Currently static fields are stored in the instanceKlass but when those are moved into native memory we'd have to have a new card mark strategy for static fields. This could be something like setting a flag in the instanceKlass and then rescanning every klass during a GC which seems expensive or marking the card for the java.lang.Class then making sure to scan the instanceKlass when scanning the Class. If we move them into the Class then almost all the existing machinery works exactly as it always has. The only execution difference is which constant is materialized for the field access.
JDK-2208433 move static fields into Class to prepare for perm gen removal
JDK-7024561 JSR 292 constant pool cache _f1 field doesn't get properly updated with parallel GC