Messages in this thread | | | Date | Thu, 17 Nov 2011 00:35:36 +0530 | From | "Srivatsa S. Bhat" <> | Subject | Re: [PATCH v2] PM/Memory-hotplug: Avoid task freezing failures |
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On 11/17/2011 12:11 AM, Tejun Heo wrote: > 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. >
Thanks a lot for the explanation! I now get an idea about your thoughts on the fundamental issues with the freezer that are causing a broad range of problems... Hmm, definitely something to ponder over...
> Maybe just throw in msleep(10) there with fat ugly comment explaining > why the hack is necessary? >
Hehe, that surely sounds like the simplest of all the approaches you suggested ;-) I'll add this to the while loop in the patch and repost it, hoping we can solve the fundamental issues effectively at a later time.
Thanks, Srivatsa S. Bhat
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