
for (ObjectPtr* current = first; current <= last; current++) {
ScavengePointer(current);
}
@@ -382,12 +379,9 @@ class ScavengerVisitorBase : public ObjectPointerVisitor,
// ScavengePointer cannot be called recursively.
ObjectPtr obj = *p;
if (obj->IsImmediateObject()) {
if (obj->IsImmediateOrOldObject()) {
return false;
}
if (obj->IsOldObject()) {
return obj->untag()->IsEvacuationCandidate();
}
ObjectPtr new_obj = ScavengeObject(obj);
@@ -414,12 +408,10 @@ class ScavengerVisitorBase : public ObjectPointerVisitor,
// ScavengePointer cannot be called recursively.
ObjectPtr obj = p->Decompress(heap_base);
if (obj->IsImmediateObject()) {
// Could be tested without decompression.
if (obj->IsImmediateOrOldObject()) {
return false;
}
if (obj->IsOldObject()) {
return obj->untag()->IsEvacuationCandidate();
}
ObjectPtr new_obj = ScavengeObject(obj);
@@ -491,7 +483,7 @@ class ScavengerVisitorBase : public ObjectPointerVisitor,
// Promoted: update age/barrier tags.
uword tags = static_cast<uword>(header);
tags = UntaggedObject::OldAndNotRememberedBit::update(true, tags);
tags = UntaggedObject::NewOrEvacuationCandidateBit::update(false, tags);
tags = UntaggedObject::NewBit::update(false, tags);
new_obj->untag()->tags_.store(tags, std::memory_order_relaxed);
}
@@ -514,7 +506,6 @@ class ScavengerVisitorBase : public ObjectPointerVisitor,
if (new_obj->IsOldObject()) {
// Abandon as a free list element.
FreeListElement::AsElement(new_addr, size);
Page::Of(new_addr)->sub_live_bytes(size);
bytes_promoted_ -= size;
} else {
// Undo to-space allocation.
@@ -871,9 +862,9 @@ intptr_t Scavenger::NewSizeInWords(intptr_t old_size_in_words,
return old_size_in_words;
}
class CollectStoreBufferScavengeVisitor : public ObjectPointerVisitor {
class CollectStoreBufferVisitor : public ObjectPointerVisitor {
public:
CollectStoreBufferScavengeVisitor(ObjectSet* in_store_buffer, const char* msg)
CollectStoreBufferVisitor(ObjectSet* in_store_buffer, const char* msg)
: ObjectPointerVisitor(IsolateGroup::Current()),
in_store_buffer_(in_store_buffer),
msg_(msg) {}
@@ -906,16 +897,14 @@ class CollectStoreBufferScavengeVisitor : public ObjectPointerVisitor {
private:
ObjectSet* const in_store_buffer_;
const char* msg_;
DISALLOW_COPY_AND_ASSIGN(CollectStoreBufferScavengeVisitor);
};
class CheckStoreBufferScavengeVisitor : public ObjectVisitor,
public ObjectPointerVisitor {
class CheckStoreBufferVisitor : public ObjectVisitor,
public ObjectPointerVisitor {
public:
CheckStoreBufferScavengeVisitor(ObjectSet* in_store_buffer,
const SemiSpace* to,
const char* msg)
CheckStoreBufferVisitor(ObjectSet* in_store_buffer,
const SemiSpace* to,
const char* msg)
: ObjectVisitor(),
ObjectPointerVisitor(IsolateGroup::Current()),
in_store_buffer_(in_store_buffer),
@@ -926,11 +915,8 @@ class CheckStoreBufferScavengeVisitor : public ObjectVisitor,
if (obj->IsPseudoObject()) return;
RELEASE_ASSERT_WITH_MSG(obj->IsOldObject(), msg_);
if (obj->untag()->IsRemembered()) {
RELEASE_ASSERT_WITH_MSG(in_store_buffer_->Contains(obj), msg_);
} else {
RELEASE_ASSERT_WITH_MSG(!in_store_buffer_->Contains(obj), msg_);
}
RELEASE_ASSERT_WITH_MSG(
obj->untag()->IsRemembered() == in_store_buffer_->Contains(obj), msg_);
visiting_ = obj;
is_remembered_ = obj->untag()->IsRemembered();
