diff --git a/src/os/linux/vm/os_linux.cpp b/src/os/linux/vm/os_linux.cpp
index a327fd91592f3893700fc6f4a07e1c93ba35142a..6d793d895fbc2ac61ccca117a5833ed020aca0ee 100644
--- a/src/os/linux/vm/os_linux.cpp
+++ b/src/os/linux/vm/os_linux.cpp
@@ -116,6 +116,20 @@ julong os::physical_memory() {
   return Linux::physical_memory();
 }
 
+julong os::allocatable_physical_memory(julong size) {
+#ifdef _LP64
+  return size;
+#else
+  julong result = MIN2(size, (julong)3800*M);
+   if (!is_allocatable(result)) {
+     // See comments under solaris for alignment considerations
+     julong reasonable_size = (julong)2*G - 2 * os::vm_page_size();
+     result =  MIN2(size, reasonable_size);
+   }
+   return result;
+#endif // _LP64
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // environment support
 
diff --git a/src/os/windows/vm/os_windows.cpp b/src/os/windows/vm/os_windows.cpp
index 7f2293385903ecad3598223cb49b381e524d54e5..54e802a9d851755f20a04c09296e1b233cde4570 100644
--- a/src/os/windows/vm/os_windows.cpp
+++ b/src/os/windows/vm/os_windows.cpp
@@ -621,7 +621,12 @@ julong os::physical_memory() {
 }
 
 julong os::allocatable_physical_memory(julong size) {
+#ifdef _LP64
+  return size;
+#else
+  // Limit to 1400m because of the 2gb address space wall
   return MIN2(size, (julong)1400*M);
+#endif
 }
 
 // VC6 lacks DWORD_PTR
diff --git a/src/os_cpu/linux_x86/vm/os_linux_x86.cpp b/src/os_cpu/linux_x86/vm/os_linux_x86.cpp
index 972ee017c4048b4fbf819e9fc349d3b4bd14e72d..57631b5cde54b368f3f63682396ba5a3fa5c716e 100644
--- a/src/os_cpu/linux_x86/vm/os_linux_x86.cpp
+++ b/src/os_cpu/linux_x86/vm/os_linux_x86.cpp
@@ -157,23 +157,8 @@ frame os::current_frame() {
   }
 }
 
-
 // Utility functions
 
-julong os::allocatable_physical_memory(julong size) {
-#ifdef AMD64
-  return size;
-#else
-  julong result = MIN2(size, (julong)3800*M);
-   if (!is_allocatable(result)) {
-     // See comments under solaris for alignment considerations
-     julong reasonable_size = (julong)2*G - 2 * os::vm_page_size();
-     result =  MIN2(size, reasonable_size);
-   }
-   return result;
-#endif // AMD64
-}
-
 // From IA32 System Programming Guide
 enum {
   trap_page_fault = 0xE