Bug 961091 - Don't compact full store buffers so often after GC has been triggered r=terrence

js/src/gc/StoreBuffer.cpp

@@ -82,6 +82,28 @@ StoreBuffer::WholeCellEdges::mark(JSTracer *trc)
 
 /*** MonoTypeBuffer ***/
 
+template <typename T>
+void
+StoreBuffer::MonoTypeBuffer<T>::handleOverflow(StoreBuffer *owner)
+{
+    if (!owner->isAboutToOverflow()) {
+        /*
+         * Compact the buffer now, and if that fails to free enough space then
+         * trigger a minor collection.
+         */
+        compact(owner);
+        if (isAboutToOverflow())
+            owner->setAboutToOverflow();
+    } else {
+         /*
+          * A minor GC has already been triggered, so there's no point
+          * compacting unless the buffer is totally full.
+          */
+        if (storage_->availableInCurrentChunk() < sizeof(T))
+            compact(owner);
+    }
+}
+
 template <typename T>
 void
 StoreBuffer::MonoTypeBuffer<T>::compactRemoveDuplicates(StoreBuffer *owner)

js/src/gc/StoreBuffer.h

@@ -115,6 +115,8 @@ class StoreBuffer
             return !storage_->isEmpty() && storage_->availableInCurrentChunk() < MinAvailableSize;
         }
 
+        void handleOverflow(StoreBuffer *owner);
+
         /* Compaction algorithms. */
         void compactRemoveDuplicates(StoreBuffer *owner);
 
@@ -135,11 +137,8 @@ class StoreBuffer
             if (!tp)
                 CrashAtUnhandlableOOM("Failed to allocate for MonoTypeBuffer::put.");
 
-            if (isAboutToOverflow()) {
+            if (isAboutToOverflow())
-                compact(owner);
+                handleOverflow(owner);
-                if (isAboutToOverflow())
-                    owner->setAboutToOverflow();
-            }
         }
 
         /* Mark the source of all edges in the store buffer. */