@@ -1013,8 +999,6 @@ class CheckStoreBufferScavengeVisitor : public ObjectVisitor,
bool is_remembered_;
bool is_card_remembered_;
const char* msg_;
DISALLOW_COPY_AND_ASSIGN(CheckStoreBufferScavengeVisitor);
};
void Scavenger::VerifyStoreBuffers(const char* msg) {
@@ -1027,12 +1011,12 @@ void Scavenger::VerifyStoreBuffers(const char* msg) {
heap_->AddRegionsToObjectSet(in_store_buffer);
{
CollectStoreBufferScavengeVisitor visitor(in_store_buffer, msg);
CollectStoreBufferVisitor visitor(in_store_buffer, msg);
heap_->isolate_group()->store_buffer()->VisitObjectPointers(&visitor);
}
{
CheckStoreBufferScavengeVisitor visitor(in_store_buffer, to_, msg);
CheckStoreBufferVisitor visitor(in_store_buffer, to_, msg);
heap_->old_space()->VisitObjects(&visitor);
}
}
@@ -1628,20 +1612,10 @@ bool ScavengerVisitorBase<parallel>::ForwardOrSetNullIfCollected(
ObjectPtr parent,
CompressedObjectPtr* slot) {
ObjectPtr target = slot->Decompress(parent->heap_base());
if (target->IsImmediateObject()) {
if (target->IsImmediateOrOldObject()) {
// Object already null (which is old) or not touched during this GC.
return false;
}
if (target->IsOldObject()) {
if (parent->IsOldObject() && target->untag()->IsEvacuationCandidate()) {
if (!parent->untag()->IsCardRemembered()) {
if (parent->untag()->TryAcquireRememberedBit()) {
Thread::Current()->StoreBufferAddObjectGC(parent);
}
}
}
return false;
}
uword header = ReadHeaderRelaxed(target);
if (IsForwarding(header)) {
// Get the new location of the object.
@@ -1670,8 +1644,7 @@ void Scavenger::VisitObjectPointers(ObjectPointerVisitor* visitor) const {
void Scavenger::VisitObjects(ObjectVisitor* visitor) const {
ASSERT(Thread::Current()->OwnsGCSafepoint() ||
(Thread::Current()->task_kind() == Thread::kMarkerTask) ||
(Thread::Current()->task_kind() == Thread::kIncrementalCompactorTask));
(Thread::Current()->task_kind() == Thread::kMarkerTask));
for (Page* page = to_->head(); page != nullptr; page = page->next()) {
page->VisitObjects(visitor);
}
@@ -1841,6 +1814,7 @@ void Scavenger::Scavenge(Thread* thread, GCType type, GCReason reason) {
}
}
ASSERT(promotion_stack_.IsEmpty());
heap_->old_space()->ResumeConcurrentMarking();
// Scavenge finished. Run accounting.
int64_t end = OS::GetCurrentMonotonicMicros();
@@ -1848,7 +1822,6 @@ void Scavenger::Scavenge(Thread* thread, GCType type, GCReason reason) {
start, end, usage_before, GetCurrentUsage(), promo_candidate_words,
bytes_promoted >> kWordSizeLog2, abandoned_bytes >> kWordSizeLog2));
Epilogue(from);
heap_->old_space()->ResumeConcurrentMarking();
if (FLAG_verify_after_gc) {
heap_->WaitForSweeperTasksAtSafepoint(thread);
@@ -1935,8 +1908,7 @@ void Scavenger::ReverseScavenge(SemiSpace** from) {
uword from_header = static_cast<uword>(to_header);
from_header =
UntaggedObject::OldAndNotRememberedBit::update(false, from_header);
from_header = UntaggedObject::NewOrEvacuationCandidateBit::update(
true, from_header);
from_header = UntaggedObject::NewBit::update(true, from_header);
WriteHeaderRelaxed(from_obj, from_header);
runtime/vm/heap/sweeper.cc
-2
View File
@@ -102,7 +102,6 @@ bool GCSweeper::SweepPage(Page* page, FreeList* freelist) {
}
// Only add to the free list if not covering the whole page.
