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Commit be53f58f authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull scheduler fixes from Ingo Molnar:
 "Misc fixes: a cgroup fix, a fair-scheduler migration accounting fix, a
  cputime fix and two cpuacct cleanups"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/cpuacct: Simplify the cpuacct code
  sched/cpuacct: Rename parameter in cpuusage_write() for readability
  sched/fair: Add comments to explain select_idle_sibling()
  sched/fair: Fix fairness issue on migration
  sched/cgroup: Fix/cleanup cgroup teardown/init
  sched/cputime: Fix steal time accounting vs. CPU hotplug
parents 19d6f04c 73e6aafd

kernel/sched/core.c

+15 −21
Original line number Diff line number Diff line
@@ -5371,6 +5371,7 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) 


	case CPU_UP_PREPARE:

		rq->calc_load_update = calc_load_update;

		account_reset_rq(rq);

		break;



	case CPU_ONLINE:
@@ -7537,7 +7538,7 @@ void 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);



static void free_sched_group(struct task_group *tg)

static void sched_free_group(struct task_group *tg)

{

	free_fair_sched_group(tg);

	free_rt_sched_group(tg);
@@ -7563,7 +7564,7 @@ struct task_group *sched_create_group(struct task_group *parent) 
	return tg;



err:

	free_sched_group(tg);

	sched_free_group(tg);

	return ERR_PTR(-ENOMEM);

}
@@ -7583,17 +7584,16 @@ void sched_online_group(struct task_group *tg, struct task_group *parent) 
}



/* rcu callback to free various structures associated with a task group */

static void free_sched_group_rcu(struct rcu_head *rhp)

static void sched_free_group_rcu(struct rcu_head *rhp)

{

	/* now it should be safe to free those cfs_rqs */

	free_sched_group(container_of(rhp, struct task_group, rcu));

	sched_free_group(container_of(rhp, struct task_group, rcu));

}



/* Destroy runqueue etc associated with a task group */

void sched_destroy_group(struct task_group *tg)

{

	/* wait for possible concurrent references to cfs_rqs complete */

	call_rcu(&tg->rcu, free_sched_group_rcu);

	call_rcu(&tg->rcu, sched_free_group_rcu);

}



void sched_offline_group(struct task_group *tg)
@@ -8052,31 +8052,26 @@ cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) 
	if (IS_ERR(tg))

		return ERR_PTR(-ENOMEM);



	sched_online_group(tg, parent);



	return &tg->css;

}



static int cpu_cgroup_css_online(struct cgroup_subsys_state *css)

static void cpu_cgroup_css_released(struct cgroup_subsys_state *css)

{

	struct task_group *tg = css_tg(css);

	struct task_group *parent = css_tg(css->parent);



	if (parent)

		sched_online_group(tg, parent);

	return 0;

	sched_offline_group(tg);

}



static void cpu_cgroup_css_free(struct cgroup_subsys_state *css)

{

	struct task_group *tg = css_tg(css);



	sched_destroy_group(tg);

}



static void cpu_cgroup_css_offline(struct cgroup_subsys_state *css)

{

	struct task_group *tg = css_tg(css);



	sched_offline_group(tg);

	/*

	 * Relies on the RCU grace period between css_released() and this.

	 */

	sched_free_group(tg);

}



static void cpu_cgroup_fork(struct task_struct *task)
@@ -8436,9 +8431,8 @@ static struct cftype cpu_files[] = { 


struct cgroup_subsys cpu_cgrp_subsys = {

	.css_alloc	= cpu_cgroup_css_alloc,

	.css_released	= cpu_cgroup_css_released,

	.css_free	= cpu_cgroup_css_free,

	.css_online	= cpu_cgroup_css_online,

	.css_offline	= cpu_cgroup_css_offline,

	.fork		= cpu_cgroup_fork,

	.can_attach	= cpu_cgroup_can_attach,

	.attach		= cpu_cgroup_attach,

kernel/sched/cpuacct.c

+10 −25
Original line number Diff line number Diff line
@@ -145,13 +145,16 @@ static u64 cpuusage_read(struct cgroup_subsys_state *css, struct cftype *cft) 
}



static int cpuusage_write(struct cgroup_subsys_state *css, struct cftype *cft,

			  u64 reset)

			  u64 val)

{

	struct cpuacct *ca = css_ca(css);

	int err = 0;

	int i;



	if (reset) {

	/*

	 * Only allow '0' here to do a reset.

	 */

	if (val) {

		err = -EINVAL;

		goto out;

	}
@@ -235,23 +238,10 @@ static struct cftype files[] = { 
void cpuacct_charge(struct task_struct *tsk, u64 cputime)

{

	struct cpuacct *ca;

	int cpu;



	cpu = task_cpu(tsk);



	rcu_read_lock();



	ca = task_ca(tsk);



	while (true) {

		u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);

		*cpuusage += cputime;



		ca = parent_ca(ca);

		if (!ca)

			break;

	}



	for (ca = task_ca(tsk); ca; ca = parent_ca(ca))

		*this_cpu_ptr(ca->cpuusage) += cputime;

	rcu_read_unlock();

}
@@ -260,18 +250,13 @@ void cpuacct_charge(struct task_struct *tsk, u64 cputime) 
 *

 * Note: it's the caller that updates the account of the root cgroup.

