Re: Externalize SLIT table

Jack Steiner
2004-11-05T16:44:49Z

On Fri, Nov 05, 2004 at 05:26:10PM +0100, Andreas Schwab wrote:
> Jack Steiner <steiner@sgi.com> writes:
>
> > @@ -111,6 +111,21 @@ static ssize_t node_read_numastat(struct
> > }
> > static SYSDEV_ATTR(numastat, S_IRUGO, node_read_numastat, NULL);
> >
> > +static ssize_t node_read_distance(struct sys_device * dev, char * buf)
> > +{
> > + int nid = dev->id;
> > + int len = 0;
> > + int i;
> > +
> > + for (i = 0; i < numnodes; i++)
> > + len += sprintf(buf + len, "%s%d", i ? " " : "", node_distance(nid, i));
>
> Can this overflow the space allocated for buf?

Good point. I think we are ok for now. AFAIK, the largest cpu count
currently supported is 512. That gives a max string of 2k (max of 3
digits + space per cpu).

However, I should probably add a BUILD_BUG_ON to check for overflow.

BUILD_BUG_ON(NR_NODES*4 > PAGE_SIZE/2);
BUILD_BUG_ON(NR_CPUS*4 > PAGE_SIZE/2);

>
> > @@ -58,6 +59,31 @@ static inline void register_cpu_control(
> > }
> > #endif /* CONFIG_HOTPLUG_CPU */
> >
> > +#ifdef CONFIG_NUMA
> > +static ssize_t cpu_read_distance(struct sys_device * dev, char * buf)
> > +{
> > + int nid = cpu_to_node(dev->id);
> > + int len = 0;
> > + int i;
> > +
> > + for (i = 0; i < num_possible_cpus(); i++)
> > + len += sprintf(buf + len, "%s%d", i ? " " : "",
> > + node_distance(nid, cpu_to_node(i)));
>
> Or this?
>
> Andreas.
>
> --
> Andreas Schwab, SuSE Labs, schwab@suse.de
> SuSE Linux AG, Maxfeldstra_e 5, 90409 N|rnberg, Germany
> Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
> "And now for something completely different."

--
Thanks

Jack Steiner (steiner@sgi.com) 651-683-5302
Principal Engineer SGI - Silicon Graphics, Inc.