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Date: Thu, 28 May 2015 10:41:10 +0530
From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
To: bsingharora@gmail.com, mingo@kernel.org
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] proc/schedstat: Expose /proc/<pid>/schedstat if delay
 accounting is enabled
Message-ID: <20150528051110.GF30276@naverao1-tp.ibm.com>
References: <1432537954-26665-1-git-send-email-naveen.n.rao@linux.vnet.ibm.com>
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Ingo, Balbir,
Any comments on this? Can you please take a look?

Thanks,
Naveen

On 2015/05/25 12:42PM, Naveen N Rao wrote:
> /proc/<pid>/schedstat is currently only available if CONFIG_SCHEDSTATS is
> enabled. But, all the fields that this exposes are available and valid
> if CONFIG_TASK_DELAY_ACCT is enabled as well.
> 
> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
> ---
>  fs/proc/base.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/proc/base.c b/fs/proc/base.c
> index 093ca14..3ece303 100644
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -304,14 +304,17 @@ static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
>  }
>  #endif
> 
> -#ifdef CONFIG_SCHEDSTATS
> +#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
>  /*
>   * Provides /proc/PID/schedstat
>   */
>  static int proc_pid_schedstat(struct seq_file *m, struct pid_namespace *ns,
>  			      struct pid *pid, struct task_struct *task)
>  {
> -	seq_printf(m, "%llu %llu %lu\n",
> +	if (unlikely(!sched_info_on()))
> +		seq_printf(m, "0 0 0\n");
> +	else
> +		seq_printf(m, "%llu %llu %lu\n",
>  		   (unsigned long long)task->se.sum_exec_runtime,
>  		   (unsigned long long)task->sched_info.run_delay,
>  		   task->sched_info.pcount);
> @@ -2600,7 +2603,7 @@ static const struct pid_entry tgid_base_stuff[] = {
>  #ifdef CONFIG_STACKTRACE
>  	ONE("stack",      S_IRUSR, proc_pid_stack),
>  #endif
> -#ifdef CONFIG_SCHEDSTATS
> +#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
>  	ONE("schedstat",  S_IRUGO, proc_pid_schedstat),
>  #endif
>  #ifdef CONFIG_LATENCYTOP
> @@ -2948,7 +2951,7 @@ static const struct pid_entry tid_base_stuff[] = {
>  #ifdef CONFIG_STACKTRACE
>  	ONE("stack",      S_IRUSR, proc_pid_stack),
>  #endif
> -#ifdef CONFIG_SCHEDSTATS
> +#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
>  	ONE("schedstat", S_IRUGO, proc_pid_schedstat),
>  #endif
>  #ifdef CONFIG_LATENCYTOP
> -- 
> 2.4.0
>