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

[Stefan Richter <stefanr@s5r6.in-berlin.de>]

akpm@linux-foundation.org wrote:
> From: Rafael J. Wysocki <rjw@sisk.pl>
> 
> 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
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