Thread-local store buffers, v2

runtime/vm/thread.cc

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/thread.h"
 
 #include "vm/isolate.h"
 #include "vm/os_thread.h"
 #include "vm/profiler.h"
 #include "vm/thread_interrupter.h"
@@ skipping 54 matching lines @@
   ASSERT(isolate->thread_state() == NULL);
   InterruptableThreadState* thread_state =
       ThreadInterrupter::GetCurrentThreadState();
 #if defined(DEBUG)
   Isolate::CheckForDuplicateThreadState(thread_state);
 #endif
   ASSERT(thread_state != NULL);
   Profiler::BeginExecution(isolate);
   isolate->set_thread_state(thread_state);
   isolate->set_vm_tag(VMTag::kVMTagId);
+  ASSERT(thread->store_buffer_block_ == NULL);
+  thread->store_buffer_block_ = isolate->store_buffer()->PopPartialOrEmpty();

[Ivan Posva, 2015/06/08 13:05:21]

Looking at this use here I am revising my suggestion: PopBlock(),
PopEmptyBlock() and PushBlock()

[koda, 2015/06/09 13:10:30]

Done.

 }
 
 
 void Thread::ExitIsolate() {
   Thread* thread = Thread::Current();
   // TODO(koda): Audit callers; they should know whether they're in an isolate.
   if (thread == NULL || thread->isolate() == NULL) return;
   Isolate* isolate = thread->isolate();
+  isolate->store_buffer()->Push(thread->store_buffer_block_);
+  thread->store_buffer_block_ = NULL;
   if (isolate->is_runnable()) {
     isolate->set_vm_tag(VMTag::kIdleTagId);
   } else {
     isolate->set_vm_tag(VMTag::kLoadWaitTagId);
   }
   isolate->set_thread_state(NULL);
   Profiler::EndExecution(isolate);
   isolate->set_mutator_thread(NULL);
   thread->isolate_ = NULL;
   ASSERT(Isolate::Current() == NULL);
 }
 
 
 void Thread::EnterIsolateAsHelper(Isolate* isolate) {
   Thread* thread = Thread::Current();
   ASSERT(thread != NULL);
   ASSERT(thread->isolate() == NULL);
   thread->isolate_ = isolate;
   // Do not update isolate->mutator_thread, but perform sanity check:
   // this thread should not be both the main mutator and helper.
   ASSERT(isolate->mutator_thread() != thread);
 }
 
 
 void Thread::ExitIsolateAsHelper() {
   Thread* thread = Thread::Current();
+  // If the helper thread chose to use the store buffer, check that it has
+  // already been flushed manually.
+  ASSERT(thread->store_buffer_block_ == NULL);
   Isolate* isolate = thread->isolate();
   ASSERT(isolate != NULL);
   thread->isolate_ = NULL;
   ASSERT(isolate->mutator_thread() != thread);
 }
 
 
+void Thread::PrepareForGC() {
+  Thread* thread = Thread::Current();
+  StoreBuffer* sb = thread->isolate()->store_buffer();
+  sb->Push(thread->store_buffer_block_, false);

[Ivan Posva, 2015/06/08 13:05:21]

Please explain in a comment why you are passing false here. The way I understand
it at the moment is because we don't want to schedule a GC during GC
preparation. This point might be lost in the future.

[koda, 2015/06/09 13:10:30]

Done.

+  thread->store_buffer_block_ = sb->PopEmpty();
+}
+
+
+void Thread::StoreBufferBlockProcess(bool check_threshold) {
+  StoreBuffer* sb = isolate()->store_buffer();
+  sb->Push(store_buffer_block_, check_threshold);

[Ivan Posva, 2015/06/08 13:05:21]

The fact that we still have a reference to the StoreBufferBlock in the thread
while calling some function makes me a bit nervous here.

ditto above.

[koda, 2015/06/09 13:10:30]

Done.

+  store_buffer_block_ = sb->PopPartialOrEmpty();
+}
+
+
+void Thread::StoreBufferAddObject(RawObject* obj) {
+  store_buffer_block_->Add(obj);
+  if (store_buffer_block_->IsFull()) {
+    StoreBufferBlockProcess(true);
+  }
+}
+
+
+void Thread::StoreBufferAddObjectGC(RawObject* obj) {
+  store_buffer_block_->Add(obj);
+  if (store_buffer_block_->IsFull()) {
+    StoreBufferBlockProcess(false);
+  }
+}
+
+
 CHA* Thread::cha() const {
   ASSERT(isolate_ != NULL);
   return isolate_->cha_;
 }
 
 
 void Thread::set_cha(CHA* value) {
   ASSERT(isolate_ != NULL);
   isolate_->cha_ = value;
 }
 
 }  // namespace dart