Re: [PATCH 2/6] mm: handle uninitialized numa nodes gracefully

[Andrew Morton <akpm@linux-foundation.org>]

On Thu, 3 Feb 2022 09:39:32 +0100 Michal Hocko <mhocko@suse.com> wrote:

> > I shuffled the words a bit, maybe this sounds better not only to me :)
> > 
> > /*
> >  * We do not want to confuse userspace by sysfs files/directories for node
> >  * without any memory attached to it, so this node is not marked as
> >  * N_MEMORY and not marked online so that topology_init() won't create
> >  * sysfs hierarchy for this node.  The pgdat will get fully initialized by
> >  * hotadd_init_pgdat() when memory is hotpluged into this node
> >  */
> 
> Yes, I like this comment more than mine. Andrew could you replace it in
> your tree or should I repost the patch?

I did this.

--- a/mm/page_alloc.c~mm-handle-uninitialized-numa-nodes-gracefully-fix
+++ a/mm/page_alloc.c
@@ -8155,12 +8155,16 @@ void __init free_area_init(unsigned long
 			}
 			arch_refresh_nodedata(nid, pgdat);
 			free_area_init_memoryless_node(nid);
+
 			/*
-			 * not marking this node online because we do not want to
-			 * confuse userspace by sysfs files/directories for node
-			 * without any memory attached to it (see topology_init)
-			 * The pgdat will get fully initialized when a memory is
-			 * hotpluged into it by hotadd_init_pgdat
+			 * We do not want to confuse userspace by sysfs
+			 * files/directories for node without any memory
+			 * attached to it, so this node is not marked as
+			 * N_MEMORY and not marked online so that no sysfs
+			 * hierarchy will be created via register_one_node for
+			 * it. The pgdat will get fully initialized by
+			 * hotadd_init_pgdat() when memory is hotplugged into
+			 * this node.
 			 */
 			continue;
 		}
_