Per-isolate v8::Locker and v8::Unlocker

src/v8threads.cc

 // Copyright 2008 the V8 project authors. 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
@@ skipping 26 matching lines @@
 namespace v8 {
 
 
 // Track whether this V8 instance has ever called v8::Locker. This allows the
 // API code to verify that the lock is always held when V8 is being entered.
 bool Locker::active_ = false;
 
 
 // Constructor for the Locker object.  Once the Locker is constructed the
 // current thread will be guaranteed to have the big V8 lock.
-Locker::Locker() : has_lock_(false), top_level_(true) {
-  // TODO(isolates): When Locker has Isolate parameter and it is provided, grab
-  // that one instead of using the current one.
-  // We pull default isolate for Locker constructor w/o p[arameter.
+Locker::Locker()
+  : has_lock_(false), top_level_(true),

[Vitaly Repeshko, 2011/04/15 00:29:39]

nit: Reformat with one initializer per line if they don't all fit on a single
line.

[Dmitry Lomov, 2011/04/19 01:50:47]

Done.

+    isolate_(internal::Isolate::GetDefaultIsolateForLocking()) {
+  // We pull default isolate for Locker constructor w/o parameter.
   // A thread should not enter an isolate before acquiring a lock,
   // in cases which mandate using Lockers.
   // So getting a lock is the first thing threads do in a scenario where
   // multple threads share an isolate. Hence, we need to access
   // 'locking isolate' before we can actually enter into default isolate.
-  internal::Isolate* isolate = internal::Isolate::GetDefaultIsolateForLocking();
-  ASSERT(isolate != NULL);
+  ASSERT(isolate_ != NULL);
+  Init();
+}
 

[Vitaly Repeshko, 2011/04/15 00:29:39]

nit: Two blank lines.

[Dmitry Lomov, 2011/04/19 01:50:47]

Done.

+Locker::Locker(v8::Isolate* isolate)
+  : has_lock_(false), top_level_(false),
+    isolate_(reinterpret_cast<i::Isolate*>(isolate)) {
+  ASSERT(isolate_ != NULL);
+  Init();
+}
+
+void Locker::Init() {
   // Record that the Locker has been used at least once.
   active_ = true;
+
+  isolate_->EnsurePreinitializedForThisThread();
   // Get the big lock if necessary.
-  if (!isolate->thread_manager()->IsLockedByCurrentThread()) {
-    isolate->thread_manager()->Lock();
+  if (!isolate_->thread_manager()->IsLockedByCurrentThread()) {
+    isolate_->thread_manager()->Lock();
     has_lock_ = true;
 
-    if (isolate->IsDefaultIsolate()) {
-      // This only enters if not yet entered.
-      internal::Isolate::EnterDefaultIsolate();
-    }
-
-    ASSERT(internal::Thread::HasThreadLocal(
-        internal::Isolate::thread_id_key()));
-
     // Make sure that V8 is initialized.  Archiving of threads interferes
     // with deserialization by adding additional root pointers, so we must
     // initialize here, before anyone can call ~Locker() or Unlocker().
-    if (!isolate->IsInitialized()) {
+    if (isolate_->IsDefaultIsolate()) {
+      // This only enters if not yet entered.
+      internal::Isolate::EnterDefaultIsolate();
+    } else if (!isolate_->IsInitialized()) {
+      isolate_->Enter();
       V8::Initialize();

[Vitaly Repeshko, 2011/04/15 00:29:39]

I really don't like that we're doing a global initialization after an isolate
has already been preinitialized (and not just allocated). Can you change
initialization order here so that it looks more like the checks in api.cc? It'd
be nice to minimize the special code for the default isolate as a side-effect.

[Dmitry Lomov, 2011/04/19 01:50:47]

Done.

+      isolate_->Exit();
     }
+
     // This may be a locker within an unlocker in which case we have to
     // get the saved state for this thread and restore it.
-    if (isolate->thread_manager()->RestoreThread()) {
+    if (isolate_->thread_manager()->RestoreThread()) {
       top_level_ = false;
     } else {
-      internal::ExecutionAccess access(isolate);
-      isolate->stack_guard()->ClearThread(access);
-      isolate->stack_guard()->InitThread(access);
+      internal::ExecutionAccess access(isolate_);
+      isolate_->stack_guard()->ClearThread(access);
+      isolate_->stack_guard()->InitThread(access);
     }
   }
-  ASSERT(isolate->thread_manager()->IsLockedByCurrentThread());
+  ASSERT(isolate_->thread_manager()->IsLockedByCurrentThread());
 }
 
 
 bool Locker::IsLocked() {
-  return internal::Isolate::Current()->thread_manager()->
-      IsLockedByCurrentThread();
+  return IsLocked(reinterpret_cast<v8::Isolate*>(
+      i::Isolate::GetDefaultIsolateForLocking()));
+}
+
+bool Locker::IsLocked(v8::Isolate* isolate) {
+  i::Isolate* internal_isolate = reinterpret_cast<i::Isolate*>(isolate);
+  internal_isolate->EnsurePreinitializedForThisThread();
+  return internal_isolate->thread_manager()->
+            IsLockedByCurrentThread();
 }
 
