Messages in this thread | | | Date | Mon, 5 Jan 2015 17:25:31 -0800 | Subject | Re: frequent lockups in 3.18rc4 | From | Linus Torvalds <> |
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On Mon, Jan 5, 2015 at 5:17 PM, John Stultz <john.stultz@linaro.org> wrote: > > Anyway, It may be worth keeping the 50% margin (and dropping the 12% > reduction to simplify things)
Again, the 50% margin is only on the multiplication overflow. Not on the mask.
So it won't do anything at all for the case we actually care about, namely a broken HPET, afaik.
I'd much rather limit to 50% of the mask too.
Also, why do we actually play games with ilog2 for that overflow calculation? It seems pointless. This is for the setup code, doing a real division there would seem to be a whole lot more straightforward, and not need that big comment. And there's no performance issue. Am I missing something?
> I've also got a capping patch that I'm testing that keeps time reads > from passing that interval. The only thing I'm really cautious about > with that change is that we have to make sure the hrtimer that > triggers update_wall_clock is always set to expire within that cap (I > need to review it again) or else we'll hang ourselves.
Yeah, that thing is fragile. And quite possibly part of the problem.
Linus
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