Re: [RFC] rcu: Avoid unnecessary softirq when system is idle

2019-01-19 Thread Paul E. McKenney
On Sat, Jan 19, 2019 at 11:14:18AM -0500, Joel Fernandes (Google) wrote: > When there are no callbacks pending on an idle system, I noticed that > RCU softirq is continuously firing. During this the cpu_no_qs is set to > false, and core_needs_qs is set to true indefinitely. This causes >

[RFC] rcu: Avoid unnecessary softirq when system is idle

2019-01-19 Thread Joel Fernandes (Google)
When there are no callbacks pending on an idle system, I noticed that RCU softirq is continuously firing. During this the cpu_no_qs is set to false, and core_needs_qs is set to true indefinitely. This causes rcu_process_callbacks to be repeatedly called, even though the node corresponding to the