Messages in this thread Patch in this message | | | Date | Mon, 14 Nov 2016 15:57:21 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 1/3] idle: add support for tasks that inject idle |
| |
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);
> @@ -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(); > + > }
| |