Re: [linux-pm] Re: [PATCH] Remove process freezer from suspend toRAM pathway

From: Miklos Szeredi
Date: Tue Jul 03 2007 - 16:20:29 EST


> > Well, but you did remove sys_sync() from the freezer, which is
> > and must be called in the hibernate path.
>
> That's not really true. We _want_ to call sys_sync() in both the
> hibernate and suspend paths (in case the batteries run down), to help
> avoid filesystem problems if something goes wrong with the resume. But
> it isn't a hard requirement.
>
> > > I'm not sure why this can't be made atomic, but assuming, that it
> > > can't, fuse should still not need to be implicated. If it is, that's
> > > an indication about something wrong in the suspend procedure.
> >
> > Nope, something's wrong in fuse. You must be able to deal with sync
> > until every task is frozen.
>
> That's ridiculous. FUSE itself runs partially as a user task. How can
> you expect it to carry out a sync or anything else when it is frozen?
>
> I suppose you could "deal" with it by having the kernel portion return
> an error if the userspace part is frozen. If the hibernate/suspend
> code bothered to check the return value, it would immediately abort
> the suspend.

I strongly believe, that we don't want to deal with it. If we want to
call sync(), do it while the system is fully operational. It's a best
effort thing anyway, and you can loose data in other ways if resume
fails.

Miklos
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