Re: [PATCH v3 2/6] mm/numa: Skip NUMA_NO_NODE and online nodes in numa_map_to_online_node()

[Dan Williams]

On Mon, Jan 20, 2020 at 5:36 PM Aneesh Kumar K.V
<aneesh.kumar@xxxxxxxxxxxxx> wrote:
>
> Dan Williams <dan.j.williams@xxxxxxxxx> writes:
>
> > Update numa_map_to_online_node() to stop falling back to numa node 0
> > when the input is NUMA_NO_NODE. Also, skip the lookup if @node is
> > online. This makes the routine compatible with other arch node mapping
> > routines.
> >
> > Reported-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
> > Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
> > Link: https://lore.kernel.org/r/157401275716.43284.13185549705765009174.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> > Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
> > ---
> >  mm/mempolicy.c |    4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> > index 4cff069279f6..30d76db718bf 100644
> > --- a/mm/mempolicy.c
> > +++ b/mm/mempolicy.c
> > @@ -137,8 +137,8 @@ int numa_map_to_online_node(int node)
> >  {
> >       int min_node;
> >
> > -     if (node == NUMA_NO_NODE)
> > -             node = 0;
> > +     if (node == NUMA_NO_NODE || node_online(node))
> > +             return node;
> >
> >       min_node = node;
> >       if (!node_online(node)) {
>
>
> The above if condition will always be true?

No, not for the node_offline case, and that's typically what callers
are passing.
>
> -aneesh