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Commit 7479f3c9 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

sched: Move SCHED_RESET_ON_FORK into attr::sched_flags 



I noticed the new sched_{set,get}attr() calls didn't properly deal
with the SCHED_RESET_ON_FORK hack.

Instead of propagating the flags in high bits nonsense use the brand
spanking new attr::sched_flags field.

Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Dario Faggioli <raistlin@linux.it>
Link: http://lkml.kernel.org/r/20140115162242.GJ31570@twins.programming.kicks-ass.net


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 0bb040a4

include/uapi/linux/sched.h

+5 −0
Original line number Diff line number Diff line
@@ -40,8 +40,13 @@ 
/* SCHED_ISO: reserved but not implemented yet */

#define SCHED_IDLE		5

#define SCHED_DEADLINE		6



/* Can be ORed in to make sure the process is reverted back to SCHED_NORMAL on fork */

#define SCHED_RESET_ON_FORK     0x40000000



/*

 * For the sched_{set,get}attr() calls

 */

#define SCHED_FLAG_RESET_ON_FORK	0x01



#endif /* _UAPI_LINUX_SCHED_H */

kernel/sched/core.c

+28 −14
Original line number Diff line number Diff line
@@ -3267,8 +3267,7 @@ static int __sched_setscheduler(struct task_struct *p, 
		reset_on_fork = p->sched_reset_on_fork;

		policy = oldpolicy = p->policy;

	} else {

		reset_on_fork = !!(policy & SCHED_RESET_ON_FORK);

		policy &= ~SCHED_RESET_ON_FORK;

		reset_on_fork = !!(attr->sched_flags & SCHED_FLAG_RESET_ON_FORK);



		if (policy != SCHED_DEADLINE &&

				policy != SCHED_FIFO && policy != SCHED_RR &&
@@ -3277,6 +3276,9 @@ static int __sched_setscheduler(struct task_struct *p, 
			return -EINVAL;

	}



	if (attr->sched_flags & ~(SCHED_FLAG_RESET_ON_FORK))

		return -EINVAL;



	/*

	 * Valid priorities for SCHED_FIFO and SCHED_RR are

	 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
@@ -3443,6 +3445,26 @@ static int __sched_setscheduler(struct task_struct *p, 
	return 0;

}



static int _sched_setscheduler(struct task_struct *p, int policy,

			       const struct sched_param *param, bool check)

{

	struct sched_attr attr = {

		.sched_policy   = policy,

		.sched_priority = param->sched_priority,

		.sched_nice	= PRIO_TO_NICE(p->static_prio),

	};



	/*

	 * Fixup the legacy SCHED_RESET_ON_FORK hack

	 */

	if (policy & SCHED_RESET_ON_FORK) {

		attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK;

		policy &= ~SCHED_RESET_ON_FORK;

		attr.sched_policy = policy;

	}



	return __sched_setscheduler(p, &attr, check);

}

/**

 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.

 * @p: the task in question.
@@ -3456,12 +3478,7 @@ static int __sched_setscheduler(struct task_struct *p, 
int sched_setscheduler(struct task_struct *p, int policy,

		       const struct sched_param *param)

{

	struct sched_attr attr = {

		.sched_policy   = policy,

		.sched_priority = param->sched_priority,

		.sched_nice	= PRIO_TO_NICE(p->static_prio),

	};

	return __sched_setscheduler(p, &attr, true);

	return _sched_setscheduler(p, policy, param, true);

}

EXPORT_SYMBOL_GPL(sched_setscheduler);
@@ -3487,12 +3504,7 @@ EXPORT_SYMBOL_GPL(sched_setattr); 
int sched_setscheduler_nocheck(struct task_struct *p, int policy,

			       const struct sched_param *param)

{

	struct sched_attr attr = {

		.sched_policy   = policy,

		.sched_priority = param->sched_priority,

		.sched_nice	= PRIO_TO_NICE(p->static_prio),

	};

	return __sched_setscheduler(p, &attr, false);

	return _sched_setscheduler(p, policy, param, false);

}



static int
@@ -3792,6 +3804,8 @@ SYSCALL_DEFINE3(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr, 
		goto out_unlock;



	attr.sched_policy = p->policy;

	if (p->sched_reset_on_fork)

		attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK;

	if (task_has_dl_policy(p))

		__getparam_dl(p, &attr);

	else if (task_has_rt_policy(p))