From: Christian Marangi <ansuelsmth@gmail•com>
To: Eric Dumazet <edumazet@google•com>
Cc: "Jason Gunthorpe" <jgg@ziepe•ca>,
"Leon Romanovsky" <leon@kernel•org>,
"Wolfgang Grandegger" <wg@grandegger•com>,
"Marc Kleine-Budde" <mkl@pengutronix•de>,
"David S. Miller" <davem@davemloft•net>,
"Jakub Kicinski" <kuba@kernel•org>,
"Paolo Abeni" <pabeni@redhat•com>,
"Chris Snook" <chris.snook@gmail•com>,
"Raju Rangoju" <rajur@chelsio•com>,
"Jeroen de Borst" <jeroendb@google•com>,
"Praveen Kaligineedi" <pkaligineedi@google•com>,
"Shailend Chand" <shailend@google•com>,
"Douglas Miller" <dougmill@linux•ibm.com>,
"Michael Ellerman" <mpe@ellerman•id.au>,
"Nicholas Piggin" <npiggin@gmail•com>,
"Christophe Leroy" <christophe.leroy@csgroup•eu>,
"Nick Child" <nnac123@linux•ibm.com>,
"Haren Myneni" <haren@linux•ibm.com>,
"Rick Lindsley" <ricklind@linux•ibm.com>,
"Dany Madden" <danymadden@us•ibm.com>,
"Thomas Falcon" <tlfalcon@linux•ibm.com>,
"Tariq Toukan" <tariqt@nvidia•com>,
"Alexandre Torgue" <alexandre.torgue@foss•st.com>,
"Jose Abreu" <joabreu@synopsys•com>,
"Maxime Coquelin" <mcoquelin.stm32@gmail•com>,
"Krzysztof Halasa" <khalasa@piap•pl>,
"Kalle Valo" <kvalo@kernel•org>,
"Jeff Johnson" <quic_jjohnson@quicinc•com>,
"Gregory Greenman" <gregory.greenman@intel•com>,
"Chandrashekar Devegowda" <chandrashekar.devegowda@intel•com>,
"Intel Corporation" <linuxwwan@intel•com>,
"Chiranjeevi Rapolu" <chiranjeevi.rapolu@linux•intel.com>,
"Liu Haijun" <haijun.liu@mediatek•com>,
"M Chetan Kumar" <m.chetan.kumar@linux•intel.com>,
"Ricardo Martinez" <ricardo.martinez@linux•intel.com>,
"Loic Poulain" <loic.poulain@linaro•org>,
"Sergey Ryazanov" <ryazanov.s.a@gmail•com>,
"Johannes Berg" <johannes@sipsolutions•net>,
"Yuanjun Gong" <ruc_gongyuanjun@163•com>,
"Simon Horman" <horms@kernel•org>,
"Rob Herring" <robh@kernel•org>,
"Ziwei Xiao" <ziweixiao@google•com>,
"Rushil Gupta" <rushilg@google•com>,
"Coco Li" <lixiaoyan@google•com>,
"Thomas Gleixner" <tglx@linutronix•de>,
"Junfeng Guo" <junfeng.guo@intel•com>,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix•de>,
"Wei Fang" <wei.fang@nxp•com>,
"Krzysztof Kozlowski" <krzysztof.kozlowski@linaro•org>,
"Yuri Karpov" <YKarpov@ispras•ru>,
"Zhengchao Shao" <shaozhengchao@huawei•com>,
"Andrew Lunn" <andrew@lunn•ch>,
"Zheng Zengkai" <zhengzengkai@huawei•com>,
"Lee Jones" <lee@kernel•org>,
"Maximilian Luz" <luzmaximilian@gmail•com>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel•com>,
"Dawei Li" <set_pte_at@outlook•com>,
Anjaneyulu <pagadala.yesu.anjaneyulu@intel•com>,
"Benjamin Berg" <benjamin.berg@intel•com>,
linux-rdma@vger•kernel.org, linux-kernel@vger•kernel.org,
linux-can@vger•kernel.org, netdev@vger•kernel.org,
linuxppc-dev@lists•ozlabs.org,
linux-stm32@st-md-mailman•stormreply.com,
linux-arm-kernel@lists•infradead.org, ath10k@lists•infradead.org,
linux-wireless@vger•kernel.org
Subject: Re: [net-next PATCH v2 4/4] netdev: use napi_schedule bool instead of napi_schedule_prep/__napi_schedule
Date: Sun, 8 Oct 2023 20:27:28 +0200 [thread overview]
Message-ID: <6522f495.df0a0220.326ed.de6c@mx.google.com> (raw)
In-Reply-To: <CANn89i+Cie+oE_hTWkyJWutTG9CnPy+dbW+-A97Q+E9Rq-f9rQ@mail.gmail.com>
On Sun, Oct 08, 2023 at 09:08:41AM +0200, Eric Dumazet wrote:
> On Fri, Oct 6, 2023 at 8:49 PM Christian Marangi <ansuelsmth@gmail•com> wrote:
> >
> > On Thu, Oct 05, 2023 at 06:16:26PM +0200, Eric Dumazet wrote:
> > > On Tue, Oct 3, 2023 at 8:36 PM Christian Marangi <ansuelsmth@gmail•com> wrote:
> > > >
> > > > Replace if condition of napi_schedule_prep/__napi_schedule and use bool
> > > > from napi_schedule directly where possible.
