On 12.02.21 11:11, Michal Hocko wrote:

On Fri 12-02-21 10:56:19, David Hildenbrand wrote:

quoted

On 12.02.21 10:55, David Hildenbrand wrote:

quoted

On 08.02.21 12:08, Mike Rapoport wrote:

[...]

quoted

quoted

quoted

@@ -6519,8 +6581,19 @@ void __init get_pfn_range_for_nid(unsigned int nid,
    		*end_pfn = max(*end_pfn, this_end_pfn);
    	}
-	if (*start_pfn == -1UL)
+	if (*start_pfn == -1UL) {
    		*start_pfn = 0;
+		return;
+	}
+
+#ifdef CONFIG_SPARSEMEM
+	/*
+	 * Sections in the memory map may not match actual populated
+	 * memory, extend the node span to cover the entire section.
+	 */
+	*start_pfn = round_down(*start_pfn, PAGES_PER_SECTION);
+	*end_pfn = round_up(*end_pfn, PAGES_PER_SECTION);

Does that mean that we might create overlapping zones when one node

s/overlapping zones/overlapping nodes/

I didn't get to review the patch yet. Just wanted to note that we can
interleave nodes/zone. Or what kind of concern do you have in mind?

I know that we can have it after boot, when hotplugging memory. How 
about during boot?

For example, which node will a PFN then actually be assigned to?

I was just wondering if this might result in issues - if that can 
already happen, then it's just fine I guess.

-- 
Thanks,

David / dhildenb