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Commit ec12cb7f authored by Paul Turner's avatar Paul Turner Committed by Ingo Molnar
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sched: Accumulate per-cfs_rq cpu usage and charge against bandwidth 



Account bandwidth usage on the cfs_rq level versus the task_groups to which
they belong.  Whether we are tracking bandwidth on a given cfs_rq is maintained
under cfs_rq->runtime_enabled.

cfs_rq's which belong to a bandwidth constrained task_group have their runtime
accounted via the update_curr() path, which withdraws bandwidth from the global
pool as desired.  Updates involving the global pool are currently protected
under cfs_bandwidth->lock, local runtime is protected by rq->lock.

This patch only assigns and tracks quota, no action is taken in the case that
cfs_rq->runtime_used exceeds cfs_rq->runtime_assigned.

Signed-off-by: default avatarPaul Turner <pjt@google.com>
Signed-off-by: default avatarNikhil Rao <ncrao@google.com>
Signed-off-by: default avatarBharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: default avatarHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110721184757.179386821@google.com


Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent a790de99

include/linux/sched.h

+4 −0
Original line number Diff line number Diff line
@@ -2040,6 +2040,10 @@ static inline void sched_autogroup_fork(struct signal_struct *sig) { } 
static inline void sched_autogroup_exit(struct signal_struct *sig) { }

#endif



#ifdef CONFIG_CFS_BANDWIDTH

extern unsigned int sysctl_sched_cfs_bandwidth_slice;

#endif



#ifdef CONFIG_RT_MUTEXES

extern int rt_mutex_getprio(struct task_struct *p);

extern void rt_mutex_setprio(struct task_struct *p, int prio);

kernel/sched.c

+3 −1
Original line number Diff line number Diff line
@@ -251,7 +251,7 @@ struct cfs_bandwidth { 
#ifdef CONFIG_CFS_BANDWIDTH

	raw_spinlock_t lock;

	ktime_t period;

	u64 quota;

	u64 quota, runtime;

	s64 hierarchal_quota;

#endif

};
@@ -407,6 +407,7 @@ static inline u64 default_cfs_period(void); 
static void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b)

{

	raw_spin_lock_init(&cfs_b->lock);

	cfs_b->runtime = 0;

	cfs_b->quota = RUNTIME_INF;

	cfs_b->period = ns_to_ktime(default_cfs_period());

}
@@ -9107,6 +9108,7 @@ static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota) 
	raw_spin_lock_irq(&cfs_b->lock);

	cfs_b->period = ns_to_ktime(period);

	cfs_b->quota = quota;

	cfs_b->runtime = quota;

	raw_spin_unlock_irq(&cfs_b->lock);



	for_each_possible_cpu(i) {

kernel/sched_fair.c

+77 −2
Original line number Diff line number Diff line
@@ -89,6 +89,20 @@ const_debug unsigned int sysctl_sched_migration_cost = 500000UL; 
 */

unsigned int __read_mostly sysctl_sched_shares_window = 10000000UL;



#ifdef CONFIG_CFS_BANDWIDTH

/*

 * Amount of runtime to allocate from global (tg) to local (per-cfs_rq) pool

 * each time a cfs_rq requests quota.

 *

 * Note: in the case that the slice exceeds the runtime remaining (either due

 * to consumption or the quota being specified to be smaller than the slice)

 * we will always only issue the remaining available time.

 *

 * default: 5 msec, units: microseconds

  */

unsigned int sysctl_sched_cfs_bandwidth_slice = 5000UL;

#endif



static const struct sched_class fair_sched_class;



/**************************************************************
@@ -292,6 +306,8 @@ find_matching_se(struct sched_entity **se, struct sched_entity **pse) 


#endif	/* CONFIG_FAIR_GROUP_SCHED */



static void account_cfs_rq_runtime(struct cfs_rq *cfs_rq,

				   unsigned long delta_exec);



/**************************************************************

 * Scheduling class tree data structure manipulation methods:
@@ -583,6 +599,8 @@ static void update_curr(struct cfs_rq *cfs_rq) 
		cpuacct_charge(curtask, delta_exec);

		account_group_exec_runtime(curtask, delta_exec);

	}



	account_cfs_rq_runtime(cfs_rq, delta_exec);

}



static inline void
@@ -1248,6 +1266,58 @@ static inline u64 default_cfs_period(void) 
{

	return 100000000ULL;

}



static inline u64 sched_cfs_bandwidth_slice(void)

{

	return (u64)sysctl_sched_cfs_bandwidth_slice * NSEC_PER_USEC;

}



static void assign_cfs_rq_runtime(struct cfs_rq *cfs_rq)

{

	struct task_group *tg = cfs_rq->tg;

	struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(tg);

	u64 amount = 0, min_amount;



	/* note: this is a positive sum as runtime_remaining <= 0 */

	min_amount = sched_cfs_bandwidth_slice() - cfs_rq->runtime_remaining;



	raw_spin_lock(&cfs_b->lock);

	if (cfs_b->quota == RUNTIME_INF)

		amount = min_amount;

	else if (cfs_b->runtime > 0) {

		amount = min(cfs_b->runtime, min_amount);

		cfs_b->runtime -= amount;

	}

	raw_spin_unlock(&cfs_b->lock);



	cfs_rq->runtime_remaining += amount;

}



static void __account_cfs_rq_runtime(struct cfs_rq *cfs_rq,

				     unsigned long delta_exec)

{

	if (!cfs_rq->runtime_enabled)

		return;



	cfs_rq->runtime_remaining -= delta_exec;

	if (cfs_rq->runtime_remaining > 0)

		return;



	assign_cfs_rq_runtime(cfs_rq);

}



static __always_inline void account_cfs_rq_runtime(struct cfs_rq *cfs_rq,

						   unsigned long delta_exec)

{

	if (!cfs_rq->runtime_enabled)

		return;



	__account_cfs_rq_runtime(cfs_rq, delta_exec);

}



#else

static void account_cfs_rq_runtime(struct cfs_rq *cfs_rq,

				     unsigned long delta_exec) {}

#endif



/**************************************************
@@ -4266,8 +4336,13 @@ static void set_curr_task_fair(struct rq *rq) 
{

	struct sched_entity *se = &rq->curr->se;



	for_each_sched_entity(se)

		set_next_entity(cfs_rq_of(se), se);

	for_each_sched_entity(se) {

		struct cfs_rq *cfs_rq = cfs_rq_of(se);



		set_next_entity(cfs_rq, se);

		/* ensure bandwidth has been allocated on our new cfs_rq */

		account_cfs_rq_runtime(cfs_rq, 0);

	}

}



#ifdef CONFIG_FAIR_GROUP_SCHED

kernel/sysctl.c

+10 −0
Original line number Diff line number Diff line
@@ -379,6 +379,16 @@ static struct ctl_table kern_table[] = { 
		.extra2		= &one,

	},

#endif

#ifdef CONFIG_CFS_BANDWIDTH

	{

		.procname	= "sched_cfs_bandwidth_slice_us",

		.data		= &sysctl_sched_cfs_bandwidth_slice,

		.maxlen		= sizeof(unsigned int),

		.mode		= 0644,

		.proc_handler	= proc_dointvec_minmax,

		.extra1		= &one,

	},

#endif

#ifdef CONFIG_PROVE_LOCKING

	{

		.procname	= "prove_locking",