> > > >
> > > > Signed-off-by: Christian Marangi <ansuelsmth@gmail•com>
> > > > ---
> > > > drivers/net/ethernet/atheros/atlx/atl1.c | 4 +---
> > > > drivers/net/ethernet/toshiba/tc35815.c | 4 +---
> > > > drivers/net/wireless/intel/iwlwifi/pcie/rx.c | 4 +---
> > > > 3 files changed, 3 insertions(+), 9 deletions(-)
> > > >
> > > > diff --git a/drivers/net/ethernet/atheros/atlx/atl1.c b/drivers/net/ethernet/atheros/atlx/atl1.c
> > > > index 02aa6fd8ebc2..a9014d7932db 100644
> > > > --- a/drivers/net/ethernet/atheros/atlx/atl1.c
> > > > +++ b/drivers/net/ethernet/atheros/atlx/atl1.c
> > > > @@ -2446,7 +2446,7 @@ static int atl1_rings_clean(struct napi_struct *napi, int budget)
> > > >
> > > > static inline int atl1_sched_rings_clean(struct atl1_adapter* adapter)
> > > > {
> > > > - if (!napi_schedule_prep(&adapter->napi))
> > > > + if (!napi_schedule(&adapter->napi))
> > > > /* It is possible in case even the RX/TX ints are disabled via IMR
> > > > * register the ISR bits are set anyway (but do not produce IRQ).
> > > > * To handle such situation the napi functions used to check is
> > > > @@ -2454,8 +2454,6 @@ static inline int atl1_sched_rings_clean(struct atl1_adapter* adapter)
> > > > */
> > > > return 0;
> > > >
> > > > - __napi_schedule(&adapter->napi);
> > > > -
> > > > /*
> > > > * Disable RX/TX ints via IMR register if it is
> > > > * allowed. NAPI handler must reenable them in same
> > > > diff --git a/drivers/net/ethernet/toshiba/tc35815.c b/drivers/net/ethernet/toshiba/tc35815.c
> > > > index 14cf6ecf6d0d..a8b8a0e13f9a 100644
> > > > --- a/drivers/net/ethernet/toshiba/tc35815.c
> > > > +++ b/drivers/net/ethernet/toshiba/tc35815.c
> > > > @@ -1436,9 +1436,7 @@ static irqreturn_t tc35815_interrupt(int irq, void *dev_id)
> > > > if (!(dmactl & DMA_IntMask)) {
> > > > /* disable interrupts */
> > > > tc_writel(dmactl | DMA_IntMask, &tr->DMA_Ctl);
> > > > - if (napi_schedule_prep(&lp->napi))
> > > > - __napi_schedule(&lp->napi);
> > > > - else {
> > > > + if (!napi_schedule(&lp->napi)) {
> > > > printk(KERN_ERR "%s: interrupt taken in poll\n",
> > > > dev->name);
> > > > BUG();
> > >
> > > Hmmm... could you also remove this BUG() ? I think this code path can be taken
> > > if some applications are using busy polling.
> > >
> > > Or simply rewrite this with the traditional
> > >
> > > if (napi_schedule_prep(&lp->napi)) {
> > > /* disable interrupts */
> > > tc_writel(dmactl | DMA_IntMask, &tr->DMA_Ctl);
> > > __napi_schedule(&lp->napi);
> > > }
> > >
> > >
> >
> > Mhhh is it safe to do so? I mean it seems very wrong to print a warning
> > and BUG() instead of disabling the interrupt only if napi can be
> > scheduled... Maybe is very old code? The more I see this the more I see
> > problem... (randomly disabling the interrupt and then make the kernel
> > die)
>
> I am pretty sure this BUG() can be hit these days with busy polling or
> setting gro_flush_timeout.
>
> I wish we could remove these bugs before someone copy-paste them.
>
> Again, this is orthogonal, I might simply stop doing reviews if this
> is not useful.
They are very useful and thanks a lot for them! I'm asking these as to
understand how to proceed. I have in queue 2 other series that depends
on this and I'm just asking info on how to speedup the progress on this!
Soo think I have to send v3 with the suggested change and BUG() dropped?
Happy to do everything to fix and improve this series!
