Re: [RFC PATCH 08/14] rcu: Convert RCU gp kthreads into kthread worker API

From: Tejun Heo
Date: Tue Jul 28 2015 - 13:41:02 EST


On Tue, Jul 28, 2015 at 04:39:25PM +0200, Petr Mladek wrote:
...
> -static int __noreturn rcu_gp_kthread(void *arg)
> +static void rcu_gp_kthread_func(struct kthread_work *work)
> {
> int fqs_state;
> int gf;
> unsigned long j;
> int ret;
> - struct rcu_state *rsp = arg;
> + struct rcu_state *rsp = container_of(work, struct rcu_state, gp_work);
> struct rcu_node *rnp = rcu_get_root(rsp);
>
> - rcu_bind_gp_kthread();
> + /* Handle grace-period start. */
> for (;;) {
> + trace_rcu_grace_period(rsp->name,
> + READ_ONCE(rsp->gpnum),
> + TPS("reqwait"));
> + rsp->gp_state = RCU_GP_WAIT_GPS;
> + wait_event_interruptible(rsp->gp_wq,
> + READ_ONCE(rsp->gp_flags) &
> + RCU_GP_FLAG_INIT);

Same here. Why not convert the waker into a queueing event?

> + /* Locking provides needed memory barrier. */
> + if (rcu_gp_init(rsp))
> + break;
> + cond_resched_rcu_qs();
> + WRITE_ONCE(rsp->gp_activity, jiffies);
> + WARN_ON(signal_pending(current));
> + trace_rcu_grace_period(rsp->name,
> + READ_ONCE(rsp->gpnum),
> + TPS("reqwaitsig"));
> + }

Thanks.

--
tejun
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