linux-kernel - Re: [PATCH v8 6/7] iommu/vt-d: Add trace events for device dma map/unmap

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Message-ID: <319db353-6641-61af-a86a-93d832b742c2@linux.intel.com>
Date:   Mon, 2 Sep 2019 10:13:57 +0800
From:   Lu Baolu <baolu.lu@...ux.intel.com>
To:     Steven Rostedt <rostedt@...dmis.org>
Cc:     baolu.lu@...ux.intel.com, David Woodhouse <dwmw2@...radead.org>,
        Joerg Roedel <joro@...tes.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Christoph Hellwig <hch@....de>, ashok.raj@...el.com,
        jacob.jun.pan@...el.com, alan.cox@...el.com, kevin.tian@...el.com,
        mika.westerberg@...ux.intel.com, Ingo Molnar <mingo@...hat.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        pengfei.xu@...el.com,
        Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Robin Murphy <robin.murphy@....com>,
        Jonathan Corbet <corbet@....net>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Juergen Gross <jgross@...e.com>,
        Stefano Stabellini <sstabellini@...nel.org>,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        Jacob Pan <jacob.jun.pan@...ux.intel.com>
Subject: Re: [PATCH v8 6/7] iommu/vt-d: Add trace events for device dma
 map/unmap

Hi Steve,

On 8/30/19 9:53 PM, Steven Rostedt wrote:
> On Fri, 30 Aug 2019 15:17:17 +0800
> Lu Baolu <baolu.lu@...ux.intel.com> wrote:
> 
>> This adds trace support for the Intel IOMMU driver. It
>> also declares some events which could be used to trace
>> the events when an IOVA is being mapped or unmapped in
>> a domain.
>>
>> Cc: Ashok Raj <ashok.raj@...el.com>
>> Cc: Jacob Pan <jacob.jun.pan@...ux.intel.com>
>> Cc: Kevin Tian <kevin.tian@...el.com>
>> Signed-off-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
>> Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
>> Reviewed-by: Steven Rostedt (VMware) <rostedt@...dmis.org>
>> ---
>>   drivers/iommu/Makefile             |  1 +
>>   drivers/iommu/intel-trace.c        | 14 +++++
>>   include/trace/events/intel_iommu.h | 84 ++++++++++++++++++++++++++++++
>>   3 files changed, 99 insertions(+)
>>   create mode 100644 drivers/iommu/intel-trace.c
>>   create mode 100644 include/trace/events/intel_iommu.h
>>
>> diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
>> index f13f36ae1af6..bfe27b2755bd 100644
>> --- a/drivers/iommu/Makefile
>> +++ b/drivers/iommu/Makefile
>> @@ -17,6 +17,7 @@ obj-$(CONFIG_ARM_SMMU) += arm-smmu.o
>>   obj-$(CONFIG_ARM_SMMU_V3) += arm-smmu-v3.o
>>   obj-$(CONFIG_DMAR_TABLE) += dmar.o
>>   obj-$(CONFIG_INTEL_IOMMU) += intel-iommu.o intel-pasid.o
>> +obj-$(CONFIG_INTEL_IOMMU) += intel-trace.o
>>   obj-$(CONFIG_INTEL_IOMMU_DEBUGFS) += intel-iommu-debugfs.o
>>   obj-$(CONFIG_INTEL_IOMMU_SVM) += intel-svm.o
>>   obj-$(CONFIG_IPMMU_VMSA) += ipmmu-vmsa.o
>> diff --git a/drivers/iommu/intel-trace.c b/drivers/iommu/intel-trace.c
>> new file mode 100644
>> index 000000000000..bfb6a6e37a88
>> --- /dev/null
>> +++ b/drivers/iommu/intel-trace.c
>> @@ -0,0 +1,14 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Intel IOMMU trace support
>> + *
>> + * Copyright (C) 2019 Intel Corporation
>> + *
>> + * Author: Lu Baolu <baolu.lu@...ux.intel.com>
>> + */
>> +
>> +#include <linux/string.h>
>> +#include <linux/types.h>
>> +
>> +#define CREATE_TRACE_POINTS
>> +#include <trace/events/intel_iommu.h>
>> diff --git a/include/trace/events/intel_iommu.h b/include/trace/events/intel_iommu.h
>> new file mode 100644
>> index 000000000000..9c28e6cae86f
>> --- /dev/null
>> +++ b/include/trace/events/intel_iommu.h
>> @@ -0,0 +1,84 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * Intel IOMMU trace support
>> + *
>> + * Copyright (C) 2019 Intel Corporation
>> + *
>> + * Author: Lu Baolu <baolu.lu@...ux.intel.com>
>> + */
>> +#ifdef CONFIG_INTEL_IOMMU
>> +#undef TRACE_SYSTEM
>> +#define TRACE_SYSTEM intel_iommu
>> +
>> +#if !defined(_TRACE_INTEL_IOMMU_H) || defined(TRACE_HEADER_MULTI_READ)
>> +#define _TRACE_INTEL_IOMMU_H
>> +
>> +#include <linux/tracepoint.h>
>> +#include <linux/intel-iommu.h>
>> +
>> +DECLARE_EVENT_CLASS(dma_map,
>> +	TP_PROTO(struct device *dev, dma_addr_t dev_addr, phys_addr_t phys_addr,
>> +		 size_t size),
>> +
>> +	TP_ARGS(dev, dev_addr, phys_addr, size),
>> +
>> +	TP_STRUCT__entry(
>> +		__string(dev_name, dev_name(dev))
>> +		__field(dma_addr_t, dev_addr)
>> +		__field(phys_addr_t, phys_addr)
>> +		__field(size_t,	size)
>> +	),
>> +
>> +	TP_fast_assign(
>> +		__assign_str(dev_name, dev_name(dev));
>> +		__entry->dev_addr = dev_addr;
>> +		__entry->phys_addr = phys_addr;
>> +		__entry->size = size;
>> +	),
>> +
>> +	TP_printk("dev=%s dev_addr=0x%llx phys_addr=0x%llx size=%zu",
>> +		  __get_str(dev_name),
>> +		  (unsigned long long)__entry->dev_addr,
>> +		  (unsigned long long)__entry->phys_addr,
>> +		  __entry->size)
>> +);
>> +
>> +DEFINE_EVENT(dma_map, bounce_map_single,
>> +	TP_PROTO(struct device *dev, dma_addr_t dev_addr, phys_addr_t phys_addr,
>> +		 size_t size),
>> +	TP_ARGS(dev, dev_addr, phys_addr, size)
>> +);
> 
> Do you plan on adding more events to these classes? This patch has two
> distinct DECLARE_EVENT_CLASS() calls, and each has one DEFINE_EVENT()
> for them.

