Implement async AbortAll for the compiler dispatcher

BUG=v8:5215
R=marja@chromium.org,vogelheim@chromium.org

Review-Url: https://codereview.chromium.org/2615603002
Cr-Commit-Position: refs/heads/master@{#42068}

src/cancelable-task.cc

@@ -93,6 +93,24 @@ void CancelableTaskManager::CancelAndWait() {
   }
 }
 
+CancelableTaskManager::TryAbortResult CancelableTaskManager::TryAbortAll() {
+  // Clean up all cancelable fore- and background tasks. Tasks are canceled on
+  // the way if possible, i.e., if they have not started yet.
+  base::LockGuard<base::Mutex> guard(&mutex_);
+
+  if (cancelable_tasks_.empty()) return kTaskRemoved;
+
+  for (auto it = cancelable_tasks_.begin(); it != cancelable_tasks_.end();) {
+    if (it->second->Cancel()) {
+      it = cancelable_tasks_.erase(it);
+    } else {
+      ++it;
+    }
+  }
+
+  return cancelable_tasks_.empty() ? kTaskAborted : kTaskRunning;
+}
+
 CancelableTask::CancelableTask(Isolate* isolate)
     : CancelableTask(isolate, isolate->cancelable_task_manager()) {}
 

src/cancelable-task.h

@@ -45,6 +45,17 @@ class V8_EXPORT_PRIVATE CancelableTaskManager {
   // already running. This disallows subsequent Register calls.
   void CancelAndWait();
 
+  // Tries to cancel all remaining registered tasks. The return value indicates
+  // whether
+  //
+  // 1) No tasks were registered (kTaskRemoved), or
+  //
+  // 2) There is at least one remaining task that couldn't be cancelled
+  // (kTaskRunning), or
+  //
+  // 3) All registered tasks were cancelled (kTaskAborted).
+  TryAbortResult TryAbortAll();
+
  private:
   // Only called by {Cancelable} destructor. The task is done with executing,
   // but needs to be removed.

src/compiler-dispatcher/compiler-dispatcher.cc

@@ -52,13 +52,11 @@ bool DoNextStepOnMainThread(Isolate* isolate, CompilerDispatcherJob* job,
       break;
   }
 
-  if (job->status() == CompileJobStatus::kFailed) {
-    DCHECK(isolate->has_pending_exception());
-    if (exception_handling == ExceptionHandling::kSwallow) {
-      isolate->clear_pending_exception();
-    }
-  } else {
-    DCHECK(!isolate->has_pending_exception());
+  DCHECK_EQ(job->status() == CompileJobStatus::kFailed,
+            isolate->has_pending_exception());
+  if (job->status() == CompileJobStatus::kFailed &&
+      exception_handling == ExceptionHandling::kSwallow) {
+    isolate->clear_pending_exception();
   }
   return job->status() != CompileJobStatus::kFailed;
 }
@@ -97,6 +95,32 @@ const double kMaxIdleTimeToExpectInMs = 40;
 
 }  // namespace
 
+class CompilerDispatcher::AbortTask : public CancelableTask {
+ public:
+  AbortTask(Isolate* isolate, CancelableTaskManager* task_manager,
+            CompilerDispatcher* dispatcher);
+  ~AbortTask() override;
+
+  // CancelableTask implementation.
+  void RunInternal() override;
+
+ private:
+  CompilerDispatcher* dispatcher_;
+
+  DISALLOW_COPY_AND_ASSIGN(AbortTask);
+};
+
+CompilerDispatcher::AbortTask::AbortTask(Isolate* isolate,
+                                         CancelableTaskManager* task_manager,
+                                         CompilerDispatcher* dispatcher)
+    : CancelableTask(isolate, task_manager), dispatcher_(dispatcher) {}
+
+CompilerDispatcher::AbortTask::~AbortTask() {}
+
+void CompilerDispatcher::AbortTask::RunInternal() {
+  dispatcher_->AbortInactiveJobs();
+}
+
 class CompilerDispatcher::BackgroundTask : public CancelableTask {
  public:
   BackgroundTask(Isolate* isolate, CancelableTaskManager* task_manager,
@@ -156,9 +180,12 @@ CompilerDispatcher::CompilerDispatcher(Isolate* isolate, Platform* platform,
       max_stack_size_(max_stack_size),
       tracer_(new CompilerDispatcherTracer(isolate_)),
       task_manager_(new CancelableTaskManager()),
+      abort_(false),
       idle_task_scheduled_(false),
       num_scheduled_background_tasks_(0),
-      main_thread_blocking_on_job_(nullptr) {}
+      main_thread_blocking_on_job_(nullptr),
+      block_for_testing_(false),
+      semaphore_for_testing_(0) {}
 
