8312180: (bf) MappedMemoryUtils passes incorrect arguments to msync (aix)

Backport-of: fdac6a6ac871366614efe44aca58ab520766b5c8

Author: Tyler Steele

src/hotspot/share/classfile/javaClasses.cpp

@@ -86,6 +86,7 @@
 #include "runtime/vframe.inline.hpp"
 #include "runtime/vm_version.hpp"
 #include "utilities/align.hpp"
+#include "utilities/globalDefinitions.hpp"
 #include "utilities/growableArray.hpp"
 #include "utilities/preserveException.hpp"
 #include "utilities/utf8.hpp"
@@ -4725,7 +4726,7 @@ class UnsafeConstantsFixup : public FieldClosure {
   UnsafeConstantsFixup() {
     // round up values for all static final fields
     _address_size = sizeof(void*);
-    _page_size = (int)os::vm_page_size();
+    _page_size = AIX_ONLY(sysconf(_SC_PAGESIZE)) NOT_AIX((int)os::vm_page_size());
     _big_endian = LITTLE_ENDIAN_ONLY(false) BIG_ENDIAN_ONLY(true);
     _use_unaligned_access = UseUnalignedAccesses;
     _data_cache_line_flush_size = (int)VM_Version::data_cache_line_flush_size();