Re: [PATCH v4 01/18] perf, x86: Support CPU specific sysfs events

[Jiri Olsa <jolsa@redhat.com>]

On Thu, Dec 20, 2012 at 04:41:31PM +0100, Stephane Eranian wrote:
> From: Andi Kleen <ak@linux.intel.com>
> 
> Add a way for the CPU initialization code to register additional events,
> and merge them into the events attribute directory. Used in the next
> patch.
> 
> Signed-off-by: Andi Kleen <ak@linux.intel.com>
> ---
>  arch/x86/kernel/cpu/perf_event.c |   29 +++++++++++++++++++++++++++++
>  arch/x86/kernel/cpu/perf_event.h |    1 +
>  2 files changed, 30 insertions(+)
> 
> diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
> index 4428fd1..83f4c1a 100644
> --- a/arch/x86/kernel/cpu/perf_event.c
> +++ b/arch/x86/kernel/cpu/perf_event.c
> @@ -1341,6 +1341,30 @@ static void __init filter_events(struct attribute **attrs)
>  	}
>  }
>  
> +/* Merge two pointer arrays */
> +static __init struct attribute **merge_attr(struct attribute **a,
> +					    struct attribute **b)
> +{
> +	struct attribute **new;
> +	int j, i;
> +
> +	for (j = 0; a[j]; j++)
> +		;
> +	for (i = 0; b[i]; i++)
> +		j++;
> +	j++;
> +	new = kmalloc(sizeof(struct attribute *) * j, GFP_KERNEL);
> +	if (!new)
> +		return a;

not likely to happen, but still.. do we want proper error handling?

other than that the patch looks ok to me

jirka