diff -up webkitgtk-2.4.2/Source/JavaScriptCore/heap/CopiedBlock.h.ppc64_align webkitgtk-2.4.2/Source/JavaScriptCore/heap/CopiedBlock.h
--- webkitgtk-2.4.2/Source/JavaScriptCore/heap/CopiedBlock.h.ppc64_align	2014-05-12 08:03:53.000000000 +0200
+++ webkitgtk-2.4.2/Source/JavaScriptCore/heap/CopiedBlock.h	2014-05-14 15:16:36.946318596 +0200
@@ -81,7 +81,7 @@ public:
     size_t size();
     size_t capacity();
 
-    static const size_t blockSize = 32 * KB;
+    static const size_t blockSize = 64 * KB;
 
     bool hasWorkList();
     CopyWorkList& workList();
diff -up webkitgtk-2.4.2/Source/JavaScriptCore/interpreter/JSStack.cpp.ppc64_align webkitgtk-2.4.2/Source/JavaScriptCore/interpreter/JSStack.cpp
--- webkitgtk-2.4.2/Source/JavaScriptCore/interpreter/JSStack.cpp.ppc64_align	2014-05-12 08:03:53.000000000 +0200
+++ webkitgtk-2.4.2/Source/JavaScriptCore/interpreter/JSStack.cpp	2014-05-14 15:17:35.617171141 +0200
@@ -49,7 +49,8 @@ JSStack::JSStack(VM& vm, size_t capacity
 {
     ASSERT(capacity && isPageAligned(capacity));
 
-    m_reservation = PageReservation::reserve(roundUpAllocationSize(capacity * sizeof(Register), commitSize), OSAllocator::JSVMStackPages);
+    size_t commitsize = pageSize();
+    m_reservation = PageReservation::reserve(roundUpAllocationSize(capacity * sizeof(Register), commitsize), OSAllocator::JSVMStackPages);
     updateStackLimit(highAddress());
     m_commitEnd = highAddress();
 
@@ -78,7 +79,8 @@ bool JSStack::growSlowCase(Register* new
     // Compute the chunk size of additional memory to commit, and see if we
     // have it is still within our budget. If not, we'll fail to grow and
     // return false.
-    long delta = roundUpAllocationSize(reinterpret_cast<char*>(m_commitEnd) - reinterpret_cast<char*>(newEnd), commitSize);
+    size_t commitsize = pageSize();
+    long delta = roundUpAllocationSize(reinterpret_cast<char*>(m_commitEnd) - reinterpret_cast<char*>(newEnd), commitsize);
     if (reinterpret_cast<char*>(m_commitEnd) - delta <= reinterpret_cast<char*>(m_useableEnd))
         return false;
 
@@ -134,7 +136,8 @@ void JSStack::enableErrorStackReserve()
 
 void JSStack::disableErrorStackReserve()
 {
-    char* useableEnd = reinterpret_cast<char*>(reservationEnd()) + commitSize;
+    size_t commitsize = pageSize();
+    char* useableEnd = reinterpret_cast<char*>(reservationEnd()) + commitsize;
     m_useableEnd = reinterpret_cast_ptr<Register*>(useableEnd);
 
     // By the time we get here, we are guaranteed to be destructing the last