[RFC PATCH v6 16/25] sched/rt: Remove support for cgroups-v1

From: Yuri Andriaccio

Date: Mon Jun 08 2026 - 08:20:40 EST


Disable control files for cgroups-v1.

Remove cpu_rt_group_init function and functions related to the
cgroup-v1 control files 'rt_runtime_us' and 'rt_period_us'.

Signed-off-by: Yuri Andriaccio <yurand2000@xxxxxxxxx>
---
kernel/sched/core.c | 50 --------------------------------------------
kernel/sched/rt.c | 49 +------------------------------------------
kernel/sched/sched.h | 4 ----
3 files changed, 1 insertion(+), 102 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 1252f45feda0..a8a81c69b3d3 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -10150,32 +10150,6 @@ static int cpu_burst_write_u64(struct cgroup_subsys_state *css,
}
#endif /* CONFIG_GROUP_SCHED_BANDWIDTH */

-#ifdef CONFIG_RT_GROUP_SCHED
-static int cpu_rt_runtime_write(struct cgroup_subsys_state *css,
- struct cftype *cft, s64 val)
-{
- return sched_group_set_rt_runtime(css_tg(css), val);
-}
-
-static s64 cpu_rt_runtime_read(struct cgroup_subsys_state *css,
- struct cftype *cft)
-{
- return sched_group_rt_runtime(css_tg(css));
-}
-
-static int cpu_rt_period_write_uint(struct cgroup_subsys_state *css,
- struct cftype *cftype, u64 rt_period_us)
-{
- return sched_group_set_rt_period(css_tg(css), rt_period_us);
-}
-
-static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css,
- struct cftype *cft)
-{
- return sched_group_rt_period(css_tg(css));
-}
-#endif /* CONFIG_RT_GROUP_SCHED */
-
#ifdef CONFIG_GROUP_SCHED_WEIGHT
static s64 cpu_idle_read_s64(struct cgroup_subsys_state *css,
struct cftype *cft)
@@ -10253,20 +10227,6 @@ static struct cftype cpu_legacy_files[] = {
};

#ifdef CONFIG_RT_GROUP_SCHED
-static struct cftype rt_group_files[] = {
- {
- .name = "rt_runtime_us",
- .read_s64 = cpu_rt_runtime_read,
- .write_s64 = cpu_rt_runtime_write,
- },
- {
- .name = "rt_period_us",
- .read_u64 = cpu_rt_period_read_uint,
- .write_u64 = cpu_rt_period_write_uint,
- },
- { } /* Terminate */
-};
-
# ifdef CONFIG_RT_GROUP_SCHED_DEFAULT_DISABLED
DEFINE_STATIC_KEY_FALSE(rt_group_sched);
# else
@@ -10289,16 +10249,6 @@ static int __init setup_rt_group_sched(char *str)
return 1;
}
__setup("rt_group_sched=", setup_rt_group_sched);
-
-static int __init cpu_rt_group_init(void)
-{
- if (!rt_group_sched_enabled())
- return 0;
-
- WARN_ON(cgroup_add_legacy_cftypes(&cpu_cgrp_subsys, rt_group_files));
- return 0;
-}
-subsys_initcall(cpu_rt_group_init);
#endif /* CONFIG_RT_GROUP_SCHED */

static int cpu_extra_stat_show(struct seq_file *sf,
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 168a92945b4a..4f1e7af2e88d 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1,3 +1,4 @@
+#pragma GCC diagnostic ignored "-Wunused-function"
// SPDX-License-Identifier: GPL-2.0
/*
* Real-Time Scheduling Class (mapped to the SCHED_FIFO and SCHED_RR
@@ -2258,54 +2259,6 @@ static int tg_set_rt_bandwidth(struct task_group *tg,
return err;
}

-int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
-{
- u64 rt_runtime, rt_period;
-
- rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
- rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
- if (rt_runtime_us < 0)
- rt_runtime = RUNTIME_INF;
- else if ((u64)rt_runtime_us > U64_MAX / NSEC_PER_USEC)
- return -EINVAL;
-
- return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
-}
-
-long sched_group_rt_runtime(struct task_group *tg)
-{
- u64 rt_runtime_us;
-
- if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
- return -1;
-
- rt_runtime_us = tg->rt_bandwidth.rt_runtime;
- do_div(rt_runtime_us, NSEC_PER_USEC);
- return rt_runtime_us;
-}
-
-int sched_group_set_rt_period(struct task_group *tg, u64 rt_period_us)
-{
- u64 rt_runtime, rt_period;
-
- if (rt_period_us > U64_MAX / NSEC_PER_USEC)
- return -EINVAL;
-
- rt_period = rt_period_us * NSEC_PER_USEC;
- rt_runtime = tg->rt_bandwidth.rt_runtime;
-
- return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
-}
-
-long sched_group_rt_period(struct task_group *tg)
-{
- u64 rt_period_us;
-
- rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
- do_div(rt_period_us, NSEC_PER_USEC);
- return rt_period_us;
-}
-
int sched_rt_can_attach(struct task_group *tg)
{
/* Don't accept real-time tasks when there is no way for them to run */
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index bde49f216081..efe52e162ba5 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -607,10 +607,6 @@ extern void start_cfs_bandwidth(struct cfs_bandwidth *cfs_b);
extern void unthrottle_cfs_rq(struct cfs_rq *cfs_rq);
extern bool cfs_task_bw_constrained(struct task_struct *p);

-extern int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us);
-extern int sched_group_set_rt_period(struct task_group *tg, u64 rt_period_us);
-extern long sched_group_rt_runtime(struct task_group *tg);
-extern long sched_group_rt_period(struct task_group *tg);
extern int sched_rt_can_attach(struct task_group *tg);

extern struct task_group *sched_create_group(struct task_group *parent);
--
2.54.0