Re: [PATCH v2] PM/Memory-hotplug: Avoid task freezing failures

[Tejun Heo <tj@kernel.org>]

Hello,

On Wed, Nov 16, 2011 at 11:54:04PM +0530, Srivatsa S. Bhat wrote:
> Ok, so by "proper solution", are you referring to a totally different
> method (than grabbing pm_mutex) to implement mutual exclusion between
> subsystems and suspend/hibernation, something like the suspend blockers
> stuff and friends?
> Or are you hinting at just the existing code itself being fixed more
> properly than what this patch does, to avoid having side effects like
> you pointed out?

Oh, nothing fancy.  Just something w/o busy looping would be fine.
The stinking thing is we don't have mutex_lock_freezable().  Lack of
proper freezable interface seems to be a continuing problem and I'm
not sure what the proper solution should be at this point.  Maybe we
should promote freezable to a proper task state.  Maybe freezable
kthread is a bad idea to begin with.  Maybe instead of removing
freezable_with_signal() we should make that default, that way,
freezable can hitch on the pending signal handling (this creates
another set of problems tho - ie. who's responsible for clearing
TIF_SIGPENDING?).  I don't know.

Maybe just throw in msleep(10) there with fat ugly comment explaining
why the hack is necessary?

Thanks.

-- 
tejun

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