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From: Oleksandr Natalenko <oleksandr@natalenko.name>
To: Alexander Duyck <alexander.duyck@gmail.com>
Cc: Jakub Kicinski <kuba@kernel.org>,
	linux-kernel@vger.kernel.org,
	Jesse Brandeburg <jesse.brandeburg@intel.com>,
	Tony Nguyen <anthony.l.nguyen@intel.com>,
	"David S. Miller" <davem@davemloft.net>,
	intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org
Subject: Re: [igb] netconsole triggers warning in netpoll_poll_dev
Date: Fri, 23 Apr 2021 10:19:44 +0200
Message-ID: <20210423081944.kvvm4v7jcdyj74l3@spock.localdomain> (raw)
In-Reply-To: <CAKgT0UcQXVOifi_2r_Y6meg_zvHDBf1me8VwA4pvEtEMzOaw2Q@mail.gmail.com>

Hello.

On Wed, Apr 07, 2021 at 04:06:29PM -0700, Alexander Duyck wrote:
> On Wed, Apr 7, 2021 at 11:07 AM Jakub Kicinski <kuba@kernel.org> wrote:
> >
> > On Wed, 7 Apr 2021 09:25:28 -0700 Alexander Duyck wrote:
> > > On Wed, Apr 7, 2021 at 8:37 AM Jakub Kicinski <kuba@kernel.org> wrote:
> > > >
> > > > On Wed, 7 Apr 2021 08:00:53 +0200 Oleksandr Natalenko wrote:
> > > > > Thanks for the effort, but reportedly [1] it made no difference,
> > > > > unfortunately.
> > > > >
> > > > > [1] https://bugzilla.kernel.org/show_bug.cgi?id=212573#c8
> > > >
> > > > The only other option I see is that somehow the NAPI has no rings.
> > > >
> > > > diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
> > > > index a45cd2b416c8..24568adc2fb1 100644
> > > > --- a/drivers/net/ethernet/intel/igb/igb_main.c
> > > > +++ b/drivers/net/ethernet/intel/igb/igb_main.c
> > > > @@ -7980,7 +7980,7 @@ static int igb_poll(struct napi_struct *napi, int budget)
> > > >         struct igb_q_vector *q_vector = container_of(napi,
> > > >                                                      struct igb_q_vector,
> > > >                                                      napi);
> > > > -       bool clean_complete = true;
> > > > +       bool clean_complete = q_vector->tx.ring || q_vector->rx.ring;
> > > >         int work_done = 0;
> > > >
> > > >  #ifdef CONFIG_IGB_DCA
> > >
> > > It might make sense to just cast the work_done as a unsigned int, and
> > > then on the end of igb_poll use:
> > >   return min_t(unsigned int, work_done, budget - 1);
> >
> > Sure, that's simplest. I wasn't sure something is supposed to prevent
> > this condition or if it's okay to cover it up.
> 
> I'm pretty sure it is okay to cover it up. In this case the "budget -
> 1" is supposed to be the upper limit on what can be reported. I think
> it was assuming an unsigned value anyway.
> 
> Another alternative would be to default clean_complete to !!budget.
> Then if budget is 0 clean_complete would always return false.

So, among all the variants, which one to try? Or there was a separate
patch sent to address this?

Thanks.

-- 
  Oleksandr Natalenko (post-factum)

  reply index

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-06 12:36 Oleksandr Natalenko
2021-04-06 18:48 ` Jakub Kicinski
2021-04-07  6:00   ` Oleksandr Natalenko
2021-04-07 15:37     ` Jakub Kicinski
2021-04-07 16:25       ` Alexander Duyck
2021-04-07 18:07         ` Jakub Kicinski
2021-04-07 23:06           ` Alexander Duyck
2021-04-23  8:19             ` Oleksandr Natalenko [this message]
2021-04-23 22:58               ` Jakub Kicinski
2021-04-26  6:47                 ` Oleksandr Natalenko
2021-04-26 15:28                   ` Alexander Duyck
2021-05-06 23:32                     ` Jesse Brandeburg
2021-05-07  0:38                       ` Alexander Duyck

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