Re: [dpdk-dev] [PATCH v4 2/4] mempool: add non-IO flag

[Dmitry Kozlyuk <dkozlyuk@oss.nvidia.com>]

> -----Original Message-----
> From: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> [...]
> > diff --git a/lib/mempool/rte_mempool.c b/lib/mempool/rte_mempool.c
> > index 51c0ba2931..2204f140b3 100644
> > --- a/lib/mempool/rte_mempool.c
> > +++ b/lib/mempool/rte_mempool.c
> > @@ -371,6 +371,8 @@ rte_mempool_populate_iova(struct rte_mempool *mp,
> > char *vaddr,
> >
> >       STAILQ_INSERT_TAIL(&mp->mem_list, memhdr, next);
> >       mp->nb_mem_chunks++;
> > +     if (iova == RTE_BAD_IOVA)
> > +             mp->flags |= MEMPOOL_F_NON_IO;
> 
> As I understand rte_mempool_populate_iova() may be called few times for
> one mempool. The flag must be set if all invocations are done with
> RTE_BAD_IOVA. So, it should be set by default and just removed when iova
> != RTE_BAD_IOVA happens.

I don't agree at all. If any object of the pool is unsuitable for IO,
the pool cannot be considered suitable for IO. So if there's a single
invocation with RTE_BAD_IOVA, the flag must be set forever.

> Yes, it is a corner case. May be it makes sense to cover it by unit test
> as well.

True for either your logic or mine, I'll add it.

Ack on the rest of the comments, thanks.