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From: John Stultz <john.stultz@linaro.org>
To: Dong Zhu <bluezhudong@gmail.com>, Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RESEND] timer stats: reset entries when disable the timer usage statistics
Date: Wed, 09 Oct 2013 21:04:48 -0700	[thread overview]
Message-ID: <52562760.9010400@linaro.org> (raw)
In-Reply-To: <20131010025947.GD2139@zhudong.nay.redhat.com>

On 10/09/2013 07:59 PM, Dong Zhu wrote:
> From f41628c61d8a9172677ba33a55b61e37ce28f7a6 Mon Sep 17 00:00:00 2001
> From: Dong Zhu <bluezhudong@gmail.com> 
> Date: Thu, 10 Oct 2013 10:38:13 +0800
>
> When we stop timer statistics collection (via echo 0 >
> /proc/timers_stats), the statistics data is still exported as if it were
> correct, which can cause applicaitons to misuse the statistics.
>
> This patch resets the statistics when we stop collecting them, to avoid
> this problem.
>
> Signed-off-by: Dong Zhu <bluezhudong@gmail.com>
> ---
>  kernel/time/timer_stats.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/kernel/time/timer_stats.c b/kernel/time/timer_stats.c
> index 0b537f2..43f05e7 100644
> --- a/kernel/time/timer_stats.c
> +++ b/kernel/time/timer_stats.c
> @@ -371,6 +371,7 @@ static ssize_t tstats_write(struct file *file, const char __user *buf,
>  	switch (ctl[0]) {
>  	case '0':
>  		if (timer_stats_active) {
> +			reset_entries();
>  			timer_stats_active = 0;
>  			time_stop = ktime_get();
>  			sync_access();

This looks ok to me. Thomas, do you have any objections here?

thanks
-john


  reply	other threads:[~2013-10-10  4:04 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-10  2:59 [PATCH RESEND] timer stats: reset entries when disable the timer usage statistics Dong Zhu
2013-10-10  4:04 ` John Stultz [this message]
2013-10-10  4:35 ` Ingo Molnar
2013-10-10  4:48   ` John Stultz
2013-10-10  6:14   ` [PATCH v2] timer stats: add a 'status' line to " Dong Zhu
2013-10-10  6:16     ` Ingo Molnar
2013-10-10  6:55       ` [PATCH v0.3] " Dong Zhu
2013-10-10  7:26         ` Ingo Molnar
2013-10-10  7:56           ` [PATCH v4] " Dong Zhu
2013-10-10 11:25             ` [tip:timers/core] timer stats: Add a 'Collection: active/inactive ' " tip-bot for Dong Zhu

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