| /* |
| * Copyright (C) 2009 Google Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are |
| * met: |
| * |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following disclaimer |
| * in the documentation and/or other materials provided with the |
| * distribution. |
| * * Neither the name of Google Inc. nor the names of its |
| * contributors may be used to endorse or promote products derived from |
| * this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #include "third_party/blink/renderer/bindings/core/v8/v8_gc_controller.h" |
| |
| #include <algorithm> |
| #include <unordered_map> |
| #include <unordered_set> |
| |
| #include "third_party/blink/public/platform/blame_context.h" |
| #include "third_party/blink/public/platform/platform.h" |
| #include "third_party/blink/renderer/bindings/core/v8/active_script_wrappable.h" |
| #include "third_party/blink/renderer/bindings/core/v8/script_source_code.h" |
| #include "third_party/blink/renderer/bindings/core/v8/v8_abstract_event_listener.h" |
| #include "third_party/blink/renderer/bindings/core/v8/v8_binding_for_core.h" |
| #include "third_party/blink/renderer/bindings/core/v8/v8_node.h" |
| #include "third_party/blink/renderer/bindings/core/v8/v8_script_runner.h" |
| #include "third_party/blink/renderer/core/dom/attr.h" |
| #include "third_party/blink/renderer/core/dom/element.h" |
| #include "third_party/blink/renderer/core/dom/node.h" |
| #include "third_party/blink/renderer/core/html/imports/html_imports_controller.h" |
| #include "third_party/blink/renderer/core/inspector/inspector_trace_events.h" |
| #include "third_party/blink/renderer/platform/bindings/script_wrappable_marking_visitor.h" |
| #include "third_party/blink/renderer/platform/bindings/wrapper_type_info.h" |
| #include "third_party/blink/renderer/platform/heap/heap_stats_collector.h" |
| #include "third_party/blink/renderer/platform/histogram.h" |
| #include "third_party/blink/renderer/platform/instrumentation/tracing/trace_event.h" |
| #include "third_party/blink/renderer/platform/wtf/allocator/partitions.h" |
| #include "third_party/blink/renderer/platform/wtf/text/string_builder.h" |
| |
| namespace blink { |
| |
| Node* V8GCController::OpaqueRootForGC(v8::Isolate*, Node* node) { |
| DCHECK(node); |
| if (node->isConnected()) |
| return &node->GetDocument().MasterDocument(); |
| |
| if (node->IsAttributeNode()) { |
| Node* owner_element = ToAttr(node)->ownerElement(); |
| if (!owner_element) |
| return node; |
| node = owner_element; |
| } |
| |
| while (Node* parent = node->ParentOrShadowHostOrTemplateHostNode()) |
| node = parent; |
| |
| return node; |
| } |
| |
| class MinorGCUnmodifiedWrapperVisitor : public v8::PersistentHandleVisitor { |
| public: |
| explicit MinorGCUnmodifiedWrapperVisitor(v8::Isolate* isolate) |
| : isolate_(isolate) {} |
| |
| void VisitPersistentHandle(v8::Persistent<v8::Value>* value, |
| uint16_t class_id) override { |
| if (class_id != WrapperTypeInfo::kNodeClassId && |
| class_id != WrapperTypeInfo::kObjectClassId) { |
| return; |
| } |
| |
| // MinorGC does not collect objects because it may be expensive to |
| // update references during minorGC |
| if (class_id == WrapperTypeInfo::kObjectClassId) { |
| v8::Persistent<v8::Object>::Cast(*value).MarkActive(); |
| return; |
| } |
| |
| v8::Local<v8::Object> wrapper = v8::Local<v8::Object>::New( |
| isolate_, v8::Persistent<v8::Object>::Cast(*value)); |
| DCHECK(V8DOMWrapper::HasInternalFieldsSet(wrapper)); |
