Messages in this thread | | | Date | Sat, 27 Mar 2010 16:36:30 -0700 | From | Joel Becker <> | Subject | Re: [PATCH] hangcheck-timer is broken on x86 |
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On Sat, Mar 27, 2010 at 06:51:01PM -0400, Yury Polyanskiy wrote: > > It's OK to tell hangcheck-timer users that suspend is not > > allowed. After all, you're running something that you don't want to see > > hang. > > Joel, what I am saying is exactly the opposite: it is totally ok to > suspend-resume with hangcheck-timer (jiffies are stopped and so is > getrawmonotonic() when system suspended).
Nope. The point of hangcheck-timer is that it reboots should the system not be running for a certain amountof time. If suspend-resume is allowed, a system can resume after days and think it wasn't more than a second. hangcheck-timer will not know to reboot.
> > Is there a clock in the system that is a true wallclock? I'm > > guessing, since getrawmonotonic() is get_cycles() based, that it doesn't > > provide accurate time in the face of cpufreq changes. Is that true? > > Of course, getrawmonotonic accounts for cpufreq changes (see > arch/x86/kernel/tsc.c:time_cpufreq_notifier()).
Excellent! That's a definite improvement over raw get_cycles().
Joel
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Joel Becker Principal Software Developer Oracle E-mail: joel.becker@oracle.com Phone: (650) 506-8127 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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