if ((current == start) && (free_end == end)) {
page->set_live_bytes(0);
return false; // Not in use.
}
obj_size = free_end - current;
@@ -132,7 +131,6 @@ bool GCSweeper::SweepPage(Page* page, FreeList* freelist) {
}
ASSERT(current == end);
ASSERT(used_in_bytes != 0);
page->set_live_bytes(used_in_bytes);
return true; // In use.
}
runtime/vm/image_snapshot.cc
+1 -1
View File
@@ -601,7 +601,7 @@ static constexpr uword kReadOnlyGCBits =
UntaggedObject::AlwaysSetBit::encode(true) |
UntaggedObject::NotMarkedBit::encode(false) |
UntaggedObject::OldAndNotRememberedBit::encode(true) |
UntaggedObject::NewOrEvacuationCandidateBit::encode(false);
UntaggedObject::NewBit::encode(false);
uword ImageWriter::GetMarkedTags(classid_t cid,
intptr_t size,
runtime/vm/isolate.cc
+1 -2
View File
@@ -2804,8 +2804,7 @@ void IsolateGroup::ForEachIsolate(
(thread->task_kind() == Thread::kMutatorTask) ||
(thread->task_kind() == Thread::kMarkerTask) ||
(thread->task_kind() == Thread::kCompactorTask) ||
(thread->task_kind() == Thread::kScavengerTask) ||
(thread->task_kind() == Thread::kIncrementalCompactorTask));
(thread->task_kind() == Thread::kScavengerTask));
for (Isolate* isolate : isolates_) {
function(isolate);
}
runtime/vm/object.cc
+1 -1
View File
@@ -2735,7 +2735,7 @@ void Object::InitializeObject(uword address,
tags = UntaggedObject::AlwaysSetBit::update(true, tags);
tags = UntaggedObject::NotMarkedBit::update(true, tags);
tags = UntaggedObject::OldAndNotRememberedBit::update(is_old, tags);
tags = UntaggedObject::NewOrEvacuationCandidateBit::update(!is_old, tags);
tags = UntaggedObject::NewBit::update(!is_old, tags);
tags = UntaggedObject::ImmutableBit::update(
Object::ShouldHaveImmutabilityBitSet(class_id), tags);
#if defined(HASH_IN_OBJECT_HEADER)
runtime/vm/object_graph_copy.cc
+1 -1
View File
@@ -235,7 +235,7 @@ void SetNewSpaceTaggingWord(ObjectPtr to, classid_t cid, uint32_t size) {
tags = UntaggedObject::NotMarkedBit::update(true, tags);
tags = UntaggedObject::OldAndNotRememberedBit::update(false, tags);
tags = UntaggedObject::CanonicalBit::update(false, tags);
tags = UntaggedObject::NewOrEvacuationCandidateBit::update(true, tags);
tags = UntaggedObject::NewBit::update(true, tags);
tags = UntaggedObject::ImmutableBit::update(
IsUnmodifiableTypedDataViewClassId(cid), tags);
#if defined(HASH_IN_OBJECT_HEADER)
runtime/vm/raw_object.cc
+5 -1
View File
@@ -48,12 +48,16 @@ void UntaggedObject::Validate(IsolateGroup* isolate_group) const {
// Validate that the tags_ field is sensible.
