On Mon, May 15, 2017 at 10:58:24AM +0200, Michal Hocko wrote:
>From: Michal Hocko <mhocko@suse.com>
>
[...]
>+void move_pfn_range_to_zone(struct zone *zone,
>+		unsigned long start_pfn, unsigned long nr_pages)
>+{
>+	struct pglist_data *pgdat = zone->zone_pgdat;
>+	int nid = pgdat->node_id;
>+	unsigned long flags;
>+	unsigned long i;

This is an unused variable:

  mm/memory_hotplug.c: In function ‘move_pfn_range_to_zone’:
  mm/memory_hotplug.c:895:16: warning: unused variable ‘i’ [-Wunused-variable]

Do you suggest me to write a patch or you would fix it in your later rework?

>+
>+	if (zone_is_empty(zone))
>+		init_currently_empty_zone(zone, start_pfn, nr_pages);
>+
>+	clear_zone_contiguous(zone);
>+
>+	/* TODO Huh pgdat is irqsave while zone is not. It used to be like that before */
>+	pgdat_resize_lock(pgdat, &flags);
>+	zone_span_writelock(zone);
>+	resize_zone_range(zone, start_pfn, nr_pages);
>+	zone_span_writeunlock(zone);
>+	resize_pgdat_range(pgdat, start_pfn, nr_pages);
>+	pgdat_resize_unlock(pgdat, &flags);
>+
>+	/*
>+	 * TODO now we have a visible range of pages which are not associated
>+	 * with their zone properly. Not nice but set_pfnblock_flags_mask
>+	 * expects the zone spans the pfn range. All the pages in the range
>+	 * are reserved so nobody should be touching them so we should be safe
>+	 */
>+	memmap_init_zone(nr_pages, nid, zone_idx(zone), start_pfn, MEMMAP_HOTPLUG);
>+	for (i = 0; i < nr_pages; i++) {
>+		unsigned long pfn = start_pfn + i;
>+		set_page_links(pfn_to_page(pfn), zone_idx(zone), nid, pfn);
> 	}
> 
>2.11.0

-- 
Wei Yang
Help you, Help me