On Tue, Jul 09, 2019 at 06:20:57PM +0300, Ilias Apalodimas wrote:
> Hi,
>
> > > Add page_pool_destroy() in bnxt_free_rx_rings() during normal RX ring
> > > cleanup, as Ilias has informed us that the following commit has been
> > > merged:
> > >
> > > 1da4bbeffe41 ("net: core: page_pool: add user refcnt and reintroduce
> > > page_pool_destroy")
> > >
> > > The special error handling code to call page_pool_free() can now be
> > > removed. bnxt_free_rx_rings() will always be called during normal
> > > shutdown or any error paths.
> > >
> > > Fixes: 322b87ca55f2 ("bnxt_en: add page_pool support")
> > > Cc: Ilias Apalodimas <ilias.apalodi...@linaro.org>
> > > Cc: Andy Gospodarek <go...@broadcom.com>
> > > Signed-off-by: Michael Chan <michael.c...@broadcom.com>
> > > ---
> > > drivers/net/ethernet/broadcom/bnxt/bnxt.c | 8 ++------
> > > 1 file changed, 2 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> > > b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> > > index e9d3bd8..2b5b0ab 100644
> > > --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> > > +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> > > @@ -2500,6 +2500,7 @@ static void bnxt_free_rx_rings(struct bnxt *bp)
> > > if (xdp_rxq_info_is_reg(&rxr->xdp_rxq))
> > > xdp_rxq_info_unreg(&rxr->xdp_rxq);
> > >
> > > + page_pool_destroy(rxr->page_pool);
> > > rxr->page_pool = NULL;
> > >
> > > kfree(rxr->rx_tpa);
> > > @@ -2560,19 +2561,14 @@ static int bnxt_alloc_rx_rings(struct bnxt *bp)
> > > return rc;
> > >
> > > rc = xdp_rxq_info_reg(&rxr->xdp_rxq, bp->dev, i);
> > > - if (rc < 0) {
> > > - page_pool_free(rxr->page_pool);
> > > - rxr->page_pool = NULL;
> > > + if (rc < 0)
> > > return rc;
> > > - }
> > >
> > > rc = xdp_rxq_info_reg_mem_model(&rxr->xdp_rxq,
> > > MEM_TYPE_PAGE_POOL,
> > > rxr->page_pool);
> > > if (rc) {
> > > xdp_rxq_info_unreg(&rxr->xdp_rxq);
> > > - page_pool_free(rxr->page_pool);
> > > - rxr->page_pool = NULL;
> >
> > Rather than deleting these lines it would also be acceptable to do:
> >
> > if (rc) {
> > xdp_rxq_info_unreg(&rxr->xdp_rxq);
> > - page_pool_free(rxr->page_pool);
> > + page_pool_destroy(rxr->page_pool);
> > rxr->page_pool = NULL;
> > return rc;
> > }
> >
> > but anytime there is a failure to bnxt_alloc_rx_rings the driver will
> > immediately follow it up with a call to bnxt_free_rx_rings, so
> > page_pool_destroy will be called.
> >
> > Thanks for pushing this out so quickly!
> >
>
> I also can't find page_pool_release_page() or page_pool_put_page() called when
> destroying the pool. Can you try to insmod -> do some traffic -> rmmod ?
> If there's stale buffers that haven't been unmapped properly you'll get a
> WARN_ON for them.
I did that test a few times with a few different bpf progs but I do not
see any WARN messages. Of course this does not mean that the code we
have is 100% correct.
Presumably you are talking about one of these messages, right?
215 /* The distance should not be able to become negative */
216 WARN(inflight < 0, "Negative(%d) inflight packet-pages", inflight);
or
356 /* Drivers should fix this, but only problematic when DMA is used */
357 WARN(1, "Still in-flight pages:%d hold:%u released:%u",
358 distance, hold_cnt, release_cnt);
> This part was added later on in the API when Jesper fixed in-flight packet
> handling
