________________________________________
From: Bruce Ashfield <bruce.ashfi...@gmail.com>
Sent: Sunday, 4 July 2021 11:25
To: Bruce Ashfield
Cc: Zhang, Qiang; linux-yocto@lists.yoctoproject.org
Subject: Re: [linux-yocto] [linux-yocto v5.10] [PATCH] iommu/arm-smmu-v3: 
Ratelimit event dump

[Please note: This e-mail is from an EXTERNAL e-mail address]

On Fri, Jul 2, 2021 at 8:54 AM Bruce Ashfield via
lists.yoctoproject.org
<bruce.ashfield=gmail....@lists.yoctoproject.org> wrote:
>
> On Fri, Jul 2, 2021 at 1:47 AM Zhang, Qiang <qiang.zh...@windriver.com> wrote:
> >
> >
> >
> > ________________________________________
> > From: Bruce Ashfield <bruce.ashfi...@gmail.com>
> > Sent: Monday, 7 June 2021 10:54
> > To: Zhang, Qiang
> > Cc: linux-yocto@lists.yoctoproject.org
> > Subject: Re: [linux-yocto] [linux-yocto v5.10] [PATCH] iommu/arm-smmu-v3: 
> > Ratelimit event dump
> >
> > [Please note: This e-mail is from an EXTERNAL e-mail address]
> >
> > On Fri, Jun 4, 2021 at 5:14 AM Zhang, Qiang <qiang.zh...@windriver.com> 
> > wrote:
> > >
> > >
> > >
> > > ________________________________________
> > > From: Bruce Ashfield <bruce.ashfi...@gmail.com>
> > > Sent: Thursday, 3 June 2021 05:05
> > > To: Zhang, Qiang
> > > Cc: linux-yocto@lists.yoctoproject.org
> > > Subject: Re: [linux-yocto] [linux-yocto v5.10] [PATCH] iommu/arm-smmu-v3: 
> > > Ratelimit event dump
> > >
> > > [Please note: This e-mail is from an EXTERNAL e-mail address]
> > >
> > > In message: [linux-yocto] [linux-yocto v5.10] [PATCH] iommu/arm-smmu-v3: 
> > > Ratelimit event dump
> > > on 02/06/2021 qiang.zh...@windriver.com wrote:
> > >
> > > > From: Zqiang <qiang.zh...@windriver.com>
> > > >
> > > > When a device or driver misbehaves, it is possible to receive events
> > > > much faster than we can print them out. Ratelimit the printing of events
> > > >
> > > > During the SVA tests when the device driver didn't properly stop DMA
> > > > before unbinding, the event queue thread would almost lock-up the server
> > > > with a flood of event 0xa. This patch helped recover from the error.
> > > >
> > > > Tested-by: Aaro Koskinen <aaro.koski...@nokia.com>
> > > > Signed-off-by: Jean-Philippe Brucker <jean-phili...@linaro.org>
> > > > Signed-off-by: Zqiang <qiang.zh...@windriver.com>
> > > >
> > > >Is there a link / reference to where this patch came from ? Judging
> > > >by the sign-offs, I assume it is from a mailing list ?
> > > >
> > > Hello Bruce
> > >
> > > https://lore.kernel.org/linux-iommu/20210526161927.24268-4-jean-phili...@linaro.org/#r
> >
> > >Are you tracking the subsystem tree ?
> > >
> > >I don't see any acked-by or reviewed-by on the list or in the lore link.
> >
> > Hello Bruce
> >
> > This change have been megre to linux-next
> >
>
> Excellent. I'll get it queued today.

>I ran into some issues when queuing the change, largely around the
>fact that the linux-next / mainline version is different than the one
>you originally submitted.

>The final version of this change depends on 395ad89d11fd93f
>[iommu/arm-smmu-v3: Add stall support for platform devices], which of
>course is a more invasive change.
>
>That being said, it did apply cleanly to 5.10, and then the ratelimit
>patch stacks cleanly as well.
>
>I'm not set up to test that the fix is correct. Can you do the same
>cherry pick and see if the result is what you are looking for ?

