linux-kernel - Re: [PATCH 2/2] time: Cleanup offs_real/wall_to_mono and offs_boot/total_sleep

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Date:	Thu, 26 Jul 2012 14:57:21 +0200
From:	Ingo Molnar <mingo@...nel.org>
To:	John Stultz <john.stultz@...aro.org>
Cc:	lkml <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Richard Cochran <richardcochran@...il.com>,
	Prarit Bhargava <prarit@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH 2/2] time: Cleanup offs_real/wall_to_mono and
 offs_boot/total_sleep_time updates


* John Stultz <john.stultz@...aro.org> wrote:

> On 07/19/2012 02:33 AM, Ingo Molnar wrote:
> >* John Stultz <john.stultz@...aro.org> wrote:
> >
> >>+static void tk_set_sleep_time(struct timekeeper *tk, struct timespec t)
> >>+{
> >>+	/* Verify consistency before modifying */
> >>+	WARN_ON_ONCE(tk->offs_boot.tv64 !=
> >>+				timespec_to_ktime(tk->total_sleep_time).tv64);
> >asserts like this can be put into a single line - we rarely need
> >to read them if they don't trigger - and making them
> >non-intrusive oneliners is a bonus.
> 
> Ack.
> 
> >>  @@ -456,8 +478,8 @@ int timekeeping_inject_offset(struct timespec *ts)
> >>  	tk_xtime_add(&timekeeper, ts);
> >>-	timekeeper.wall_to_monotonic =
> >>-				timespec_sub(timekeeper.wall_to_monotonic, *ts);
> >>+	tk_set_wall_to_mono(&timekeeper,
> >>+			timespec_sub(timekeeper.wall_to_monotonic, *ts));
> >There's a *lot* of unnecessary ugliness here and in many other
> >places in kernel/time/ due to repeating patterns of
> >"timekeeper.", which gets repeated many times and blows up line
> >length.
> >
> >Please add this to the highest level (system call, irq handler,
> >etc.) code:
> >
> >	struct timekeeper *tk = &timekeeper;
> >
> >and pass that down to lower levels. The tk-> pattern will be the
> >obvious thing to type in typical time handling functions.
> >
> >This increases readability and clarifies the data flow and might
> >bring other advantages in the future.
> 
> Sounds good. Are you ok if this is done in a follow-on patch?

Yeah, sure - the code is going in the right direction in 
general, so no hurry.

Thanks,

	Ingo
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