Bug 1097302, increase the number of major forget skippables, r=mccr8

--HG--
extra : rebase_source : b465ff26006f688cb76d0f3bfe0ed1a564081992

dom/base/nsCCUncollectableMarker.cpp

@@ -394,19 +394,56 @@ nsCCUncollectableMarker::Observe(nsISupports* aSubject, const char* aTopic,
   }
 #endif
 
-  static bool previousWasJSCleanup = false;
+  enum ForgetSkippableCleanupState
+  {
+    eInitial = 0,
+    eUnmarkJSEventListeners = 1,
+    eUnmarkMessageManagers = 2,
+    eUnmarkStrongObservers = 3,
+    eUnmarkJSHolders = 4,
+    eDone = 5
+  };
+
+  static_assert(eDone == NS_MAJOR_FORGET_SKIPPABLE_CALLS,
+                "There must be one forgetSkippable call per cleanup state.");
+
+  static uint32_t sFSState = eDone;
+  if (prepareForCC) {
+    sFSState = eDone;
+    return NS_OK;
+  }
+
   if (cleanupJS) {
-    nsContentUtils::UnmarkGrayJSListenersInCCGenerationDocuments(sGeneration);
-    MarkMessageManagers();
+    // After a GC we start clean up phases from the beginning,
+    // but we don't want to do the additional clean up phases here
+    // since we have done already plenty of gray unmarking while going through
+    // frame message managers and docshells.
+    sFSState = eInitial;
+    return NS_OK;
+  } else {
+    ++sFSState;
+  }
 
-    nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
-    static_cast<nsObserverService *>(obs.get())->UnmarkGrayStrongObservers();
-
-    previousWasJSCleanup = true;
-  } else if (previousWasJSCleanup) {
-    previousWasJSCleanup = false;
-    if (!prepareForCC) {
+  switch(sFSState) {
+    case eUnmarkJSEventListeners: {
+      nsContentUtils::UnmarkGrayJSListenersInCCGenerationDocuments(sGeneration);
+      break;
+    }
+    case eUnmarkMessageManagers: {
+      MarkMessageManagers();
+      break;
+    }
+    case eUnmarkStrongObservers: {
+      nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
+      static_cast<nsObserverService *>(obs.get())->UnmarkGrayStrongObservers();
+      break;
+    }
+    case eUnmarkJSHolders: {
       xpc_UnmarkSkippableJSHolders();
+      break;
+    }
+    default: {
+      break;
     }
   }
 

dom/base/nsJSEnvironment.cpp

@@ -117,7 +117,7 @@ const size_t gStackSize = 8192;
 // and doing the actual CC.
 #define NS_CC_DELAY                 6000 // ms
 
-#define NS_CC_SKIPPABLE_DELAY       400 // ms
+#define NS_CC_SKIPPABLE_DELAY       250 // ms
 
 // Maximum amount of time that should elapse between incremental CC slices
 static const int64_t kICCIntersliceDelay = 32; // ms
@@ -144,8 +144,6 @@ static const uint32_t kMaxICCDuration = 2000; // ms
 // Large value used to specify that a script should run essentially forever
 #define NS_UNLIMITED_SCRIPT_RUNTIME (0x40000000LL << 32)
 
-#define NS_MAJOR_FORGET_SKIPPABLE_CALLS 2
-
 // if you add statics here, add them to the list in StartupJSEnvironment
 
 static nsITimer *sGCTimer;
@@ -2036,8 +2034,10 @@ CCTimerFired(nsITimer *aTimer, void *aClosure)
       // any because that will allow us to include the GC time in the CC pause.
       nsJSContext::RunCycleCollectorSlice();
     }
-  } else if ((sPreviousSuspectedCount + 100) <= suspected) {
-      // Only do a forget skippable if there are more than a few new objects.
+  } else if (((sPreviousSuspectedCount + 100) <= suspected) ||
+             (sCleanupsSinceLastGC < NS_MAJOR_FORGET_SKIPPABLE_CALLS)) {
+      // Only do a forget skippable if there are more than a few new objects
+      // or we're doing the initial forget skippables.
       FireForgetSkippable(suspected, false);
   }
 

dom/base/nsJSEnvironment.h

@@ -36,6 +36,8 @@ struct CycleCollectorResults;
 // a page) and doing the actual GC.
 #define NS_GC_DELAY                 4000 // ms
 
+#define NS_MAJOR_FORGET_SKIPPABLE_CALLS 5
+
 class nsJSContext : public nsIScriptContext
 {
 public: