[$] ktask: optimizing CPU-intensive kernel work

As a general rule, the kernel is supposed to use the least amount of CPU
time possible; any time taken by the kernel is not available for the
applications the user actually wants to run. As a result, not a lot of
thought has gone into optimizing the execution of kernel-side work requiring large
amounts of CPU. But the kernel does occasionally have to take on
CPU-intensive tasks, such as the initialization of the large amounts of
memory found on current systems. The ktask
subsystem posted by Daniel Jordan is an attempt to improve how the
kernel handles such jobs.