Do V8 GC ASAP if system memory is pressured

third_party/WebKit/Source/core/workers/WorkerBackingThread.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/workers/WorkerBackingThread.h"
 
 #include "bindings/core/v8/V8Binding.h"
 #include "bindings/core/v8/V8GCController.h"
 #include "bindings/core/v8/V8IdleTaskRunner.h"
 #include "bindings/core/v8/V8Initializer.h"
 #include "bindings/core/v8/V8PerIsolateData.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/ThreadSafeFunctional.h"
 #include "platform/WebThreadSupportingGC.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebTraceLocation.h"
 
 namespace blink {
 
+#define DEFINE_STATIC_LOCAL_WITH_LOCK(type, name, arguments) \
+    ASSERT(isolatesMutex().locked()); \
+    static type& name = *new type arguments
+
+static Mutex& isolatesMutex()
+{
+    DEFINE_THREAD_SAFE_STATIC_LOCAL(Mutex, mutex, new Mutex);
+    return mutex;
+}
+
+static HashSet<v8::Isolate*>& isolates()
+{
+    DEFINE_STATIC_LOCAL_WITH_LOCK(HashSet<v8::Isolate*>, isolates, ());
+    return isolates;
+}
+
+static void addWorkerIsolate(v8::Isolate* isolate)
+{
+    MutexLocker lock(isolatesMutex());
+    isolates().add(isolate);
+}
+
+static void removeWorkerIsolate(v8::Isolate* isolate)
+{
+    MutexLocker lock(isolatesMutex());
+    isolates().remove(isolate);
+}
+
 WorkerBackingThread::WorkerBackingThread(const char* name, bool shouldCallGCOnShutdown)
     : m_backingThread(WebThreadSupportingGC::create(name))
     , m_isOwningThread(true)
     , m_shouldCallGCOnShutdown(shouldCallGCOnShutdown)
 {
 }
 
 WorkerBackingThread::WorkerBackingThread(WebThread* thread, bool shouldCallGCOnShutdown)
     : m_backingThread(WebThreadSupportingGC::createForThread(thread))
     , m_isOwningThread(false)
@@ skipping 26 matching lines @@
         if (--m_workerScriptCount > 0)
             return;
     }
     shutdown();
 }
 
 void WorkerBackingThread::initialize()
 {
     ASSERT(!m_isolate);
     m_isolate = V8PerIsolateData::initialize();
+    addWorkerIsolate(m_isolate);
     V8Initializer::initializeWorker(m_isolate);
     m_backingThread->initialize();
 
     OwnPtr<V8IsolateInterruptor> interruptor = adoptPtr(new V8IsolateInterruptor(m_isolate));
     ThreadState::current()->addInterruptor(interruptor.release());
     ThreadState::current()->registerTraceDOMWrappers(m_isolate, V8GCController::traceDOMWrappers);
     if (RuntimeEnabledFeatures::v8IdleTasksEnabled())
         V8PerIsolateData::enableIdleTasks(m_isolate, adoptPtr(new V8IdleTaskRunner(backingThread().platformThread().scheduler())));
     if (m_isOwningThread)
         Platform::current()->didStartWorkerThread();
 }
 
 void WorkerBackingThread::shutdown()
 {
     if (m_isOwningThread)
         Platform::current()->willStopWorkerThread();
 
     V8PerIsolateData::willBeDestroyed(m_isolate);
     // TODO(yhirano): Remove this when https://crbug.com/v8/1428 is fixed.
     if (m_shouldCallGCOnShutdown) {
         // This statement runs only in tests.
         V8GCController::collectAllGarbageForTesting(m_isolate);
     }
     m_backingThread->shutdown();
 
     V8PerIsolateData::destroy(m_isolate);
+    removeWorkerIsolate(m_isolate);
     m_isolate = nullptr;
 }
 
+// static
+void WorkerBackingThread::MemoryPressureNotificationToWorkerThreadIsolates(
+    v8::MemoryPressureLevel level)
+{
+    MutexLocker lock(isolatesMutex());
+    for (HashSet<v8::Isolate*>::iterator it = isolates().begin();

[esprehn, 2016/04/18 21:57:59]

range loop

for (v8::Isolate* isolate : isolates())
  isolate-> MemoryPressureNotification(level)

[hong.zheng, 2016/04/19 06:27:43]

Done.

+        it != isolates().end(); ++it) {
+        v8::Isolate* isolate = *it;
+        isolate->MemoryPressureNotification(level);
+    }
+}
+
 } // namespace blink