It's not final yet, but we're getting closer to that. Linus has just released another RC release to public after more than two weeks from the last RC (due to long holidays). New feature on this release is the SLUB support of /proc/slabinfo made by Pekka J Enberg. Read the news on LWN or directly at the Changelog.
If nothing big happened, we could see the result in the next one or two weeks (hopefully it will be the final)