On Fri 27-05-11 16:30:33, David Rientjes wrote:
> On Sat, 28 May 2011, Michal Hocko wrote:
>
> > > --- a/include/linux/nodemask.h~cpusets-randomize-node-rotor-used-in-cpuset_mem_spread_node-fix-2
> > > +++ a/include/linux/nodemask.h
> > > @@ -433,8 +433,6 @@ static inline void node_set_offline(int
> > > nr_online_nodes = num_node_state(N_ONLINE);
> > > }
> > >
> > > -extern int node_random(const nodemask_t *maskp);
> > > -
> > > #else
> > >
> > > static inline int node_state(int node, enum node_states state)
> > > @@ -466,7 +464,15 @@ static inline int num_node_state(enum no
> > > #define node_set_online(node) node_set_state((node), N_ONLINE)
> > > #define node_set_offline(node) node_clear_state((node), N_ONLINE)
> > >
> > > -static inline int node_random(const nodemask_t *mask) { return 0; }
> > > +#endif
> > > +
> > > +#if defined(CONFIG_NUMA) && (MAX_NUMNODES > 1)
> > > +extern int node_random(const nodemask_t *maskp);
> > > +#else
> > > +static inline int node_random(const nodemask_t *mask)
> > > +{
> > > + return 0;
> > > +}
> > > #endif
> >
> > I have to admit that I quite don't understand concept of several nodes
> > with UMA archs but do we really want to provide the sane node all the
> > time?
> >
>
> They aren't nodes on UMA machines, they are memory regions for
> DISCONTIGMEM which are separated by large holes in the address space.
> These archs will never sanely use node_random(), so it doesn't really
> matter except for CONFIG_NUMA where MAX_NUMNODES > 1, since they won't be
> selecting random memory regions.
OK, I see. Then it makes much more sense. Thanks for clarification.
--
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9
Czech Republic
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