On Tue, Oct 10, 2017 at 02:42:01PM +0200, Stanislaw Gruszka wrote: > > > + u64 steal, steal_time; > > > + s64 steal_delta; > > > + > > > + steal_time = paravirt_steal_clock(smp_processor_id()); > > > + steal = steal_delta = steal_time - this_rq()->prev_steal_time; > > > + > > > + if (unlikely(steal_delta < 0)) { > > > + this_rq()->prev_steal_time = steal_time; > > I don't think setting prev_steal_time to smaller value is right > thing to do. > > Beside, I don't think we need to check for overflow condition for > cputime variables (it will happen after 279 years :-). So instead > of introducing signed steal_delta variable I would just add > below check, which should be sufficient to fix the problem: > > if (unlikely(steal <= this_rq()->prev_steal_time)) > return 0;
How about you just fix up paravirt_steal_time() on migration and not muck with the users ? _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel