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authorMike Galbraith <efault@gmx.de>2009-10-29 06:48:30 -0400
committerIngo Molnar <mingo@elte.hu>2009-11-03 01:25:00 -0500
commitb84ff7d6f1b7f8a43414e74d972ec4c8f3361db4 (patch)
tree7e8db08b8dd7d28780f3d08466928c907e5e0440 /kernel
parent6b9de613ae9c79b637e070136585dde029578065 (diff)
sched: Fix kthread_bind() by moving the body of kthread_bind() to sched.c
Eric Paris reported that commit f685ceacab07d3f6c236f04803e2f2f0dbcc5afb causes boot time PREEMPT_DEBUG complaints. [ 4.590699] BUG: using smp_processor_id() in preemptible [00000000] code: rmmod/1314 [ 4.593043] caller is task_hot+0x86/0xd0 Since kthread_bind() messes with scheduler internals, move the body to sched.c, and lock the runqueue. Reported-by: Eric Paris <eparis@redhat.com> Signed-off-by: Mike Galbraith <efault@gmx.de> Tested-by: Eric Paris <eparis@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1256813310.7574.3.camel@marge.simson.net> [ v2: fix !SMP build and clean up ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/kthread.c23
-rw-r--r--kernel/sched.c32
2 files changed, 32 insertions, 23 deletions
diff --git a/kernel/kthread.c b/kernel/kthread.c
index 5fe709982caa..ab7ae57773e1 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -150,29 +150,6 @@ struct task_struct *kthread_create(int (*threadfn)(void *data),
150EXPORT_SYMBOL(kthread_create); 150EXPORT_SYMBOL(kthread_create);
151 151
152/** 152/**
153 * kthread_bind - bind a just-created kthread to a cpu.
154 * @k: thread created by kthread_create().
155 * @cpu: cpu (might not be online, must be possible) for @k to run on.
156 *
157 * Description: This function is equivalent to set_cpus_allowed(),
158 * except that @cpu doesn't need to be online, and the thread must be
159 * stopped (i.e., just returned from kthread_create()).
160 */
161void kthread_bind(struct task_struct *k, unsigned int cpu)
162{
163 /* Must have done schedule() in kthread() before we set_task_cpu */
164 if (!wait_task_inactive(k, TASK_UNINTERRUPTIBLE)) {
165 WARN_ON(1);
166 return;
167 }
168 set_task_cpu(k, cpu);
169 k->cpus_allowed = cpumask_of_cpu(cpu);
170 k->rt.nr_cpus_allowed = 1;
171 k->flags |= PF_THREAD_BOUND;
172}
173EXPORT_SYMBOL(kthread_bind);
174
175/**
176 * kthread_stop - stop a thread created by kthread_create(). 153 * kthread_stop - stop a thread created by kthread_create().
177 * @k: thread created by kthread_create(). 154 * @k: thread created by kthread_create().
178 * 155 *
diff --git a/kernel/sched.c b/kernel/sched.c
index bf21adb6c9fc..5cb7d637e33a 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1996,6 +1996,38 @@ static inline void check_class_changed(struct rq *rq, struct task_struct *p,
1996 p->sched_class->prio_changed(rq, p, oldprio, running); 1996 p->sched_class->prio_changed(rq, p, oldprio, running);
1997} 1997}
1998 1998
1999/**
2000 * kthread_bind - bind a just-created kthread to a cpu.
2001 * @k: thread created by kthread_create().
2002 * @cpu: cpu (might not be online, must be possible) for @k to run on.
2003 *
2004 * Description: This function is equivalent to set_cpus_allowed(),
2005 * except that @cpu doesn't need to be online, and the thread must be
2006 * stopped (i.e., just returned from kthread_create()).
2007 *
2008 * Function lives here instead of kthread.c because it messes with
2009 * scheduler internals which require locking.
2010 */
2011void kthread_bind(struct task_struct *p, unsigned int cpu)
2012{
2013 struct rq *rq = cpu_rq(cpu);
2014 unsigned long flags;
2015
2016 /* Must have done schedule() in kthread() before we set_task_cpu */
2017 if (!wait_task_inactive(p, TASK_UNINTERRUPTIBLE)) {
2018 WARN_ON(1);
2019 return;
2020 }
2021
2022 spin_lock_irqsave(&rq->lock, flags);
2023 set_task_cpu(p, cpu);
2024 p->cpus_allowed = cpumask_of_cpu(cpu);
2025 p->rt.nr_cpus_allowed = 1;
2026 p->flags |= PF_THREAD_BOUND;
2027 spin_unlock_irqrestore(&rq->lock, flags);
2028}
2029EXPORT_SYMBOL(kthread_bind);
2030
1999#ifdef CONFIG_SMP 2031#ifdef CONFIG_SMP
2000/* 2032/*
2001 * Is this task likely cache-hot: 2033 * Is this task likely cache-hot: