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flutter_flutter/engine/bindings/core/v8/V8GCController.cpp
Adam Barth fc451b47eb Unfork Sky's trace events 
This CL remove the body of Sky's TraceEvent.h in favor of the version in base.
There's still some more of the system to unwind before we can remove all the
other boilerplate.

R=eseidel@chromium.org

Review URL: https://codereview.chromium.org/691663002
2014-10-30 09:39:46 -07:00

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/*
* 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 "config.h"
#include "bindings/core/v8/V8GCController.h"
#include "bindings/core/v8/RetainedDOMInfo.h"
#include "bindings/core/v8/V8AbstractEventListener.h"
#include "bindings/core/v8/V8Binding.h"
#include "bindings/core/v8/V8MutationObserver.h"
#include "bindings/core/v8/V8Node.h"
#include "bindings/core/v8/V8ScriptRunner.h"
#include "bindings/core/v8/WrapperTypeInfo.h"
#include "core/dom/Attr.h"
#include "core/dom/Document.h"
#include "core/dom/NodeTraversal.h"
#include "core/dom/TemplateContentDocumentFragment.h"
#include "core/dom/shadow/ElementShadow.h"
#include "core/dom/shadow/ShadowRoot.h"
#include "core/html/HTMLImageElement.h"
#include "core/html/HTMLTemplateElement.h"
#include "core/html/imports/HTMLImportsController.h"
#include "core/inspector/InspectorTraceEvents.h"
#include "platform/Partitions.h"
#include "platform/TraceEvent.h"
#include "wtf/Vector.h"
#include <algorithm>
namespace blink {
// FIXME: This should use opaque GC roots.
static void addReferencesForNodeWithEventListeners(v8::Isolate* isolate, Node* node, const v8::Persistent<v8::Object>& wrapper)
{
ASSERT(node->hasEventListeners());
EventListenerIterator iterator(node);
while (EventListener* listener = iterator.nextListener()) {
V8AbstractEventListener* v8listener = static_cast<V8AbstractEventListener*>(listener);
if (!v8listener->hasExistingListenerObject())
continue;
isolate->SetReference(wrapper, v8::Persistent<v8::Value>::Cast(v8listener->existingListenerObjectPersistentHandle()));
}
}
Node* V8GCController::opaqueRootForGC(Node* node, v8::Isolate*)
{
ASSERT(node);
// FIXME: Remove the special handling for image elements.
// The same special handling is in V8GCController::gcTree().
// Maybe should image elements be active DOM nodes?
// See https://code.google.com/p/chromium/issues/detail?id=164882
if (node->inDocument() || (isHTMLImageElement(*node) && toHTMLImageElement(*node).hasPendingActivity())) {
Document& document = node->document();
if (HTMLImportsController* controller = document.importsController())
return controller->master();
return &document;
}
if (node->isAttributeNode()) {
Node* ownerElement = toAttr(node)->ownerElement();
if (!ownerElement)
return node;
node = ownerElement;
}
while (Node* parent = node->parentOrShadowHostOrTemplateHostNode())
node = parent;
return node;
}
// Regarding a minor GC algorithm for DOM nodes, see this document:
// https://docs.google.com/a/google.com/presentation/d/1uifwVYGNYTZDoGLyCb7sXa7g49mWNMW2gaWvMN5NLk8/edit#slide=id.p
class MinorGCWrapperVisitor : public v8::PersistentHandleVisitor {
public:
explicit MinorGCWrapperVisitor(v8::Isolate* isolate)
: m_isolate(isolate)
{ }
virtual void VisitPersistentHandle(v8::Persistent<v8::Value>* value, uint16_t classId) override
{
// A minor DOM GC can collect only Nodes.
if (classId != WrapperTypeInfo::NodeClassId)
return;
// To make minor GC cycle time bounded, we limit the number of wrappers handled
// by each minor GC cycle to 10000. This value was selected so that the minor
// GC cycle time is bounded to 20 ms in a case where the new space size
// is 16 MB and it is full of wrappers (which is almost the worst case).
// Practically speaking, as far as I crawled real web applications,
// the number of wrappers handled by each minor GC cycle is at most 3000.
// So this limit is mainly for pathological micro benchmarks.
const unsigned wrappersHandledByEachMinorGC = 10000;
if (m_nodesInNewSpace.size() >= wrappersHandledByEachMinorGC)
return;
// Casting to a Handle is safe here, since the Persistent doesn't get GCd
// during the GC prologue.
