Re: [RFC] Make need_resched() return true when rcu_urgent_qs requested
From: Peter Zijlstra
Date: Mon Jul 09 2018 - 10:43:59 EST
On Mon, Jul 09, 2018 at 07:29:32AM -0700, Paul E. McKenney wrote:
> OK, so here are our options:
>
> 1. Add the RCU conditional to need_resched(), as David suggests.
> Peter has concerns about overhead.
Not only overhead, its plain broken, because:
1) we keep preemption state in other places too
2) we check need_resched() in asm