Hi Wei Yang,

On 02/05/20 at 05:59pm, Wei Yang wrote:

quoted

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index f294918f7211..8dafa1ba8d9f 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c

@@ -393,6 +393,9 @@ static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,

		if (pfn) {
			zone->zone_start_pfn = pfn;
			zone->spanned_pages = zone_end_pfn - pfn;
+		} else {
+			zone->zone_start_pfn = 0;
+			zone->spanned_pages = 0;
		}
	} else if (zone_end_pfn == end_pfn) {
		/*

@@ -405,34 +408,11 @@ static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,

					       start_pfn);
		if (pfn)
			zone->spanned_pages = pfn - zone_start_pfn + 1;
+		else {
+			zone->zone_start_pfn = 0;
+			zone->spanned_pages = 0;
+		}
	}

If it is me, I would like to take out these two similar logic out.

I also like this style. 

For example:

	if () {
	} else if () {
	} else {
		goto out;

Here the last else is unnecessary, right?

	}

Like this, I believe both David and I will be satisfactory. Even though
I still think his 2nd resetting is not needed :-)

	/* The zone has no valid section */
	if (!pfn) {
			zone->zone_start_pfn = 0;
			zone->spanned_pages = 0;
	}

out:
	zone_span_writeunlock(zone);

Well, this is just my personal taste :-)

quoted

-
-	/*
-	 * The section is not biggest or smallest mem_section in the zone, it
-	 * only creates a hole in the zone. So in this case, we need not
-	 * change the zone. But perhaps, the zone has only hole data. Thus
-	 * it check the zone has only hole or not.
-	 */
-	pfn = zone_start_pfn;
-	for (; pfn < zone_end_pfn; pfn += PAGES_PER_SUBSECTION) {
-		if (unlikely(!pfn_to_online_page(pfn)))
-			continue;
-
-		if (page_zone(pfn_to_page(pfn)) != zone)
-			continue;
-
-		/* Skip range to be removed */
-		if (pfn >= start_pfn && pfn < end_pfn)
-			continue;
-
-		/* If we find valid section, we have nothing to do */
-		zone_span_writeunlock(zone);
-		return;
-	}
-
-	/* The zone has no valid section */
-	zone->zone_start_pfn = 0;
-	zone->spanned_pages = 0;
	zone_span_writeunlock(zone);
}

-- 
2.21.0

-- 
Wei Yang
Help you, Help me