 CompilerDispatcher::~CompilerDispatcher() {
   // To avoid crashing in unit tests due to unfished jobs.
@@ -169,6 +196,11 @@ CompilerDispatcher::~CompilerDispatcher() {
 bool CompilerDispatcher::Enqueue(Handle<SharedFunctionInfo> function) {
   if (!IsEnabled()) return false;
 
+  {
+    base::LockGuard<base::Mutex> lock(&mutex_);
+    if (abort_) return false;
+  }
+
   // We only handle functions (no eval / top-level code / wasm) that are
   // attached to a script.
   if (!function->script()->IsScript() || !function->is_function() ||
@@ -223,17 +255,68 @@ bool CompilerDispatcher::FinishNow(Handle<SharedFunctionInfo> function) {
   bool result = job->second->status() != CompileJobStatus::kFailed;
   job->second->ResetOnMainThread();
   jobs_.erase(job);
+  if (jobs_.empty()) {
+    base::LockGuard<base::Mutex> lock(&mutex_);
+    abort_ = false;
+  }
   return result;
 }
 
 void CompilerDispatcher::AbortAll(BlockingBehavior blocking) {
-  // TODO(jochen): Implement support for non-blocking abort.
-  DCHECK(blocking == BlockingBehavior::kBlock);
-  for (auto& kv : jobs_) {
-    WaitForJobIfRunningOnBackground(kv.second.get());
-    kv.second->ResetOnMainThread();
+  bool background_tasks_running =
+      task_manager_->TryAbortAll() == CancelableTaskManager::kTaskRunning;
+  if (!background_tasks_running || blocking == BlockingBehavior::kBlock) {
+    for (auto& it : jobs_) {
+      WaitForJobIfRunningOnBackground(it.second.get());
+      it.second->ResetOnMainThread();
+    }
+    jobs_.clear();
+    {
+      base::LockGuard<base::Mutex> lock(&mutex_);
+      DCHECK(pending_background_jobs_.empty());
+      DCHECK(running_background_jobs_.empty());
+      abort_ = false;
+    }
+    return;
+  }
+
+  {
+    base::LockGuard<base::Mutex> lock(&mutex_);
+    abort_ = true;
+    pending_background_jobs_.clear();
+  }
+  AbortInactiveJobs();
+
+  // All running background jobs might already have scheduled idle tasks instead
+  // of abort tasks. Schedule a single abort task here to make sure they get
+  // processed as soon as possible (and not first when we have idle time).
+  ScheduleAbortTask();
+}
+
+void CompilerDispatcher::AbortInactiveJobs() {
+  {
+    base::LockGuard<base::Mutex> lock(&mutex_);
+    // Since we schedule two abort tasks per async abort, we might end up
+    // here with nothing left to do.
+    if (!abort_) return;
+  }
+  for (auto it = jobs_.begin(); it != jobs_.end();) {
+    auto job = it;
+    ++it;
+    {
+      base::LockGuard<base::Mutex> lock(&mutex_);
+      if (running_background_jobs_.find(job->second.get()) !=
+          running_background_jobs_.end()) {
+        continue;
+      }
+    }
+    job->second->ResetOnMainThread();
+    jobs_.erase(job);
+  }
+  if (jobs_.empty()) {
+    base::LockGuard<base::Mutex> lock(&mutex_);
+    abort_ = false;
   }
-  jobs_.clear();
 }
 
