Re: [PATCH v8 10/10] tracing/hyper-v: trace hyperv_mmu_flush_tlb_others()

[Steven Rostedt]

On Fri,  9 Jun 2017 15:27:36 +0200
Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> wrote:

> Add Hyper-V tracing subsystem and trace hyperv_mmu_flush_tlb_others().
> Tracing is done the same way we do xen_mmu_flush_tlb_others().
> 
> Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
> ---
>  MAINTAINERS                         |  1 +
>  arch/x86/hyperv/mmu.c               |  7 +++++++
>  arch/x86/include/asm/trace/hyperv.h | 38 +++++++++++++++++++++++++++++++++++++
>  3 files changed, 46 insertions(+)
>  create mode 100644 arch/x86/include/asm/trace/hyperv.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index e3f44fd..001614b 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -6168,6 +6168,7 @@ M:	Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>
>  L:	devel@xxxxxxxxxxxxxxxxxxxxxx
>  S:	Maintained
>  F:	arch/x86/include/asm/mshyperv.h
> +F:	arch/x86/include/asm/trace/hyperv.h
>  F:	arch/x86/include/uapi/asm/hyperv.h
>  F:	arch/x86/kernel/cpu/mshyperv.c
>  F:	arch/x86/hyperv
> diff --git a/arch/x86/hyperv/mmu.c b/arch/x86/hyperv/mmu.c
> index 0712111..cb35453 100644
> --- a/arch/x86/hyperv/mmu.c
> +++ b/arch/x86/hyperv/mmu.c
> @@ -8,6 +8,9 @@
>  #include <asm/msr.h>
>  #include <asm/tlbflush.h>
>  
> +#define CREATE_TRACE_POINTS
> +#include <asm/trace/hyperv.h>
> +
>  /* HvFlushVirtualAddressSpace, HvFlushVirtualAddressList hypercalls */
>  struct hv_flush_pcpu {
>  	u64 address_space;
> @@ -103,6 +106,8 @@ static void hyperv_flush_tlb_others(const struct cpumask *cpus,
>  	u64 status = U64_MAX;
>  	unsigned long flags;
>  
> +	trace_hyperv_mmu_flush_tlb_others(cpus, mm, start, end);
> +
>  	if (!pcpu_flush || !hv_hypercall_pg)
>  		goto do_native;
>  
> @@ -172,6 +177,8 @@ static void hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
>  	u64 status = U64_MAX;
>  	unsigned long flags;
>  
> +	trace_hyperv_mmu_flush_tlb_others(cpus, mm, start, end);
> +
>  	if (!pcpu_flush_ex || !hv_hypercall_pg)
>  		goto do_native;
>  
> diff --git a/arch/x86/include/asm/trace/hyperv.h b/arch/x86/include/asm/trace/hyperv.h
> new file mode 100644
> index 0000000..e44ece1
> --- /dev/null
> +++ b/arch/x86/include/asm/trace/hyperv.h
> @@ -0,0 +1,38 @@
> +#undef TRACE_SYSTEM
> +#define TRACE_SYSTEM hyperv
> +
> +#if !defined(_TRACE_HYPERV_H) || defined(TRACE_HEADER_MULTI_READ)
> +#define _TRACE_HYPERV_H
> +
> +#include <linux/tracepoint.h>
> +
> +#if IS_ENABLED(CONFIG_HYPERV)

Hmm, this is new to me. I know you can use IS_ENABLED() inside C code,
but I've never seen it used for preprocessor directives. This usually
is just:

#ifdef CONFIG_HYPERV

Other than that, this looks fine to me.

-- Steve

> +
> +TRACE_EVENT(hyperv_mmu_flush_tlb_others,
> +	    TP_PROTO(const struct cpumask *cpus, struct mm_struct *mm,
> +		     unsigned long addr, unsigned long end),
> +	    TP_ARGS(cpus, mm, addr, end),
> +	    TP_STRUCT__entry(
> +		    __field(unsigned int, ncpus)
> +		    __field(struct mm_struct *, mm)
> +		    __field(unsigned long, addr)
> +		    __field(unsigned long, end)
> +		    ),
> +	    TP_fast_assign(__entry->ncpus = cpumask_weight(cpus);
> +			   __entry->mm = mm;
> +			   __entry->addr = addr,
> +			   __entry->end = end),
> +	    TP_printk("ncpus %d mm %p addr %lx, end %lx",
> +		      __entry->ncpus, __entry->mm, __entry->addr, __entry->end)
> +	);
> +
> +#endif /* CONFIG_HYPERV */
> +
> +#undef TRACE_INCLUDE_PATH
> +#define TRACE_INCLUDE_PATH asm/trace/
> +#undef TRACE_INCLUDE_FILE
> +#define TRACE_INCLUDE_FILE hyperv
> +#endif /* _TRACE_HYPERV_H */
> +
> +/* This part must be outside protection */
> +#include <trace/define_trace.h>