Re: syncing the disks when entering sleep

Pavel Machek
2010-01-26T13:59:43Z

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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