vmscan: unevictable LRU scan sysctl

This patch adds a function to scan individual or all zones' unevictable
lists and move any pages that have become evictable onto the respective
zone's inactive list, where shrink_inactive_list() will deal with them.

Adds sysctl to scan all nodes, and per node attributes to individual
nodes' zones.

Kosaki: If evictable page found in unevictable lru when write
/proc/sys/vm/scan_unevictable_pages, print filename and file offset of
these pages.

[[email protected]: fix one CONFIG_MMU=n build error]
[[email protected]: adapt vmscan-unevictable-lru-scan-sysctl.patch to new sysfs API]
Signed-off-by: Lee Schermerhorn <[email protected]>
Signed-off-by: Rik van Riel <[email protected]>
Signed-off-by: KOSAKI Motohiro <[email protected]>
Signed-off-by: KOSAKI Motohiro <[email protected]>
Signed-off-by: Hugh Dickins <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/base/node.c b/drivers/base/node.c
index fb45d88a2446..f5207090885a 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -13,6 +13,7 @@
 #include <linux/nodemask.h>
 #include <linux/cpu.h>
 #include <linux/device.h>
+#include <linux/swap.h>
 
 static struct sysdev_class node_class = {
 	.name = "node",
@@ -191,6 +192,8 @@ int register_node(struct node *node, int num, struct node *parent)
 		sysdev_create_file(&node->sysdev, &attr_meminfo);
 		sysdev_create_file(&node->sysdev, &attr_numastat);
 		sysdev_create_file(&node->sysdev, &attr_distance);
+
+		scan_unevictable_register_node(node);
 	}
 	return error;
 }
@@ -210,6 +213,8 @@ void unregister_node(struct node *node)
 	sysdev_remove_file(&node->sysdev, &attr_numastat);
 	sysdev_remove_file(&node->sysdev, &attr_distance);
 
+	scan_unevictable_unregister_node(node);
+
 	sysdev_unregister(&node->sysdev);
 }