On Thu, Apr 02, 2015 at 04:21:21PM +0530, Viresh Kumar wrote:
'active_bases' indicates which clock-base have active timers. While it is updated (almost) correctly, it is hardly used. Next commit will start using it to make code more efficient, but before that we need to fix a problem.
While removing hrtimers, in __remove_hrtimer():
- We first remove the hrtimer from the queue.
- Then reprogram clockevent device if required (hrtimer_force_reprogram()).
- And then finally clear 'active_bases', if no more timers are pending on the current clock base (from which we are removing the hrtimer).
hrtimer_force_reprogram() needs to loop over all active clock bases to find the next expiry event, and while doing so it will use 'active_bases' (after next commit). And it will find the current base active, as we haven't cleared it until now, even if current clock base has no more hrtimers queued.
To fix this issue, clear active_bases before calling hrtimer_force_reprogram().
This is a small inefficiency right? Not an actual bug or anything.