Yes, we will add more. This patch only adds the trace events that are
necessary for this patch series's development. It's easy to extend to
other events.

> 
> It's fine to do this, but I'm curious to why you did not use
> the "TRACE_EVENT()" macro, which basically is just a single
> DECLARE_EVENT_CLASS() followed by a single DEFINE_EVENT(). In other
> words, you just open coded TRACE_EVENT().

Fair enough.

> 
> -- Steve

Best regards,
Lu Baolu

> 
>> +
>> +DECLARE_EVENT_CLASS(dma_unmap,
>> +	TP_PROTO(struct device *dev, dma_addr_t dev_addr, size_t size),
>> +
>> +	TP_ARGS(dev, dev_addr, size),
>> +
>> +	TP_STRUCT__entry(
>> +		__string(dev_name, dev_name(dev))
>> +		__field(dma_addr_t, dev_addr)
>> +		__field(size_t,	size)
>> +	),
>> +
>> +	TP_fast_assign(
>> +		__assign_str(dev_name, dev_name(dev));
>> +		__entry->dev_addr = dev_addr;
>> +		__entry->size = size;
>> +	),
>> +
>> +	TP_printk("dev=%s dev_addr=0x%llx size=%zu",
>> +		  __get_str(dev_name),
>> +		  (unsigned long long)__entry->dev_addr,
>> +		  __entry->size)
>> +);
>> +
>> +DEFINE_EVENT(dma_unmap, bounce_unmap_single,
>> +	TP_PROTO(struct device *dev, dma_addr_t dev_addr, size_t size),
>> +	TP_ARGS(dev, dev_addr, size)
>> +);
>> +
>> +#endif /* _TRACE_INTEL_IOMMU_H */
>> +
>> +/* This part must be outside protection */
>> +#include <trace/define_trace.h>
>> +#endif /* CONFIG_INTEL_IOMMU */
> 
>