linux-kernel - Re: [PATCH 2/7] perf/cgroup: order events in RB tree by cgroup id

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Date:   Mon, 8 Jul 2019 18:16:36 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Ian Rogers <irogers@...gle.com>
Cc:     Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        linux-kernel@...r.kernel.org,
        Kan Liang <kan.liang@...ux.intel.com>,
        Stephane Eranian <eranian@...gle.com>
Subject: Re: [PATCH 2/7] perf/cgroup: order events in RB tree by cgroup id

On Mon, Jul 01, 2019 at 11:59:50PM -0700, Ian Rogers wrote:
> +static int visit_groups_merge(struct perf_event_context *ctx,
> +			      struct perf_cpu_context *cpuctx,
> +			      struct perf_event_groups *groups,
> +			      int (*func)(struct perf_event_context *,
> +					  struct perf_cpu_context *,
> +					  struct perf_event *,
> +					  int *),
> +			      int *data)

> -struct sched_in_data {
> -	struct perf_event_context *ctx;
> -	struct perf_cpu_context *cpuctx;
> -	int can_add_hw;
> -};
> -
> -static int pinned_sched_in(struct perf_event *event, void *data)
> +static int pinned_sched_in(struct perf_event_context *ctx,
> +			   struct perf_cpu_context *cpuctx,
> +			   struct perf_event *event,
> +			   int *unused)
>  {
> -	struct sched_in_data *sid = data;
> -
>  	if (event->state <= PERF_EVENT_STATE_OFF)
>  		return 0;
>  
>  	if (!event_filter_match(event))
>  		return 0;
>  
> -	if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
> -		if (!group_sched_in(event, sid->cpuctx, sid->ctx))
> -			list_add_tail(&event->active_list, &sid->ctx->pinned_active);
> +	if (group_can_go_on(event, cpuctx, 1)) {
> +		if (!group_sched_in(event, cpuctx, ctx))
> +			list_add_tail(&event->active_list, &ctx->pinned_active);
>  	}
>  
>  	/*
> @@ -3317,24 +3444,25 @@ static int pinned_sched_in(struct perf_event *event, void *data)
>  	return 0;
>  }
>  
> -static int flexible_sched_in(struct perf_event *event, void *data)
> +static int flexible_sched_in(struct perf_event_context *ctx,
> +			     struct perf_cpu_context *cpuctx,
> +			     struct perf_event *event,
> +			     int *can_add_hw)
>  {
> -	struct sched_in_data *sid = data;
> -
>  	if (event->state <= PERF_EVENT_STATE_OFF)
>  		return 0;
>  
>  	if (!event_filter_match(event))
>  		return 0;
>  
> -	if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
> -		int ret = group_sched_in(event, sid->cpuctx, sid->ctx);
> +	if (group_can_go_on(event, cpuctx, *can_add_hw)) {
> +		int ret = group_sched_in(event, cpuctx, ctx);
>  		if (ret) {
> -			sid->can_add_hw = 0;
> -			sid->ctx->rotate_necessary = 1;
> +			*can_add_hw = 0;
> +			ctx->rotate_necessary = 1;
>  			return 0;
>  		}
> -		list_add_tail(&event->active_list, &sid->ctx->flexible_active);
> +		list_add_tail(&event->active_list, &ctx->flexible_active);
>  	}
>  
>  	return 0;
> @@ -3344,30 +3472,24 @@ static void
>  ctx_pinned_sched_in(struct perf_event_context *ctx,
>  		    struct perf_cpu_context *cpuctx)
>  {
> -	struct sched_in_data sid = {
> -		.ctx = ctx,
> -		.cpuctx = cpuctx,
> -		.can_add_hw = 1,
> -	};
> -
> -	visit_groups_merge(&ctx->pinned_groups,
> -			   smp_processor_id(),
> -			   pinned_sched_in, &sid);
> +	visit_groups_merge(ctx,
> +			   cpuctx,
> +			   &ctx->pinned_groups,
> +			   pinned_sched_in,
> +			   NULL);
>  }
>  
>  static void
>  ctx_flexible_sched_in(struct perf_event_context *ctx,
>  		      struct perf_cpu_context *cpuctx)
>  {
> -	struct sched_in_data sid = {
> -		.ctx = ctx,
> -		.cpuctx = cpuctx,
> -		.can_add_hw = 1,
> -	};
> +	int can_add_hw = 1;
>  
> -	visit_groups_merge(&ctx->flexible_groups,
> -			   smp_processor_id(),
> -			   flexible_sched_in, &sid);
> +	visit_groups_merge(ctx,
> +			   cpuctx,
> +			   &ctx->flexible_groups,
> +			   flexible_sched_in,
> +			   &can_add_hw);
>  }

It is not clear to me why you're doing away with that sched_in_data
abstraction. AFAICT that has no material impact on this patch.