Re: [linux-pm] Re: Hibernation considerations

From: Nigel Cunningham
Date: Sat Jul 21 2007 - 08:43:46 EST


Hi.

On Saturday 21 July 2007 21:44:32 Miklos Szeredi wrote:
> > The problem with FUSE is related to the fact that the freezer can't
> > freeze uninterruptible tasks and we said that perhaps we might avoid
> > it if FUSE was made freezing-aware. Still, no one has gone in this
> > direction and I don't know of any plans to do that.
>
> I thought we have fully explored this direction. Lots of emails, and
> an IRC session with Pavel. Conclusion:

What am I missing in the following suggested solution?

1) In the freezer code, we implement a new TIF_LATEFREEZE process flag, which,
when set, causes a userspace process to be frozen with kernel threads
instead of with userspace ones. When freezing, we freezing !TIF_LATEFREEZE,
sync and then freeze TIF_LATEFREEZE and freezable kernel threads.

2) In the fuse code, the PID of the process that will do the work gets passed
to the fuse kernel code when the mount is done. The kernel code sets the
TIF_LATEFREEZE flag, and resets it on umount.

Sorry, but this is a hit-and-run email - I'm off to bed now.

Regards,

Nigel

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