Re: [PATCH v3] rcu/nocb: Avoid polling when myrdp->nocb_head_rdp list is empty

From: Frederic Weisbecker
Date: Tue Jun 14 2022 - 07:42:34 EST


On Sat, Jun 11, 2022 at 07:00:44PM +0800, Zqiang wrote:
> Currently, If the 'rcu_nocb_poll' bootargs is enable, all rcuog kthreads
> enter polling mode. however, due to only insert CPU's rdp which belong to
> rcu_nocb_mask to 'nocb_head_rdp' list or all CPU's rdp served by rcuog
> kthread have been de-offloaded, these cause the 'nocb_head_rdp' list
> served by rcuog kthread is empty, when the 'nocb_head_rdp' is empty,
> the rcuog kthread in polling mode not actually do anything. fix it by
> exiting polling mode when the 'nocb_head_rdp'list is empty, otherwise
> entering polling mode.
>
> Co-developed-by: Frederic Weisbecker <frederic@xxxxxxxxxx>

Acked-by: Frederic Weisbecker <frederic@xxxxxxxxxx>

Thanks!

(might be worth testing with TREE01 and --bootargs "rcu_gp_poll" )