Re: tuning a VERY heavily (30.0) loaded s cerver

[Rik van Riel]

On Thu, 22 Mar 2001, thinker wrote:
> On Wed, Mar 21, 2001 at 04:14:32PM -0300, Rik van Riel wrote:
> > The (maybe too lightweight) structure I have in my patch
> > looks like this:
> > 
> > struct pte_chain {
> >     struct pte_chain * next;
> >     pte_t * ptep;
> > };
> > 
> > Each pte_chain hangs off a page of physical memory and the
> > ptep is a pointer to a page table entry.
> > 
> > The page struct of the page table page itself is used to
> > note down which address space and offset we have. This means
> > that FreeBSD's pv_pmap, pv_va and pv_ptem are in the page
> > table page and NOT in each pte_chain structure...
>
> How about portability? It maybe efficient, but it is not easy
> to port to other platforms.

IIRC the pmap layer is in the architecture-dependent code in
the BSDs.  For Linux we have forward pagetables in every
architecture, whether it be in software or hardware.  They
turn out to be quite adequate as an alternative to vnodes ;)

regards,

Rik
--
Virtual memory is like a game you can't win;
However, without VM there's truly nothing to lose...

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