Use idle task to perform incremental marking steps.

test/cctest/test-incremental-marking.cc

Index: test/cctest/test-incremental-marking.cc
diff --git a/test/cctest/test-incremental-marking.cc b/test/cctest/test-incremental-marking.cc
new file mode 100644
index 0000000000000000000000000000000000000000..d8bdeeee37bb2afbdd536e86626a0f188c9a86e9
--- /dev/null
+++ b/test/cctest/test-incremental-marking.cc
@@ -0,0 +1,168 @@
+// Copyright 2015 the V8 project 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 <stdlib.h>
+
+#ifdef __linux__
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+#endif
+
+#include <utility>
+
+#include "src/v8.h"
+
+#include "src/full-codegen/full-codegen.h"
+#include "src/global-handles.h"
+#include "test/cctest/cctest.h"
+
+using v8::IdleTask;
+using v8::Task;
+using v8::Isolate;
+
+
+class MockPlatform : public v8::Platform {
+ public:
+  explicit MockPlatform(v8::Platform* platform)
+      : platform_(platform), idle_task_(nullptr), delayed_task_(nullptr) {}
+  virtual ~MockPlatform() {
+    delete idle_task_;
+    delete delayed_task_;
+  }
+
+  void CallOnBackgroundThread(Task* task,
+                              ExpectedRuntime expected_runtime) override {
+    platform_->CallOnBackgroundThread(task, expected_runtime);
+  }
+
+  void CallOnForegroundThread(Isolate* isolate, Task* task) override {
+    platform_->CallOnForegroundThread(isolate, task);
+  }
+
+  void CallDelayedOnForegroundThread(Isolate* isolate, Task* task,
+                                     double delay_in_seconds) override {
+    if (delayed_task_ != nullptr) {
+      delete delayed_task_;
+    }
+    delayed_task_ = task;
+  }
+
+  double MonotonicallyIncreasingTime() override {
+    return platform_->MonotonicallyIncreasingTime();
+  }
+
+  void CallIdleOnForegroundThread(Isolate* isolate, IdleTask* task) override {
+    CHECK(nullptr == idle_task_);
+    idle_task_ = task;
+  }
+
+  bool IdleTasksEnabled(Isolate* isolate) override { return true; }
+
+  bool PendingIdleTask() { return idle_task_ != nullptr; }
+
+  void PerformIdleTask(double idle_time_in_seconds) {
+    IdleTask* task = idle_task_;
+    idle_task_ = nullptr;
+    task->Run(MonotonicallyIncreasingTime() + idle_time_in_seconds);
+    delete task;
+  }
+
+  bool PendingDelayedTask() { return delayed_task_ != nullptr; }
+
+  void PerformDelayedTask() {
+    Task* task = delayed_task_;
+    delayed_task_ = nullptr;
+    task->Run();
+    delete task;
+  }
+
+ private:
+  v8::Platform* platform_;
+  IdleTask* idle_task_;
+  Task* delayed_task_;
+};
+
+
+TEST(IncrementalMarkingUsingIdleTasks) {
+  if (!i::FLAG_incremental_marking) return;
+  CcTest::InitializeVM();
+  v8::Platform* old_platform = i::V8::GetCurrentPlatform();
+  MockPlatform platform(old_platform);
+  i::V8::SetPlatformForTesting(&platform);
+  SimulateFullSpace(CcTest::heap()->old_space());
+  i::IncrementalMarking* marking = CcTest::heap()->incremental_marking();
+  marking->Stop();
+  marking->Start();
+  CHECK(platform.PendingIdleTask());
+  const double kLongIdleTimeInSeconds = 1;
+  const double kShortIdleTimeInSeconds = 0.010;
+  const int kShortStepCount = 10;
+  for (int i = 0; i < kShortStepCount && platform.PendingIdleTask(); i++) {
+    platform.PerformIdleTask(kShortIdleTimeInSeconds);
+  }
+  while (platform.PendingIdleTask()) {
+    platform.PerformIdleTask(kLongIdleTimeInSeconds);
+  }
+  CHECK(marking->IsStopped());
+  i::V8::SetPlatformForTesting(old_platform);
+}
+
+
+TEST(IncrementalMarkingUsingIdleTasksAfterGC) {
+  if (!i::FLAG_incremental_marking) return;
+  CcTest::InitializeVM();
+  v8::Platform* old_platform = i::V8::GetCurrentPlatform();
+  MockPlatform platform(old_platform);
+  i::V8::SetPlatformForTesting(&platform);
+  SimulateFullSpace(CcTest::heap()->old_space());
+  CcTest::heap()->CollectAllGarbage();
+  i::IncrementalMarking* marking = CcTest::heap()->incremental_marking();
+  marking->Stop();
+  marking->Start();
+  CHECK(platform.PendingIdleTask());
+  const double kLongIdleTimeInSeconds = 1;
+  const double kShortIdleTimeInSeconds = 0.010;
+  const int kShortStepCount = 10;
+  for (int i = 0; i < kShortStepCount && platform.PendingIdleTask(); i++) {
+    platform.PerformIdleTask(kShortIdleTimeInSeconds);
+  }
+  while (platform.PendingIdleTask()) {
+    platform.PerformIdleTask(kLongIdleTimeInSeconds);
+  }
+  CHECK(marking->IsStopped());
+  i::V8::SetPlatformForTesting(old_platform);
+}
+
+
+TEST(IncrementalMarkingUsingDelayedTasks) {
+  if (!i::FLAG_incremental_marking) return;
+  CcTest::InitializeVM();
+  v8::Platform* old_platform = i::V8::GetCurrentPlatform();
+  MockPlatform platform(old_platform);
+  i::V8::SetPlatformForTesting(&platform);
+  SimulateFullSpace(CcTest::heap()->old_space());
+  i::IncrementalMarking* marking = CcTest::heap()->incremental_marking();
+  marking->Stop();
+  marking->Start();
+  CHECK(platform.PendingIdleTask());
+  // The delayed task should be a no-op if the idle task makes progress.
+  const int kIgnoredDelayedTaskStepCount = 1000;
+  for (int i = 0; i < kIgnoredDelayedTaskStepCount; i++) {
+    // Dummy idle task progress.
+    marking->incremental_marking_job()->NotifyIdleTaskProgress();
+    CHECK(platform.PendingDelayedTask());
+    platform.PerformDelayedTask();
+  }
+  // Once we stop notifying idle task progress, the delayed tasks
+  // should finish marking.
+  while (!marking->IsStopped() && platform.PendingDelayedTask()) {
+    platform.PerformDelayedTask();
+  }
+  // There could be pending delayed task from memory reducer after GC finishes.
+  CHECK(marking->IsStopped());
+  i::V8::SetPlatformForTesting(old_platform);
+}