On Fri 27-05-11 12:07:30, David Rientjes wrote:
> On Fri, 27 May 2011, Michal Hocko wrote:
>
> > > alpha allmodconfig:
> > >
> > > kernel/built-in.o: In function `cpuset_slab_spread_node':
> > > (.text+0x67360): undefined reference to `node_random'
> > > kernel/built-in.o: In function `cpuset_slab_spread_node':
> > > (.text+0x67368): undefined reference to `node_random'
> > > kernel/built-in.o: In function `cpuset_mem_spread_node':
> > > (.text+0x673b8): undefined reference to `node_random'
> > > kernel/built-in.o: In function `cpuset_mem_spread_node':
> > > (.text+0x673c0): undefined reference to `node_random'
> > >
> > > because it has CONFIG_NUMA=n, CONFIG_NODES_SHIFT=7.
> >
> > non-NUMA with MAX_NUMA_NODES? Hmm, really weird and looks like a numa
> > misuse.
> >
>
> CONFIG_NODES_SHIFT is used for UMA machines that are using DISCONTIGMEM
> usually because they have very large holes; such machines don't need
> things like mempolicies but do need the data structures that abstract
> ranges of memory in the physical address space. This build breakage
> probably isn't restricted to only alpha, you could probably see it with at
> least ia64 and mips as well.
Hmmm. I just find strange that some UMA arch uses functions like
{first,next}_online_node.
[...]
> > +/*
> > + * Return the bit number of a random bit set in the nodemask.
> > + * (returns -1 if nodemask is empty)
> > + */
> > +static inline int node_random(const nodemask_t *maskp)
> > +{
> > + int w, bit = -1;
> > +
> > + w = nodes_weight(*maskp);
> > + if (w)
> > + bit = bitmap_ord_to_pos(maskp->bits,
> > + get_random_int() % w, MAX_NUMNODES);
> > + return bit;
> > +}
> >
> > #else
> >
>
> Probably should have a no-op definition when MAX_NUMNODES == 1 that just
> returns 0?
There is one, which has been added by the patch which introduced the
function. This is just an incremental patch for the compilation fix.
--
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9
Czech Republic
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