Re: [PATCH 0/4] allow multiple kthreadd's

J. Bruce Fields
2020-05-05T02:15:23Z

On Fri, May 01, 2020 at 02:21:54PM -0400, Tejun Heo wrote:
> Hello,
>
> On Fri, May 01, 2020 at 10:59:24AM -0700, Linus Torvalds wrote:
> > Which kind of makes me want to point a finger at Tejun. But it's been
> > mostly PeterZ touching this file lately..
>
> Looks fine to me too. I don't quite understand the usecase tho. It looks
> like all it's being used for is to tag some kthreads as belonging to the
> same group. Can't that be done with kthread_data()?

Yeah, so I'd forgotten about kthread->data.

We're currently using it to pass the struct svc_rqst that a new nfsd
thread needs. But once the new thread has gotten that, I guess it could
set kthread->data to some global value that it uses to say "I'm a knfsd
thread"?

I suppose that would work.

Though now I'm feeling greedy: it would be nice to have both some kind
of global flag, *and* keep kthread->data pointing to svc_rqst (as that
would give me a simpler and quicker way to figure out which client is
conflicting). Could I take a flag bit in kthread->flags, maybe?

--b.