Re: [PATCH] perf/x86/intel: Export mem events only if there's PEBs support

[Peter Zijlstra]

On Mon, Aug 27, 2018 at 11:06:24AM +0200, Jiri Olsa wrote:
> +static __init struct attribute **get_hsw_events_attrs(bool *alloc)
>  {
> +     if (boot_cpu_has(X86_FEATURE_RTM)) {
> +             *alloc = true;
> +             return merge_attr(hsw_events_attrs, hsw_tsx_events_attrs);
> +     }
> +     return hsw_events_attrs;
>  }



> @@ -4357,6 +4374,15 @@ __init int intel_pmu_init(void)
>               WARN_ON(!x86_pmu.format_attrs);
>       }
>  
> +     if (x86_pmu.pebs && mem_attr) {
> +             struct attribute **attr = x86_pmu.cpu_events;
> +
> +             x86_pmu.cpu_events = merge_attr(x86_pmu.cpu_events, mem_attr);
> +
> +             if (alloc_events)
> +                     kfree(attr);
> +     }
> +
>       if (x86_pmu.num_counters > INTEL_PMC_MAX_GENERIC) {
>               WARN(1, KERN_ERR "hw perf events %d > max(%d), clipping!",
>                    x86_pmu.num_counters, INTEL_PMC_MAX_GENERIC);


static __init struct attribute **
get_events_attrs(struct attribute **base,
                 struct attribute **mem,
                 struct attribute **tsx)
{
        struct attribute **attrs = base;
        struct attribute **old;

        if (mem) {
                old = attrs;
                attrs = merge_attrs(attrs, mem);
                if (old != base)
                        kfree(old);
        }

        if (tsx && boot_cpu_has(X86_FEATURE_RTM)) {
                old = attrs;
                attrs = merge_attrs(attrs, tsx);
                if (old != base)
                        kfree(old);
        }

        return attrs;
}

Would that not help to concentrate things a little more?