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

Steven Rostedt
2019-08-30T13:53:55Z

On Fri, 30 Aug 2019 15:17:17 +0800
Lu Baolu <baolu.lu@linux.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@intel.com>
> Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Cc: Kevin Tian <kevin.tian@intel.com>
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.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@linux.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@linux.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.

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().

-- Steve

> +
> +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 */