Messages in this thread | | | Date | Thu, 18 Aug 2022 12:36:21 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v5 7/9] sched/fair: allow changing cgroup of new forked task |
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On Thu, Aug 18, 2022 at 11:43:41AM +0800, Chengming Zhou wrote:
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 8e3f1c3f0b2c..157f7461a08a 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -4550,11 +4550,11 @@ int sched_fork(unsigned long clone_flags, struct task_struct *p) > { > __sched_fork(clone_flags, p); > /* > - * We mark the process as NEW here. This guarantees that > + * We mark the process as running here. This guarantees that > * nobody will actually run it, and a signal or other external > * event cannot wake it up and insert it on the runqueue either. > */ > - p->__state = TASK_NEW; > + p->__state = TASK_RUNNING; > > /* > * Make sure we do not leak PI boosting priority to the child. > @@ -4672,7 +4672,6 @@ void wake_up_new_task(struct task_struct *p) > struct rq *rq; > > raw_spin_lock_irqsave(&p->pi_lock, rf.flags); > - WRITE_ONCE(p->__state, TASK_RUNNING); > #ifdef CONFIG_SMP > /* > * Fork balancing, do it here and not earlier because: > @@ -10290,36 +10289,19 @@ static void cpu_cgroup_css_free(struct cgroup_subsys_state *css) > sched_unregister_group(tg); > }
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index eba8a64f905a..e0d34ecdabae 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -11840,6 +11840,13 @@ void init_cfs_rq(struct cfs_rq *cfs_rq) > #ifdef CONFIG_FAIR_GROUP_SCHED > static void task_change_group_fair(struct task_struct *p) > { > + /* > + * We couldn't detach or attach a forked task which > + * hasn't been woken up by wake_up_new_task(). > + */ > + if (!p->on_rq && !p->se.sum_exec_runtime) > + return; > + > detach_task_cfs_rq(p);
Wouldn't that be much clearer when expressed in TASK_NEW ?
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