It's a subscriber-only article at lwn.net, which means it isn't available to the public for a week. I saw it last week too, but HN can only link to it today.

FWIW: lwn.net is a great site, and very much worth the subscription cost. Better kernel articles than anywehre else, and a higher signal-to-noise ratio in the comments than anywhere else on the internet I'm aware of. Lots of famous geeks post there regularly.