From: Stephen Hemminger <stephen@networkplumber.org>
To: "Limonciello, Mario" <mario.limonciello@amd.com>
Cc: Jakub Kicinski <kuba@kernel.org>,
hayeswang@realtek.com, edumazet@google.com,
LKML <linux-kernel@vger.kernel.org>,
netdev@vger.kernel.org, davem@davemloft.net,
linux-usb@vger.kernel.org, pabeni@redhat.com,
Paul Menzel <pmenzel@molgen.mpg.de>
Subject: Re: Error 'netif_napi_add_weight() called with weight 256'
Date: Mon, 31 Jul 2023 13:47:32 -0700 [thread overview]
Message-ID: <20230731134732.597cb2c0@hermes.local> (raw)
In-Reply-To: <673bc252-2b34-6ef9-1765-9c7cac1e8658@amd.com>
On Mon, 31 Jul 2023 13:23:47 -0500
"Limonciello, Mario" <mario.limonciello@amd.com> wrote:
> On 7/31/2023 1:13 PM, Jakub Kicinski wrote:
> > On Mon, 31 Jul 2023 11:02:40 -0500 Limonciello, Mario wrote:
> >> Hi,
> >>
> >> I noticed today with 6.5-rc4 and also on 6.1.42 that I'm getting an
> >> error from an r8152 based dongle (Framework ethernet expansion card).
> >>
> >> netif_napi_add_weight() called with weight 256
> >>
> >> It seems that this message is likely introduced by
> >> 8ded532cd1cbe ("r8152: switch to netif_napi_add_weight()")
> >>
> >> which if the card has support_2500full set will program the value to 256:
> >>
> >> netif_napi_add_weight(netdev, &tp->napi, r8152_poll,
> >> tp->support_2500full ? 256 : 64);
> >>
> >> It's err level from
> >> 82dc3c63c692b ("net: introduce NAPI_POLL_WEIGHT")
> >>
> >> Why is this considered an error but the driver uses the bigger value?
> >> Should it be downgraded to a warning?
> >
> > Could you double check that the warning wasn't there before? The code
> > added by commit 195aae321c82 ("r8152: support new chips") in 5.13 looks
> > very much equivalent.
>
> Yeah; looking through the history I agree it was probably was there from
> the beginning of being introduced.
>
> 6.1 is the earliest kernel that is usable with this laptop (for other
> reasons).
>
> > The custom weight is probably due to a misunderstanding. We have 200G
> > adapters using the standard weight of 64, IDK why 2.5G adapter would
> > need anything special.
>
> Perhaps Hayes Wang can comment on this (as the author of 195aae321c82).
>
Large NAPI weights mean that one busy device (DOS attack) can starve the
system. Really doubt that > 64 makes any visible difference in throughput.
next prev parent reply other threads:[~2023-07-31 20:47 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-31 16:02 Error 'netif_napi_add_weight() called with weight 256' Limonciello, Mario
2023-07-31 18:13 ` Jakub Kicinski
2023-07-31 18:23 ` Limonciello, Mario
2023-07-31 20:47 ` Stephen Hemminger [this message]
2023-08-07 9:57 ` Hayes Wang
2023-08-07 16:37 ` Jakub Kicinski
2023-08-09 13:11 ` Hayes Wang
2023-08-09 18:37 ` Jakub Kicinski
2023-08-14 7:07 ` Hayes Wang
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