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Date:   Tue, 4 Dec 2018 10:02:28 +0100
From:   Ingo Molnar <mingo@kernel.org>
To:     Michal Hocko <mhocko@kernel.org>
Cc:     Pavel Machek <pavel@ucw.cz>, Oleg Nesterov <oleg@redhat.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        Chanho Min <chanho.min@lge.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH] Revert "exec: make de_thread() freezable (was: Re: Linux
 4.20-rc4)
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* Michal Hocko <mhocko@kernel.org> wrote:

> > Do we actually have reports of this happening for people outside
> > Android?
> 
> Not that I am aware of.

I'd say outside of Android 99% of the use of hibernation is the fail-safe 
that distributions offer on laptops with very low battery levels: the 
emergency hibernation when there's almost no power left anymore.

Do these hibernation failure messages typically make it to persistent 
logs before the system uses power?

In practice if that is buggy the kernel won't hibernate and the laptop 
will run out of power and the user will conclude "ugh, I shouldn't have 
left my laptop turned on" - without looking into the logs and reporting, 
as they'll perceive it as a user failure not a system failure.

I certainly saw random Linux laptops fail to hibernate over the years and 
didn't report it, so if the distribution doesn't do the reporting 
automatically then chances are we'll never see it.

Thanks,

	Ingo