linux-kernel - Re: [PATCH v3 3/7] sched: make schedstats helpers independent of fair sched class

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Message-ID: <YS4Nbzz6Kosfhx5M@hirez.programming.kicks-ass.net>
Date:   Tue, 31 Aug 2021 13:07:27 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Yafang Shao <laoar.shao@...il.com>
Cc:     mingo@...hat.com, mgorman@...e.de, juri.lelli@...hat.com,
        vincent.guittot@...aro.org, dietmar.eggemann@....com,
        rostedt@...dmis.org, bsegall@...gle.com, bristot@...hat.com,
        achaiken@...ora.tech, lkp@...el.com, linux-kernel@...r.kernel.org,
        linux-rt-users@...r.kernel.org
Subject: Re: [PATCH v3 3/7] sched: make schedstats helpers independent of
 fair sched class

On Tue, Aug 24, 2021 at 11:29:42AM +0000, Yafang Shao wrote:
> diff --git a/kernel/sched/stats.c b/kernel/sched/stats.c
> index 3f93fc3b5648..b2542f4d3192 100644
> --- a/kernel/sched/stats.c
> +++ b/kernel/sched/stats.c
> @@ -4,6 +4,109 @@
>   */
>  #include "sched.h"
>  
> +void __update_stats_wait_start(struct rq *rq, struct task_struct *p,
> +			       struct sched_statistics *stats)
> +{
> +u64 wait_start, prev_wait_start;

indent fail...

> +
> +	wait_start = rq_clock(rq);
> +	prev_wait_start = schedstat_val(stats->wait_start);
> +
> +	if (p && likely(wait_start > prev_wait_start))
> +		wait_start -= prev_wait_start;
> +
> +	__schedstat_set(stats->wait_start, wait_start);
> +}

> diff --git a/kernel/sched/stats.h b/kernel/sched/stats.h
> index e6905e369c5d..9ecd81b91f26 100644
> --- a/kernel/sched/stats.h
> +++ b/kernel/sched/stats.h

> @@ -40,6 +42,33 @@ rq_sched_info_dequeue(struct rq *rq, unsigned long long delta)
>  #define   schedstat_val(var)		(var)
>  #define   schedstat_val_or_zero(var)	((schedstat_enabled()) ? (var) : 0)
>  
> +void __update_stats_wait_start(struct rq *rq, struct task_struct *p,
> +			       struct sched_statistics *stats);
> +
> +void __update_stats_wait_end(struct rq *rq, struct task_struct *p,
> +			     struct sched_statistics *stats);
> +void __update_stats_enqueue_sleeper(struct rq *rq, struct task_struct *p,
> +				    struct sched_statistics *stats);
> +
> +static inline void
> +check_schedstat_required(void)
> +{
> +	if (schedstat_enabled())
> +		return;
> +
> +	/* Force schedstat enabled if a dependent tracepoint is active */
> +	if (trace_sched_stat_wait_enabled()    ||
> +		trace_sched_stat_sleep_enabled()   ||
> +		trace_sched_stat_iowait_enabled()  ||
> +		trace_sched_stat_blocked_enabled() ||
> +		trace_sched_stat_runtime_enabled())  {
> +		printk_deferred_once("Scheduler tracepoints stat_sleep, stat_iowait, "
> +					"stat_blocked and stat_runtime require the "
> +					"kernel parameter schedstats=enable or "
> +					"kernel.sched_schedstats=1\n");
> +	}
> +}

If you're moving this, you might as well reflow it to not have broken
indentation.