Messages in this thread | | | Date | Mon, 11 May 2015 22:34:11 +0300 (EEST) | From | Julian Anastasov <> | Subject | Re: [PATCH] sched: Introduce TASK_NOLOAD and TASK_IDLE |
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Hello,
On Mon, 11 May 2015, Peter Zijlstra wrote:
> > - schedule_timeout_idle (instead of schedule_timeout call): > > __set_current_state(TASK_IDLE); > > return schedule_timeout(timeout); > > > > - we here are really idle, so "N" looks ok > > So I don't get the point of the schedule_timeout_*() stubs. What are > they for? Why would one use an unconditional schedule_timeout() call? > Isn't that what msleep() is for?
msleep will not return until timeout has expired. Instead, we want to notice the kthread_should_stop() event immediately. Additionally, TASK_UNINTERRUPTIBLE will increase the load average. We can do it with extra wait queue and the new __wait_event_idle_timeout but I guess schedule_timeout_idle will be a good replacement for schedule_timeout_interruptible calls when used for kthreads.
> + * like wait_event_timeout() -- except it uses TASK_IDLE to avoid loadavg > + */ > +#define wait_event_idle_timeout(wq, condition, timeout) \ > +({ \ > + long __ret = timeout; \ > + might_sleep(); \ > + if (!___wait_cond_timeout(condition)) \ > + ret = __wait_event_idle_timeout(wq, condition, timeout);\
ret may need underscores here...
Regards
-- Julian Anastasov <ja@ssi.bg>
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