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Subject: Re: [PATCH] i386: Selectable Frequency of the Timer Interrupt
From: Eric St-Laurent <ericstl34@sympatico.ca>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
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Date: Thu, 14 Jul 2005 21:17:43 -0400
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On Thu, 2005-07-14 at 23:37 +0100, Alan Cox wrote:

> In actual fact you also want to fix users of
> 
> 	while(time_before(foo, jiffies)) { whack(mole); }
> 
> to become
> 
> 	init_timeout(&timeout);
> 	timeout.expires = jiffies + n
> 	add_timeout(&timeout);
> 	while(!timeout_expired(&timeout)) {}
> 
> Which is a trivial wrapper around timers as we have them now

Or something like this:

struct timeout_timer {
	unsigned long expires;
};

static inline void timeout_set(struct timeout_timer *timer,
	unsigned int msecs)
{
	timer->expires = jiffies + msecs_to_jiffies(msecs);
}

static inline int timeout_expired(struct timeout_timer *timer)
{
	return (time_after(jiffies, timer->expires));
}

It provides a nice API for relative timeouts without adding overhead.


- Eric St-Laurent