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From: Aaro Koskinen <aaro.koskinen@iki.fi>
To: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: iommu@lists.linux-foundation.org, devicetree@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org,
	linux-mm@kvack.org, mark.rutland@arm.com, kevin.tian@intel.com,
	jacob.jun.pan@linux.intel.com, catalin.marinas@arm.com,
	joro@8bytes.org, robin.murphy@arm.com, robh+dt@kernel.org,
	yi.l.liu@intel.com, Jonathan.Cameron@huawei.com,
	zhangfei.gao@linaro.org, will@kernel.org,
	christian.koenig@amd.com, baolu.lu@linux.intel.com
Subject: Re: [PATCH v4 21/26] iommu/arm-smmu-v3: Ratelimit event dump
Date: Fri, 28 May 2021 11:09:58 +0300	[thread overview]
Message-ID: <20210528080958.GA60351@darkstar.musicnaut.iki.fi> (raw)
In-Reply-To: <20200224182401.353359-22-jean-philippe@linaro.org>

Hi,

On Mon, Feb 24, 2020 at 07:23:56PM +0100, Jean-Philippe Brucker wrote:
> 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.
> 
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>

Tested-by: Aaro Koskinen <aaro.koskinen@nokia.com>

> 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.

I was just debugging a similar case, and this patch was required to
prevent system from locking up.

Could you please resend this patch independently from the other patches
in the series, as it seems it's a worthwhile fix and still relevent for
current kernels. Thanks,

A.

> ---
>  drivers/iommu/arm-smmu-v3.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> index 28f8583cd47b..6a5987cce03f 100644
> --- a/drivers/iommu/arm-smmu-v3.c
> +++ b/drivers/iommu/arm-smmu-v3.c
> @@ -2243,17 +2243,20 @@ 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]);
> +			}
>  		}
>  
>  		/*


  reply	other threads:[~2021-05-28  8:10 UTC|newest]

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-24 18:23 [PATCH v4 00/26] iommu: Shared Virtual Addressing and SMMUv3 support Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 01/26] mm/mmu_notifiers: pass private data down to alloc_notifier() Jean-Philippe Brucker
2020-02-24 19:00   ` Jason Gunthorpe
2020-02-25  9:24     ` Jean-Philippe Brucker
2020-02-25 14:08       ` Jason Gunthorpe
2020-02-28 14:39         ` Jean-Philippe Brucker
2020-02-28 14:48           ` Jason Gunthorpe
2020-02-28 15:04             ` Jean-Philippe Brucker
2020-02-28 15:13               ` Jason Gunthorpe
2020-03-06  9:56                 ` Jean-Philippe Brucker
2020-03-06 13:09                   ` Jason Gunthorpe
2020-03-06 14:35                     ` Jean-Philippe Brucker
2020-03-06 14:52                       ` Jason Gunthorpe
2020-03-06 16:15                         ` Jean-Philippe Brucker
2020-03-06 17:42                           ` Jason Gunthorpe
2020-03-13 18:49                             ` Jean-Philippe Brucker
2020-03-13 19:13                               ` Jason Gunthorpe
2020-03-16 15:46                     ` Christoph Hellwig
2020-03-17 18:40                       ` Jason Gunthorpe
2020-03-05 16:36   ` Christoph Hellwig
2020-02-24 18:23 ` [PATCH v4 02/26] iommu/sva: Manage process address spaces Jean-Philippe Brucker
2020-02-26 12:35   ` Jonathan Cameron
2020-02-28 14:43     ` Jean-Philippe Brucker
2020-02-28 16:26       ` Jonathan Cameron
2020-02-26 19:13   ` Jacob Pan
2020-02-28 14:40     ` Jean-Philippe Brucker
2020-02-28 14:57       ` Jason Gunthorpe
2020-02-24 18:23 ` [PATCH v4 03/26] iommu: Add a page fault handler Jean-Philippe Brucker
2020-02-25  3:30   ` Xu Zaibo
2020-02-25  9:25     ` Jean-Philippe Brucker
2020-02-26  3:05       ` Xu Zaibo
2020-02-26 13:59   ` Jonathan Cameron
2020-02-28 14:44     ` Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 04/26] iommu/sva: Search mm by PASID Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 05/26] iommu/iopf: Handle mm faults Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 06/26] iommu/sva: Register page fault handler Jean-Philippe Brucker
2020-02-26 19:39   ` Jacob Pan
2020-02-28 14:44     ` Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 07/26] arm64: mm: Pin down ASIDs for sharing mm with devices Jean-Philippe Brucker
2020-02-27 17:43   ` Jonathan Cameron
2020-03-04 14:10     ` Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 08/26] iommu/io-pgtable-arm: Move some definitions to a header Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 09/26] iommu/arm-smmu-v3: Manage ASIDs with xarray Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 10/26] arm64: cpufeature: Export symbol read_sanitised_ftr_reg() Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 11/26] iommu/arm-smmu-v3: Share process page tables Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 12/26] iommu/arm-smmu-v3: Seize private ASID Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 13/26] iommu/arm-smmu-v3: Add support for VHE Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 14/26] iommu/arm-smmu-v3: Enable broadcast TLB maintenance Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 15/26] iommu/arm-smmu-v3: Add SVA feature checking Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 16/26] iommu/arm-smmu-v3: Add dev_to_master() helper Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 17/26] iommu/arm-smmu-v3: Implement mm operations Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 18/26] iommu/arm-smmu-v3: Hook up ATC invalidation to mm ops Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 19/26] iommu/arm-smmu-v3: Add support for Hardware Translation Table Update Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 20/26] iommu/arm-smmu-v3: Maintain a SID->device structure Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 21/26] iommu/arm-smmu-v3: Ratelimit event dump Jean-Philippe Brucker
2021-05-28  8:09   ` Aaro Koskinen [this message]
2021-05-28 16:25     ` Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 22/26] dt-bindings: document stall property for IOMMU masters Jean-Philippe Brucker
2020-02-24 18:23 ` [PATCH v4 23/26] iommu/arm-smmu-v3: Add stall support for platform devices Jean-Philippe Brucker
2020-02-26  8:44   ` Xu Zaibo
2020-03-04 14:09     ` Jean-Philippe Brucker
2020-02-27 18:17   ` Jonathan Cameron
2020-03-04 14:08     ` Jean-Philippe Brucker
2020-03-09 10:48       ` Jonathan Cameron
2020-02-24 18:23 ` [PATCH v4 24/26] PCI/ATS: Add PRI stubs Jean-Philippe Brucker
2020-02-27 20:55   ` Bjorn Helgaas
2020-02-24 18:24 ` [PATCH v4 25/26] PCI/ATS: Export symbols of PRI functions Jean-Philippe Brucker
2020-02-27 20:55   ` Bjorn Helgaas
2020-02-24 18:24 ` [PATCH v4 26/26] iommu/arm-smmu-v3: Add support for PRI Jean-Philippe Brucker
2020-02-27 18:22 ` [PATCH v4 00/26] iommu: Shared Virtual Addressing and SMMUv3 support Jonathan Cameron

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