________________________________________ 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 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
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