Valgrind garbage collection shutdown fix attempt

arangod/V8Server/ApplicationV8.cpp

@@ -1449,10 +1449,20 @@ void ApplicationV8::shutdownV8Instance(size_t i) {
     double availableTime = 30.0;
 
     if (RUNNING_ON_VALGRIND) {
+      // running under Valgrind
       availableTime *= 10;
-    }
+      int tries = 0;
 
-    TRI_RunGarbageCollectionV8(isolate, availableTime);
+      while (tries++ < 10 &&  
+             TRI_RunGarbageCollectionV8(isolate, availableTime)) {
+        if (tries > 3) {
+          LOG_WARNING("waiting for garbage v8 collection to end");
+        }
+      }
+    }
+    else {
+      TRI_RunGarbageCollectionV8(isolate, availableTime);
+    }
 
     TRI_GET_GLOBALS();
     if (v8g != nullptr) {

lib/V8/v8-utils.cpp

@@ -4068,10 +4068,11 @@ static bool SingleRunGarbageCollectionV8(v8::Isolate* isolate,
 
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief run the V8 garbage collection for at most a specifiable amount of
-/// time
+/// time. returns a boolean indicating whether or not the caller should attempt
+/// to do more gc 
 ////////////////////////////////////////////////////////////////////////////////
 
-void TRI_RunGarbageCollectionV8(v8::Isolate* isolate, double availableTime) {
+bool TRI_RunGarbageCollectionV8(v8::Isolate* isolate, double availableTime) {
   int idleTimeInMs = 1000;
 
   if (availableTime >= 5.0) {
@@ -4097,7 +4098,7 @@ void TRI_RunGarbageCollectionV8(v8::Isolate* isolate, double availableTime) {
 
   while (++gcTries <= gcAttempts) {
     if (SingleRunGarbageCollectionV8(isolate, idleTimeInMs)) {
-      return;
+      return false;
     }
   }
 
@@ -4108,12 +4109,14 @@ void TRI_RunGarbageCollectionV8(v8::Isolate* isolate, double availableTime) {
       // much CPU
       if (++gcTries > gcAttempts ||
           SingleRunGarbageCollectionV8(isolate, idleTimeInMs)) {
-        return;
+        return false;
       }
     }
 
     usleep(100);
   }
+
+  return true;
 }
 
 ////////////////////////////////////////////////////////////////////////////////

lib/V8/v8-utils.h

@@ -182,7 +182,7 @@ void TRI_normalize_V8_Obj(const v8::FunctionCallbackInfo<v8::Value>& args,
 /// time
 ////////////////////////////////////////////////////////////////////////////////
 
-void TRI_RunGarbageCollectionV8(v8::Isolate*, double);
+bool TRI_RunGarbageCollectionV8(v8::Isolate*, double);
 
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief clear the instance-local cache of wrapped objects