6629887: 64-bit windows should not restrict default heap size to 1400m

Reviewed-by: jmasa, sbohne, ikrylov, xlu

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
 

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

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