[Cbe-oss-dev] [RFC] [PATCH 4:8] SPU Gang Scheduling - Add gang structure for standalone ctxts

[Arnd Bergmann]

On Monday 03 March 2008, Luke Browning wrote:
> +
> +       for (n = 0, nspus = 0; n < MAX_NUMNODES; n++)
> +               nspus += cbe_spu_info[n].n_spus -
> +                       atomic_read(&cbe_spu_info[n].reserved_spus);
> +       if (nspus < gang->contexts + 1)
> +               goto out_free_gang;

In your description, you mentioned that the whole gang should
get loaded on a single NUMA node, so I'd expect this check to
test for the maximum number of SPUs on one node,not the total
amount of them in the system.

I'm also not sure how much we can trust the  logic for number
of reserved spus,  as they can change at any time when we get
a new reserved spu later,  preventing a large gang from being
loaded. Maybe we should rather ignore that number and let the
user do stupid things like creating a gang of dozens contexts
that can never possibly get scheduled?

	Arnd <><