[$] Reimplementing printk()

The venerable printk() function has been part of Linux since the very
beginning, though it has undergone a fair number of changes along the way.
Now, John Ogness is proposing to fundamentally rework printk() in
order to get
rid of handful of issues that currently plague it. The proposed code does this
by adding
yet another ring-buffer implementation to the kernel; this one is aimed at
making printk() work better from hard-to-handle contexts. For
a task that seems conceptually simple—printing messages to the
console—printk() is actually a rather complex beast; that won't
change if these patches
are merged, though many of the problems with the current implementation
will be removed.