From 9bd23cd65964a168938843b82218754e329d5838 Mon Sep 17 00:00:00 2001
From: David Rientjes <rientjes@google.com>
Date: Mon, 14 Dec 2009 17:58:33 -0800
Subject: [PATCH] --- yaml --- r: 176249 b: refs/heads/master c:
 8fe23e057172223fe2048768a4d87ab7de7477bc h: refs/heads/master i:   176247:
 b59554b176955aae7516652be9f3657aff3431d9 v: v3

---
 [refs]                     |  2 +-
 trunk/include/linux/swap.h |  1 +
 trunk/mm/memory_hotplug.c  |  4 ++++
 trunk/mm/vmscan.c          | 28 ++++++++++++++++++++++------
 4 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/[refs] b/[refs]
index db2597708a55..14c2fbbc9157 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 9b5e5d0fdc91b73bba8cf5e0fbe3521a953e4e4d
+refs/heads/master: 8fe23e057172223fe2048768a4d87ab7de7477bc
diff --git a/trunk/include/linux/swap.h b/trunk/include/linux/swap.h
index 4ec90019c1a4..abce8a0b2507 100644
--- a/trunk/include/linux/swap.h
+++ b/trunk/include/linux/swap.h
@@ -273,6 +273,7 @@ extern int scan_unevictable_register_node(struct node *node);
 extern void scan_unevictable_unregister_node(struct node *node);
 
 extern int kswapd_run(int nid);
+extern void kswapd_stop(int nid);
 
 #ifdef CONFIG_MMU
 /* linux/mm/shmem.c */
diff --git a/trunk/mm/memory_hotplug.c b/trunk/mm/memory_hotplug.c
index e8116f8bdffa..bc5a08138f1e 100644
--- a/trunk/mm/memory_hotplug.c
+++ b/trunk/mm/memory_hotplug.c
@@ -853,6 +853,10 @@ int offline_pages(unsigned long start_pfn,
 
 	setup_per_zone_wmarks();
 	calculate_zone_inactive_ratio(zone);
+	if (!node_present_pages(node)) {
+		node_clear_state(node, N_HIGH_MEMORY);
+		kswapd_stop(node);
+	}
 
 	vm_total_pages = nr_free_pagecache_pages();
 	writeback_set_ratelimit();
diff --git a/trunk/mm/vmscan.c b/trunk/mm/vmscan.c
index 777af57fd8c8..d0a631a428a0 100644
--- a/trunk/mm/vmscan.c
+++ b/trunk/mm/vmscan.c
@@ -2173,6 +2173,7 @@ static int kswapd(void *p)
 	order = 0;
 	for ( ; ; ) {
 		unsigned long new_order;
+		int ret;
 
 		prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE);
 		new_order = pgdat->kswapd_max_order;
@@ -2184,19 +2185,23 @@ static int kswapd(void *p)
 			 */
 			order = new_order;
 		} else {
-			if (!freezing(current))
+			if (!freezing(current) && !kthread_should_stop())
 				schedule();
 
 			order = pgdat->kswapd_max_order;
 		}
 		finish_wait(&pgdat->kswapd_wait, &wait);
 
-		if (!try_to_freeze()) {
-			/* We can speed up thawing tasks if we don't call
-			 * balance_pgdat after returning from the refrigerator
-			 */
+		ret = try_to_freeze();
+		if (kthread_should_stop())
+			break;
+
+		/*
+		 * We can speed up thawing tasks if we don't call balance_pgdat
+		 * after returning from the refrigerator
+		 */
+		if (!ret)
 			balance_pgdat(pgdat, order);
-		}
 	}
 	return 0;
 }
@@ -2451,6 +2456,17 @@ int kswapd_run(int nid)
 	return ret;
 }
 
+/*
+ * Called by memory hotplug when all memory in a node is offlined.
+ */
+void kswapd_stop(int nid)
+{
+	struct task_struct *kswapd = NODE_DATA(nid)->kswapd;
+
+	if (kswapd)
+		kthread_stop(kswapd);
+}
+
 static int __init kswapd_init(void)
 {
 	int nid;