Re: Long Format VHPT patches

From: Peter Chubb <peterc_at_gelato.unsw.edu.au>
Date: 2004-08-27 07:20:07
>>>>> "Christoph" == Christoph Lameter <christoph@lameter.com> writes:

Christoph> One issue that bothers me is that it is no longer possible
Christoph> to swap pte, pmd and pgd entries via cmpxchg. My page fault
Christoph> scalability patches are based on that ability. The Itanium
Christoph> can only do a cmpxchg with a 64 bit value.  The long VHPT
Christoph> entries are 32 bytes long.

I don't think that that's an issue at present: in our patch, the
hardware-walked long format VHPT is used as a cache of the existing
linux 3-level table, kind of like a software loaded TLB.  Thus your
cmpxchg stuff on the pagetables will still work.

And if/when we add new page table structures (inevitable eventually for the
superpage work, I think) they can be designed from the start with
scalability in mind.

-- 
Dr Peter Chubb  http://www.gelato.unsw.edu.au  peterc AT gelato.unsw.edu.au
The technical we do immediately,  the political takes *forever*
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Received on Thu Aug 26 18:16:06 2004

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