[RFC PATCH 3/3] mm/memory-tiers: Show toptier memory usage for cgroup

[Tim Chen <tim.c.chen@linux.intel.com>]

Show toptier memory usage for a cgroup via sysfs:

/sys/fs/cgroup/<group>/memory.toptier
---
 mm/memcontrol.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 2f20ec2712b8..5fd1e3b686cd 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -6205,6 +6205,14 @@ static u64 memory_current_read(struct cgroup_subsys_state *css,
 	return (u64)page_counter_read(&memcg->memory) * PAGE_SIZE;
 }
 
+static u64 memory_toptier_read(struct cgroup_subsys_state *css,
+			       struct cftype *cft)
+{
+	struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+
+	return (u64)mem_cgroup_toptier_usage(memcg) * PAGE_SIZE;
+}
+
 static u64 memory_peak_read(struct cgroup_subsys_state *css,
 			    struct cftype *cft)
 {
@@ -6516,6 +6524,11 @@ static struct cftype memory_files[] = {
 		.flags = CFTYPE_NOT_ON_ROOT,
 		.read_u64 = memory_current_read,
 	},
+	{
+		.name = "toptier",
+		.flags = CFTYPE_NOT_ON_ROOT,
+		.read_u64 = memory_toptier_read,
+	},
 	{
 		.name = "peak",
 		.flags = CFTYPE_NOT_ON_ROOT,
-- 
2.35.1