Messages in this thread | | | Date | Sun, 8 Aug 2010 23:23:11 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] lockup_detector: Make DETECT_HUNT_TASK default depend on LOCKUP_DETECTOR |
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* Frederic Weisbecker <fweisbec@gmail.com> wrote:
> > The thing is, CONFIG_DETECT_SOFTLOCKUP was default-y before, so many > > people had it enabled [and had it forced-enabled if DEBUG_KERNEL was off], > > even if they didnt really want or need it. > > Hmm. It was: > > config DETECT_SOFTLOCKUP > bool "Detect Soft Lockups" > depends on DEBUG_KERNEL && !S390 > default y > > It means it's default enabled only if DEBUG_KERNEL, right? Then if you don't > select CONFIG_DEBUG_KERNEL, it's fine as it won't be selected.
Indeed, you are right.
Anyway, i think the general point remains: i'm not sure we should default-enable this feature.
> But I agree with you. There is a bunch of config options for which selection > is a duty when you are a kernel developer: PROVE_LOCKING, DETECT_HUNG_TASK, > DEBUG_PREEMPT, PROVE_RCU, etc... Because they all show (or prove we can > have) bugs that one might miss without these options. Softlockups are rarely > part of them because even without the lockup detector enabled, you'll > observe something is wrong.
Note that it's now detecting all kinds of lockups: softlockups, hard lockups and even unkillable hung tasks.
Ingo
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