Messages in this thread | | | Subject | Re: [PATCH 0/2] Ajust lockdep static allocations | From | Babu Moger <> | Date | Fri, 23 Sep 2016 09:50:52 -0500 |
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On 9/23/2016 9:34 AM, Peter Zijlstra wrote: > On Fri, Sep 23, 2016 at 09:04:42AM -0500, Babu Moger wrote: >> On 9/23/2016 2:12 AM, Peter Zijlstra wrote: >>> On Thu, Sep 22, 2016 at 11:43:34AM -0700, Babu Moger wrote: >>>> These patches adjust the static allocations for lockdep >>>> data structures used for debugging locking correctness. The current >>>> code reserves about 4MB extra space for these data structures. Most >>>> of the configurations do not need these many data structures. While >>>> testing, I have not seen it go beyond 20% of already reserved entries. >>>> >>>> $grep "lock-classes" /proc/lockdep_stats >>>> lock-classes: 1560 [max: 8191] >>>> >>>> Reserving even more space seems unreasonable. So, keeping the default >>>> entries small as before the Commit 1413c0389333 ("lockdep: Increase static >>>> allocations"). Added new CONFIG_PROVE_LOCKING_PLUS in case someone >>>> needs more entries to debug their large configuration. >>> Why make this more complicated? There's absolutely no upside to this >>> change as far as I can see. >> Peter, What do you mean? > I mean I see no point to the patches you send. > >> Revert the commit 1413c038933? > Nah, why would I? > >> Right now, I cannot boot my setup after enabling lockdep. How do you >> think we can handle this? > Why can't you boot? You have that little memories? 4MB doesn't seem like > a worthwhile amount of memory. > > Also, you didn't say. This seems a somewhat crucial point.
Correct, We can't boot with lockdep. Sorry I did not make that clear. We have a limit on static size of the kernel.
> > In any case, maybe invert this, add make it depend on CONFIG_BASE_SMALL, > since this really only matters for really dinky systems. Sure. Will use CONFIG_BASE_SMALL and re-post the patches. Thanks >
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