Le Wed, Jan 17, 2024 at 06:26:16PM +0800, Zqiang a écrit :
> Currently, only rdp_gp->nocb_timer is used, for nocb_timer of
> no-rdp_gp structure, the timer_pending() is always return false,
> this commit therefore need to check rdp_gp->nocb_timer in
> __call_rcu_nocb_wake().
>
> Signed-off-by: Zqiang <qiang.zhang1211@xxxxxxxxx>
> ---
> kernel/rcu/tree_nocb.h | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h
> index 54971afc3a9b..3f85577bddd4 100644
> --- a/kernel/rcu/tree_nocb.h
> +++ b/kernel/rcu/tree_nocb.h
> @@ -564,6 +564,7 @@ static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_alldone,
> long lazy_len;
> long len;
> struct task_struct *t;
> + struct rcu_data *rdp_gp = rdp->nocb_gp_rdp;
>
> // If we are being polled or there is no kthread, just leave.
> t = READ_ONCE(rdp->nocb_gp_kthread);
> @@ -608,7 +609,7 @@ static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_alldone,
> smp_mb(); /* Enqueue before timer_pending(). */
> if ((rdp->nocb_cb_sleep ||
> !rcu_segcblist_ready_cbs(&rdp->cblist)) &&
> - !timer_pending(&rdp->nocb_timer)) {
> + !timer_pending(&rdp_gp->nocb_timer)) {
Hehe, good eyes ;-)
I had that change in mind but while checking that area further I actually
wondered what is the actual purpose of this RCU_NOCB_WAKE_FORCE thing. If
we reach that place, it means that the nocb_gp kthread should be awaken
already (or the timer pending), so what does a force wake up solve in that
case?
Paul, any recollection of that?
In the meantime:
Reviewed-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
