Re: [RFC][PATCH] rcu: Hotplug and PROVE_RCU_DELAY not playing welltogether

From: Steven Rostedt
Date: Mon Jun 03 2013 - 14:19:59 EST


On Sun, 2013-06-02 at 07:18 -0700, Paul E. McKenney wrote:

> ------------------------------------------------------------------------
>
> diff --git a/kernel/rcutree.c b/kernel/rcutree.c
> index d12470e..9a08bdc 100644
> --- a/kernel/rcutree.c
> +++ b/kernel/rcutree.c
> @@ -1320,9 +1320,9 @@ static int rcu_gp_init(struct rcu_state *rsp)
> rnp->grphi, rnp->qsmask);
> raw_spin_unlock_irq(&rnp->lock);
> #ifdef CONFIG_PROVE_RCU_DELAY
> - if ((prandom_u32() % (rcu_num_nodes * 8)) == 0 &&
> + if ((prandom_u32() % (rcu_num_nodes + 1)) == 0 &&
> system_state == SYSTEM_RUNNING)
> - schedule_timeout_uninterruptible(2);
> + udelay(200);
> #endif /* #ifdef CONFIG_PROVE_RCU_DELAY */
> cond_resched();
> }

I ran this for a bit. Where it usually crashes in less than a minute,
this ran for over 10 minutes without issue.

Tested-by: Steven Rostedt <rostedt@xxxxxxxxxxx>

-- Steve


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