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Commit 57785df5 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

sched: Fix task priority bug 



83f9ac removed a call to effective_prio() in wake_up_new_task(), which
leads to tasks running at MAX_PRIO.

This is caused by the idle thread being set to MAX_PRIO before forking
off init. O(1) used that to make sure idle was always preempted, CFS
uses check_preempt_curr_idle() for that so we can savely remove this bit
of legacy code.

Reported-by: default avatarMike Galbraith <efault@gmx.de>
Tested-by: default avatarMike Galbraith <efault@gmx.de>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1259754383.4003.610.camel@laptop>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent cd8ad40d

kernel/sched.c

+0 −6
Original line number Diff line number Diff line
@@ -3158,10 +3158,6 @@ static void pull_task(struct rq *src_rq, struct task_struct *p, 
	deactivate_task(src_rq, p, 0);

	set_task_cpu(p, this_cpu);

	activate_task(this_rq, p, 0);

	/*

	 * Note that idle threads have a prio of MAX_PRIO, for this test

	 * to be always true for them.

	 */

	check_preempt_curr(this_rq, p, 0);

}
@@ -6992,7 +6988,6 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu) 
	__sched_fork(idle);

	idle->se.exec_start = sched_clock();



	idle->prio = idle->normal_prio = MAX_PRIO;

	cpumask_copy(&idle->cpus_allowed, cpumask_of(cpu));

	__set_task_cpu(idle, cpu);
@@ -7696,7 +7691,6 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) 
		spin_lock_irq(&rq->lock);

		update_rq_clock(rq);

		deactivate_task(rq, rq->idle, 0);

		rq->idle->static_prio = MAX_PRIO;

		__setscheduler(rq, rq->idle, SCHED_NORMAL, 0);

		rq->idle->sched_class = &idle_sched_class;

		migrate_dead_tasks(cpu);