Re: [RFC] tick: don't call hrtimer_active() after starting tick-sched hrtimer

On 9 July 2014 10:49, Preeti U Murthy preeti@linux.vnet.ibm.com wrote:

Is it possible that between the time we start the hrtimer and we check for hrtimer_active(), we can get a timer interrupt which can dequeue the tick sched timer if it were to be in the past? In this case the hrtimer_active() can have a failed return value right?

Most of the programming for tick-sched is done from interrupt-context and so interrupts might be disabled then.

Also, the checks in tick-sched and other kernel layers are not for checking if hrtimer is still enqueued or not. It is for checking if it was added in past.

And in case it is added in past, we will raise a softirq and quit. And would be handled on next interrupt..