Commit f3a5ae44 authored by Steve Sistare's avatar Steve Sistare Committed by Cheng Jian
Browse files

sched/fair: Dynamically update cfs_overload_cpus 

hulk inclusion
category: feature
bugzilla: 38261, https://bugzilla.openeuler.org/show_bug.cgi?id=23


CVE: NA

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

An overloaded CPU has more than 1 runnable task.  When a CFS task wakes
on a CPU, if h_nr_running transitions from 1 to more, then set the CPU in
the cfs_overload_cpus bitmap.  When a CFS task sleeps, if h_nr_running
transitions from 2 to less, then clear the CPU in cfs_overload_cpus.

Signed-off-by: default avatarSteve Sistare <steven.sistare@oracle.com>
Signed-off-by: default avatarCheng Jian <cj.chengjian@huawei.com>
Reviewed-by: default avatarHanjun Guo <guohanjun@huawei.com>
Signed-off-by: default avatarYang Yingliang <yangyingliang@huawei.com>
Reviewed-by: default avatarXie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: default avatarYang Yingliang <yangyingliang@huawei.com>
parent b3cf6ed8

kernel/sched/fair.c

+47 −4
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
 *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra

 */

#include "sched.h"

#include "sparsemask.h"



#include <trace/events/sched.h>
@@ -3810,6 +3811,28 @@ util_est_dequeue(struct cfs_rq *cfs_rq, struct task_struct *p, bool task_sleep) 
	WRITE_ONCE(p->se.avg.util_est, ue);

}



static void overload_clear(struct rq *rq)

{

	struct sparsemask *overload_cpus;



	rcu_read_lock();

	overload_cpus = rcu_dereference(rq->cfs_overload_cpus);

	if (overload_cpus)

		sparsemask_clear_elem(overload_cpus, rq->cpu);

	rcu_read_unlock();

}



static void overload_set(struct rq *rq)

{

	struct sparsemask *overload_cpus;



	rcu_read_lock();

	overload_cpus = rcu_dereference(rq->cfs_overload_cpus);

	if (overload_cpus)

		sparsemask_set_elem(overload_cpus, rq->cpu);

	rcu_read_unlock();

}



#else /* CONFIG_SMP */



#define UPDATE_TG	0x0
@@ -3833,6 +3856,9 @@ static inline int idle_balance(struct rq *rq, struct rq_flags *rf) 
	return 0;

}



static inline void overload_clear(struct rq *rq) {}

static inline void overload_set(struct rq *rq) {}



static inline void

util_est_enqueue(struct cfs_rq *cfs_rq, struct task_struct *p) {}
@@ -4482,6 +4508,7 @@ static int tg_throttle_down(struct task_group *tg, void *data) 
static void throttle_cfs_rq(struct cfs_rq *cfs_rq)

{

	struct rq *rq = rq_of(cfs_rq);

	unsigned int prev_nr = rq->cfs.h_nr_running;

	struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);

	struct sched_entity *se;

	long task_delta, idle_task_delta, dequeue = 1;
@@ -4511,8 +4538,12 @@ static void throttle_cfs_rq(struct cfs_rq *cfs_rq) 
			dequeue = 0;

	}



	if (!se)

	if (!se) {

		sub_nr_running(rq, task_delta);

		if (prev_nr >= 2 && prev_nr - task_delta < 2)

			overload_clear(rq);



	}



	cfs_rq->throttled = 1;

	cfs_rq->throttled_clock = rq_clock(rq);
@@ -4542,6 +4573,7 @@ static void throttle_cfs_rq(struct cfs_rq *cfs_rq) 
void unthrottle_cfs_rq(struct cfs_rq *cfs_rq)

{

	struct rq *rq = rq_of(cfs_rq);

	unsigned int prev_nr = rq->cfs.h_nr_running;

	struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);

	struct sched_entity *se;

	int enqueue = 1;
@@ -4582,8 +4614,11 @@ void unthrottle_cfs_rq(struct cfs_rq *cfs_rq) 


	assert_list_leaf_cfs_rq(rq);



	if (!se)

	if (!se) {

		add_nr_running(rq, task_delta);

		if (prev_nr < 2 && prev_nr + task_delta >= 2)

			overload_set(rq);

	}



	/* Determine whether we need to wake up potentially idle CPU: */

	if (rq->curr == rq->idle && rq->cfs.nr_running)
@@ -5161,6 +5196,7 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) 
	struct cfs_rq *cfs_rq;

	struct sched_entity *se = &p->se;

	int idle_h_nr_running = task_has_idle_policy(p);

	unsigned int prev_nr = rq->cfs.h_nr_running;



	/*

	 * The code below (indirectly) updates schedutil which looks at
@@ -5210,8 +5246,11 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) 
		update_cfs_group(se);

	}



	if (!se)

	if (!se) {

		add_nr_running(rq, 1);

		if (prev_nr == 1)

			overload_set(rq);

	}



	if (cfs_bandwidth_used()) {

		/*
@@ -5246,6 +5285,7 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) 
	struct sched_entity *se = &p->se;

	int task_sleep = flags & DEQUEUE_SLEEP;

	int idle_h_nr_running = task_has_idle_policy(p);

	unsigned int prev_nr = rq->cfs.h_nr_running;



	for_each_sched_entity(se) {

		cfs_rq = cfs_rq_of(se);
@@ -5289,8 +5329,11 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) 
		update_cfs_group(se);

	}



	if (!se)

	if (!se) {

		sub_nr_running(rq, 1);

		if (prev_nr == 2)

			overload_clear(rq);

	}



	util_est_dequeue(&rq->cfs, p, task_sleep);

	hrtick_update(rq);