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Date:   Mon, 3 Dec 2018 15:14:59 +0100
From:   Pavel Machek <pavel@ucw.cz>
To:     Michal Hocko <mhocko@kernel.org>
Cc:     Oleg Nesterov <oleg@redhat.com>, Ingo Molnar <mingo@kernel.org>,
        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)
Message-ID: <20181203141459.GA14789@amd>
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On Mon 2018-12-03 14:53:51, Michal Hocko wrote:
> On Mon 03-12-18 14:10:06, Pavel Machek wrote:
> > On Mon 2018-12-03 13:38:57, Michal Hocko wrote:
> > > On Mon 03-12-18 13:31:49, Oleg Nesterov wrote:
> > > > On 12/03, Michal Hocko wrote:
> > > > >
> > > > > Now, I wouldn't mind to revert this because the code is really ol=
d and
> > > > > we haven't seen many bug reports about failing suspend yet. But w=
hat is
> > > > > the actual plan to make this work properly?
> > > >=20
> > > > I don't see a simple solution...
> > > >=20
> > > > But we need to fix exec/de_thread anyway, then we can probably reco=
nsider
> > > > this patch.
> > >=20
> > > My concern is that de_thread fix might be too disruptive for stable
> > > kernels while we might want to have a simple enough fix for the the
> > > suspend issue in the meantime. That was actually the primary reason I=
've
> > > acked the hack even though I didn't like it.
> >=20
> > Do we care about failing sleep in stable? Does someone hit the issue th=
ere?
> >=20
> > This sounds like issue only Android is hitting, and they run very
> > heavily patched kernels, far away from mainline or stable.
>=20
> But the underlying issue is the same and independent on their patches
> AFAIU. And is this really a common problem to care about in stable? I
> dunno to be honest but it sounds annoying for sure. Failing suspend is
> something that doesn't make your day when you are in hurry and want
> find out only later when your laptop heats up your bag ;)

In general, yes. In practice, if it happens 1 in 1000000 suspends, you
don't care that much (but Android cares).

Do we actually have reports of this happening for people outside
Android?

									Pavel
--=20
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo=
g.html

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