sched: Introduce CONFIG_GROUP_SCHED_WEIGHT

sched_ext will soon add cgroup cpu.weigh support. The cgroup interface code
is currently gated behind CONFIG_FAIR_GROUP_SCHED. As the fair class and/or
SCX may implement the feature, put the interface code behind the new
CONFIG_CGROUP_SCHED_WEIGHT which is selected by CONFIG_FAIR_GROUP_SCHED.
This allows either sched class to enable the itnerface code without ading
more complex CONFIG tests.

When !CONFIG_FAIR_GROUP_SCHED, a dummy version of sched_group_set_shares()
is added to support later CONFIG_CGROUP_SCHED_WEIGHT &&
!CONFIG_FAIR_GROUP_SCHED builds.

No functional changes.

Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/init/Kconfig b/init/Kconfig
index a465ea9525bd590c2b60dd4a4a08c90015bf17f5..84332d3594d0d1d26acd0a75b4baecc7a4f358f9 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1024,9 +1024,13 @@ menuconfig CGROUP_SCHED
          tasks.
 
 if CGROUP_SCHED
+config GROUP_SCHED_WEIGHT
+       def_bool n
+
 config FAIR_GROUP_SCHED
        bool "Group scheduling for SCHED_OTHER"
        depends on CGROUP_SCHED
+       select GROUP_SCHED_WEIGHT
        default CGROUP_SCHED
 
 config CFS_BANDWIDTH

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 362918de593f50d3a31d254f92efcedae7982726..d302115b1522e04e6bd863a81ecccc8227c447af 100644 (file)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -9193,7 +9193,7 @@ static int cpu_uclamp_max_show(struct seq_file *sf, void *v)
 }
 #endif /* CONFIG_UCLAMP_TASK_GROUP */
 
-#ifdef CONFIG_FAIR_GROUP_SCHED
+#ifdef CONFIG_GROUP_SCHED_WEIGHT
 static unsigned long tg_weight(struct task_group *tg)
 {
        return scale_load_down(tg->shares);
@@ -9212,6 +9212,7 @@ static u64 cpu_shares_read_u64(struct cgroup_subsys_state *css,
 {
        return tg_weight(css_tg(css));
 }
+#endif /* CONFIG_GROUP_SCHED_WEIGHT */
 
 #ifdef CONFIG_CFS_BANDWIDTH
 static DEFINE_MUTEX(cfs_constraints_mutex);
@@ -9557,7 +9558,6 @@ static int cpu_cfs_local_stat_show(struct seq_file *sf, void *v)
        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,
@@ -9585,7 +9585,7 @@ static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css,
 }
 #endif /* CONFIG_RT_GROUP_SCHED */
 
-#ifdef CONFIG_FAIR_GROUP_SCHED
+#ifdef CONFIG_GROUP_SCHED_WEIGHT
 static s64 cpu_idle_read_s64(struct cgroup_subsys_state *css,
                               struct cftype *cft)
 {
@@ -9600,7 +9600,7 @@ static int cpu_idle_write_s64(struct cgroup_subsys_state *css,
 #endif
 
 static struct cftype cpu_legacy_files[] = {
-#ifdef CONFIG_FAIR_GROUP_SCHED
+#ifdef CONFIG_GROUP_SCHED_WEIGHT
        {
                .name = "shares",
                .read_u64 = cpu_shares_read_u64,
@@ -9710,7 +9710,7 @@ static int cpu_local_stat_show(struct seq_file *sf,
        return 0;
 }
 
-#ifdef CONFIG_FAIR_GROUP_SCHED
+#ifdef CONFIG_GROUP_SCHED_WEIGHT
 
 static u64 cpu_weight_read_u64(struct cgroup_subsys_state *css,
                               struct cftype *cft)
@@ -9764,7 +9764,7 @@ static int cpu_weight_nice_write_s64(struct cgroup_subsys_state *css,
 
        return sched_group_set_shares(css_tg(css), scale_load(weight));
 }
-#endif
+#endif /* CONFIG_GROUP_SCHED_WEIGHT */
 
 static void __maybe_unused cpu_period_quota_print(struct seq_file *sf,
                                                  long period, long quota)
@@ -9824,7 +9824,7 @@ static ssize_t cpu_max_write(struct kernfs_open_file *of,
 #endif
 
 static struct cftype cpu_files[] = {
-#ifdef CONFIG_FAIR_GROUP_SCHED
+#ifdef CONFIG_GROUP_SCHED_WEIGHT
        {
                .name = "weight",
                .flags = CFTYPE_NOT_ON_ROOT,

diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index b052ce72cdcdd1a9868b4a93a18eeaf1c17d81c8..0163f4af1c6ef92cbb5c93b5eca5125f6340386a 100644 (file)
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -483,7 +483,7 @@ struct task_group {
 
 };
 
-#ifdef CONFIG_FAIR_GROUP_SCHED
+#ifdef CONFIG_GROUP_SCHED_WEIGHT
 #define ROOT_TASK_GROUP_LOAD   NICE_0_LOAD
 
 /*
@@ -575,6 +575,8 @@ extern void set_task_rq_fair(struct sched_entity *se,
 static inline void set_task_rq_fair(struct sched_entity *se,
                             struct cfs_rq *prev, struct cfs_rq *next) { }
 #endif /* CONFIG_SMP */
+#else /* !CONFIG_FAIR_GROUP_SCHED */
+static inline int sched_group_set_shares(struct task_group *tg, unsigned long shares) { return 0; }
 #endif /* CONFIG_FAIR_GROUP_SCHED */
 
 #else /* CONFIG_CGROUP_SCHED */