Hi Eric,
On Fri, Mar 1, 2024 at 2:30 AM Eric Dumazet <edumazet@xxxxxxxxxx> wrote:
>
> I could not see the reason for 1sec (HZ) delays.
>
> Would calling rcu_softirq_qs() every ~10ms instead be a serious issue ?
>
The trouble scenarios are often when we need to detach an ad-hoc BPF
tracing program, or restart a monitoring service. It is fine as long
as they do not block for 10+ seconds or even completely stall under
heavy traffic. Raising a QS every few ms or HZ both work in such
cases.
> In anycase, if this all about rcu_tasks, I would prefer using a macro
> defined in kernel/rcu/tasks.h
> instead of having a hidden constant in a networking core function.
Paul E. McKenney was suggesting either current form or
local_bh_enable();
if (!IS_ENABLED(CONFIG_PREEMPT_RT))
rcu_softirq_qs_enable(local_bh_enable());
else
local_bh_enable();
With an interval it might have to be
"rcu_softirq_qs_enable(local_bh_enable(), &next_qs);" to avoid an
unnecessary extern/static var. Will it make more sense to you?
thanks
>
> Thanks.
