Messages in this thread | | | Date | Mon, 14 Nov 2016 16:01:56 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 1/3] idle: add support for tasks that inject idle |
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On Mon, Nov 14, 2016 at 03:57:21PM +0100, Peter Zijlstra wrote: > On Wed, Nov 09, 2016 at 11:05:10AM -0800, Jacob Pan wrote: > > static inline bool is_idle_task(const struct task_struct *p) > > { > > - return p->pid == 0; > > + return !!(p->flags & PF_IDLE); > > } > > > +void play_idle() > > +{ > > + /* > > + * Only FIFO tasks can disable the tick since they don't need the forced > > + * preemption. > > + */ > > + WARN_ON_ONCE(current->policy != SCHED_FIFO); > > + WARN_ON_ONCE(current->nr_cpus_allowed != 1); > > + WARN_ON_ONCE(!(current->flags & PF_KTHREAD)); > > + WARN_ON_ONCE(!(current->flags & PF_NO_SETAFFINITY)); > > + rcu_sleep_check(); > > + > > + preempt_disable(); > > + current->flags |= PF_IDLE; > > + do_idle(); > > + current->flags &= ~PF_IDLE; > > Whoops, that will clear PF_IDLE from the idle thread. Maybe do something > like: > > unsigned int idle_flag = (~current->flags & PF_IDLE) > > current->flags |= PF_IDLE; > > current->flags ^= idle_flag; > > > + > > + preempt_fold_need_resched(); > > + preempt_enable(); > > +} > > +EXPORT_SYMBOL_GPL(play_idle);
n/m I cannot read, the actual idle loop below uses do_idle(), not play_idle.
> > @@ -299,5 +313,7 @@ void cpu_startup_entry(enum cpuhp_state state) > > #endif > > arch_cpu_idle_prepare(); > > cpuhp_online_idle(state); > > - cpu_idle_loop(); > > + while (1) > > + do_idle(); > > + > > }
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