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

Oliver Neukum
2007-07-05T20:49:44Z

Am Donnerstag, 5. Juli 2007 schrieb Miklos Szeredi:
> > > 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?
> >
> > OK, you made me reach for literatur on theoretical computer science.
> >
> > IMHO the range of actions a fuse server is inherently limited.
> > You must never ever block on a lock one of your clients is holding. In
> > this case the limitation is not influenced by the freezer.
>
> Obviously.  But I wasn't about the server trying to acquire a lock
> held by a client.  I was talking about a client trying to acquire a
> lock held by _another_ client.
>
> If this coincides with the server (or some other task which the server
> is depending on) being frozen before the clients, the freezer has a
> problem.

True, but that case can only happen if servers are frozen before clients.
You don't need a full dependency graph. A simple set sequence of two
classes of tasks will do.

Regards
Oliver