On Wed, Aug 02, 2023 at 01:24:59PM +0200, Peter Zijlstra wrote: > Just like nr_cpu_ids, nr_node_ids covers the side of possible_map and > is thus constant after init. > > Mark the variable __ro_after_init to both improve performance and > enhance security, since the variable is exported. A module writing to > it would be 'unfortunate'. > > Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Reviewed-by: Mike Rapoport (IBM) <rppt@xxxxxxxxxx> > --- > mm/page_alloc.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -305,7 +305,7 @@ int movable_zone; > EXPORT_SYMBOL(movable_zone); > > #if MAX_NUMNODES > 1 > -unsigned int nr_node_ids __read_mostly = MAX_NUMNODES; > +unsigned int nr_node_ids __ro_after_init = MAX_NUMNODES; > unsigned int nr_online_nodes __read_mostly = 1; > EXPORT_SYMBOL(nr_node_ids); > EXPORT_SYMBOL(nr_online_nodes); > > -- Sincerely yours, Mike.
