Re: [PATCH v2 2/2] of, numa: Fetch empty NUMA node ID from distance map

From: Gavin Shan
Date: Mon Sep 27 2021 - 19:59:41 EST

Hi Rob,

On 9/28/21 12:49 AM, Rob Herring wrote:
On Mon, Sep 27, 2021 at 1:42 AM Gavin Shan <gshan@xxxxxxxxxx> wrote:

There is no device node for the empty NUMA node. However, the
corresponding NUMA node ID and distance map is still valid in
"numa-distance-map-v1" compatible device node.

This fetches the NUMA node ID and distance map for these empty
NUMA node from "numa-distance-map-v1" compatible device node.

This is much nicer.

Indeed, thanks for your suggestions :)

Signed-off-by: Gavin Shan <gshan@xxxxxxxxxx>
drivers/of/of_numa.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/of/of_numa.c b/drivers/of/of_numa.c
index fe6b13608e51..5949829a1b00 100644
--- a/drivers/of/of_numa.c
+++ b/drivers/of/of_numa.c
@@ -111,6 +111,8 @@ static int __init of_numa_parse_distance_map_v1(struct device_node *map)
return -EINVAL;

+ node_set(nodea, numa_nodes_parsed);

With this, couldn't we remove of_numa_parse_cpu_nodes() as the only
thing it does is node_set()?

I don't think so for couple of reasons:

(1) With problematic device-tree, the distance map node might be missed
or incomplete. In this case, of_numa_parse_cpu_nodes() still helps.

(2) @numa_nodes_parsed is also updated when the memory nodes are iterated
in of_numa_parse_memory_nodes() and numa_add_memblk().

So @numa_nodes_parsed, which is synchronized to @node_possible_map afterwards,
is the gathering output of CPU nodes, memory nodes and distance map node.

numa_set_distance(nodea, nodeb, distance);

/* Set default distance of node B->A same as A->B */