RE: [PATCH] percpu: add optimized generic percpu accessors

From: Christoph Lameter
Date: Wed Jan 28 2009 - 12:58:32 EST


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.

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