From ea5ab721e479a19257c14baa357be547825162af Mon Sep 17 00:00:00 2001
From: "yangguo@chromium.org"
 <yangguo@chromium.org@ce2b1a6d-e550-0410-aec6-3dcde31c8c00>
Date: Mon, 16 Sep 2013 15:34:46 +0000
Subject: [PATCH] Add mutex when accessing concurrent recompilation output
 queue.

Also small refactorings.

R=mstarzinger@chromium.org
BUG=291236

Review URL: https://codereview.chromium.org/23902033

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16740 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
---
 src/execution.cc                  |  2 +-
 src/optimizing-compiler-thread.cc | 17 +++++++++++++----
 src/optimizing-compiler-thread.h  |  4 +++-
 3 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/src/execution.cc b/src/execution.cc
index 979641a..bb01dcf 100644
--- a/src/execution.cc
+++ b/src/execution.cc
@@ -952,7 +952,7 @@ MaybeObject* Execution::HandleStackGuardInterrupt(Isolate* isolate) {
   }
   if (stack_guard->IsInstallCodeRequest()) {
     ASSERT(FLAG_concurrent_recompilation);
-    stack_guard->Continue(INSTALL_CODE);
+    isolate_->stack_guard()->Continue(INSTALL_CODE);
     isolate->optimizing_compiler_thread()->InstallOptimizedFunctions();
   }
   isolate->runtime_profiler()->OptimizeNow();
diff --git a/src/optimizing-compiler-thread.cc b/src/optimizing-compiler-thread.cc
index 085143d..8d5e166 100644
--- a/src/optimizing-compiler-thread.cc
+++ b/src/optimizing-compiler-thread.cc
@@ -74,7 +74,6 @@ void OptimizingCompilerThread::Run() {
         { AllowHandleDereference allow_handle_dereference;
           FlushInputQueue(true);
         }
-        Release_Store(&queue_length_, static_cast<AtomicWord>(0));
         Release_Store(&stop_thread_, static_cast<AtomicWord>(CONTINUE));
         stop_semaphore_.Signal();
         // Return to start of consumer loop.
@@ -114,6 +113,7 @@ void OptimizingCompilerThread::CompileNext() {
     osr_candidates_.RemoveElement(optimizing_compiler);
     ready_for_osr_.Add(optimizing_compiler);
   } else {
+    LockGuard<Mutex> access_queue(&queue_mutex_);
     output_queue_.Enqueue(optimizing_compiler);
     isolate_->stack_guard()->RequestInstallCode();
   }
@@ -134,13 +134,20 @@ void OptimizingCompilerThread::FlushInputQueue(bool restore_function_code) {
     }
     delete info;
   }
+  Release_Store(&queue_length_, static_cast<AtomicWord>(0));
+
+  LockGuard<Mutex> access_osr_lists(&osr_list_mutex_);
+  osr_candidates_.Clear();
 }
 
 
 void OptimizingCompilerThread::FlushOutputQueue(bool restore_function_code) {
   OptimizingCompiler* optimizing_compiler;
   // The optimizing compiler is allocated in the CompilationInfo's zone.
-  while (output_queue_.Dequeue(&optimizing_compiler)) {
+  while (true) {
+    { LockGuard<Mutex> access_queue(&queue_mutex_);
+      if (!output_queue_.Dequeue(&optimizing_compiler)) break;
+    }
     CompilationInfo* info = optimizing_compiler->info();
     if (restore_function_code) {
       Handle<JSFunction> function = info->closure();
@@ -149,7 +156,6 @@ void OptimizingCompilerThread::FlushOutputQueue(bool restore_function_code) {
     delete info;
   }
 
-  osr_candidates_.Clear();
   RemoveStaleOSRCandidates(0);
 }
 
@@ -196,9 +202,12 @@ void OptimizingCompilerThread::Stop() {
 void OptimizingCompilerThread::InstallOptimizedFunctions() {
   ASSERT(!IsOptimizerThread());
   HandleScope handle_scope(isolate_);
+
   OptimizingCompiler* compiler;
   while (true) {
-    if (!output_queue_.Dequeue(&compiler)) return;
+    { LockGuard<Mutex> access_queue(&queue_mutex_);
+      if (!output_queue_.Dequeue(&optimizing_compiler)) break;
+    }
     Compiler::InstallOptimizedCode(compiler);
   }
 
diff --git a/src/optimizing-compiler-thread.h b/src/optimizing-compiler-thread.h
index d1ed6a2..4231765 100644
--- a/src/optimizing-compiler-thread.h
+++ b/src/optimizing-compiler-thread.h
@@ -115,7 +115,7 @@ class OptimizingCompilerThread : public Thread {
   UnboundQueue<OptimizingCompiler*> input_queue_;
   // Queue of recompilation tasks ready to be installed (excluding OSR).
   UnboundQueue<OptimizingCompiler*> output_queue_;
-  // List of all OSR related recompilation tasks (both incoming and ready ones).
+  // List of recompilation tasks for OSR in the input queue.
   List<OptimizingCompiler*> osr_candidates_;
   // List of recompilation tasks ready for OSR.
   List<OptimizingCompiler*> ready_for_osr_;
@@ -125,6 +125,8 @@ class OptimizingCompilerThread : public Thread {
   TimeDelta time_spent_compiling_;
   TimeDelta time_spent_total_;
 
+  // TODO(yangguo): remove this once the memory leak has been figured out.
+  Mutex queue_mutex_;
   Mutex osr_list_mutex_;
   int osr_hits_;
   int osr_attempts_;
-- 
2.7.4