mm,memory_hotplug: factor out adjusting present pages into adjust_present_page_count()

Let's have a single place (inspired by adjust_managed_page_count())
where we adjust present pages.

In contrast to adjust_managed_page_count(), only memory onlining or
offlining is allowed to modify the number of present pages.

Link: https://lkml.kernel.org/r/20210421102701.25051-4-osalvador@suse.de
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index b8467fa..04f01fa 100644 (file)
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -829,6 +829,16 @@ struct zone * zone_for_pfn_range(int online_type, int nid, unsigned start_pfn,
        return default_zone_for_pfn(nid, start_pfn, nr_pages);
 }
 
+static void adjust_present_page_count(struct zone *zone, long nr_pages)
+{
+       unsigned long flags;
+
+       zone->present_pages += nr_pages;
+       pgdat_resize_lock(zone->zone_pgdat, &flags);
+       zone->zone_pgdat->node_present_pages += nr_pages;
+       pgdat_resize_unlock(zone->zone_pgdat, &flags);
+}
+
 int __ref online_pages(unsigned long pfn, unsigned long nr_pages,
                       int online_type, int nid)
 {
@@ -884,11 +894,7 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages,
        }
 
        online_pages_range(pfn, nr_pages);
-       zone->present_pages += nr_pages;
-
-       pgdat_resize_lock(zone->zone_pgdat, &flags);
-       zone->zone_pgdat->node_present_pages += nr_pages;
-       pgdat_resize_unlock(zone->zone_pgdat, &flags);
+       adjust_present_page_count(zone, nr_pages);
 
        node_states_set_node(nid, &arg);
        if (need_zonelists_rebuild)
@@ -1706,11 +1712,7 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages)
 
        /* removal success */
        adjust_managed_page_count(pfn_to_page(start_pfn), -nr_pages);
-       zone->present_pages -= nr_pages;
-
-       pgdat_resize_lock(zone->zone_pgdat, &flags);
-       zone->zone_pgdat->node_present_pages -= nr_pages;
-       pgdat_resize_unlock(zone->zone_pgdat, &flags);
+       adjust_present_page_count(zone, -nr_pages);
 
        init_per_zone_wmark_min();