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From: Arnd Bergmann <arnd@arndb.de>
To: Andreas Schwab <schwab@linux-m68k.org>
Cc: linux-kernel@vger.kernel.org, Michal Hocko <mhocko@suse.cz>,
	"Artem S. Tashkinov" <t.artem@mailcity.com>,
	Dave Jones <davej@redhat.com>,
	Alexey Dobriyan <adobriyan@gmail.com>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH] procfs: do not confuse jiffies with cputime64_t
Date: Mon, 12 Dec 2011 09:22:13 +0000	[thread overview]
Message-ID: <201112120922.13633.arnd@arndb.de> (raw)
In-Reply-To: <m28vmi7ip3.fsf@igel.home>

On Monday 12 December 2011, Andreas Schwab wrote:
> @@ -46,7 +46,7 @@ static cputime64_t get_iowait_time(int cpu)
>                 /* !NO_HZ so we can rely on cpustat.iowait */
>                 iowait = kstat_cpu(cpu).cpustat.iowait;
>         else
> -               iowait = nsecs_to_jiffies64(1000 * iowait_time);
> +               iowait = jiffies64_to_cputime64(nsecs_to_jiffies64(1000 * iowait_time));
>  
>         return iowait;

Hmm, shouldn't this be using nsecs_to_cputime64()? For some reason however, that function
is (incorrectly?) defined as 

include/asm-generic/cputime.h:#define nsecs_to_cputime64(__ct)  nsecs_to_jiffies64(__ct)

and only used in one place, in

kernel/sched.c: if (cputime64_gt(nsecs_to_cputime64(latest_ns), cpustat->irq))
kernel/sched.c: if (cputime64_gt(nsecs_to_cputime64(latest_ns), cpustat->softirq))

I'm not sure what the correct solution is, but I would assume that ia64 and powerpc
should fix their definitions of nsecs_to_cputime64() anyway.

	Arnd

  parent reply	other threads:[~2011-12-12  9:23 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <m28vmi7ip3.fsf@igel.home>
2011-12-12  8:16 ` Michal Hocko
2011-12-12  9:22 ` Arnd Bergmann [this message]
2011-12-12 10:17   ` Andreas Schwab
2011-12-12 11:51   ` [PATCH v2] " Andreas Schwab
2011-12-12 12:43     ` Michal Hocko
2011-12-12 13:07       ` [PATCH v3] " Andreas Schwab
2011-12-12 13:12         ` Michal Hocko
2011-12-21 10:03           ` [resend PATCH for 3.2] " Michal Hocko
2011-12-21 19:43             ` Andrew Morton
2011-12-21 19:59             ` Andrew Morton
2011-12-21 23:50               ` Andreas Schwab
2011-12-21 23:56                 ` Andrew Morton
2011-12-22  0:14                   ` Andreas Schwab
2011-12-22  0:19                     ` Andrew Morton
2011-12-22 10:18                       ` Andreas Schwab
2011-12-21 23:55               ` Andreas Schwab
2011-12-21 23:59                 ` Andrew Morton
2011-12-22  0:20                   ` Andreas Schwab
2011-12-22  9:55               ` Martin Schwidefsky
2011-12-22 10:19               ` Andreas Schwab

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