diff --git a/xpcom/base/nsCycleCollector.cpp b/xpcom/base/nsCycleCollector.cpp
index 51467605222..94f715e6815 100644
--- a/xpcom/base/nsCycleCollector.cpp
+++ b/xpcom/base/nsCycleCollector.cpp
@@ -748,7 +748,7 @@ struct nsPurpleBuffer
 private:
     struct Block {
         Block *mNext;
-        nsPurpleBufferEntry mEntries[128];
+        nsPurpleBufferEntry mEntries[255];
 
         Block() : mNext(nsnull) {}
     };