ASSERT((*reinterpret_cast<v8::Handle<v8::Value>*>(value))->IsObject());
v8::Handle<v8::Object>* wrapper = reinterpret_cast<v8::Handle<v8::Object>*>(value);
ASSERT(V8DOMWrapper::isDOMWrapper(*wrapper));
ASSERT(V8Node::hasInstance(*wrapper, m_isolate));
Node* node = V8Node::toNative(*wrapper);
// A minor DOM GC can handle only node wrappers in the main world.
// Note that node->wrapper().IsEmpty() returns true for nodes that
// do not have wrappers in the main world.
if (node->containsWrapper()) {
const WrapperTypeInfo* type = toWrapperTypeInfo(*wrapper);
ActiveDOMObject* activeDOMObject = type->toActiveDOMObject(*wrapper);
if (activeDOMObject && activeDOMObject->hasPendingActivity())
return;
// FIXME: Remove the special handling for image elements.
// The same special handling is in V8GCController::opaqueRootForGC().
// Maybe should image elements be active DOM nodes?
// See https://code.google.com/p/chromium/issues/detail?id=164882
if (isHTMLImageElement(*node) && toHTMLImageElement(*node).hasPendingActivity())
return;
m_nodesInNewSpace.append(node);
node->markV8CollectableDuringMinorGC();
}
}
void notifyFinished()
{
for (size_t i = 0; i < m_nodesInNewSpace.size(); i++) {
Node* node = m_nodesInNewSpace[i];
ASSERT(node->containsWrapper());
if (node->isV8CollectableDuringMinorGC()) { // This branch is just for performance.
gcTree(m_isolate, node);
node->clearV8CollectableDuringMinorGC();
}
}
}
private:
bool traverseTree(Node* rootNode, Vector<RawPtr<Node>, initialNodeVectorSize>* partiallyDependentNodes)
{
// To make each minor GC time bounded, we might need to give up
// traversing at some point for a large DOM tree. That being said,
// I could not observe the need even in pathological test cases.
for (Node* node = rootNode; node; node = NodeTraversal::next(*node)) {
if (node->containsWrapper()) {
if (!node->isV8CollectableDuringMinorGC()) {
// This node is not in the new space of V8. This indicates that
// the minor GC cannot anyway judge reachability of this DOM tree.
// Thus we give up traversing the DOM tree.
return false;
}
node->clearV8CollectableDuringMinorGC();
partiallyDependentNodes->append(node);
}
if (ShadowRoot* shadowRoot = node->youngestShadowRoot()) {
if (!traverseTree(shadowRoot, partiallyDependentNodes))
return false;
} else if (node->isShadowRoot()) {
if (ShadowRoot* shadowRoot = toShadowRoot(node)->olderShadowRoot()) {
if (!traverseTree(shadowRoot, partiallyDependentNodes))
return false;
}
}
// <template> has a |content| property holding a DOM fragment which we must traverse,
// just like we do for the shadow trees above.
if (isHTMLTemplateElement(*node)) {
if (!traverseTree(toHTMLTemplateElement(*node).content(), partiallyDependentNodes))
return false;
}
// Document maintains the list of imported documents through HTMLImportsController.
if (node->isDocumentNode()) {
Document* document = toDocument(node);
HTMLImportsController* controller = document->importsController();
if (controller && document == controller->master()) {
for (unsigned i = 0; i < controller->loaderCount(); ++i) {
if (!traverseTree(controller->loaderDocumentAt(i), partiallyDependentNodes))
return false;
}
}
}
}
return true;
}
void gcTree(v8::Isolate* isolate, Node* startNode)
{
Vector<RawPtr<Node>, initialNodeVectorSize> partiallyDependentNodes;
Node* node = startNode;
while (Node* parent = node->parentOrShadowHostOrTemplateHostNode())
node = parent;
if (!traverseTree(node, &partiallyDependentNodes))
return;
// We completed the DOM tree traversal. All wrappers in the DOM tree are
// stored in partiallyDependentNodes and are expected to exist in the new space of V8.