Hello Bruce

Yes, this patch can apply to v5.10, the v5.13 is not apply, in v5.13 this patch 
depend on 395ad89d11fd93f [iommu/arm-smmu-v3: Add stall support for platform 
devices].
I just migrated this change 9cff922bba [iommu/arm-smmu-v3: Ratelimit event dump 
] to v5.10, and this be talk in 

https://patchwork.kernel.org/project/linux-arm-kernel/patch/20200224182401.353359-22-jean-phili...@linaro.org/

this patch [iommu/arm-smmu-v3: Ratelimit event dump ]  can be sent 
independently of other patches.

Thanks
Qiang


>
>Bruce

>
> Bruce
>
> > commit 9cff922bba429b310507eac3b6cb5eb1b57e9ad1
> > Author: Jean-Philippe Brucker <jean-phili...@linaro.org>
> > Date:   Mon May 31 11:56:50 2021 +0200
> >
> >     iommu/arm-smmu-v3: Ratelimit event dump
> >
> >     When a device or driver misbehaves, it is possible to receive DMA fault
> >     events much faster than we can print them out, causing a lock up of the
> >     system and inability to cancel the source of the problem. Ratelimit
> >     printing of events to help recovery.
> >
> >     Tested-by: Aaro Koskinen <aaro.koski...@nokia.com>
> >     Signed-off-by: Jean-Philippe Brucker <jean-phili...@linaro.org>
> >     Link: 
> > https://lore.kernel.org/r/20210531095648.118282-1-jean-phili...@linaro.org
> >     Signed-off-by: Will Deacon <w...@kernel.org>
> >
> > Thanks
> > Qiang
> >
> >
> > >I'm trying to track down that this has been queued for linux-next and
> > >merging, that gives us confidence for v5.10/standard/base
> > >
> > >Without that, I'd prefer to merge this to branches just for the BSPs
> > >that are seeing issues with the event dump. Do we have a list of
> > >impacted boards or is it generally hitting various ARM BSPs ?
> > >
> > >Bruce
> >
> > >
> > > thanks
> > > Qiang
> > > >Also, were you targetting v5.10/standard/base ? If so, we want that
> > > >link even more.
> > > >
> > > >Bruce
> > >
> > > > ---
> > > >  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 12 ++++++++----
> > > >  1 file changed, 8 insertions(+), 4 deletions(-)
> > > >
> > > > diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c 
> > > > b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> > > > index 7067b7c11626..583db3dd1465 100644
> > > > --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> > > > +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> > > > @@ -1357,16 +1357,20 @@ static irqreturn_t arm_smmu_evtq_thread(int 
> > > > irq, void *dev)
> > > >       struct arm_smmu_device *smmu = dev;
> > > >       struct arm_smmu_queue *q = &smmu->evtq.q;
> > > >       struct arm_smmu_ll_queue *llq = &q->llq;
> > > > +     static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL,
> > > > +                                     DEFAULT_RATELIMIT_BURST);
> > > >       u64 evt[EVTQ_ENT_DWORDS];
> > > >
> > > >       do {
> > > >               while (!queue_remove_raw(q, evt)) {
> > > >                       u8 id = FIELD_GET(EVTQ_0_ID, evt[0]);
> > > >
> > > > -                     dev_info(smmu->dev, "event 0x%02x received:\n", 
> > > > id);
> > > > -                     for (i = 0; i < ARRAY_SIZE(evt); ++i)
> > > > -                             dev_info(smmu->dev, "\t0x%016llx\n",
> > > > -                                      (unsigned long long)evt[i]);
> > > > +                     if (__ratelimit(&rs)) {
> > > > +                             dev_info(smmu->dev, "event 0x%02x 
> > > > received:\n", id);
> > > > +                             for (i = 0; i < ARRAY_SIZE(evt); ++i)
> > > > +                                     dev_info(smmu->dev, 
> > > > "\t0x%016llx\n",
> > > > +                                             (unsigned long 
> > > > long)evt[i]);
> > > > +                     }
> > > >
> > > >               }
> > > >
> > > > --
> > > > 2.31.1
> > > >
> >
> >
> >
> > --
> > - Thou shalt not follow the NULL pointer, for chaos and madness await
> > thee at its end
> > - "Use the force Harry" - Gandalf, Star Trek II
>
>
>
> --
> - Thou shalt not follow the NULL pointer, for chaos and madness await
> thee at its end
> - "Use the force Harry" - Gandalf, Star Trek II
>
> 
>


--
- Thou shalt not follow the NULL pointer, for chaos and madness await
thee at its end
- "Use the force Harry" - Gandalf, Star Trek II
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