During JDK-8199868 code review:

Ian Rogers wrote:

Re JDK-8199868 - should pinning be limited to just critical APIs? The non-critical variants could also pin to avoid copies.
I see this as related to JDK-8199919. It'd be nice to just move the critical APIs to use the same logic as the non-critical APIs, then pinning just becomes a performance optimization to avoid copying. Re JDK-8199919's comment that there is no deprecation mechanism, compilers like GCC allow function attributes that warn when a deprecated function is used.

Thanks,
Ian

http://mail.openjdk.java.net/pipermail/hotspot-dev/2018-May/032030.html