[PATCH] Do not override definition of node_set_online() with macro

Mel Gorman
2009-04-24T13:31:39Z

On Thu, Apr 23, 2009 at 12:29:27PM -0700, David Rientjes wrote:
> On Thu, 23 Apr 2009, Mel Gorman wrote:
>
> > > > diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h
> > > > index 848025c..474e73e 100644
> > > > --- a/include/linux/nodemask.h
> > > > +++ b/include/linux/nodemask.h
> > > > @@ -408,6 +408,19 @@ static inline int num_node_state(enum node_states state)
> > > > #define next_online_node(nid) next_node((nid), node_states[N_ONLINE])
> > > >
> > > > extern int nr_node_ids;
> > > > +extern int nr_online_nodes;
> > > > +
> > > > +static inline void node_set_online(int nid)
> > > > +{
> > > > + node_set_state(nid, N_ONLINE);
> > > > + nr_online_nodes = num_node_state(N_ONLINE);
> > > > +}
> > > > +
> > > > +static inline void node_set_offline(int nid)
> > > > +{
> > > > + node_clear_state(nid, N_ONLINE);
> > > > + nr_online_nodes = num_node_state(N_ONLINE);
> > > > +}
> > > > #else
> > > >
> > > > static inline int node_state(int node, enum node_states state)
> > >
> > > The later #define's of node_set_online() and node_set_offline() in
> > > include/linux/nodemask.h should probably be removed now.
> > >
> >
> > You'd think, but you can enable memory hotplug without NUMA and
> > node_set_online() is called when adding memory. Even though those
> > functions are nops on !NUMA, they're necessary.
> >
>
> The problem is that your new functions above are never used because
> node_set_online and node_set_offline are macro defined later in this
> header for all cases, not just !CONFIG_NUMA.
>
> You need this.

You're absolutly correct, well spotted. I mistook what the #endif was
closing. Here it the patch again with a changelog. Thanks very much

==== CUT HERE ====
From: David Rientjes <rientjes@google.com>

Do not override definition of node_set_online() with macro

node_set_online() updates node_states[] and updates the value of
nr_online_nodes. However, its definition is being accidentally overridden
by a macro definition intended for use in the !CONFIG_NUMA case. This patch
fixes the problem by moving the !CONFIG_NUMA macro definition.

This should be considered a fix to the patch
page-allocator-use-a-pre-calculated-value-instead-of-num_online_nodes-in-fast-paths.patch

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
---
include/linux/nodemask.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h
index 474e73e..829b94b 100644
--- a/include/linux/nodemask.h
+++ b/include/linux/nodemask.h
@@ -448,6 +448,9 @@ static inline int num_node_state(enum node_states state)
#define next_online_node(nid) (MAX_NUMNODES)
#define nr_node_ids 1
#define nr_online_nodes 1
+
+#define node_set_online(node) node_set_state((node), N_ONLINE)
+#define node_set_offline(node) node_clear_state((node), N_ONLINE)
#endif

#define node_online_map node_states[N_ONLINE]
@@ -467,9 +470,6 @@ static inline int num_node_state(enum node_states state)
#define node_online(node) node_state((node), N_ONLINE)
#define node_possible(node) node_state((node), N_POSSIBLE)

-#define node_set_online(node) node_set_state((node), N_ONLINE)
-#define node_set_offline(node) node_clear_state((node), N_ONLINE)
-
#define for_each_node(node) for_each_node_state(node, N_POSSIBLE)
#define for_each_online_node(node) for_each_node_state(node, N_ONLINE)