Re: [PATCH] Revert "perf: Add a counter for number of user access events in context"

[Peter Zijlstra <peterz@infradead.org>]

On Mon, Aug 05, 2024 at 04:10:31PM -0700, Song Liu wrote:
> This reverts commit 82ff0c022d19c2ad69a472692bb7ee01ac07a40b.
> 
> perf_event->nr_user is not used any more. Remove it.

Might be helpful to know where the user went..

> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Rob Herring <robh@kernel.org>
> Cc: Will Deacon <will@kernel.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Signed-off-by: Song Liu <song@kernel.org>
> ---
>  include/linux/perf_event.h | 1 -
>  kernel/events/core.c       | 4 ----
>  2 files changed, 5 deletions(-)
> 
> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
> index 1a8942277dda..509ae4770bbe 100644
> --- a/include/linux/perf_event.h
> +++ b/include/linux/perf_event.h
> @@ -931,7 +931,6 @@ struct perf_event_context {
>  	struct list_head		event_list;
>  
>  	int				nr_events;
> -	int				nr_user;
>  	int				is_active;
>  
>  	int				nr_task_data;
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index aa3450bdc227..6f44755ae907 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -1793,8 +1793,6 @@ list_add_event(struct perf_event *event, struct perf_event_context *ctx)
>  
>  	list_add_rcu(&event->event_entry, &ctx->event_list);
>  	ctx->nr_events++;
> -	if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
> -		ctx->nr_user++;
>  	if (event->attr.inherit_stat)
>  		ctx->nr_stat++;
>  
> @@ -2017,8 +2015,6 @@ list_del_event(struct perf_event *event, struct perf_event_context *ctx)
>  	event->attach_state &= ~PERF_ATTACH_CONTEXT;
>  
>  	ctx->nr_events--;
> -	if (event->hw.flags & PERF_EVENT_FLAG_USER_READ_CNT)
> -		ctx->nr_user--;
>  	if (event->attr.inherit_stat)
>  		ctx->nr_stat--;
>  
> -- 
> 2.43.5
>