Re: [PATCH v5 10/12] MIPS/Perf-events: allow modules to get pmu number of counters

[David Daney <david.s.daney@gmail.com>]

On 05/27/2010 06:03 AM, Deng-Cheng Zhu wrote:
> Oprofile module needs a function to get the number of pmu counters in its
> high level interfaces.
>
> Signed-off-by: Deng-Cheng Zhu<dengcheng.zhu@gmail.com>
> ---
>   arch/mips/include/asm/pmu.h   |    1 +
>   arch/mips/kernel/perf_event.c |    6 ++++++
>   2 files changed, 7 insertions(+), 0 deletions(-)
>
> diff --git a/arch/mips/include/asm/pmu.h b/arch/mips/include/asm/pmu.h
> index 16d4fcd..023a915 100644
> --- a/arch/mips/include/asm/pmu.h
> +++ b/arch/mips/include/asm/pmu.h
> @@ -114,5 +114,6 @@ enum mips_pmu_id {
>   extern const char *mips_pmu_names[];
>
>   extern enum mips_pmu_id mipspmu_get_pmu_id(void);
> +extern int mipspmu_get_max_events(void);
>
>   #endif /* __MIPS_PMU_H__ */
> diff --git a/arch/mips/kernel/perf_event.c b/arch/mips/kernel/perf_event.c
> index f05e2b1..dc3a553 100644
> --- a/arch/mips/kernel/perf_event.c
> +++ b/arch/mips/kernel/perf_event.c
> @@ -140,6 +140,12 @@ enum mips_pmu_id mipspmu_get_pmu_id(void)
>   }
>   EXPORT_SYMBOL_GPL(mipspmu_get_pmu_id);
>
> +int mipspmu_get_max_events(void)
> +{
> +       return mipspmu ? mipspmu->num_counters : 0;
> +}
> +EXPORT_SYMBOL_GPL(mipspmu_get_max_events);
> +
Why is it called 'max_events' when it is returning the number of 
counters?  How about mipspmu_get_max_counters?
Do we even need this accessor?

Why not just query it from the struct mips_pmu?  Don't you need the 
mipspmu structure anyhow to be able to use the counters?
David Daney