On 2 April 2015 at 19:17, Peter Zijlstra <pet...@infradead.org> wrote: > 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.
So, what's explained in this patch is a BUG, which isn't harming us today. But overall both patches combined are about improving on the small inefficiency :) Sorry for the political answer :) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/