From: Mel Gorman <mgorman@techsingularity.net>
Date: Thu, 6 Aug 2015 22:46:51 +0000 (-0700)
Subject: mm: initialize hotplugged pages as reserved
X-Git-Tag: v4.2-rc6~15^2~7
X-Git-Url: http://git.cascardo.eti.br/?a=commitdiff_plain;h=e298ff75f133f2524bb6a9a305b17c5f6ff1a6b2;p=cascardo%2Flinux.git

mm: initialize hotplugged pages as reserved

Commit 92923ca3aace ("mm: meminit: only set page reserved in the
memblock region") broke memory hotplug which expects the memmap for
newly added sections to be reserved until onlined by
online_pages_range().  This patch marks hotplugged pages as reserved
when adding new zones.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Reported-by: David Vrabel <david.vrabel@citrix.com>
Tested-by: David Vrabel <david.vrabel@citrix.com>
Cc: Nathan Zimmer <nzimmer@sgi.com>
Cc: Robin Holt <holt@sgi.com>
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 26fbba7d888f..003dbe4b060d 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -446,7 +446,7 @@ static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn)
 	int nr_pages = PAGES_PER_SECTION;
 	int nid = pgdat->node_id;
 	int zone_type;
-	unsigned long flags;
+	unsigned long flags, pfn;
 	int ret;
 
 	zone_type = zone - pgdat->node_zones;
@@ -461,6 +461,14 @@ static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn)
 	pgdat_resize_unlock(zone->zone_pgdat, &flags);
 	memmap_init_zone(nr_pages, nid, zone_type,
 			 phys_start_pfn, MEMMAP_HOTPLUG);
+
+	/* online_page_range is called later and expects pages reserved */
+	for (pfn = phys_start_pfn; pfn < phys_start_pfn + nr_pages; pfn++) {
+		if (!pfn_valid(pfn))
+			continue;
+
+		SetPageReserved(pfn_to_page(pfn));
+	}
 	return 0;
 }