 */

void cpuacct_account_field(struct task_struct *p, int index, u64 val)

void cpuacct_account_field(struct task_struct *tsk, int index, u64 val)

{

	struct kernel_cpustat *kcpustat;

	struct cpuacct *ca;



	rcu_read_lock();

	ca = task_ca(p);

	while (ca != &root_cpuacct) {

		kcpustat = this_cpu_ptr(ca->cpustat);

		kcpustat->cpustat[index] += val;

		ca = parent_ca(ca);

	}

	for (ca = task_ca(tsk); ca != &root_cpuacct; ca = parent_ca(ca))

		this_cpu_ptr(ca->cpustat)->cpustat[index] += val;

	rcu_read_unlock();

}

kernel/sched/cpuacct.h

+2 −2
Original line number Diff line number Diff line 
#ifdef CONFIG_CGROUP_CPUACCT



extern void cpuacct_charge(struct task_struct *tsk, u64 cputime);

extern void cpuacct_account_field(struct task_struct *p, int index, u64 val);

extern void cpuacct_account_field(struct task_struct *tsk, int index, u64 val);



#else
@@ -10,7 +10,7 @@ static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) 
}



static inline void

cpuacct_account_field(struct task_struct *p, int index, u64 val)

cpuacct_account_field(struct task_struct *tsk, int index, u64 val)

{

}

kernel/sched/fair.c

+32 −7
Original line number Diff line number Diff line
@@ -3181,17 +3181,25 @@ static inline void check_schedstat_required(void) 
static void

enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)

{

	bool renorm = !(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_WAKING);

	bool curr = cfs_rq->curr == se;



	/*

	 * Update the normalized vruntime before updating min_vruntime

	 * through calling update_curr().

	 * If we're the current task, we must renormalise before calling

	 * update_curr().

	 */

	if (!(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_WAKING))

	if (renorm && curr)

		se->vruntime += cfs_rq->min_vruntime;



	update_curr(cfs_rq);



	/*

	 * Update run-time statistics of the 'current'.

	 * Otherwise, renormalise after, such that we're placed at the current

	 * moment in time, instead of some random moment in the past.

	 */

	update_curr(cfs_rq);

	if (renorm && !curr)

		se->vruntime += cfs_rq->min_vruntime;



	enqueue_entity_load_avg(cfs_rq, se);

	account_entity_enqueue(cfs_rq, se);

	update_cfs_shares(cfs_rq);
@@ -3207,7 +3215,7 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) 
		update_stats_enqueue(cfs_rq, se);

		check_spread(cfs_rq, se);

	}

	if (se != cfs_rq->curr)

	if (!curr)

		__enqueue_entity(cfs_rq, se);

	se->on_rq = 1;
@@ -5071,7 +5079,19 @@ static int select_idle_sibling(struct task_struct *p, int target) 
		return i;



	/*

	 * Otherwise, iterate the domains and find an elegible idle cpu.

	 * Otherwise, iterate the domains and find an eligible idle cpu.

	 *

	 * A completely idle sched group at higher domains is more

	 * desirable than an idle group at a lower level, because lower

	 * domains have smaller groups and usually share hardware

	 * resources which causes tasks to contend on them, e.g. x86

	 * hyperthread siblings in the lowest domain (SMT) can contend

	 * on the shared cpu pipeline.

	 *

	 * However, while we prefer idle groups at higher domains

	 * finding an idle cpu at the lowest domain is still better than

	 * returning 'target', which we've already established, isn't

	 * idle.

	 */

	sd = rcu_dereference(per_cpu(sd_llc, target));

	for_each_lower_domain(sd) {
@@ -5081,11 +5101,16 @@ static int select_idle_sibling(struct task_struct *p, int target) 
						tsk_cpus_allowed(p)))

				goto next;



			/* Ensure the entire group is idle */

			for_each_cpu(i, sched_group_cpus(sg)) {

				if (i == target || !idle_cpu(i))

					goto next;

			}



			/*

			 * It doesn't matter which cpu we pick, the

			 * whole group is idle.

			 */

			target = cpumask_first_and(sched_group_cpus(sg),

					tsk_cpus_allowed(p));

			goto done;

kernel/sched/sched.h

+13 −0
Original line number Diff line number Diff line
@@ -1841,3 +1841,16 @@ static inline void cpufreq_trigger_update(u64 time) 
static inline void cpufreq_update_util(u64 time, unsigned long util, unsigned long max) {}

static inline void cpufreq_trigger_update(u64 time) {}

#endif /* CONFIG_CPU_FREQ */



static inline void account_reset_rq(struct rq *rq)

{

#ifdef CONFIG_IRQ_TIME_ACCOUNTING

	rq->prev_irq_time = 0;

#endif

#ifdef CONFIG_PARAVIRT

	rq->prev_steal_time = 0;

#endif

#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING

	rq->prev_steal_time_rq = 0;

#endif

}