Messages in this thread | | | Date | Tue, 2 Dec 2014 08:33:53 -0800 | Subject | Re: frequent lockups in 3.18rc4 | From | Linus Torvalds <> |
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On Tue, Dec 2, 2014 at 6:13 AM, Mike Galbraith <umgwanakikbuti@gmail.com> wrote: > > The bean counting problem below can contribute. > > https://lkml.org/lkml/2014/3/30/7
Hmm. That never got applied. I didn't apply it originally because of timing and wanting clarifications, but apparently it never made it into the -tip tree either.
Ingo, PeterZ - comments?
Looking again at that patch (the commit message still doesn't strike me as wonderfully explanatory :^) makes me worry, though.
Is that
if (rq->skip_clock_update-- > 0) return;
really right? If skip_clock_update was zero (normal), it now gets set to -1, which has its own specific meaning (see "force clock update" comment in kernel/sched/rt.c). Is that intentional? That seems insane.
Or should it be
if (rq->skip_clock_update > 0) { rq->skip_clock_update = 0; return; }
or what? Maybe there was a reason the patch never got applied even to -tip.
At the same time, the whole "incapacitated by the rt throttle long enough for the hard lockup detector to trigger" commentary about that skip_clock_update issue does make me go "Hmmm..". It would certainly explain Dave's incomprehensible watchdog messages..
Linus
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