Commit fd5207be authored by Guan Jing's avatar Guan Jing Committed by Zheng Zengkai
Browse files

sched: Implement the function of qos smt expeller 

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I52611


CVE: NA

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

We implement the function of qos smt expeller by this following two points：
a)when online tasks and offline tasks are running on the same physical cpu,
online tasks will send ipi to expel offline tasks on the smt sibling cpus.
b)when online tasks are running, the smt sibling cpus will not allow
offline tasks to be selected.

Signed-off-by: default avatarGuan Jing <guanjing6@huawei.com>
Reviewed-by: default avatarChen Hui <judy.chenhui@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent 4e57e412

include/linux/sched.h

+7 −0
Original line number Diff line number Diff line
@@ -1830,9 +1830,16 @@ extern char *__get_task_comm(char *to, size_t len, struct task_struct *tsk); 
	__get_task_comm(buf, sizeof(buf), tsk);		\

})



#ifdef CONFIG_QOS_SCHED_SMT_EXPELLER

void qos_smt_check_need_resched(void);

#endif



#ifdef CONFIG_SMP

static __always_inline void scheduler_ipi(void)

{

#ifdef CONFIG_QOS_SCHED_SMT_EXPELLER

	qos_smt_check_need_resched();

#endif

	/*

	 * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting

	 * TIF_NEED_RESCHED remotely (for the first time) will also send

kernel/sched/fair.c

+183 −2
Original line number Diff line number Diff line
@@ -130,6 +130,10 @@ unsigned int sysctl_offline_wait_interval = 100; /* in ms */ 
static int unthrottle_qos_cfs_rqs(int cpu);

#endif



#ifdef CONFIG_QOS_SCHED_SMT_EXPELLER

static DEFINE_PER_CPU(int, qos_smt_status);

#endif



#ifdef CONFIG_CFS_BANDWIDTH

/*

 * Amount of runtime to allocate from global (tg) to local (per-cfs_rq) pool
@@ -7381,6 +7385,131 @@ void init_qos_hrtimer(int cpu) 
}

#endif



#ifdef CONFIG_QOS_SCHED_SMT_EXPELLER

static bool qos_smt_check_siblings_status(int this_cpu)

{

	int cpu;



	if (!sched_smt_active())

		return false;



	for_each_cpu(cpu, cpu_smt_mask(this_cpu)) {

		if (cpu == this_cpu)

			continue;



		if (per_cpu(qos_smt_status, cpu) == QOS_LEVEL_ONLINE)

			return true;

	}



	return false;

}



static bool qos_smt_expelled(int this_cpu)

{

	/*

	 * The qos_smt_status of siblings cpu is online, and current cpu only has

	 * offline tasks enqueued, there is not suitable task,

	 * so pick_next_task_fair return null.

	 */

	if (qos_smt_check_siblings_status(this_cpu) && sched_idle_cpu(this_cpu))

		return true;



	return false;

}



static bool qos_smt_update_status(struct task_struct *p)

{

	int status = QOS_LEVEL_OFFLINE;



	if (p != NULL && task_group(p)->qos_level >= QOS_LEVEL_ONLINE)

		status = QOS_LEVEL_ONLINE;



	if (__this_cpu_read(qos_smt_status) == status)

		return false;



	__this_cpu_write(qos_smt_status, status);



	return true;

}



static void qos_smt_send_ipi(int this_cpu)

{

	int cpu;

	struct rq *rq = NULL;



	if (!sched_smt_active())

		return;



	for_each_cpu(cpu, cpu_smt_mask(this_cpu)) {

		if (cpu == this_cpu)

			continue;



		rq = cpu_rq(cpu);



		/*

		* There are two cases where current don't need to send scheduler_ipi:

		* a) The qos_smt_status of siblings cpu is online;

		* b) The cfs.h_nr_running of siblings cpu is 0.

