sched: Introduce qos scheduler for co-location

hulk inclusion
category: feature
bugzilla: 51828, https://gitee.com/openeuler/kernel/issues/I4K96G


CVE: NA

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

We introduce the idea of qos level to scheduler, which now is
supported with different scheduler policies. The qos scheduler
will change the policy of correlative tasks when the qos level
of a task group is modified with cpu.qos_level cpu cgroup file.
In this way we are able to satisfy different needs of tasks in
different qos levels.

Signed-off-by: Zhang Qiao <zhangqiao22@huawei.com>
Signed-off-by: Zheng Zucheng <zhengzucheng@huawei.com>
Reviewed-by: Chen Hui <judy.chenhui@huawei.com>
Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>

init/Kconfig

@@ -777,6 +777,14 @@ menuconfig CGROUP_SCHED
 	  tasks.
 
 if CGROUP_SCHED
+config QOS_SCHED
+    bool "Qos task scheduling"
+    depends on CGROUP_SCHED
+    depends on CFS_BANDWIDTH
+    depends on X86
+
+    default n
+
 config FAIR_GROUP_SCHED
 	bool "Group scheduling for SCHED_OTHER"
 	depends on CGROUP_SCHED

kernel/sched/core.c

@@ -6338,6 +6338,15 @@ void ia64_set_curr_task(int cpu, struct task_struct *p)
 /* task_group_lock serializes the addition/removal of task groups */
 static DEFINE_SPINLOCK(task_group_lock);
 
+#ifdef CONFIG_QOS_SCHED
+static int alloc_qos_sched_group(struct task_group *tg, struct task_group *parent)
+{
+	tg->qos_level = parent->qos_level;
+
+	return 1;
+}
+#endif
+
 static void sched_free_group(struct task_group *tg)
 {
 	free_fair_sched_group(tg);
@@ -6358,6 +6367,11 @@ struct task_group *sched_create_group(struct task_group *parent)
 	if (!alloc_fair_sched_group(tg, parent))
 		goto err;
 
+#ifdef CONFIG_QOS_SCHED
+	if (!alloc_qos_sched_group(tg, parent))
+		goto err;
+#endif
+
 	if (!alloc_rt_sched_group(tg, parent))
 		goto err;
 
@@ -6426,6 +6440,30 @@ static void sched_change_group(struct task_struct *tsk, int type)
 	tg = autogroup_task_group(tsk, tg);
 	tsk->sched_task_group = tg;
 
+#ifdef CONFIG_QOS_SCHED
+	/*
+	 * No need to re-setcheduler when a task is exiting or the task
+	 * is in an autogroup.
+	 */
+	if (!rt_task(tsk)
+	    && !(tsk->flags & PF_EXITING)
+	    && !task_group_is_autogroup(tg)) {
+		struct rq *rq = task_rq(tsk);
+		struct sched_attr attr = {
+			.sched_priority = 0,
+		};
+
+		if (tg->qos_level == -1) {
+			attr.sched_policy = SCHED_IDLE;
+		} else {
+			attr.sched_policy = SCHED_NORMAL;
+		}
+		attr.sched_nice = PRIO_TO_NICE(tsk->static_prio);
+
+		__setscheduler(rq, tsk, &attr, 0);
+	}
+#endif
+
 #ifdef CONFIG_FAIR_GROUP_SCHED
 	if (tsk->sched_class->task_change_group)
 		tsk->sched_class->task_change_group(tsk, type);
@@ -6886,6 +6924,54 @@ static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css,
 }
 #endif /* CONFIG_RT_GROUP_SCHED */
 
+#ifdef CONFIG_QOS_SCHED
+static int cpu_qos_write(struct cgroup_subsys_state *css,
+			struct cftype *cftype, s64 qos_level)
+{
+	struct css_task_iter it;
+	struct task_struct *tsk;
+	struct task_group *tg;
+	struct sched_param param;
+	int pid, policy;
+	tg = css_tg(css);
+
+	if (!tg->se[0])
+		return -EINVAL;
+
+	if (qos_level != -1 && qos_level != 0)
+		return -EINVAL;
+
+	if (tg->qos_level == qos_level)
+		goto done;
+
+	if (qos_level == -1) {
+		policy = SCHED_IDLE;
+	} else {
+		policy = SCHED_NORMAL;
+	}
+
+	tg->qos_level = qos_level;
+
+	param.sched_priority = 0;
+	css_task_iter_start(css, 0, &it);
+	while ((tsk = css_task_iter_next(&it))) {
+		pid = task_tgid_vnr(tsk);
+
+		if (pid > 0 && !rt_task(tsk))
+			sched_setscheduler(tsk, policy, &param);
+	}
+	css_task_iter_end(&it);
+
+done:
+	return 0;
+}
+
+static s64 cpu_qos_read(struct cgroup_subsys_state *css, struct cftype *cft)
+{
+	return css_tg(css)->qos_level;
+}
+#endif /* CONFIG_QOS_SCHED */
+
 static struct cftype cpu_legacy_files[] = {
 #ifdef CONFIG_FAIR_GROUP_SCHED
 	{
@@ -6921,6 +7007,13 @@ static struct cftype cpu_legacy_files[] = {
 		.read_u64 = cpu_rt_period_read_uint,
 		.write_u64 = cpu_rt_period_write_uint,
 	},
+#endif
+#ifdef CONFIG_QOS_SCHED
+	{
+		.name = "qos_level",
+		.read_s64 = cpu_qos_read,
+		.write_s64 = cpu_qos_write,
+	},
 #endif
 	{ }	/* Terminate */
 };

kernel/sched/sched.h

@@ -402,7 +402,11 @@ struct task_group {
 
 	struct cfs_bandwidth	cfs_bandwidth;
 
+#if defined(CONFIG_QOS_SCHED) && !defined(__GENKSYMS__)
+	long qos_level;
+#else
 	KABI_RESERVE(1)
+#endif
 	KABI_RESERVE(2)
 };