On Tue, Jun 19, 2018 at 03:14:17PM -0700, Joel Fernandes wrote:
> From: "Joel Fernandes (Google)" <j...@joelfernandes.org>
>
> rcutorture boost tests fail even with CONFIG_RCU_BOOST set because
> rcutorture's threads are equal priority to the default RCU kthreads (RT
> class with priority of 1).
>
> This patch checks if RCU torture is built into the kernel and if so,
> assigns a higher priority to the RCU threads. With this the rcutorture
> boost tests pass.
>
> Signed-off-by: Joel Fernandes (Google) <j...@joelfernandes.org>
I queued all three for testing and further review. I reworked the commit
logs a bit and also pulled the error string onto one line to make it
easier on people grepping for the message. Please let me know if I
messed anything up.
Thanx, Paul
> ---
> kernel/rcu/tree.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> index deb2508be923..92c29439eba6 100644
> --- a/kernel/rcu/tree.c
> +++ b/kernel/rcu/tree.c
> @@ -3884,12 +3884,16 @@ static int __init rcu_spawn_gp_kthread(void)
> struct task_struct *t;
>
> /* Force priority into range. */
> - if (IS_ENABLED(CONFIG_RCU_BOOST) && kthread_prio < 1)
> + if (IS_ENABLED(CONFIG_RCU_BOOST) && kthread_prio < 2
> + && IS_BUILTIN(CONFIG_RCU_TORTURE_TEST))
> + kthread_prio = 2;
> + else if (IS_ENABLED(CONFIG_RCU_BOOST) && kthread_prio < 1)
> kthread_prio = 1;
> else if (kthread_prio < 0)
> kthread_prio = 0;
> else if (kthread_prio > 99)
> kthread_prio = 99;
> +
> if (kthread_prio != kthread_prio_in)
> pr_alert("rcu_spawn_gp_kthread(): Limited prio to %d from %d\n",
> kthread_prio, kthread_prio_in);
> --
> 2.18.0.rc1.244.gcf134e6275-goog
>