		*/

		if (per_cpu(qos_smt_status, cpu) == QOS_LEVEL_ONLINE ||

		    rq->cfs.h_nr_running == 0)

			continue;



		smp_send_reschedule(cpu);

	}

}



static void qos_smt_expel(int this_cpu, struct task_struct *p)

{

	if (qos_smt_update_status(p))

		qos_smt_send_ipi(this_cpu);

}



static bool _qos_smt_check_need_resched(int this_cpu, struct rq *rq)

{

	int cpu;



	if (!sched_smt_active())

		return false;



	for_each_cpu(cpu, cpu_smt_mask(this_cpu)) {

		if (cpu == this_cpu)

			continue;



		/*

		* There are two cases rely on the set need_resched to drive away

		* offline task：

		* a) The qos_smt_status of siblings cpu is online, the task of current cpu is offline;

		* b) The qos_smt_status of siblings cpu is offline, the task of current cpu is idle,

		*    and current cpu only has SCHED_IDLE tasks enqueued.

		*/

		if (per_cpu(qos_smt_status, cpu) == QOS_LEVEL_ONLINE &&

		    task_group(current)->qos_level < QOS_LEVEL_ONLINE)

			return true;



		if (per_cpu(qos_smt_status, cpu) == QOS_LEVEL_OFFLINE &&

		    rq->curr == rq->idle && sched_idle_cpu(this_cpu))

			return true;

	}



	return false;

}



void qos_smt_check_need_resched(void)

{

	struct rq *rq = this_rq();

	int this_cpu = rq->cpu;



	if (test_tsk_need_resched(current))

		return;



	if (_qos_smt_check_need_resched(this_cpu, rq)) {

		set_tsk_need_resched(current);

		set_preempt_need_resched();

	}

}

#endif



struct task_struct *

pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)

{
@@ -7389,14 +7518,32 @@ pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf 
	struct task_struct *p;

	int new_tasks;

	unsigned long time;

#ifdef CONFIG_QOS_SCHED_SMT_EXPELLER

	int this_cpu = rq->cpu;

#endif



again:

#ifdef CONFIG_QOS_SCHED_SMT_EXPELLER

	if (qos_smt_expelled(this_cpu)) {

		__this_cpu_write(qos_smt_status, QOS_LEVEL_OFFLINE);

		return NULL;

	}

#endif



	if (!sched_fair_runnable(rq))

		goto idle;



#ifdef CONFIG_FAIR_GROUP_SCHED

	if (!prev || prev->sched_class != &fair_sched_class)

	if (!prev || prev->sched_class != &fair_sched_class) {

#ifdef CONFIG_QOS_SCHED

		if (cfs_rq->idle_h_nr_running != 0 && rq->online)

			goto qos_simple;

		else

#endif

			goto simple;

	}







	/*

	 * Because of the set_next_buddy() in dequeue_task_fair() it is rather
@@ -7480,6 +7627,34 @@ pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf 
	}



	goto done;



#ifdef CONFIG_QOS_SCHED

qos_simple:

	if (prev)

		put_prev_task(rq, prev);



	do {

		se = pick_next_entity(cfs_rq, NULL);

		if (check_qos_cfs_rq(group_cfs_rq(se))) {

			cfs_rq = &rq->cfs;

			if (!cfs_rq->nr_running)

				goto idle;

			continue;

		}



		cfs_rq = group_cfs_rq(se);

	} while (cfs_rq);



	p = task_of(se);



	while (se) {

		set_next_entity(cfs_rq_of(se), se);

		se = parent_entity(se);

	}



	goto done;

#endif



simple:

#endif

	if (prev)
@@ -7508,6 +7683,9 @@ done: __maybe_unused; 


	update_misfit_status(p, rq);



#ifdef CONFIG_QOS_SCHED_SMT_EXPELLER

	qos_smt_expel(this_cpu, p);

#endif

	return p;



idle:
@@ -7556,6 +7734,9 @@ done: __maybe_unused; 
	 */

	update_idle_rq_clock_pelt(rq);



#ifdef CONFIG_QOS_SCHED_SMT_EXPELLER

	qos_smt_expel(this_cpu, NULL);

#endif

	return NULL;

}

kernel/sched/sched.h

+5 −0
Original line number Diff line number Diff line
@@ -1136,6 +1136,11 @@ static inline int cpu_of(struct rq *rq) 
}



#ifdef CONFIG_QOS_SCHED

enum task_qos_level {

	QOS_LEVEL_OFFLINE = -1,

	QOS_LEVEL_ONLINE = 0,

	QOS_LEVEL_MAX

};

void init_qos_hrtimer(int cpu);

#endif