[RFC PATCH v1 04/11] mm: Report top tier memory usage in sysfs

[Tim Chen]

In memory cgroup's sysfs, report the memory cgroup's usage
of top tier memory in a new field: "toptier_usage_in_bytes".

Signed-off-by: Tim Chen <tim.c.c...@linux.intel.com>
---
 mm/memcontrol.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index fe7bb8613f5a..68590f46fa76 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3631,6 +3631,7 @@ enum {
        RES_FAILCNT,
        RES_SOFT_LIMIT,
        RES_TOPTIER_SOFT_LIMIT,
+       RES_TOPTIER_USAGE,
 };
 
 static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css,
@@ -3673,6 +3674,8 @@ static u64 mem_cgroup_read_u64(struct cgroup_subsys_state 
*css,
                return (u64)memcg->soft_limit * PAGE_SIZE;
        case RES_TOPTIER_SOFT_LIMIT:
                return (u64)memcg->toptier_soft_limit * PAGE_SIZE;
+       case RES_TOPTIER_USAGE:
+               return (u64)page_counter_read(&memcg->toptier) * PAGE_SIZE;
        default:
                BUG();
        }
@@ -5073,6 +5076,11 @@ static struct cftype mem_cgroup_legacy_files[] = {
                .write = mem_cgroup_write,
                .read_u64 = mem_cgroup_read_u64,
        },
+       {
+               .name = "toptier_usage_in_bytes",
+               .private = MEMFILE_PRIVATE(_MEM, RES_TOPTIER_USAGE),
+               .read_u64 = mem_cgroup_read_u64,
+       },
        {
                .name = "failcnt",
                .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
-- 
2.20.1