linux-kernel - [PART4 Patch v2 2/2] memory_hotplug: allow online/offline memory to result movable node

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Date:	Fri, 16 Nov 2012 19:58:10 +0800
From:	Wen Congyang <wency@...fujitsu.com>
To:	linux-kernel@...r.kernel.org, linux-mm@...ck.org
Cc:	Rob Landley <rob@...dley.net>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>,
	Lai Jiangshan <laijs@...fujitsu.com>,
	Jiang Liu <jiang.liu@...wei.com>,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	Minchan Kim <minchan.kim@...il.com>,
	Mel Gorman <mgorman@...e.de>,
	David Rientjes <rientjes@...gle.com>,
	Yinghai Lu <yinghai@...nel.org>,
	Rusty Russell <rusty@...tcorp.com.au>,
	Wen Congyang <wency@...fujitsu.com>
Subject: [PART4 Patch v2 2/2] memory_hotplug: allow online/offline memory to result movable node

From: Lai Jiangshan <laijs@...fujitsu.com>

Now, memory management can handle movable node or nodes which don't have
any normal memory, so we can dynamic configure and add movable node by:
	online a ZONE_MOVABLE memory from a previous offline node
	offline the last normal memory which result a non-normal-memory-node

movable-node is very important for power-saving,
hardware partitioning and high-available-system(hardware fault management).

Signed-off-by: Lai Jiangshan <laijs@...fujitsu.com>
Tested-by: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
Signed-off-by: Wen Congyang <wency@...fujitsu.com>
---
 mm/memory_hotplug.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index d07c66f..4aceb03 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -589,11 +589,19 @@ static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
 	return 0;
 }
 
+#ifdef CONFIG_MOVABLE_NODE
+/* when CONFIG_MOVABLE_NODE, we allow online node don't have normal memory */
+static bool can_online_high_movable(struct zone *zone)
+{
+	return true;
+}
+#else /* #ifdef CONFIG_MOVABLE_NODE */
 /* ensure every online node has NORMAL memory */
 static bool can_online_high_movable(struct zone *zone)
 {
 	return node_state(zone_to_nid(zone), N_NORMAL_MEMORY);
 }
+#endif /* #ifdef CONFIG_MOVABLE_NODE */
 
 /* check which state of node_states will be changed when online memory */
 static void node_states_check_changes_online(unsigned long nr_pages,
@@ -1097,6 +1105,13 @@ check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
 	return offlined;
 }
 
+#ifdef CONFIG_MOVABLE_NODE
+/* when CONFIG_MOVABLE_NODE, we allow online node don't have normal memory */
+static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
+{
+	return true;
+}
+#else /* #ifdef CONFIG_MOVABLE_NODE */
 /* ensure the node has NORMAL memory if it is still online */
 static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
 {
@@ -1120,6 +1135,7 @@ static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
 	 */
 	return present_pages == 0;
 }
+#endif /* #ifdef CONFIG_MOVABLE_NODE */
 
 /* check which state of node_states will be changed when offline memory */
 static void node_states_check_changes_offline(unsigned long nr_pages,
-- 
1.8.0

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