Re: syncing the disks when entering sleep

[Pavel Machek <pavel@ucw.cz>]

Hi!

> > I noticed when we enter sleep states, it seems there's always a
> > sys_sync given.
> > 
> > When having an embedded system doing WOL (already in laptop mode to
> > cache
> > all the writes), it reasonable to wake up dozens of times of day and
> > quickly go back to sleep.  If the disk is not spun up,
> > and there's some work to be done, won't the sys_sync spin up the disk
> > before going to sleep?
> > 
> > It would be good to have a knob (in /sys) you can tweak from usespace to
> > 
> > configure the behavior of whether you want to do a sync when entering
> > sleep.
> > 
> > The ideal behavior would be:
> > 
> >     if(disk is spun up)
> >         then let the sync happen
> 
> I'm not against that.  Patch welcome. :-)

I'd say such knob would be ugly. But maybe acceptable way would be
echo mem-nosync > power, or maybe it can already be done using s2disk
ioctl interface...?
									Pavel
-- 
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