Add a new cgroup file memory.nomlock to control the behavior of mlock.
This is a preparation of the followup patch.
0: Disable nomlock
1: Enable nomlock
Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
---
include/linux/memcontrol.h | 3 +++
mm/memcontrol.c | 35 +++++++++++++++++++++++++++++++++++
2 files changed, 38 insertions(+)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index b28180269e75..b3a4e28ae0f9 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -220,6 +220,9 @@ struct mem_cgroup {
*/
bool oom_group;
+ /* Folios won't be mlocked in this memcg. */
+ bool nomlock;
+
int swappiness;
/* memory.events and memory.events.local */
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 7b3503d12aaf..08bb65c1612f 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4374,6 +4374,35 @@ static ssize_t memory_reclaim(struct kernfs_open_file *of, char *buf,
return nbytes;
}
+static int memory_nomlock_show(struct seq_file *m, void *v)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
+
+ seq_printf(m, "%d\n", READ_ONCE(memcg->nomlock));
+ return 0;
+}
+
+static ssize_t memory_nomlock_write(struct kernfs_open_file *of,
+ char *buf, size_t nbytes, loff_t off)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
+ int ret, nomlock;
+
+ buf = strstrip(buf);
+ if (!buf)
+ return -EINVAL;
+
+ ret = kstrtoint(buf, 0, &nomlock);
+ if (ret)
+ return ret;
+
+ if (nomlock != 0 && nomlock != 1)
+ return -EINVAL;
+
+ WRITE_ONCE(memcg->nomlock, nomlock);
+ return nbytes;
+}
+
static struct cftype memory_files[] = {
{
.name = "current",
@@ -4445,6 +4474,12 @@ static struct cftype memory_files[] = {
.flags = CFTYPE_NS_DELEGATABLE,
.write = memory_reclaim,
},
+ {
+ .name = "nomlock",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .seq_show = memory_nomlock_show,
+ .write = memory_nomlock_write,
+ },
{ } /* terminate */
};
--
2.43.5