| if (ToWrapperTypeInfo(wrapper)->IsActiveScriptWrappable() && |
| ToScriptWrappable(wrapper)->HasPendingActivity()) { |
| v8::Persistent<v8::Object>::Cast(*value).MarkActive(); |
| return; |
| } |
| |
| if (class_id == WrapperTypeInfo::kNodeClassId) { |
| DCHECK(V8Node::hasInstance(wrapper, isolate_)); |
| Node* node = V8Node::ToImpl(wrapper); |
| if (node->HasEventListeners()) { |
| v8::Persistent<v8::Object>::Cast(*value).MarkActive(); |
| return; |
| } |
| // FIXME: Remove the special handling for SVG elements. |
| // We currently can't collect SVG Elements from minor gc, as we have |
| // strong references from SVG property tear-offs keeping context SVG |
| // element alive. |
| if (node->IsSVGElement()) { |
| v8::Persistent<v8::Object>::Cast(*value).MarkActive(); |
| return; |
| } |
| } |
| } |
| |
| private: |
| v8::Isolate* isolate_; |
| }; |
| |
| static unsigned long long UsedHeapSize(v8::Isolate* isolate) { |
| v8::HeapStatistics heap_statistics; |
| isolate->GetHeapStatistics(&heap_statistics); |
| return heap_statistics.used_heap_size(); |
| } |
| |
| namespace { |
| |
| void VisitWeakHandlesForMinorGC(v8::Isolate* isolate) { |
| MinorGCUnmodifiedWrapperVisitor visitor(isolate); |
| isolate->VisitWeakHandles(&visitor); |
| } |
| |
| } // namespace |
| |
| void V8GCController::GcPrologue(v8::Isolate* isolate, |
| v8::GCType type, |
| v8::GCCallbackFlags flags) { |
| RUNTIME_CALL_TIMER_SCOPE(isolate, RuntimeCallStats::CounterId::kGcPrologue); |
| ScriptForbiddenScope::Enter(); |
| |
| // Attribute garbage collection to the all frames instead of a specific |
| // frame. |
| if (BlameContext* blame_context = |
| Platform::Current()->GetTopLevelBlameContext()) |
| blame_context->Enter(); |
| |
| // TODO(haraken): A GC callback is not allowed to re-enter V8. This means |
| // that it's unsafe to run Oilpan's GC in the GC callback because it may |
| // run finalizers that call into V8. To avoid the risk, we should post |
| // a task to schedule the Oilpan's GC. |
| // (In practice, there is no finalizer that calls into V8 and thus is safe.) |
| |
| v8::HandleScope scope(isolate); |
| switch (type) { |
| case v8::kGCTypeScavenge: |
| TRACE_EVENT_BEGIN1("devtools.timeline,v8", "MinorGC", |
| "usedHeapSizeBefore", UsedHeapSize(isolate)); |
| VisitWeakHandlesForMinorGC(isolate); |
| break; |
| case v8::kGCTypeMarkSweepCompact: |
| if (ThreadState::Current()) |
| ThreadState::Current()->WillStartV8GC(BlinkGC::kV8MajorGC); |
| |
| TRACE_EVENT_BEGIN2("devtools.timeline,v8", "MajorGC", |
| "usedHeapSizeBefore", UsedHeapSize(isolate), "type", |
| "atomic pause"); |
| break; |
| case v8::kGCTypeIncrementalMarking: |
| if (ThreadState::Current()) |
| ThreadState::Current()->WillStartV8GC(BlinkGC::kV8MajorGC); |
| |
| TRACE_EVENT_BEGIN2("devtools.timeline,v8", "MajorGC", |
| "usedHeapSizeBefore", UsedHeapSize(isolate), "type", |
| "incremental marking"); |
| break; |
| case v8::kGCTypeProcessWeakCallbacks: |
| TRACE_EVENT_BEGIN2("devtools.timeline,v8", "MajorGC", |
| "usedHeapSizeBefore", UsedHeapSize(isolate), "type", |
| "weak processing"); |
| break; |
| default: |
| NOTREACHED(); |
| } |
| } |
| |
| namespace { |
| |
| void UpdateCollectedPhantomHandles(v8::Isolate* isolate) { |
| ThreadHeapStatsCollector* stats_collector = |
| ThreadState::Current()->Heap().stats_collector(); |
| const size_t count = isolate->NumberOfPhantomHandleResetsSinceLastCall(); |
| stats_collector->DecreaseWrapperCount(count); |
