[RFC] mod_timer() helper functions?

From: Chris Peterson
Date: Sat May 16 2009 - 03:36:35 EST


Reviewing the kernel's nearly one-thousand calls to mod_timer(), there
are three basic patterns:

* multi-second timeouts
* millisecond timeouts
* +1 jiffie ASAP events

Few mod_timer() calls actually use the function's 'expires' deadline
time without manually calculating 'jiffies + delay'. The following
helper functions could provide a simpler, more descriptive interface
than the low-level mod_timer() function. Also, when scheduling longer
timers, these helper functions could use round_jiffies() to (secretly)
batch timers on whole seconds to reduce power usage.

Any suggestions? Is there enough value to warrant adding helper
function like these as an alternative to mod_timer()?


chris

---
static inline int mod_timer_seconds(struct timer_list *timer, time_t seconds)
{
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));
}

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