[aarch64-port-dev ] [OpenJDK8u] java.nio.Bits.unaligned() doesn't handle aarch64

[White, Derek]

In aarch64-port/jdk8u, java.nio.Bits.unaligned() only returns true for x86(s).

This ends up being important because Apache Spark uses Bits.unaligned() to decide if it can use off-heap memory or not.

In mainline jdk8u, this was updated to include PPC as well (See https://bugs.openjdk.java.net/browse/JDK-8165231). JDK9 has a much better fix that supports aarch64 already.

Tested on Spark and off-heap memory was being used. Note: The PPC fix also patched sun/security/provider/ByteArrayAccess.java, but I didn't include this in the patch below (not sure if it matters, or how to test it).

This is my first attempt at an aarch64-jdk8u patch. Please let me know if I'm not following protocol correctly.

Thanks,

-        Derek


Patch follows (in jdk/src).

--- old/src/share/classes/java/nio/Bits.java            2017-05-11 13:10:31.916219496 -0400
+++ new/src/share/classes/java/nio/Bits.java       2017-05-11 13:10:31.832221728 -0400
@@ -614,7 +614,9 @@
         String arch = AccessController.doPrivileged(
             new sun.security.action.GetPropertyAction("os.arch"));
         unaligned = arch.equals("i386") || arch.equals("x86")
-            || arch.equals("amd64") || arch.equals("x86_64");
+            || arch.equals("amd64") || arch.equals("x86_64")
+            || arch.equals("ppc64") || arch.equals("ppc64le")
+            || arch.equals("aarch64");
         unalignedKnown = true;
         return unaligned;
     }