Re: [patch 1/1] Update laptop mode control script with XFS_HZ=100

[Bart Samwel <bart@xxxxxxxxx>]

Andrew Morton wrote:

> Nathan Scott <nathans@xxxxxxx> wrote:
>
> > What's the right way to convert milli/centiseconds into jiffies for
> > subsequent use in time_before()/schedule_timeout()?
>
>
> erm,
>
>         millisecs = (jiffies * 1000) / HZ
>         centisecs = (jiffies * 100) / HZ
>         jiffies = (millisecs * HZ) / 1000
>         jiffies = (centisecs * HZ) / 100
>
> obviously one needs to watch out for overflows, but I think we can safely
> assume the user is asking for less than 4 million seconds.

The XFS tunables are all guarded by max/min values, so this is 
guaranteed to not overflow.

--Bart