 CompilerDispatcher::JobMap::const_iterator CompilerDispatcher::GetJobFor(
@@ -265,6 +348,12 @@ void CompilerDispatcher::ScheduleIdleTaskIfNeeded() {
   ScheduleIdleTaskFromAnyThread();
 }
 
+void CompilerDispatcher::ScheduleAbortTask() {
+  v8::Isolate* v8_isolate = reinterpret_cast<v8::Isolate*>(isolate_);
+  platform_->CallOnForegroundThread(
+      v8_isolate, new AbortTask(isolate_, task_manager_.get(), this));
+}
+
 void CompilerDispatcher::ConsiderJobForBackgroundProcessing(
     CompilerDispatcherJob* job) {
   if (!CanRunOnAnyThread(job)) return;
@@ -304,6 +393,12 @@ void CompilerDispatcher::DoBackgroundWork() {
     }
   }
   if (job == nullptr) return;
+
+  if (V8_UNLIKELY(block_for_testing_.Value())) {
+    block_for_testing_.SetValue(false);
+    semaphore_for_testing_.Wait();
+  }
+
   DoNextStepOnBackgroundThread(job);
 
   ScheduleMoreBackgroundTasksIfNeeded();
@@ -315,6 +410,13 @@ void CompilerDispatcher::DoBackgroundWork() {
     base::LockGuard<base::Mutex> lock(&mutex_);
     running_background_jobs_.erase(job);
 
+    if (running_background_jobs_.empty() && abort_) {
+      // This is the last background job that finished. The abort task
+      // scheduled by AbortAll might already have ran, so schedule another
+      // one to be on the safe side.
+      ScheduleAbortTask();
+    }
+
     if (main_thread_blocking_on_job_ == job) {
       main_thread_blocking_on_job_ = nullptr;
       main_thread_blocking_signal_.NotifyOne();
@@ -325,9 +427,16 @@ void CompilerDispatcher::DoBackgroundWork() {
 }
 
 void CompilerDispatcher::DoIdleWork(double deadline_in_seconds) {
+  bool aborted = false;
   {
     base::LockGuard<base::Mutex> lock(&mutex_);
     idle_task_scheduled_ = false;
+    aborted = abort_;
+  }
+
+  if (aborted) {
+    AbortInactiveJobs();
+    return;
   }
 
   // Number of jobs that are unlikely to make progress during any idle callback

src/compiler-dispatcher/compiler-dispatcher.h

@@ -10,9 +10,11 @@
 #include <unordered_set>
 #include <utility>
 
+#include "src/base/atomic-utils.h"
 #include "src/base/macros.h"
 #include "src/base/platform/condition-variable.h"
 #include "src/base/platform/mutex.h"
+#include "src/base/platform/semaphore.h"
 #include "src/globals.h"
 #include "testing/gtest/include/gtest/gtest_prod.h"
 
@@ -85,20 +87,28 @@ class V8_EXPORT_PRIVATE CompilerDispatcher {
   FRIEND_TEST(CompilerDispatcherTest, IdleTaskSmallIdleTime);
   FRIEND_TEST(IgnitionCompilerDispatcherTest, CompileOnBackgroundThread);
   FRIEND_TEST(IgnitionCompilerDispatcherTest, FinishNowWithBackgroundTask);
+  FRIEND_TEST(IgnitionCompilerDispatcherTest,
+              AsyncAbortAllPendingBackgroundTask);
+  FRIEND_TEST(IgnitionCompilerDispatcherTest,
+              AsyncAbortAllRunningBackgroundTask);
+  FRIEND_TEST(IgnitionCompilerDispatcherTest, FinishNowDuringAbortAll);
 
   typedef std::multimap<std::pair<int, int>,
                         std::unique_ptr<CompilerDispatcherJob>>
       JobMap;
+  class AbortTask;
   class BackgroundTask;
   class IdleTask;
 
