Re: syncing the disks when entering sleep

Rafael J. Wysocki
2010-01-26T18:17:37Z

On Tuesday 26 January 2010, Pavel Machek wrote:
> 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.

Define "ugly", please.

> But maybe acceptable way would be echo mem-nosync > power, or maybe it can
> already be done using s2disk ioctl interface...?

Nope.

Rafael