On Sun, May 17, 2020 at 08:53:22AM -0700, Paul E. McKenney wrote: > On Sun, May 17, 2020 at 03:31:16PM +0200, Frederic Weisbecker wrote: > > On Fri, May 15, 2020 at 08:07:18PM -0700, Paul E. McKenney wrote: > > > On Fri, May 15, 2020 at 02:34:29AM +0200, Frederic Weisbecker wrote: > > > > So far setting a tick dependency on any task, including current, used to > > > > trigger an IPI to all CPUs. That's of course suboptimal but it wasn't > > > > an issue as long as it was only used by posix-cpu-timers on nohz_full, > > > > a combo that nobody seemed to use in real life. > > > > > > > > But RCU started to use task tick dependency on current task to fix > > > > stall issues on callbacks processing. These trigger regular and > > > > undesired system wide IPIs on nohz_full. > > > > > > > > The fix is very easy while setting a tick dependency on the current > > > > task, only its CPU needs an IPI. > > > > > > This passes moderate rcutorture testing. If you want me to take it, > > > please > > > let me know, and otherwise: > > > > > > Tested-by: Paul E. McKenney <paul...@kernel.org> > > > > If you already have a pending urgent queue, I'd love you to take it. > > If not I can take it. > > Nothing urgent yet in -rcu, so if you would like it in the next merge > window, please take it through your normal upstream path.
Got it, thanks!
