Re: [PATCH] net: core: page_pool: add user refcnt and reintroduce page_pool_destroy

[Ivan Khoronzhuk]

On Tue, Jul 02, 2019 at 04:52:30PM +0200, Jesper Dangaard Brouer wrote:
> On Tue, 2 Jul 2019 17:44:27 +0300
> Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxx> wrote:
>
> > On Tue, Jul 02, 2019 at 04:31:39PM +0200, Jesper Dangaard Brouer wrote:
> > >From: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxx>
> > >
> > >Jesper recently removed page_pool_destroy() (from driver invocation) and
> > >moved shutdown and free of page_pool into xdp_rxq_info_unreg(), in-order to
> > >handle in-flight packets/pages. This created an asymmetry in drivers
> > >create/destroy pairs.
> > >
> > >This patch add page_pool user refcnt and reintroduce page_pool_destroy.
> > >This serves two purposes, (1) simplify drivers error handling as driver now
> > >drivers always calls page_pool_destroy() and don't need to track if
> > >xdp_rxq_info_reg_mem_model() was unsuccessful. (2) allow special cases
> > >where a single RX-queue (with a single page_pool) provides packets for two
> > >net_device'es, and thus needs to register the same page_pool twice with two
> > >xdp_rxq_info structures.
> >
> > As I tend to use xdp level patch there is no more reason to mention (2) case
> > here. XDP patch serves it better and can prevent not only obj deletion but also
> > pool flush, so, this one patch I could better leave only for (1) case.
>
> I don't understand what you are saying.
>
> Do you approve this patch, or do you reject this patch?
It's not reject, it's proposition to use both, XDP and page pool patches,
each having its goal.

--
Regards,
Ivan Khoronzhuk