| stats_collector->IncreaseCollectedWrapperCount(count); |
| } |
| |
| } // namespace |
| |
| void V8GCController::GcEpilogue(v8::Isolate* isolate, |
| v8::GCType type, |
| v8::GCCallbackFlags flags) { |
| RUNTIME_CALL_TIMER_SCOPE(isolate, RuntimeCallStats::CounterId::kGcEpilogue); |
| UpdateCollectedPhantomHandles(isolate); |
| switch (type) { |
| case v8::kGCTypeScavenge: |
| TRACE_EVENT_END1("devtools.timeline,v8", "MinorGC", "usedHeapSizeAfter", |
| UsedHeapSize(isolate)); |
| // Scavenger might have dropped nodes. |
| if (ThreadState::Current()) { |
| ThreadState::Current()->ScheduleV8FollowupGCIfNeeded( |
| BlinkGC::kV8MinorGC); |
| } |
| break; |
| case v8::kGCTypeMarkSweepCompact: |
| TRACE_EVENT_END1("devtools.timeline,v8", "MajorGC", "usedHeapSizeAfter", |
| UsedHeapSize(isolate)); |
| if (ThreadState::Current()) |
| ThreadState::Current()->ScheduleV8FollowupGCIfNeeded( |
| BlinkGC::kV8MajorGC); |
| break; |
| case v8::kGCTypeIncrementalMarking: |
| TRACE_EVENT_END1("devtools.timeline,v8", "MajorGC", "usedHeapSizeAfter", |
| UsedHeapSize(isolate)); |
| break; |
| case v8::kGCTypeProcessWeakCallbacks: |
| TRACE_EVENT_END1("devtools.timeline,v8", "MajorGC", "usedHeapSizeAfter", |
| UsedHeapSize(isolate)); |
| break; |
| default: |
| NOTREACHED(); |
| } |
| |
| ScriptForbiddenScope::Exit(); |
| |
| if (BlameContext* blame_context = |
| Platform::Current()->GetTopLevelBlameContext()) |
| blame_context->Leave(); |
| |
| ThreadState* current_thread_state = ThreadState::Current(); |
| if (current_thread_state && !current_thread_state->IsGCForbidden()) { |
| // v8::kGCCallbackFlagForced forces a Blink heap garbage collection |
| // when a garbage collection was forced from V8. This is either used |
| // for tests that force GCs from JavaScript to verify that objects die |
| // when expected. |
| if (flags & v8::kGCCallbackFlagForced) { |
| // This single GC is not enough for two reasons: |
| // (1) The GC is not precise because the GC scans on-stack pointers |
| // conservatively. |
| // (2) One GC is not enough to break a chain of persistent handles. It's |
| // possible that some heap allocated objects own objects that |
| // contain persistent handles pointing to other heap allocated |
| // objects. To break the chain, we need multiple GCs. |
| // |
| // Regarding (1), we force a precise GC at the end of the current event |
| // loop. So if you want to collect all garbage, you need to wait until the |
| // next event loop. Regarding (2), it would be OK in practice to trigger |
| // only one GC per gcEpilogue, because GCController.collectAll() forces |
| // multiple V8's GC. |
| current_thread_state->CollectGarbage( |
| BlinkGC::kHeapPointersOnStack, BlinkGC::kAtomicMarking, |
| BlinkGC::kEagerSweeping, BlinkGC::GCReason::kForcedGC); |
| |
| // Forces a precise GC at the end of the current event loop. |
| current_thread_state->ScheduleFullGC(); |
| } |
| |
| // v8::kGCCallbackFlagCollectAllAvailableGarbage is used when V8 handles |
| // low memory notifications. |
| if ((flags & v8::kGCCallbackFlagCollectAllAvailableGarbage) || |
| (flags & v8::kGCCallbackFlagCollectAllExternalMemory)) { |
| // This single GC is not enough. See the above comment. |
| current_thread_state->CollectGarbage( |
| BlinkGC::kHeapPointersOnStack, BlinkGC::kAtomicMarking, |
| BlinkGC::kEagerSweeping, BlinkGC::GCReason::kForcedGC); |
| |
| // The conservative GC might have left floating garbage. Schedule |
| // precise GC to ensure that we collect all available garbage. |
