On 06/08, Oleg Nesterov wrote:
>
> And I simply can not understand the complication in hrtimer_active(),
> please help!
Sorry for another off-topic email, but I don't even understand the
usage of hrtimer_active().
Say, do_nanosleep()
hrtimer_start_expires(&t->timer, mode);
if (!hrtimer_active(&t->timer))
t->task = NULL;
why? Assuming that hrtimer_active() is correct, it can only return
false if t->task was already cleared by hrtimer_wakeup().
OTOH. perf_cpu_hrtimer_restart() does
if (hrtimer_active(hr))
return;
if (!hrtimer_callback_running(hr))
__hrtimer_start_range_ns(...);
why it can't simply do
if (!hrtimer_active(hr)) // implies !hrtimer_callback_running()
__hrtimer_start_range_ns(...);
Confused.
Oleg.
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