uword tags = tags_;
if (IsNewObject()) {
if (!NewOrEvacuationCandidateBit::decode(tags)) {
if (!NewBit::decode(tags)) {
FATAL("New object missing kNewBit: %" Px "\n", tags);
}
if (OldAndNotRememberedBit::decode(tags)) {
FATAL("New object has kOldAndNotRememberedBit: %" Px "\n", tags);
}
} else {
if (NewBit::decode(tags)) {
FATAL("Old object has kNewBit: %" Px "\n", tags);
}
}
const intptr_t class_id = ClassIdTag::decode(tags);
if (!isolate_group->class_table()->IsValidIndex(class_id)) {
runtime/vm/raw_object.h
+10 -33
View File
@@ -10,7 +10,6 @@
#endif
#include "platform/assert.h"
#include "platform/thread_sanitizer.h"
#include "vm/class_id.h"
#include "vm/compiler/method_recognizer.h"
#include "vm/compiler/runtime_api.h"
@@ -163,10 +162,10 @@ class UntaggedObject {
enum TagBits {
kCardRememberedBit = 0,
kCanonicalBit = 1,
kNotMarkedBit = 2, // Incremental barrier target.
kNewOrEvacuationCandidateBit = 3, // Generational barrier target.
kAlwaysSetBit = 4, // Incremental barrier source.
kOldAndNotRememberedBit = 5, // Generational barrier source.
kNotMarkedBit = 2, // Incremental barrier target.
kNewBit = 3, // Generational barrier target.
kAlwaysSetBit = 4, // Incremental barrier source.
kOldAndNotRememberedBit = 5, // Generational barrier source.
kImmutableBit = 6,
kReservedBit = 7,
@@ -178,13 +177,11 @@ class UntaggedObject {
kHashTagSize = 32,
};
static constexpr intptr_t kGenerationalBarrierMask =
1 << kNewOrEvacuationCandidateBit;
static constexpr intptr_t kGenerationalBarrierMask = 1 << kNewBit;
static constexpr intptr_t kIncrementalBarrierMask = 1 << kNotMarkedBit;
static constexpr intptr_t kBarrierOverlapShift = 2;
COMPILE_ASSERT(kNotMarkedBit + kBarrierOverlapShift == kAlwaysSetBit);
COMPILE_ASSERT(kNewOrEvacuationCandidateBit + kBarrierOverlapShift ==
kOldAndNotRememberedBit);
COMPILE_ASSERT(kNewBit + kBarrierOverlapShift == kOldAndNotRememberedBit);
// The bit in the Smi tag position must be something that can be set to 0
// for a dead filler object of either generation.
@@ -249,8 +246,7 @@ class UntaggedObject {
class NotMarkedBit : public BitField<uword, bool, kNotMarkedBit, 1> {};
class NewOrEvacuationCandidateBit
: public BitField<uword, bool, kNewOrEvacuationCandidateBit, 1> {};
class NewBit : public BitField<uword, bool, kNewBit, 1> {};
class CanonicalBit : public BitField<uword, bool, kCanonicalBit, 1> {};
@@ -296,12 +292,14 @@ class UntaggedObject {
}
uword tags() const { return tags_; }
uword tags_ignore_race() const { return tags_.load_ignore_race(); }
// Support for GC marking bit. Marked objects are either grey (not yet
// visited) or black (already visited).
