Re: [Xen-devel] [PATCH v4 1/9] numa: __node_distance() should return u8

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

On 03/10/2015 07:53 AM, Andrew Cooper wrote:
> On 10/03/15 02:27, Boris Ostrovsky wrote:
> > SLIT values are byte-sized and some of them (0-9 and 255) have
> > special meaning. Adjust __node_distance() to reflect this and
> > modify scrub_heap_pages() to deal with __node_distance() returning
> > an invalid SLIT entry.
> >
> > Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
> You also need to teach XEN_SYSCTL_numainfo about the new NUMA_NO_DISTANCE.
The sysctl is updated later in the series but this may indeed break 
bisection.
> > ---
> >   xen/arch/x86/srat.c        |   15 +++++++++++----
> >   xen/common/page_alloc.c    |    4 ++--
> >   xen/include/asm-x86/numa.h |    2 +-
> >   xen/include/xen/numa.h     |    3 ++-
> >   4 files changed, 16 insertions(+), 8 deletions(-)
> >
> > diff --git a/xen/arch/x86/srat.c b/xen/arch/x86/srat.c
> > index dfabba3..aa2eda3 100644
> > --- a/xen/arch/x86/srat.c
> > +++ b/xen/arch/x86/srat.c
> > @@ -496,14 +496,21 @@ static unsigned node_to_pxm(nodeid_t n)
> >         return 0;
> >   }
> >   
> > -int __node_distance(nodeid_t a, nodeid_t b)
> > +u8 __node_distance(nodeid_t a, nodeid_t b)
> >   {
> > -       int index;
> > +       u8 slit_val;
> >   
> >   	if (!acpi_slit)
> >                 return a == b ? 10 : 20;
> > -       index = acpi_slit->locality_count * node_to_pxm(a);
> > -       return acpi_slit->entry[index + node_to_pxm(b)];
> > +
> > +       slit_val = acpi_slit->entry[acpi_slit->locality_count * node_to_pxm(a) +
> > +                                               node_to_pxm(b)];
> This would be easier to read if you kept the old index temporary
> (although making it a u64).
Yes.

-boris



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