On Thu, 2019-06-20 at 14:10 -0700, Paul E. McKenney wrote: > On Tue, Jun 18, 2019 at 08:19:07PM -0500, Scott Wood wrote: > > [Note: Just before posting this I noticed that the invoke_rcu_core stuff > > is part of the latest RCU pull request, and it has a patch that > > addresses this in a more complicated way that appears to deal with the > > bare irq-disabled sequence as well. > > Far easier to deal with it than to debug the lack of it. ;-) > > > Assuming we need/want to support such sequences, is the > > invoke_rcu_core() call actually going to result in scheduling any > > sooner? resched_curr() just does the same setting of need_resched > > when it's the same cpu. > > ] > > Yes, invoke_rcu_core() can in some cases invoke the scheduler sooner. > Setting the CPU-local bits might not have effect until the next interrupt. Maybe I'm missing something, but I don't see how (in the non-use_softirq case). It just calls wake_up_process(), which in resched_curr() will set need_resched but not do an IPI-to-self. -Scott
