Re: [PATCH] perf_counter: extensible perf_counter_attr

[Paul Mackerras <paulus@samba.org>]

Peter Zijlstra writes:

> Allow extending the perf_counter_attr structure by linking extended
> structures to it.

...

> @@ -175,6 +175,13 @@ struct perf_counter_attr {
>  	__u32			__reserved_3;
>  
>  	__u64			__reserved_4;
> +
> +	struct perf_counter_attr_ext *ext_attrs;
> +};

Since this is a user-visible structure, you've just introduced an ABI
difference between 32-bit and 64-bit processes, which we've managed to
avoid so far.  Assuming that is that you intend eventually to use the
value that userspace puts there, which you don't at the moment.  Was
that your intention?

Paul.