RE: [RFC PATCH 2/7] RDMA/rxe: Convert the triple tasklets to workqueues

[matsuda-daisuke@xxxxxxxxxxx]

On Mon, Sep 12, 2022 12:09 AM Bart Van Assche wrote:
> On 9/11/22 00:10, Yanjun Zhu wrote:
> > I also implemented a workqueue for rxe. IMO, can we add a variable to
> > decide to use tasklet or workqueue?
> >
> > If user prefer using tasklet, he can set the variable to use
> > tasklet. And the default is tasklet. Set the variable to another
> > value to use workqueue.

That's an interesting idea, but I am not sure how users specify it.
IIRC, tasklets are generated when rdma link is added, typically by 
executing ' rdma link add' command. I don't think we can add
an device specific option to the utility(iproute2/rdma).

> 
> I'm in favor of removing all uses of the tasklet mechanism because of
> the disadvantages of that mechanism. See also:
> * "Eliminating tasklets" (https://lwn.net/Articles/239633/).
> * "Modernizing the tasklet API" (https://lwn.net/Articles/830964/).
> * Sebastian Andrzej Siewior's opinion about tasklets
> (https://lore.kernel.org/all/YvovfXMJQAUBsvBZ@xxxxxxxxxxxxx/).

I am also in favor of using workqueues alone not only because of the
disadvantages above but also to avoid complexity. I would like to know
if there is anybody who will bothered by the change especially in terms
of performance.

Thanks,
Daisuke

> 
> Thanks,
> 
> Bart.