mm/mm_init.c: do not calculate zone_start_pfn/zone_end_pfn in zone_absent_pages_in_node()

In calculate_node_totalpages(), zone_start_pfn/zone_end_pfn are already
calculated in zone_spanned_pages_in_node(), so use them as parameters
instead of node_start_pfn/node_end_pfn and the duplicated calculation
process can de dropped.

Link: https://lkml.kernel.org/r/20230526085251.1977-2-haifeng.xu@shopee.com
Signed-off-by: Haifeng Xu <haifeng.xu@shopee.com>
Suggested-by: Mike Rapoport <rppt@kernel.org>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Haifeng Xu <haifeng.xu@shopee.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/mm_init.c b/mm/mm_init.c
index 6f7da396b67b5a22c2508d64b6e419c525bc46c9..19652c1b3426a3a37ca951fb8436d1edaba56d6c 100644 (file)
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -1168,20 +1168,15 @@ unsigned long __init absent_pages_in_range(unsigned long start_pfn,
 /* Return the number of page frames in holes in a zone on a node */
 static unsigned long __init zone_absent_pages_in_node(int nid,
                                        unsigned long zone_type,
-                                       unsigned long node_start_pfn,
-                                       unsigned long node_end_pfn)
+                                       unsigned long zone_start_pfn,
+                                       unsigned long zone_end_pfn)
 {
-       unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
-       unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
-       unsigned long zone_start_pfn, zone_end_pfn;
        unsigned long nr_absent;
 
-       zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
-       zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
+       /* zone is empty, we don't have any absent pages */
+       if (zone_start_pfn == zone_end_pfn)
+               return 0;
 
-       adjust_zone_range_for_zone_movable(nid, zone_type,
-                       node_start_pfn, node_end_pfn,
-                       &zone_start_pfn, &zone_end_pfn);
        nr_absent = __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
 
        /*
@@ -1274,7 +1269,7 @@ static void __init calculate_node_totalpages(struct pglist_data *pgdat,
                struct zone *zone = pgdat->node_zones + i;
                unsigned long zone_start_pfn, zone_end_pfn;
                unsigned long spanned, absent;
-               unsigned long size, real_size;
+               unsigned long real_size;
 
                spanned = zone_spanned_pages_in_node(pgdat->node_id, i,
                                                     node_start_pfn,
@@ -1282,23 +1277,22 @@ static void __init calculate_node_totalpages(struct pglist_data *pgdat,
                                                     &zone_start_pfn,
                                                     &zone_end_pfn);
                absent = zone_absent_pages_in_node(pgdat->node_id, i,
-                                                  node_start_pfn,
-                                                  node_end_pfn);
+                                                  zone_start_pfn,
+                                                  zone_end_pfn);
 
-               size = spanned;
-               real_size = size - absent;
+               real_size = spanned - absent;
 
-               if (size)
+               if (spanned)
                        zone->zone_start_pfn = zone_start_pfn;
                else
                        zone->zone_start_pfn = 0;
-               zone->spanned_pages = size;
+               zone->spanned_pages = spanned;
                zone->present_pages = real_size;
 #if defined(CONFIG_MEMORY_HOTPLUG)
                zone->present_early_pages = real_size;
 #endif
 
-               totalpages += size;
+               totalpages += spanned;
                realtotalpages += real_size;
        }