On Thu, Sep 16, 2021 at 06:57:12AM -0700, Paul E. McKenney wrote: > RT systems they avoid expedited grace periods by booting with either > the rcupdate.rcu_normal or the rcupdate.rcu_normal_after_boot kernel > boot parameters. And here is the definition for the latter: > > static int rcu_normal_after_boot = IS_ENABLED(CONFIG_PREEMPT_RT); > > In other words, RT systems shut off expedited grace periods by default, > and are thus free to use nohz_full CPU or not, as they choose. When using > nohz_full, they can also enable expedited grace periods by booting with > rcupdate.rcu_normal_after_boot=0. Or not, sysadm's choice. > > So I am not seeing a problem here. What am I missing? That wasn't at all clear to me from the Changelog. I thought it was enabling expedited crud for RT.