| current_thread_state->SchedulePreciseGC(); |
| } |
| |
| // Schedules a precise GC for the next idle time period. |
| if (flags & v8::kGCCallbackScheduleIdleGarbageCollection) { |
| current_thread_state->ScheduleIdleGC(); |
| } |
| } |
| |
| TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), |
| "UpdateCounters", TRACE_EVENT_SCOPE_THREAD, "data", |
| InspectorUpdateCountersEvent::Data()); |
| } |
| |
| void V8GCController::CollectGarbage(v8::Isolate* isolate, bool only_minor_gc) { |
| v8::HandleScope handle_scope(isolate); |
| scoped_refptr<ScriptState> script_state = ScriptState::Create( |
| v8::Context::New(isolate), |
| DOMWrapperWorld::Create(isolate, |
| DOMWrapperWorld::WorldType::kGarbageCollector)); |
| ScriptState::Scope scope(script_state.get()); |
| StringBuilder builder; |
| builder.Append("if (gc) gc("); |
| builder.Append(only_minor_gc ? "true" : "false"); |
| builder.Append(")"); |
| V8ScriptRunner::CompileAndRunInternalScript( |
| isolate, script_state.get(), |
| ScriptSourceCode(builder.ToString(), ScriptSourceLocationType::kInternal, |
| nullptr, KURL(), TextPosition())); |
| script_state->DisposePerContextData(); |
| } |
| |
| void V8GCController::CollectAllGarbageForTesting(v8::Isolate* isolate) { |
| for (unsigned i = 0; i < 5; i++) |
| isolate->RequestGarbageCollectionForTesting( |
| v8::Isolate::kFullGarbageCollection); |
| } |
| |
| namespace { |
| |
| // Traces all DOM persistent handles using the provided visitor. |
| class DOMWrapperTracer final : public v8::PersistentHandleVisitor { |
| public: |
| explicit DOMWrapperTracer(Visitor* visitor) : visitor_(visitor) { |
| DCHECK(visitor_); |
| } |
| |
| void VisitPersistentHandle(v8::Persistent<v8::Value>* value, |
| uint16_t class_id) final { |
| if (class_id != WrapperTypeInfo::kNodeClassId && |
| class_id != WrapperTypeInfo::kObjectClassId) |
| return; |
| |
| visitor_->Trace( |
| ToScriptWrappable(v8::Persistent<v8::Object>::Cast(*value))); |
| } |
| |
| private: |
| Visitor* const visitor_; |
| }; |
| |
| // Purges all DOM persistent handles. |
| class DOMWrapperPurger final : public v8::PersistentHandleVisitor { |
| public: |
| explicit DOMWrapperPurger(v8::Isolate* isolate) |
| : isolate_(isolate), scope_(isolate) {} |
| |
| void VisitPersistentHandle(v8::Persistent<v8::Value>* value, |
| uint16_t class_id) final { |
| if (class_id != WrapperTypeInfo::kNodeClassId && |
| class_id != WrapperTypeInfo::kObjectClassId) |
| return; |
| |
| // Clear out wrapper type information, essentially disconnecting the Blink |
| // wrappable from the V8 wrapper. This way, V8 cannot find the C++ object |
| // anymore. |
| int indices[] = {kV8DOMWrapperObjectIndex, kV8DOMWrapperTypeIndex}; |
| void* values[] = {nullptr, nullptr}; |
| v8::Local<v8::Object> wrapper = v8::Local<v8::Object>::New( |
| isolate_, v8::Persistent<v8::Object>::Cast(*value)); |
| wrapper->SetAlignedPointerInInternalFields(base::size(indices), indices, |
| values); |
| value->Reset(); |
| } |
| |
| private: |
| v8::Isolate* isolate_; |
| v8::HandleScope scope_; |
| }; |
| |
| } // namespace |
| |
| void V8GCController::TraceDOMWrappers(v8::Isolate* isolate, Visitor* visitor) { |
| DOMWrapperTracer tracer(visitor); |
| isolate->VisitHandlesWithClassIds(&tracer); |
| } |
| |
| void V8GCController::ClearDOMWrappers(v8::Isolate* isolate) { |
| DOMWrapperPurger purger(isolate); |
| isolate->VisitHandlesWithClassIds(&purger); |
| } |
| |
| } // namespace blink |
