Re: [RFC v2] net: sched: implement TCQ_F_CAN_BYPASS for lockless qdisc

[Cong Wang]

On Mon, Mar 15, 2021 at 2:07 PM Jakub Kicinski <kuba@xxxxxxxxxx> wrote:
>
> I thought pfifo was supposed to be "lockless" and this change
> re-introduces a lock between producer and consumer, no?

It has never been truly lockless, it uses two spinlocks in the ring buffer
implementation, and it introduced a q->seqlock recently, with this patch
now we have priv->lock, 4 locks in total. So our "lockless" qdisc ends
up having more locks than others. ;) I don't think we are going to a
right direction...

Thanks.