// We report those wrappers to V8 as an object group.
if (!partiallyDependentNodes.size())
return;
Node* groupRoot = partiallyDependentNodes[0];
for (size_t i = 0; i < partiallyDependentNodes.size(); i++) {
partiallyDependentNodes[i]->markAsDependentGroup(groupRoot, isolate);
}
}
Vector<RawPtr<Node> > m_nodesInNewSpace;
v8::Isolate* m_isolate;
};
class MajorGCWrapperVisitor : public v8::PersistentHandleVisitor {
public:
explicit MajorGCWrapperVisitor(v8::Isolate* isolate, bool constructRetainedObjectInfos)
: m_isolate(isolate)
, m_liveRootGroupIdSet(false)
, m_constructRetainedObjectInfos(constructRetainedObjectInfos)
{
}
virtual void VisitPersistentHandle(v8::Persistent<v8::Value>* value, uint16_t classId) override
{
if (classId != WrapperTypeInfo::NodeClassId && classId != WrapperTypeInfo::ObjectClassId)
return;
// Casting to a Handle is safe here, since the Persistent doesn't get GCd
// during the GC prologue.
ASSERT((*reinterpret_cast<v8::Handle<v8::Value>*>(value))->IsObject());
v8::Handle<v8::Object>* wrapper = reinterpret_cast<v8::Handle<v8::Object>*>(value);
ASSERT(V8DOMWrapper::isDOMWrapper(*wrapper));
if (value->IsIndependent())
return;
const WrapperTypeInfo* type = toWrapperTypeInfo(*wrapper);
ActiveDOMObject* activeDOMObject = type->toActiveDOMObject(*wrapper);
if (activeDOMObject && activeDOMObject->hasPendingActivity())
m_isolate->SetObjectGroupId(*value, liveRootId());
if (classId == WrapperTypeInfo::NodeClassId) {
ASSERT(V8Node::hasInstance(*wrapper, m_isolate));
Node* node = V8Node::toNative(*wrapper);
if (node->hasEventListeners())
addReferencesForNodeWithEventListeners(m_isolate, node, v8::Persistent<v8::Object>::Cast(*value));
Node* root = V8GCController::opaqueRootForGC(node, m_isolate);
m_isolate->SetObjectGroupId(*value, v8::UniqueId(reinterpret_cast<intptr_t>(root)));
if (m_constructRetainedObjectInfos)
m_groupsWhichNeedRetainerInfo.append(root);
} else if (classId == WrapperTypeInfo::ObjectClassId) {
type->visitDOMWrapper(toScriptWrappableBase(*wrapper), v8::Persistent<v8::Object>::Cast(*value), m_isolate);
} else {
ASSERT_NOT_REACHED();
}
}
void notifyFinished()
{
if (!m_constructRetainedObjectInfos)
return;
std::sort(m_groupsWhichNeedRetainerInfo.begin(), m_groupsWhichNeedRetainerInfo.end());
Node* alreadyAdded = 0;
v8::HeapProfiler* profiler = m_isolate->GetHeapProfiler();
for (size_t i = 0; i < m_groupsWhichNeedRetainerInfo.size(); ++i) {
Node* root = m_groupsWhichNeedRetainerInfo[i];
if (root != alreadyAdded) {
profiler->SetRetainedObjectInfo(v8::UniqueId(reinterpret_cast<intptr_t>(root)), new RetainedDOMInfo(root));
alreadyAdded = root;
}
}
}
private:
v8::UniqueId liveRootId()
{
const v8::Persistent<v8::Value>& liveRoot = V8PerIsolateData::from(m_isolate)->ensureLiveRoot();
const intptr_t* idPointer = reinterpret_cast<const intptr_t*>(&liveRoot);
v8::UniqueId id(*idPointer);
if (!m_liveRootGroupIdSet) {
m_isolate->SetObjectGroupId(liveRoot, id);
m_liveRootGroupIdSet = true;
}
return id;
}
v8::Isolate* m_isolate;
Vector<RawPtr<Node> > m_groupsWhichNeedRetainerInfo;
bool m_liveRootGroupIdSet;
bool m_constructRetainedObjectInfos;
};
static unsigned long long usedHeapSize(v8::Isolate* isolate)
{
v8::HeapStatistics heapStatistics;
isolate->GetHeapStatistics(&heapStatistics);
return heapStatistics.used_heap_size();
}
void V8GCController::gcPrologue(v8::GCType type, v8::GCCallbackFlags flags)
{
// FIXME: It would be nice if the GC callbacks passed the Isolate directly....
