Re: [PATCH v4 3/7] x86: mm/gup: add gup trace points

From: Steven Rostedt
Date: Wed Dec 09 2015 - 16:07:57 EST


On Wed, 9 Dec 2015 09:29:20 -0800
Yang Shi <yang.shi@xxxxxxxxxx> wrote:

> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
> Cc: x86@xxxxxxxxxx
> Signed-off-by: Yang Shi <yang.shi@xxxxxxxxxx>
> ---
> arch/x86/mm/gup.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/arch/x86/mm/gup.c b/arch/x86/mm/gup.c
> index ae9a37b..a96bcb7 100644
> --- a/arch/x86/mm/gup.c
> +++ b/arch/x86/mm/gup.c
> @@ -12,6 +12,9 @@
>
> #include <asm/pgtable.h>
>
> +#define CREATE_TRACE_POINTS
> +#include <trace/events/gup.h>>

First off, does the above even compile?

Second, you already created the tracepoints in mm/gup.c, why are you
creating them here again? CREATE_TRACE_POINTS must be defined only once
per events/.h file.

-- Steve

> +
> static inline pte_t gup_get_pte(pte_t *ptep)
> {
> #ifndef CONFIG_X86_PAE
> @@ -270,6 +273,8 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
> (void __user *)start, len)))
> return 0;
>
> + trace_gup_get_user_pages_fast(start, nr_pages);
> +
> /*
> * XXX: batch / limit 'nr', to avoid large irq off latency
> * needs some instrumenting to determine the common sizes used by
> @@ -373,6 +378,8 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
> } while (pgdp++, addr = next, addr != end);
> local_irq_enable();
>
> + trace_gup_get_user_pages_fast(start, nr_pages);
> +
> VM_BUG_ON(nr != (end - start) >> PAGE_SHIFT);
> return nr;
>

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