Messages in this thread | | | Subject | Re: [PATCH] sched: don't allow rt_runtime_us to be zero for groups having rt tasks | From | Peter Zijlstra <> | Date | Wed, 27 Feb 2008 15:11:50 +0100 |
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On Wed, 2008-02-27 at 18:54 +0530, Dhaval Giani wrote:
> This patch checks if we can set the rt_runtime_us to 0. If there is a > realtime task in the group, we don't want to set the rt_runtime_us as 0 > or bad things will happen. > > Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
> --- > kernel/sched.c | 17 +++++++++++++++++ > 1 files changed, 17 insertions(+) > > Index: linux-2.6.25-rc3/kernel/sched.c > =================================================================== > --- linux-2.6.25-rc3.orig/kernel/sched.c > +++ linux-2.6.25-rc3/kernel/sched.c > @@ -7960,6 +7960,17 @@ static int __rt_schedulable(struct task_ > return total + to_ratio(period, runtime) < global_ratio; > } > > +/* Must be called with tasklist_lock held */ > +static inline int tg_has_rt_tasks(struct task_group *tg) > +{ > + struct task_struct *p; > + for_each_process(p) { > + if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg) > + return 1; > + } > + return 0; > +} > + > int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) > { > u64 rt_runtime, rt_period; > @@ -7971,6 +7982,11 @@ int sched_group_set_rt_runtime(struct ta > rt_runtime = rt_period; > > mutex_lock(&rt_constraints_mutex); > + read_lock(&tasklist_lock); > + if (rt_runtime_us == 0 && tg_has_rt_tasks(tg)) { > + err = -EINVAL; > + goto unlock; > + } > if (!__rt_schedulable(tg, rt_period, rt_runtime)) { > err = -EINVAL; > goto unlock; > @@ -7979,6 +7995,7 @@ int sched_group_set_rt_runtime(struct ta > rt_runtime = RUNTIME_INF; > tg->rt_runtime = rt_runtime; > unlock: > + read_unlock(&tasklist_lock); > mutex_unlock(&rt_constraints_mutex); > > return err;
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