Re: [PATCH net-next 6/6] selftests: net: exercise page pool reporting via netlink

[Jakub Kicinski <kuba@kernel.org>]

On Fri, 12 Apr 2024 10:20:47 +0200 Petr Machata wrote:
> > +    def up(self):
> > +        ip("link set dev {} up".format(self.ifname))
> > +
> > +    def down(self):
> > +        ip("link set dev {} down".format(self.ifname))  
> 
> Yeah, what I meant by integration pain with LNST the other day was
> basically this. You end up rewriting the iproute2 API in Python.
> But it is what it is.

Yes, I wasn't sure where to make it a local helper in the test or 
a method of the class. I also don't think we should wrap too much but
I was worried someone will give me feedback in the opposite direction :)

Let me make it a local helper in the test.

I should probably move to format strings, too, not sure now what made 
me use .format().

> > +        ksft_eq(len(attached), 1)
> > +        ksft_eq(len(undetached), 1)
> > +
> > +        # Free the old page and the old pp is gone
> > +        nsim.dfs_write("pp_hold", "n")
> > +        # Freeing check is once a second so we may need to retry
> > +        for i in range(50):
> > +            pp_list = nf.page_pool_get({}, dump=True)
> > +            pp_list = [pp for pp in pp_list if pp.get("ifindex") == nsim.ifindex]
> > +            if len(pp_list) == 1:
> > +                break
> > +            time.sleep(0.05)
> > +        ksft_eq(len(pp_list), 1)  
> 
> Yeah, I don't know if busywait / slowwait sort of a helper is practical
> to write in Python. No idea how to go about it. But the bash experience
> shows it would useful fairly often.

If I wrap:

            pp_list = nf.page_pool_get({}, dump=True)
            pp_list = [pp for pp in pp_list if pp.get("ifindex") == nsim.ifindex]

into a helper, I can probably pass the condition in as a lambda 🤔️
Let me try..