Commit f83f9ac2 authored by Peter Williams's avatar Peter Williams Committed by Ingo Molnar
Browse files

sched: Set correct normal_prio and prio values in sched_fork() 



normal_prio should be updated if policy changes from RT to
SCHED_MORMAL or if static_prio/nice is changed.

Some paths through sched_fork() ignore this requirement and may
result in normal_prio having an invalid value.

Fixing this issue allows the call to effective_prio() in
wake_up_new_task() to be removed.

Signed-off-by: default avatarPeter Williams <pwil3058@bigpond.net.au>
Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <f8f46736fd4e7f090ac0.1253774830@mudlark.pw.nest>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 374576a8

kernel/sched.c

+9 −11
Original line number Diff line number Diff line
@@ -2514,23 +2514,18 @@ void sched_fork(struct task_struct *p, int clone_flags) 


	__sched_fork(p);



	/*

	 * Make sure we do not leak PI boosting priority to the child.

	 */

	p->prio = current->normal_prio;



	/*

	 * Revert to default priority/policy on fork if requested.

	 */

	if (unlikely(p->sched_reset_on_fork)) {

		if (p->policy == SCHED_FIFO || p->policy == SCHED_RR)

		if (p->policy == SCHED_FIFO || p->policy == SCHED_RR) {

			p->policy = SCHED_NORMAL;



		if (p->normal_prio < DEFAULT_PRIO)

			p->prio = DEFAULT_PRIO;

			p->normal_prio = p->static_prio;

		}



		if (PRIO_TO_NICE(p->static_prio) < 0) {

			p->static_prio = NICE_TO_PRIO(0);

			p->normal_prio = p->static_prio;

			set_load_weight(p);

		}
@@ -2541,6 +2536,11 @@ void sched_fork(struct task_struct *p, int clone_flags) 
		p->sched_reset_on_fork = 0;

	}



	/*

	 * Make sure we do not leak PI boosting priority to the child.

	 */

	p->prio = current->normal_prio;



	if (!rt_prio(p->prio))

		p->sched_class = &fair_sched_class;
@@ -2581,8 +2581,6 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags) 
	BUG_ON(p->state != TASK_RUNNING);

	update_rq_clock(rq);



	p->prio = effective_prio(p);



	if (!p->sched_class->task_new || !current->se.on_rq) {

		activate_task(rq, p, 0);

	} else {

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