DTrace is the CDDL-licensed dynamic tracing framework from Sun Microsystems (now obviously, Oracle) that was long one of the strong, unique features of the Solaris operating system. Since being put out under the Common Development and Distribution License, this technology has been ported to Mac OS X and *BSD, but it hasn't made it into the Linux kernel due to the Sun license being incompatible with the GPL.
However, Oracle now plans to bring DTrace to a new version of their "Unbreakable" Linux kernel on Oracle Enterprise Linux -- their "clone" of Red Hat Enterprise Linux. Details are scarce, but The Register has provided slides and a few details about the bits of information that were announced. Even one of the creators of DTrace is uncertain about what Oracle's plans are for DTrace on Linux (see his blog post).
Oracle is unlikely to re-license (or dual license) DTrace under the GPL, so that it could be merged into the mainline Linux kernel. If they did so, Red Hat and Oracle's other competitors could ship this DTrace technology too. What Oracle is likely to do is ship a kernel module targeting their Oracle Linux kernel that provides the DTrace support. I don't see them being too kind towards the open-source and wider Linux communities with this work, but rather to just benefit their enterprise Linux distribution.
Likewise, Oracle also announced they would be bringing Sun's Zones from Solaris to Oracle Enterprise Linux. It will be interesting to see what their ultimate play is with bring more of the Solaris "jewels" to Oracle Enterprise Linux. Solaris 11 is imminent, but its future beyond that should be interesting. As of right now, they haven't yet announced plans to officially support the ZFS file-system under Oracle Enterprise Linux, but that's probably not too far out.