On Fri, Aug 09, 2019 at 04:22:26PM -0400, Joel Fernandes wrote: > > > > o With any of the above, invoke rcu_momentary_dyntick_idle() along > > > > with cond_resched() in your kfree_rcu() loop. This simulates > > > > a trip to userspace for nohz_full CPUs, so if this helps for > > > > non-nohz_full CPUs, adjustments to the kernel might be called for. > > I did not try this yet. But I am thinking why would this help in nohz_idle > case? In nohz_idle we already have the tick active when CPU is idle. I guess > it is because there may be a long time that elapses before > rcu_data.rcu_need_heavy_qs == true ? Sorry, here I meant 'tick active when CPU is not idle'. thanks, - Joel