On Tue, 27 Jan 2009, Luck, Tony wrote:

Managing a larger space could be done ... but at the expense of making
the Alt-DTLB miss handler do a memory lookup to find the physical address
of the per-cpu page needed (assuming that we allocate a bunch of random
physical pages for use as per-cpu space rather than a single contiguous
block of physical memory).

We cannot resize the area by using a single larger TLB entry?

When do we know the total amount of per-cpu memory needed?
1) CONFIG time?

Would be easiest.

2) Boot time?

We could make the TLB entry size configurable with a kernel parameter

3) Arbitrary run time?

We could reserve a larger virtual space and switch TLB entries as needed?
We would need do get larger order pages to do this.