Re: [PATCH] Consolidate multiple implementations of jiffies-msecs conversions.

On Fri, 26 Mar 2004, Edgar Toernig wrote:

Sridhar Samudrala wrote:

quoted

The following patch to 2.6.5-rc2 consolidates 6 different implementations
of msecs to jiffies and 3 different implementation of jiffies to msecs.
All of them now use the generic msecs_to_jiffies() and jiffies_to_msecs()
that are added to include/linux/time.h
[...]
-#define MSECS(ms)  (((ms)*HZ/1000)+1)
-return (((ms)*HZ+999)/1000);
+return (msecs / 1000) * HZ + (msecs % 1000) * HZ / 1000;

Did you check that all users of the new version will work correctly
with your rounding?  Explicit round-up of delays is often required,
especially when talking to hardware...

I don't see any issues with the 2.6 default HZ value of 1000 as they become
no-ops and there is no need for any rounding.
I guess you are referring to cases when HZ < 1000(ex: 100) and msecs is
less than 10. In those cases, the new version returns 0, whereas some of the
older versions return 1.

If i am not mistaken, Jeff Garjik/David Miller are the maintainers for most
of the users of these routines and i have got an OK from them.
   drivers/block/carmel.c
   drivers/net/tulip/de204x.c
   include/linux/libata.h
   include/net/irda/irda.h
   drivers/atm/fore200e.c
   include/net/sctp/sctp.h

The only other place where the older version is different is
   drivers/char/watchdot/shwdt.c

Dave, Jeff
  Do you see any issues with the new generic versions of these routines?

Thanks
Sridhar

Ciao, ET.