Re: [PATCH] perf/x86/intel/uncore: Fix for iio mapping on Skylake Server

[Alexander Antonov <alexander.antonov@linux.intel.com>]

Hello Kyle,

Currently we do not have plans on supporting the Uncore units to IIO PMON
mapping on multiple segment platforms due to a variety of such platforms.
It would be great if you describe your case, I mean how you configure 
segments
on your platform. It will help to cover your configuration and determine a
common approach for the mapping algorithm.

Thanks,
Alexander

On 10/09/2020 05:11 PM, Meyer, Kyle wrote:
> Hello Alexander,
>
> Do you plan on supporting multiple segment platforms?
>
> Thanks,
> Kyle Meyer
>
> ________________________________________
> From: alexander.antonov@linux.intel.com <alexander.antonov@linux.intel.com>
> Sent: Monday, September 28, 2020 5:21 AM
> To: peterz@infradead.org; linux-kernel@vger.kernel.org; x86@kernel.org
> Cc: alexander.shishkin@linux.intel.com; kan.liang@linux.intel.com; alexey.budankov@linux.intel.com; ak@linux.intel.com; acme@kernel.org; mingo@redhat.com; alexander.antonov@linux.intel.com; Meyer, Kyle; Anderson, Russ
> Subject: [PATCH] perf/x86/intel/uncore: Fix for iio mapping on Skylake Server
>
> From: Alexander Antonov <alexander.antonov@linux.intel.com>
>
> Introduced early attributes /sys/devices/uncore_iio_<pmu_idx>/die* are
> initialized by skx_iio_set_mapping(), however, for example, for multiple
> segment platforms skx_iio_get_topology() returns -EPERM before a list of
> attributes in skx_iio_mapping_group will have been initialized.
> As a result the list is being NULL. Thus the warning
> "sysfs: (bin_)attrs not set by subsystem for group: uncore_iio_*/" appears
> and uncore_iio pmus are not available in sysfs. Clear IIO attr_update
> to properly handle the cases when topology information cannot be
> retrieved.
>
> Fixes: bb42b3d39781 ("perf/x86/intel/uncore: Expose an Uncore unit to IIO PMON mapping")
> Reported-by: Kyle Meyer <kyle.meyer@hpe.com>
> Suggested-by: Kan Liang <kan.liang@linux.intel.com>
> Reviewed-by: Alexei Budankov <alexey.budankov@linux.intel.com>
> Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
> Signed-off-by: Alexander Antonov <alexander.antonov@linux.intel.com>
> ---
>   arch/x86/events/intel/uncore_snbep.c | 7 +++++--
>   1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/events/intel/uncore_snbep.c b/arch/x86/events/intel/uncore_snbep.c
> index 62e88ad919ff..ccfa1d6b6aa0 100644
> --- a/arch/x86/events/intel/uncore_snbep.c
> +++ b/arch/x86/events/intel/uncore_snbep.c
> @@ -3749,7 +3749,9 @@ static int skx_iio_set_mapping(struct intel_uncore_type *type)
>
>          ret = skx_iio_get_topology(type);
>          if (ret)
> -               return ret;
> +               goto clear_attr_update;
> +
> +       ret = -ENOMEM;
>
>          /* One more for NULL. */
>          attrs = kcalloc((uncore_max_dies() + 1), sizeof(*attrs), GFP_KERNEL);
> @@ -3781,8 +3783,9 @@ static int skx_iio_set_mapping(struct intel_uncore_type *type)
>          kfree(eas);
>          kfree(attrs);
>          kfree(type->topology);
> +clear_attr_update:
>          type->attr_update = NULL;
> -       return -ENOMEM;
> +       return ret;
>   }
>
>   static void skx_iio_cleanup_mapping(struct intel_uncore_type *type)
>
> base-commit: a1b8638ba1320e6684aa98233c15255eb803fac7
> --
> 2.19.1
>