On Mon, Sep 27, 2021 at 6:59 PM Gavin Shan [off-list ref] wrote:

Hi Rob,

On 9/28/21 12:49 AM, Rob Herring wrote:

quoted

On Mon, Sep 27, 2021 at 1:42 AM Gavin Shan [off-list ref] wrote:

quoted

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 :)

quoted

quoted

Signed-off-by: Gavin Shan <redacted>
---
  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.

It's not the kernel's job to validate the DT (if it was, it is doing a
terrible job). I would suggest writing some checks for dtc if we're
worried about correctness. (The schemas don't work too well for cross
node checks.)

(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.

Is it valid to have node id's that are not in the distance map?

Rob

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel