Re: [patch 1] Xen core patch : ptep_establish_new

[Keir Fraser]

> > On Wed, Nov 17, 2004 at 11:46:50PM +0000, Ian Pratt wrote:
> > > 
> > > This patch adds 'ptep_establish_new', in keeping with the
> > > existing 'ptep_establish', but for use where a mapping is being
> > > established where there was previously none present. This
> > > function is useful (rather than just using set_pte) because
> > > having the virtual address available enables a very important
> > > optimisation for arch-xen. We introduce
> > > HAVE_ARCH_PTEP_ESTABLISH_NEW and define a generic implementation
> > > in asm-generic/pgtable.h, following the pattern of the existing
> > > ptep_establish.
> > 
> > What would be the problem of always passing the virtual address to
> > ptep_establish?  We already have a rather twisted maze of pte manipulation
> > macros.
> 
> ptep_establish already takes a virtual address. Perhaps you mean
> 'set_pte'? That would work, but is a much bigger change that
> would impact all architectures. I think introducing
> ptep_establish_new is cleaner.

Also, we want to know which PTE updates are to a virtual address
within the *current* address space. Just adding a VA to every set_pte
use wouldn't tell us that (without yet another parameter ;-).

 -- Keir
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/