[PATCH RFC 4/4] drivers/base/node: add demote_src and demote_dst to numastat

[Li Zhijian]

node0 and node1 is DRAM node, node3 is a PMEM node.

$ cat /sys/devices/system/node/node1/numastat
numa_hit 646590
numa_miss 3963
numa_foreign 30651
interleave_hit 416
local_node 645252
other_node 5301
demote_src 200478
demote_dst 0

Of cousre, the userspace numastat will be extened to support these 2
new fields in the future like:
$ numastat
                           node0           node1           node3
numa_hit                  741793          702460          364154
numa_miss                   1759            8104           28893
numa_foreign                8105           30651               0
interleave_hit               653             416               0
local_node                741762          701115               0
other_node                  1790            9449          393047
demote_src                163612          203828               0
demote_dst                     0               0          367440

Signed-off-by: Li Zhijian <lizhijian@xxxxxxxxxxx>
---
 drivers/base/node.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/base/node.c b/drivers/base/node.c
index 27e8502548a7..d3fc70599b6a 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -496,20 +496,32 @@ static DEVICE_ATTR(meminfo, 0444, node_read_meminfo, NULL);
 static ssize_t node_read_numastat(struct device *dev,
 				  struct device_attribute *attr, char *buf)
 {
+	struct pglist_data *pgdat = NODE_DATA(dev->id);
+	unsigned long demote_src, demote_dst;
+
 	fold_vm_numa_events();
+	demote_src = node_page_state_pages(pgdat, PGDEMOTE_SRC_KSWAPD) +
+		     node_page_state_pages(pgdat, PGDEMOTE_SRC_DIRECT) +
+		     node_page_state_pages(pgdat, PGDEMOTE_SRC_KHUGEPAGED);
+	demote_dst = node_page_state_pages(pgdat, PGDEMOTE_DST_KSWAPD) +
+		     node_page_state_pages(pgdat, PGDEMOTE_DST_DIRECT) +
+		     node_page_state_pages(pgdat, PGDEMOTE_DST_KHUGEPAGED);
 	return sysfs_emit(buf,
 			  "numa_hit %lu\n"
 			  "numa_miss %lu\n"
 			  "numa_foreign %lu\n"
 			  "interleave_hit %lu\n"
 			  "local_node %lu\n"
-			  "other_node %lu\n",
+			  "other_node %lu\n"
+			  "demote_src %lu\n"
+			  "demote_dst %lu\n",
 			  sum_zone_numa_event_state(dev->id, NUMA_HIT),
 			  sum_zone_numa_event_state(dev->id, NUMA_MISS),
 			  sum_zone_numa_event_state(dev->id, NUMA_FOREIGN),
 			  sum_zone_numa_event_state(dev->id, NUMA_INTERLEAVE_HIT),
 			  sum_zone_numa_event_state(dev->id, NUMA_LOCAL),
-			  sum_zone_numa_event_state(dev->id, NUMA_OTHER));
+			  sum_zone_numa_event_state(dev->id, NUMA_OTHER),
+			  demote_src, demote_dst);
 }
 static DEVICE_ATTR(numastat, 0444, node_read_numastat, NULL);
 
-- 
2.29.2