Re: [PATCH 1/3] perf: comment on usage of perf_invalid_context

[Peter Zijlstra <peterz@infradead.org>]

On Thu, Jan 09, 2014 at 03:51:30PM -0800, Cody P Schafer wrote:
> Context numbers less than 0 are treated specially within the events
> code, add a comment to document this.
> 
> Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
> ---
>  include/linux/sched.h | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 53f97eb..f574820 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -1033,6 +1033,10 @@ struct sched_rt_entity {
>  struct rcu_node;
>  
>  enum perf_event_task_context {
> +	/*
> +	 * When <0, allocate a pmu local pmu->pmu_cpu_context (instead
> +	 * of sharing among pmus in the same context) and forbid task tracking.
> +	 */

Please explain things in terms of the existing enum names; we don't want
people to start using randon negative values instead of
'perf_invalid_context'.

>  	perf_invalid_context = -1,
>  	perf_hw_context = 0,
>  	perf_sw_context,
> -- 
> 1.8.5.2
>