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From: Andi Kleen <andi@firstfloor.org>
To: Chris Peterson <cpeterso@cpeterso.com>
Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de
Subject: Re: [RFC] mod_timer() helper functions?
Date: Mon, 18 May 2009 09:14:21 +0200	[thread overview]
Message-ID: <87eiumq3w2.fsf@basil.nowhere.org> (raw)
In-Reply-To: <a24804730905160036j2720c557o347cec1513df9c4a@mail.gmail.com> (Chris Peterson's message of "Sat, 16 May 2009 00:36:15 -0700")

Chris Peterson <cpeterso@cpeterso.com> writes:
>
> Any suggestions? Is there enough value to warrant adding helper
> function like these as an alternative to mod_timer()?

I like the basic idea. The opencoding has always annoyed me.
>
>
> chris
>
> ---
> static inline int mod_timer_seconds(struct timer_list *timer, time_t seconds)

I would prefer a name like mod_timer_in_secs() to make it clear it's relative

> {
> 	return mod_timer(timer, round_jiffies(jiffies + seconds * HZ));
> }

>
> static inline int mod_timer_msecs(struct timer_list *timer, unsigned int msecs)
> {
> 	/* TODO? Round jiffies if within some epsilon of a whole second? */
> 	return mod_timer(timer, jiffies + msecs_to_jiffies(msecs));

This is a bit misleading because depending on HZ the accuracy is far from
a millisecond (worst case 10ms error with HZ==100). Naming should make
that clearer. Or maybe these users should all switch to hrtimers,
but then those could be not available either.

I suspect you also want a helper for longer term delays that uses
deferred timers or more aggressive rounding.


> }
>
> static inline int mod_timer_yield(struct timer_list *timer)
> {
> 	/* After these messages, we'll be right back. */
> 	return mod_timer(timer, jiffies + 1);

Can't say I like the name here, although I don't have a better one.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only.

  parent reply	other threads:[~2009-05-18  7:14 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-16  7:36 [RFC] mod_timer() helper functions? Chris Peterson
2009-05-17  6:03 ` Andrew Morton
2009-05-17  7:50   ` Chris Peterson
2009-05-17  8:03     ` Andrew Morton
2009-05-17 12:13       ` Thomas Gleixner
2009-05-18  7:14 ` Andi Kleen [this message]
2009-05-20  7:11   ` Chris Peterson
2009-05-20  8:14     ` Andi Kleen
2009-05-21  5:11       ` Chris Peterson

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