 
 Locker::~Locker() {
-  // TODO(isolate): this should use a field storing the isolate it
-  // locked instead.
-  internal::Isolate* isolate = internal::Isolate::Current();
-  ASSERT(isolate->thread_manager()->IsLockedByCurrentThread());
+  ASSERT(isolate_->thread_manager()->IsLockedByCurrentThread());
   if (has_lock_) {
     if (top_level_) {
-      isolate->thread_manager()->FreeThreadResources();
+      isolate_->thread_manager()->FreeThreadResources();
     } else {
-      isolate->thread_manager()->ArchiveThread();
+      isolate_->thread_manager()->ArchiveThread();
     }
-    isolate->thread_manager()->Unlock();
+    isolate_->thread_manager()->Unlock();
   }
 }
 
 
-Unlocker::Unlocker() {
-  internal::Isolate* isolate = internal::Isolate::Current();
-  ASSERT(isolate->thread_manager()->IsLockedByCurrentThread());
-  isolate->thread_manager()->ArchiveThread();
-  isolate->thread_manager()->Unlock();
+Unlocker::Unlocker() : isolate_(i::Isolate::GetDefaultIsolateForLocking()) {
+  Init();
+}
+
+Unlocker::Unlocker(v8::Isolate* isolate)
+  : isolate_(reinterpret_cast<i::Isolate*>(isolate)) {
+  Init();
+}
+
+
+void Unlocker::Init() {
+  ASSERT(isolate_->thread_manager()->IsLockedByCurrentThread());
+  isolate_->thread_manager()->ArchiveThread();
+  isolate_->thread_manager()->Unlock();
 }
 
 
 Unlocker::~Unlocker() {
-  // TODO(isolates): check it's the isolate we unlocked.
-  internal::Isolate* isolate = internal::Isolate::Current();
-  ASSERT(!isolate->thread_manager()->IsLockedByCurrentThread());
-  isolate->thread_manager()->Lock();
-  isolate->thread_manager()->RestoreThread();
+  ASSERT(!isolate_->thread_manager()->IsLockedByCurrentThread());
+  isolate_->thread_manager()->Lock();
+  isolate_->thread_manager()->RestoreThread();
 }
 
 
 void Locker::StartPreemption(int every_n_ms) {
   v8::internal::ContextSwitcher::StartPreemption(every_n_ms);
 }
 
 
 void Locker::StopPreemption() {
   v8::internal::ContextSwitcher::StopPreemption();
 }
 
 
 namespace internal {
 
 
+
 bool ThreadManager::RestoreThread() {
+  ASSERT(IsLockedByCurrentThread());
   // First check whether the current thread has been 'lazily archived', ie
   // not archived at all.  If that is the case we put the state storage we
   // had prepared back in the free list, since we didn't need it after all.
   if (lazily_archived_thread_.Equals(ThreadId::Current())) {
     lazily_archived_thread_ = ThreadId::Invalid();
-    ASSERT(Isolate::CurrentPerIsolateThreadData()->thread_state() ==
-           lazily_archived_thread_state_);
+    Isolate::PerIsolateThreadData* per_thread =
+        isolate_->FindPerThreadDataForThisThread();
+    ASSERT(per_thread != NULL);
+    ASSERT(per_thread->thread_state() == lazily_archived_thread_state_);
     lazily_archived_thread_state_->set_id(ThreadId::Invalid());
     lazily_archived_thread_state_->LinkInto(ThreadState::FREE_LIST);
     lazily_archived_thread_state_ = NULL;
-    Isolate::CurrentPerIsolateThreadData()->set_thread_state(NULL);
+    per_thread->set_thread_state(NULL);
     return true;
   }
 
   // Make sure that the preemption thread cannot modify the thread state while
   // it is being archived or restored.
   ExecutionAccess access(isolate_);
 
   // If there is another thread that was lazily archived then we have to really
   // archive it now.
-  if (lazily_archived_thread_.IsValid()) {
+  if (!lazily_archived_thread_.Equals(ThreadId::Invalid())) {

[Vitaly Repeshko, 2011/04/15 00:29:39]

Accidental edit? IsValid() should work.

[Dmitry Lomov, 2011/04/19 01:50:47]

Done.

