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

[Lu Baolu]

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@xxxxxxxxxxxxxxx> 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@xxxxxxxxx>
> > Cc: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> > Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
> > Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> > Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> > Reviewed-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
> > ---
> >   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@xxxxxxxxxxxxxxx>
> > + */
> > +
> > +#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@xxxxxxxxxxxxxxx>
> > + */
> > +#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 */