sched: programmable: Add a tag for the task group

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5KUFB
CVE: NA

--------------------------------

Add a tag for the task group, to support the tag-based
scheduling mechanism.

The tag is used to identify a special task or a type of
special tasks, there are many special tasks in the real
world, such as foreground and background tasks, online
and offline tasks, ect. so, we can identify such special
tasks, and execute specific policies.
Signed-off-by: NChen Hui <judy.chenhui@huawei.com>
Signed-off-by: NRen Zhijie <renzhijie2@huawei.com>
Signed-off-by: NHui Tang <tanghui20@huawei.com>

kernel/sched/core.c

@@ -8603,6 +8603,13 @@ static void sched_free_group(struct task_group *tg)
 	kmem_cache_free(task_group_cache, tg);
 }
 
+#ifdef CONFIG_BPF_SCHED
+static inline void tg_init_tag(struct task_group *tg, struct task_group *ptg)
+{
+	tg->tag = ptg->tag;
+}
+#endif
+
 /* allocate runqueue etc for a new task group */
 struct task_group *sched_create_group(struct task_group *parent)
 {
@@ -8623,6 +8630,10 @@ struct task_group *sched_create_group(struct task_group *parent)
 	if (!alloc_rt_sched_group(tg, parent))
 		goto err;
 
+#ifdef CONFIG_BPF_SCHED
+	tg_init_tag(tg, parent);
+#endif
+
 	alloc_uclamp_sched_group(tg, parent);
 
 	return tg;
@@ -8694,6 +8705,14 @@ static void sched_change_group(struct task_struct *tsk, int type)
 	sched_change_qos_group(tsk, tg);
 #endif
 
+#ifdef CONFIG_BPF_SCHED
+	/*
+	 * This function has cleared and restored the task status,
+	 * so we do not need to dequeue and enqueue the task again.
+	 */
+	tsk->tag = tg->tag;
+#endif
+
 #ifdef CONFIG_FAIR_GROUP_SCHED
 	if (tsk->sched_class->task_change_group)
 		tsk->sched_class->task_change_group(tsk, type);

kernel/sched/sched.h

@@ -454,7 +454,12 @@ struct task_group {
 	struct uclamp_se	uclamp[UCLAMP_CNT];
 #endif
 
+#ifdef CONFIG_BPF_SCHED
+	/* Used to pad the tag of a group */
+	KABI_USE(1, long tag)
+#else
 	KABI_RESERVE(1)
+#endif
 	KABI_RESERVE(2)
 	KABI_RESERVE(3)
 	KABI_RESERVE(4)