--
Ansuel
next prev parent reply other threads:[~2023-10-08 18:27 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-03 14:51 [net-next PATCH v2 1/4] netdev: replace simple napi_schedule_prep/__napi_schedule to napi_schedule Christian Marangi
2023-10-03 14:51 ` [net-next PATCH v2 2/4] netdev: make napi_schedule return bool on NAPI successful schedule Christian Marangi
2023-10-03 14:51 ` [net-next PATCH v2 3/4] netdev: replace napi_reschedule with napi_schedule Christian Marangi
2023-10-05 16:11 ` Eric Dumazet
2023-10-05 16:32 ` Jakub Kicinski
2023-10-05 16:41 ` Eric Dumazet
2023-10-06 18:52 ` Christian Marangi
2023-10-08 7:00 ` Eric Dumazet
2023-10-03 14:51 ` [net-next PATCH v2 4/4] netdev: use napi_schedule bool instead of napi_schedule_prep/__napi_schedule Christian Marangi
2023-10-05 16:16 ` Eric Dumazet
2023-10-06 18:49 ` Christian Marangi
2023-10-08 7:08 ` Eric Dumazet
2023-10-08 18:27 ` Christian Marangi [this message]
2023-10-09 8:27 ` Eric Dumazet
2023-10-05 16:09 ` [net-next PATCH v2 1/4] netdev: replace simple napi_schedule_prep/__napi_schedule to napi_schedule Eric Dumazet
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=6522f495.df0a0220.326ed.de6c@mx.google.com \
--to=ansuelsmth@gmail$(echo .)com \
--cc=YKarpov@ispras$(echo .)ru \
--cc=alexandre.torgue@foss$(echo .)st.com \
--cc=andrew@lunn$(echo .)ch \
--cc=ath10k@lists$(echo .)infradead.org \
--cc=benjamin.berg@intel$(echo .)com \
--cc=chandrashekar.devegowda@intel$(echo .)com \
--cc=chiranjeevi.rapolu@linux$(echo .)intel.com \
--cc=chris.snook@gmail$(echo .)com \
--cc=christophe.leroy@csgroup$(echo .)eu \
--cc=danymadden@us$(echo .)ibm.com \
--cc=davem@davemloft$(echo .)net \
--cc=dougmill@linux$(echo .)ibm.com \
--cc=edumazet@google$(echo .)com \
--cc=gregory.greenman@intel$(echo .)com \
--cc=haijun.liu@mediatek$(echo .)com \
--cc=haren@linux$(echo .)ibm.com \
--cc=horms@kernel$(echo .)org \
--cc=jeroendb@google$(echo .)com \
--cc=jgg@ziepe$(echo .)ca \
--cc=joabreu@synopsys$(echo .)com \
--cc=johannes@sipsolutions$(echo .)net \
--cc=junfeng.guo@intel$(echo .)com \
--cc=khalasa@piap$(echo .)pl \
--cc=krzysztof.kozlowski@linaro$(echo .)org \
--cc=kuba@kernel$(echo .)org \
--cc=kvalo@kernel$(echo .)org \
--cc=lee@kernel$(echo .)org \
--cc=leon@kernel$(echo .)org \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
--cc=linux-can@vger$(echo .)kernel.org \
--cc=linux-kernel@vger$(echo .)kernel.org \
--cc=linux-rdma@vger$(echo .)kernel.org \
--cc=linux-stm32@st-md-mailman$(echo .)stormreply.com \
--cc=linux-wireless@vger$(echo .)kernel.org \
--cc=linuxppc-dev@lists$(echo .)ozlabs.org \
--cc=linuxwwan@intel$(echo .)com \
--cc=lixiaoyan@google$(echo .)com \
--cc=loic.poulain@linaro$(echo .)org \
--cc=luzmaximilian@gmail$(echo .)com \
--cc=m.chetan.kumar@linux$(echo .)intel.com \
--cc=mcoquelin.stm32@gmail$(echo .)com \
--cc=mkl@pengutronix$(echo .)de \
--cc=mpe@ellerman$(echo .)id.au \
--cc=netdev@vger$(echo .)kernel.org \
--cc=nnac123@linux$(echo .)ibm.com \
--cc=npiggin@gmail$(echo .)com \
--cc=pabeni@redhat$(echo .)com \
--cc=pagadala.yesu.anjaneyulu@intel$(echo .)com \
--cc=pkaligineedi@google$(echo .)com \
--cc=quic_jjohnson@quicinc$(echo .)com \
--cc=rafael.j.wysocki@intel$(echo .)com \
--cc=rajur@chelsio$(echo .)com \
--cc=ricardo.martinez@linux$(echo .)intel.com \
--cc=ricklind@linux$(echo .)ibm.com \
--cc=robh@kernel$(echo .)org \
--cc=ruc_gongyuanjun@163$(echo .)com \
--cc=rushilg@google$(echo .)com \
--cc=ryazanov.s.a@gmail$(echo .)com \
--cc=set_pte_at@outlook$(echo .)com \
--cc=shailend@google$(echo .)com \
--cc=shaozhengchao@huawei$(echo .)com \
--cc=tariqt@nvidia$(echo .)com \
--cc=tglx@linutronix$(echo .)de \
--cc=tlfalcon@linux$(echo .)ibm.com \
--cc=u.kleine-koenig@pengutronix$(echo .)de \
--cc=wei.fang@nxp$(echo .)com \
--cc=wg@grandegger$(echo .)com \
--cc=zhengzengkai@huawei$(echo .)com \
--cc=ziweixiao@google$(echo .)com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox