Messages in this thread | | | Date | Mon, 3 Dec 2007 10:55:01 +0100 | From | Andi Kleen <> | Subject | Re: [feature] automatically detect hung TASK_UNINTERRUPTIBLE tasks |
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On Sun, Dec 02, 2007 at 04:59:13PM -0800, Arjan van de Ven wrote: > On Mon, 3 Dec 2007 01:07:41 +0100 > Andi Kleen <andi@firstfloor.org> wrote: > > > > We really need to get better diagnostics for the > > > bad-kernel-behavior-that-is-seen-as-bug cases. If we ever want to > > > get to the scenario where we have a more or less robust measure of > > > kernel quality (and we're not all that far off for several cases), > > > one thing > > > > One measure to kernel quality is to recover well from IO errors > > (like network problems or broken block devices) > > yes. and this patch will flag cases that don't (yet) work well
If the device/server/... takes more than 2 minutes to recover, how does this imply the error path "does not work well" ? Or is your goal to handle all possible errors in less than two minutes? [That might be a worthy goal, but is probably far from easy and likely impossible in some cases]
> > This patch will likely work against that by breaking error paths. > > it won't break error paths, it will at most put a warning in the log. > It doesn't kill or otherwise damage the system or process.
From the user perspective a kernel randomly throwing backtraces is a broken kernel.
> > > > > > This patch is a step in the right direction there, by quite a > > > lot. > > > > > > I really don't understand what your objection is to this patch... > > > is it that an enterprise distro can't ship with it on? (Which is > > > fine btw) > > > > Any distribution aimed at end users cannot ship with it on. > > That's a pretty bold statement; assuming that the TASK_KILLABLE patch > is in, I don't see the problem.
iirc TASK_KILLABLE fixed NFS only. While that's a good thing there are unfortunately a lot more subsystems that would need the same treatment.
> > Also in general I have my doubts that the false positive:real bug > > ratio of this warning is well balanced. > > I'll just have to disagree with you then; but both of us are making > wild guesses. Only one way to get the real false positive percentage.
Yes let's break things first instead of looking at the implications closely.
-Andi
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