[PATCH 3/4] sched: Export per task_cgroup nr_iowait to userspace

From: Kirill Tkhai
Date: Mon Nov 06 2017 - 09:40:54 EST


Make "stat" file always exist in cpu cgroup directory
(not only in CONFIG_CFS_BANDWIDTH case), and show
task_cgroup's nr_iowait there.

This may be useful for containers to check a statistics
of a single container.

Signed-off-by: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
---
kernel/sched/core.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 86d1ad5f49bd..1b54707f5344 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6665,20 +6665,27 @@ static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota)

return ret;
}
+#endif /* CONFIG_CFS_BANDWIDTH */
+#endif /* CONFIG_FAIR_GROUP_SCHED */

static int cpu_stats_show(struct seq_file *sf, void *v)
{
struct task_group *tg = css_tg(seq_css(sf));
+ int i, nr_iowait = 0;
+#ifdef CONFIG_CFS_BANDWIDTH
struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;

seq_printf(sf, "nr_periods %d\n", cfs_b->nr_periods);
seq_printf(sf, "nr_throttled %d\n", cfs_b->nr_throttled);
seq_printf(sf, "throttled_time %llu\n", cfs_b->throttled_time);
+#endif
+ for_each_possible_cpu(i) {
+ nr_iowait += atomic_read(&tg->stat[i].nr_iowait);
+ }
+ seq_printf(sf, "nr_iowait %d\n", nr_iowait);

return 0;
}
-#endif /* CONFIG_CFS_BANDWIDTH */
-#endif /* CONFIG_FAIR_GROUP_SCHED */

#ifdef CONFIG_RT_GROUP_SCHED
static int cpu_rt_runtime_write(struct cgroup_subsys_state *css,
@@ -6707,6 +6714,10 @@ static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css,
#endif /* CONFIG_RT_GROUP_SCHED */

static struct cftype cpu_files[] = {
+ {
+ .name = "stat",
+ .seq_show = cpu_stats_show,
+ },
#ifdef CONFIG_FAIR_GROUP_SCHED
{
.name = "shares",
@@ -6725,10 +6736,6 @@ static struct cftype cpu_files[] = {
.read_u64 = cpu_cfs_period_read_u64,
.write_u64 = cpu_cfs_period_write_u64,
},
- {
- .name = "stat",
- .seq_show = cpu_stats_show,
- },
#endif
#ifdef CONFIG_RT_GROUP_SCHED
{