On Mon, Apr 02 2018, Dilger, Andreas wrote: >> On Mar 30, 2018, at 13:02, James Simmons <jsimm...@infradead.org> wrote: >> >> >>> This function simply multiplies by HZ and adds jiffies. >>> This is simple enough to be opencoded, and doing so >>> makes the code easier to read. >>> >>> Same for cfs_time_shift_64() >> >> Reviewed-by: James Simmons <jsimm...@infradead.org> > > Hmm, I thought we were trying to get rid of direct HZ usage in modules, > because of tickless systems, and move to e.g. msecs_to_jiffies() or similar?
Are we? I hadn't heard but I could easily have missed it.
Documentation/scheduler/completion.txt does say
Timeouts are preferably calculated with
msecs_to_jiffies() or usecs_to_jiffies().
but is isn't clear what they are preferred to. Do you remember where
you heard? or have a reference?
$ git grep ' \* *HZ' |wc
2244 15679 170016
$ git grep msecs_to_jiffies | wc
3301 13151 276725
so msecs_to_jiffies is slightly more popular than "* HZ" (even if you add
in "HZ *"). But that could just be a preference for using milliseconds
over using seconds.
$ git grep msecs_to_jiffies | grep -c '[0-9]000'
587
so there are only 587 places that msecs_to_jiffies is clearly used in
place of multiplying by HZ.
If we were to pursue this, I would want to add secs_to_jiffies() to
include/linux/jiffies.h and use that.
Thanks,
NeilBrown
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