Re: [RFC PATCH 08/35] Add Xen-specific memory management definitions

Pete Zaitcev
2006-05-17T16:08:26Z

On Tue, 09 May 2006 00:00:08 -0700, Chris Wright <chrisw@sous-sol.org> wrote:

> +static inline unsigned long pfn_to_mfn(unsigned long pfn)
> +{
> +#ifndef CONFIG_XEN_SHADOW_MODE
> + if (xen_feature(XENFEAT_auto_translated_physmap))
> + return pfn;
> + return phys_to_machine_mapping[(unsigned int)(pfn)] &
> + ~FOREIGN_FRAME_BIT;
> +#else
> + return pfn;
> +#endif
> +}

Why do we need several modes in Linux guests?

If a significant tradeoff exists (for example, between performance
and maximum addressable memory), then we need to think about the
real issue instead of throwing config options into the pot.

-- Pete