Re: Re: [PATCH] Remove process freezer from suspend to RAM pathway

Oliver Neukum
2007-07-06T07:32:30Z

Am Freitag, 6. Juli 2007 schrieb Benjamin Herrenschmidt:
> > Yes, fuse could handle being frozen there.  However that would only
> > solve part of the problem: an operation waiting for a reply could be
> > holding a VFS mutex and some other task may be blocked on that mutex.
> >
> > How would you solve freezing those tasks?
>
> That task is implicitely frozen... but the kernel doesn't know it and
> thus the freezer timeouts or fails or deadlocks or whatever.
>
> The freezer could be made to ignore tasks that are sleeping in the
> kernel assuming that if they go out of it, they'll ultimately reach
> do_signal and freeze, but that means they can potentially still issues
> IOs which is what the freezer tries to avoid ...
>
> Or the kernel could start tracking dependencies, but then, good luck
> implementing that crap.

Do we need dependencies? Don't we know that fuse can deadlock only
on a limited number of locks in VFS?

Regards
Oliver