A path toward removal of kernel high-memory support

As a followup to his OSS Europe talk on thefuture of 32-bit support in the kernel, Arnd Bergmann has put togetheradetailed plan for the eventual removal of high-memory support, which hecalls "one of the least popular features of the Linux kernel". Theintent is "to gradually phase out highmem over the next 2 years formainline kernels". This plan is posted as a prompt for a discussion tobe held at the Kernel Summit in December, so chances are it will evolveconsiderably in the next few months.