From: Wen Congyang <wency@cn.fujitsu.com>
Date: Fri, 9 Nov 2012 03:04:03 +0000 (+1100)
Subject: memory-hotplug: allocate zone's pcp before onlining pages
X-Git-Tag: next-20121112~5^2~242
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=fca6d73b53200ed52de69ed0ef8d4b56f9d4feac;p=karo-tx-linux.git

memory-hotplug: allocate zone's pcp before onlining pages

We use __free_page() to put a page to buddy system when onlining pages.
__free_page() will store NR_FREE_PAGES in zone's pcp.vm_stat_diff, so we
should allocate zone's pcp before onlining pages, otherwise we will lose
some free pages.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Jiang Liu <liuj97@gmail.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 72f4fef2b728..5c8ad6dcd18f 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -505,12 +505,16 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages)
 	 * So, zonelist must be updated after online.
 	 */
 	mutex_lock(&zonelists_mutex);
-	if (!populated_zone(zone))
+	if (!populated_zone(zone)) {
 		need_zonelists_rebuild = 1;
+		build_all_zonelists(NULL, zone);
+	}
 
 	ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
 		online_pages_range);
 	if (ret) {
+		if (need_zonelists_rebuild)
+			zone_pcp_reset(zone);
 		mutex_unlock(&zonelists_mutex);
 		printk(KERN_DEBUG "online_pages [mem %#010llx-%#010llx] failed\n",
 		       (unsigned long long) pfn << PAGE_SHIFT,
@@ -525,9 +529,7 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages)
 	zone->zone_pgdat->node_present_pages += onlined_pages;
 	if (onlined_pages) {
 		node_set_state(zone_to_nid(zone), N_HIGH_MEMORY);
-		if (need_zonelists_rebuild)
-			build_all_zonelists(NULL, zone);
-		else
+		if (!need_zonelists_rebuild)
 			zone_pcp_update(zone);
 	}