static bool IsMarked(uword tags) { return !NotMarkedBit::decode(tags); }
bool IsMarked() const { return !tags_.Read<NotMarkedBit>(); }
bool IsMarkedIgnoreRace() const {
return !tags_.ReadIgnoreRace<NotMarkedBit>();
}
void SetMarkBit() {
ASSERT(!IsMarked());
tags_.UpdateBool<NotMarkedBit>(false);
@@ -326,25 +324,6 @@ class UntaggedObject {
DART_WARN_UNUSED_RESULT
bool TryAcquireMarkBit() { return tags_.TryClear<NotMarkedBit>(); }
static bool IsEvacuationCandidate(uword tags) {
return NewOrEvacuationCandidateBit::decode(tags);
}
bool IsEvacuationCandidate() {
return tags_.Read<NewOrEvacuationCandidateBit>();
}
void SetIsEvacuationCandidate() {
ASSERT(IsOldObject());
tags_.UpdateBool<NewOrEvacuationCandidateBit>(true);
}
void SetIsEvacuationCandidateUnsynchronized() {
ASSERT(IsOldObject());
tags_.UpdateUnsynchronized<NewOrEvacuationCandidateBit>(true);
}
void ClearIsEvacuationCandidateUnsynchronized() {
ASSERT(IsOldObject());
tags_.UpdateUnsynchronized<NewOrEvacuationCandidateBit>(false);
}
// Canonical objects have the property that two canonical objects are
// logically equal iff they are the same object (pointer equal).
bool IsCanonical() const { return tags_.Read<CanonicalBit>(); }
@@ -3244,8 +3223,6 @@ class UntaggedArray : public UntaggedInstance {
template <typename Table, bool kAllCanonicalObjectsAreIncludedIntoSet>
friend class CanonicalSetDeserializationCluster;
friend class Page;
template <bool>
friend class MarkingVisitorBase;
friend class FastObjectCopy; // For initializing fields.
friend void UpdateLengthField(intptr_t, ObjectPtr, ObjectPtr); // length_
};
runtime/vm/thread.cc
+2 -12
View File
@@ -670,7 +670,7 @@ void Thread::FreeActiveThread(Thread* thread, bool bypass_safepoint) {
}
void Thread::ReleaseStoreBuffer() {
ASSERT(IsAtSafepoint() || OwnsSafepoint() || task_kind_ == kMarkerTask);
ASSERT(IsAtSafepoint() || OwnsSafepoint());
if (store_buffer_block_ == nullptr || store_buffer_block_->IsEmpty()) {
return; // Nothing to release.
}
@@ -813,17 +813,6 @@ void Thread::StoreBufferAcquire() {
store_buffer_block_ = isolate_group()->store_buffer()->PopNonFullBlock();
}
void Thread::StoreBufferReleaseGC() {
StoreBufferBlock* block = store_buffer_block_;
store_buffer_block_ = nullptr;
isolate_group()->store_buffer()->PushBlock(block,
StoreBuffer::kIgnoreThreshold);
}
void Thread::StoreBufferAcquireGC() {
store_buffer_block_ = isolate_group()->store_buffer()->PopNonFullBlock();
}
void Thread::MarkingStackBlockProcess() {
MarkingStackRelease();
MarkingStackAcquire();
@@ -976,6 +965,7 @@ class RestoreWriteBarrierInvariantVisitor : public ObjectPointerVisitor {
void VisitPointers(ObjectPtr* first, ObjectPtr* last) override {
for (; first != last + 1; first++) {
ObjectPtr obj = *first;
// Stores into new-space objects don't need a write barrier.
if (obj->IsImmediateObject()) continue;
// To avoid adding too much work into the remembered set, skip large
runtime/vm/thread.h
-3
View File
@@ -351,7 +351,6 @@ class Thread : public ThreadState {
kCompactorTask = 0x10,
kScavengerTask = 0x20,
kSampleBlockTask = 0x40,
kIncrementalCompactorTask = 0x80,
};
// Converts a TaskKind to its corresponding C-String name.
static const char* TaskKindToCString(TaskKind kind);
@@ -663,8 +662,6 @@ class Thread : public ThreadState {
}
#endif
void StoreBufferBlockProcess(StoreBuffer::ThresholdPolicy policy);
void StoreBufferReleaseGC();
void StoreBufferAcquireGC();
static intptr_t store_buffer_block_offset() {
return OFFSET_OF(Thread, store_buffer_block_);
}