     EagerlyArchiveThread();
   }
   Isolate::PerIsolateThreadData* per_thread =
-      Isolate::CurrentPerIsolateThreadData();
+      isolate_->FindPerThreadDataForThisThread();
   if (per_thread == NULL || per_thread->thread_state() == NULL) {
     // This is a new thread.
     isolate_->stack_guard()->InitThread(access);
     return false;
   }
   ThreadState* state = per_thread->thread_state();
   char* from = state->data();
   from = isolate_->handle_scope_implementer()->RestoreThread(from);
   from = isolate_->RestoreThread(from);
-  from = Relocatable::RestoreState(from);
+  from = Relocatable::RestoreState(isolate_, from);
 #ifdef ENABLE_DEBUGGER_SUPPORT
   from = isolate_->debug()->RestoreDebug(from);
 #endif
   from = isolate_->stack_guard()->RestoreStackGuard(from);
   from = isolate_->regexp_stack()->RestoreStack(from);
   from = isolate_->bootstrapper()->RestoreState(from);
   per_thread->set_thread_state(NULL);
   if (state->terminate_on_restore()) {
     isolate_->stack_guard()->TerminateExecution();
     state->set_terminate_on_restore(false);
@@ skipping 101 matching lines @@
 
 
 ThreadManager::~ThreadManager() {
   // TODO(isolates): Destroy mutexes.
 }
 
 
 void ThreadManager::ArchiveThread() {
   ASSERT(lazily_archived_thread_.Equals(ThreadId::Invalid()));
   ASSERT(!IsArchived());
+  ASSERT(IsLockedByCurrentThread());
   ThreadState* state = GetFreeThreadState();
   state->Unlink();
-  Isolate::CurrentPerIsolateThreadData()->set_thread_state(state);
+  Isolate::PerIsolateThreadData* per_thread =
+      isolate_->FindOrAllocatePerThreadDataForThisThread();
+  per_thread->set_thread_state(state);
   lazily_archived_thread_ = ThreadId::Current();
   lazily_archived_thread_state_ = state;
   ASSERT(state->id().Equals(ThreadId::Invalid()));
   state->set_id(CurrentId());
   ASSERT(!state->id().Equals(ThreadId::Invalid()));
 }
 
 
 void ThreadManager::EagerlyArchiveThread() {
+  ASSERT(IsLockedByCurrentThread());
   ThreadState* state = lazily_archived_thread_state_;
   state->LinkInto(ThreadState::IN_USE_LIST);
   char* to = state->data();
   // Ensure that data containing GC roots are archived first, and handle them
   // in ThreadManager::Iterate(ObjectVisitor*).
   to = isolate_->handle_scope_implementer()->ArchiveThread(to);
   to = isolate_->ArchiveThread(to);
-  to = Relocatable::ArchiveState(to);
+  to = Relocatable::ArchiveState(isolate_, to);
 #ifdef ENABLE_DEBUGGER_SUPPORT
   to = isolate_->debug()->ArchiveDebug(to);
 #endif
   to = isolate_->stack_guard()->ArchiveStackGuard(to);
   to = isolate_->regexp_stack()->ArchiveStack(to);
   to = isolate_->bootstrapper()->ArchiveState(to);
   lazily_archived_thread_ = ThreadId::Invalid();
   lazily_archived_thread_state_ = NULL;
 }
 
 
 void ThreadManager::FreeThreadResources() {
   isolate_->handle_scope_implementer()->FreeThreadResources();
   isolate_->FreeThreadResources();
 #ifdef ENABLE_DEBUGGER_SUPPORT
   isolate_->debug()->FreeThreadResources();
 #endif
   isolate_->stack_guard()->FreeThreadResources();
   isolate_->regexp_stack()->FreeThreadResources();
   isolate_->bootstrapper()->FreeThreadResources();
 }
 
 
 bool ThreadManager::IsArchived() {
-  Isolate::PerIsolateThreadData* data = Isolate::CurrentPerIsolateThreadData();
+  Isolate::PerIsolateThreadData* data =
+      isolate_->FindPerThreadDataForThisThread();
   return data != NULL && data->thread_state() != NULL;
 }
 
-
 void ThreadManager::Iterate(ObjectVisitor* v) {
   // Expecting no threads during serialization/deserialization
   for (ThreadState* state = FirstThreadStateInUse();
        state != NULL;
        state = state->Next()) {
     char* data = state->data();
     data = HandleScopeImplementer::Iterate(v, data);
     data = isolate_->Iterate(v, data);
     data = Relocatable::Iterate(v, data);
   }
@@ skipping 82 matching lines @@
 // Acknowledge the preemption by the receiving thread.
 void ContextSwitcher::PreemptionReceived() {
   ASSERT(Locker::IsLocked());
   // There is currently no accounting being done for this. But could be in the
   // future, which is why we leave this in.
 }
 
 
 }  // namespace internal
 }  // namespace v8