v8::Isolate* isolate = v8::Isolate::GetCurrent();
TRACE_EVENT_BEGIN1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "GCEvent", "usedHeapSizeBefore", usedHeapSize(isolate));
if (type == v8::kGCTypeScavenge)
minorGCPrologue(isolate);
else if (type == v8::kGCTypeMarkSweepCompact)
majorGCPrologue(flags & v8::kGCCallbackFlagConstructRetainedObjectInfos, isolate);
}
void V8GCController::minorGCPrologue(v8::Isolate* isolate)
{
TRACE_EVENT_BEGIN0("v8", "minorGC");
if (isMainThread()) {
ScriptForbiddenScope::enter();
{
TRACE_EVENT_SCOPED_SAMPLING_STATE("blink", "DOMMinorGC");
v8::HandleScope scope(isolate);
MinorGCWrapperVisitor visitor(isolate);
v8::V8::VisitHandlesForPartialDependence(isolate, &visitor);
visitor.notifyFinished();
}
V8PerIsolateData::from(isolate)->setPreviousSamplingState(TRACE_EVENT_GET_SAMPLING_STATE());
TRACE_EVENT_SET_SAMPLING_STATE("v8", "V8MinorGC");
}
}
// Create object groups for DOM tree nodes.
void V8GCController::majorGCPrologue(bool constructRetainedObjectInfos, v8::Isolate* isolate)
{
v8::HandleScope scope(isolate);
TRACE_EVENT_BEGIN0("v8", "majorGC");
if (isMainThread()) {
ScriptForbiddenScope::enter();
{
TRACE_EVENT_SCOPED_SAMPLING_STATE("blink", "DOMMajorGC");
MajorGCWrapperVisitor visitor(isolate, constructRetainedObjectInfos);
v8::V8::VisitHandlesWithClassIds(&visitor);
visitor.notifyFinished();
}
V8PerIsolateData::from(isolate)->setPreviousSamplingState(TRACE_EVENT_GET_SAMPLING_STATE());
TRACE_EVENT_SET_SAMPLING_STATE("v8", "V8MajorGC");
} else {
MajorGCWrapperVisitor visitor(isolate, constructRetainedObjectInfos);
v8::V8::VisitHandlesWithClassIds(&visitor);
visitor.notifyFinished();
}
}
void V8GCController::gcEpilogue(v8::GCType type, v8::GCCallbackFlags flags)
{
// FIXME: It would be nice if the GC callbacks passed the Isolate directly....
v8::Isolate* isolate = v8::Isolate::GetCurrent();
if (type == v8::kGCTypeScavenge)
minorGCEpilogue(isolate);
else if (type == v8::kGCTypeMarkSweepCompact)
majorGCEpilogue(isolate);
TRACE_EVENT_END1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "GCEvent", "usedHeapSizeAfter", usedHeapSize(isolate));
TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "UpdateCounters", TRACE_EVENT_SCOPE_PROCESS, "data", InspectorUpdateCountersEvent::data());
}
void V8GCController::minorGCEpilogue(v8::Isolate* isolate)
{
TRACE_EVENT_END0("v8", "minorGC");
if (isMainThread())
ScriptForbiddenScope::exit();
}
void V8GCController::majorGCEpilogue(v8::Isolate* isolate)
{
v8::HandleScope scope(isolate);
TRACE_EVENT_END0("v8", "majorGC");
if (isMainThread())
ScriptForbiddenScope::exit();
}
void V8GCController::collectGarbage(v8::Isolate* isolate)
{
v8::HandleScope handleScope(isolate);
RefPtr<ScriptState> scriptState = ScriptState::create(v8::Context::New(isolate), DOMWrapperWorld::create());
ScriptState::Scope scope(scriptState.get());
V8ScriptRunner::compileAndRunInternalScript(v8String(isolate, "if (gc) gc();"), isolate);
scriptState->disposePerContextData();
}
void V8GCController::reportDOMMemoryUsageToV8(v8::Isolate* isolate)
{
if (!isMainThread())
return;
static size_t lastUsageReportedToV8 = 0;
size_t currentUsage = Partitions::currentDOMMemoryUsage();
int64_t diff = static_cast<int64_t>(currentUsage) - static_cast<int64_t>(lastUsageReportedToV8);
isolate->AdjustAmountOfExternalAllocatedMemory(diff);
lastUsageReportedToV8 = currentUsage;
}
} // namespace blink
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