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

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

On Sun, 2007-07-08 at 23:45 +0200, Rafael J. Wysocki wrote:
> 
> Workqueues are kernel threads and the creator decides if they are going to
> freeze.  There are only two freezable worqueues in the entire tree right now.

That and keventd workqueues... my point is you may well end up with
something in a workqueue doing things that should have been blocked
after the freeze.

> Actaully, I'm perfectly fine with that, as long as each task blocked by the
> driver due to suspend has PF_FROZEN (or something similar) set.  Then, at
> least theoretically, we'll be able to drop the freezer from the suspend code
> path and move it after device_suspend() (or the hibernation-specific
> equivalent) for hibernation (in that case there shouldn't be a problem with
> any task waiting on I/O while the freezer is running ;-)).

I don't see the need for a freezer for snapshot but that's a different
issue. (stop_machine looks good enough to me).

Ben

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