On Thu, Feb 25, 2021 at 11:23:18PM +0100, Peter Zijlstra wrote: > On Thu, Feb 25, 2021 at 10:33:21AM -0800, Paul E. McKenney wrote: > > One question for Peter... Does each and every context switch imply a > > full barrier? > > Yes, also see the smp_mb__after_spinlock() in __schedule() :-) Whew!!! ;-) Yeah, I could make RCU Tasks Trace deal with lack of a full barrier in that case, but I would rather not... I could imagine optimizing so that the full barrier happened only when tasks migrated, but I could also imagine a world of hurt stemming from such an optimization! Thanx, Paul
