Re: [PATCH v6 1/7] perf: provide sysfs_show for struct perf_pmu_events_attr

[Jiri Olsa <jolsa@redhat.com>]

On Sun, Dec 21, 2014 at 11:48:46PM -0800, Sukadev Bhattiprolu wrote:
> From: Cody P Schafer <cody@linux.vnet.ibm.com>
> 
> (struct perf_pmu_events_attr) is defined in include/linux/perf_event.h,
> but the only "show" for it is in x86 and contains x86 specific stuff.
> 
> Make a generic one for those of us who are just using the event_str.
> 
> CC: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
> CC: Haren Myneni <hbabu@us.ibm.com>
> CC: Cody P Schafer <dev@codyps.com>
> Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
> ---
>  include/linux/perf_event.h | 3 +++
>  kernel/events/core.c       | 8 ++++++++
>  2 files changed, 11 insertions(+)
> 
> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
> index 486e84c..58f59bd 100644
> --- a/include/linux/perf_event.h
> +++ b/include/linux/perf_event.h
> @@ -897,6 +897,9 @@ struct perf_pmu_events_attr {
>  	const char *event_str;
>  };
>  
> +ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
> +			      char *page);
> +
>  #define PMU_EVENT_ATTR(_name, _var, _id, _show)				\
>  static struct perf_pmu_events_attr _var = {				\
>  	.attr = __ATTR(_name, 0444, _show, NULL),			\
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index af0a5ba..1808d0e 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -8276,6 +8276,14 @@ void __init perf_event_init(void)
>  		     != 1024);
>  }
>  
> +ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
> +			      char *page)
> +{
> +	struct perf_pmu_events_attr *pmu_attr =
> +		container_of(attr, struct perf_pmu_events_attr, attr);
> +	return sprintf(page, "%s\n", pmu_attr->event_str);
> +}
> +

Stephane just added same local one for RAPL pmu:
  433678bdc6ed perf/rapl: Fix sysfs_show() initialization for RAPL PMU

with additional pmu_attr->event_str check

same for PMU_EVENT_ATTR_STRING macro

if you could add this additional check plus the id initialization
in the PMU_EVENT_ATTR_STRING macro, we could use the generic
version in RAPL object as well

thanks,
jirka