   void WaitForJobIfRunningOnBackground(CompilerDispatcherJob* job);
   bool IsEnabled() const;
+  void AbortInactiveJobs();
   JobMap::const_iterator GetJobFor(Handle<SharedFunctionInfo> shared) const;
   void ConsiderJobForBackgroundProcessing(CompilerDispatcherJob* job);
   void ScheduleMoreBackgroundTasksIfNeeded();
   void ScheduleIdleTaskFromAnyThread();
   void ScheduleIdleTaskIfNeeded();
+  void ScheduleAbortTask();
   void DoBackgroundWork();
   void DoIdleWork(double deadline_in_seconds);
 
@@ -117,6 +127,9 @@ class V8_EXPORT_PRIVATE CompilerDispatcher {
   // the mutex |mutex_| while accessing them.
   base::Mutex mutex_;
 
+  // True if the dispatcher is in the process of aborting running tasks.
+  bool abort_;
+
   bool idle_task_scheduled_;
 
   // Number of currently scheduled BackgroundTask objects.
@@ -134,6 +147,10 @@ class V8_EXPORT_PRIVATE CompilerDispatcher {
   CompilerDispatcherJob* main_thread_blocking_on_job_;
   base::ConditionVariable main_thread_blocking_signal_;
 
+  // Test support.
+  base::AtomicValue<bool> block_for_testing_;
+  base::Semaphore semaphore_for_testing_;
+
   DISALLOW_COPY_AND_ASSIGN(CompilerDispatcher);
 };
 

test/unittests/cancelable-tasks-unittest.cc

@@ -214,5 +214,50 @@ TEST(CancelableTask, RemoveUnmanagedId) {
   EXPECT_FALSE(manager.TryAbort(3));
 }
 
+TEST(CancelableTask, EmptyTryAbortAll) {
+  CancelableTaskManager manager;
+  EXPECT_EQ(manager.TryAbortAll(), CancelableTaskManager::kTaskRemoved);
+}
+
+TEST(CancelableTask, ThreadedMultipleTasksNotRunTryAbortAll) {
+  CancelableTaskManager manager;
+  ResultType result1 = 0;
+  ResultType result2 = 0;
+  TestTask* task1 = new TestTask(&manager, &result1, TestTask::kCheckNotRun);
+  TestTask* task2 = new TestTask(&manager, &result2, TestTask::kCheckNotRun);
+  ThreadedRunner runner1(task1);
+  ThreadedRunner runner2(task2);
+  EXPECT_EQ(manager.TryAbortAll(), CancelableTaskManager::kTaskAborted);
+  // Tasks are canceled, hence the runner will bail out and not update result.
+  runner1.Start();
+  runner2.Start();
+  runner1.Join();
+  runner2.Join();
+  EXPECT_EQ(GetValue(&result1), 0);
+  EXPECT_EQ(GetValue(&result2), 0);
+}
+
+TEST(CancelableTask, ThreadedMultipleTasksStartedTryAbortAll) {
+  CancelableTaskManager manager;
+  ResultType result1 = 0;
+  ResultType result2 = 0;
+  TestTask* task1 =
+      new TestTask(&manager, &result1, TestTask::kWaitTillCanceledAgain);
+  TestTask* task2 =
+      new TestTask(&manager, &result2, TestTask::kWaitTillCanceledAgain);
+  ThreadedRunner runner1(task1);
+  ThreadedRunner runner2(task2);
+  runner1.Start();
+  // Busy wait on result to make sure task1 is done.
+  while (GetValue(&result1) == 0) {
+  }
+  EXPECT_EQ(manager.TryAbortAll(), CancelableTaskManager::kTaskRunning);
+  runner2.Start();
+  runner1.Join();
+  runner2.Join();
+  EXPECT_EQ(GetValue(&result1), 1);
+  EXPECT_EQ(GetValue(&result2), 0);
+}
+
 }  // namespace internal
 }  // namespace v8