On Thu, Feb 13, 2025 at 11:02:44AM -0500, Yury Norov wrote: ... > > Cc: Yury Norov <yury.norov@xxxxxxxxx> > > Signed-off-by: Andrea Righi <arighi@xxxxxxxxxx> > > Suggested-by: Yury Norov [NVIDIA] <yury.norov@xxxxxxxxx> Ok. > > > --- > > include/linux/topology.h | 30 ++++++++++++++++++++++++++++++ > > 1 file changed, 30 insertions(+) > > > > diff --git a/include/linux/topology.h b/include/linux/topology.h > > index 52f5850730b3e..932d8b819c1b7 100644 > > --- a/include/linux/topology.h > > +++ b/include/linux/topology.h > > @@ -261,6 +261,36 @@ sched_numa_hop_mask(unsigned int node, unsigned int hops) > > } > > #endif /* CONFIG_NUMA */ > > > > +/** > > + * for_each_node_numadist() - iterate over nodes in increasing distance > > + * order, starting from a given node > > + * @node: the iteration variable and the starting node. > > + * @unvisited: a nodemask to keep track of the unvisited nodes. > > + * > > + * This macro iterates over NUMA node IDs in increasing distance from the > > + * starting @node and yields MAX_NUMNODES when all the nodes have been > > + * visited. > > + * > > + * Note that by the time the loop completes, the @unvisited nodemask will > > + * be fully cleared, unless the loop exits early. > > + * > > + * The difference between for_each_node() and for_each_node_numadist() is > > + * that the former allows to iterate over nodes in numerical order, whereas > > + * the latter iterates over nodes in increasing order of distance. > > + * > > + * This complexity of this iterator is O(N^2), where N represents the > > + * number of nodes, as each iteration involves scanning all nodes to > > + * find the one with the shortest distance. > > + * > > + * Requires rcu_lock to be held. > > + */ > > +#define for_each_node_numadist(node, unvisited) \ > > + for (int start = (node), \ > > + node = nearest_node_nodemask((start), &(unvisited)); \ > > + node < MAX_NUMNODES; \ > > + node_clear(node, (unvisited)), \ > > + node = nearest_node_nodemask((start), &(unvisited))) > > the 'node' should be protected with braces inside the macro, the start should > not because you declare it just inside. Also, the 'start' is a common word, > so there's a chance that you'll mask out already existing 'start' in the scope. > Maybe __start, or simply __s? Right, will also fix this (good thing I needed to send a new version anyway, because the test robot found a build bug). :) Thanks! -Andrea
