Re: [patch 128/197] freezer: add try_to_freeze calls to all kernelthreads

From: Stefan Richter
Date: Wed May 09 2007 - 06:45:16 EST


akpm@xxxxxxxxxxxxxxxxxxxx wrote:
> From: Rafael J. Wysocki <rjw@xxxxxxx>
>
> Add try_to_freeze() calls to the remaining kernel threads that do not call
> try_to_freeze() already, although they set PF_NOFREEZE.
>
> In the future we are going to replace PF_NOFREEZE with a set of flags that
> will be set to indicate in which situations the task should not be frozen (for
> example, there can be a task that should be frozen for the CPU hotplugging and
> should not be frozen for the system suspend). For this reason every kernel
> thread should be able to freeze itself (ie. call try_to_freeze()), so that it
> can be frozen whenever necessary.

A few questions:

Does try_to_freeze()'s kerneldoc document that try_to_freeze() is a
no-op sometimes but should nevertheless be called for this and that
reason? (I don't know the entire patch series.)

Why add no-op-try_to_freeze() everywhere now, instead of adding it later
when it will actually be needed? (I.e. "in the future".)

Can we please have a future where no device driver has to care if and
when and how to freeze its threads?
--
Stefan Richter
-=====-=-=== -=-= -=--=
http://arcgraph.de/sr/
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