On Fri, Oct 23, 2020 at 05:05:44PM +0200, Peter Zijlstra wrote: > On Mon, Oct 19, 2020 at 09:43:16PM -0400, Joel Fernandes (Google) wrote: > > From: Peter Zijlstra <[email protected]> > > > > Instead of only selecting a local task, select a task for all SMT > > siblings for every reschedule on the core (irrespective which logical > > CPU does the reschedule). > > This: > > > > > During a CPU hotplug event, schedule would be called with the hotplugged > > CPU not in the cpumask. So use for_each_cpu(_wrap)_or to include the > > current cpu in the task pick loop. > > > > There are multiple loops in pick_next_task that iterate over CPUs in > > smt_mask. During a hotplug event, sibling could be removed from the > > smt_mask while pick_next_task is running. So we cannot trust the mask > > across the different loops. This can confuse the logic. Add a retry logic > > if smt_mask changes between the loops. > > isn't entirely accurate anymore, is it?
Yes you are right, we need to delete this bit from the changelog. :-(. I'll go do that. thanks, - Joel
