Messages in this thread | | | Date | Thu, 26 Jan 2023 20:07:16 -0800 | From | Boqun Feng <> | Subject | Re: BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low! |
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On Thu, Jan 26, 2023 at 10:37:56PM -0500, Chris Murphy wrote: > > > On Thu, Jan 26, 2023, at 7:20 PM, Waiman Long wrote: > > On 1/26/23 17:42, Mikhail Gavrilov wrote: > >>> I'm not sure whether these options are better than just increasing the > >>> number, maybe to unblock your ASAP, you can try make it 30 and make sure > >>> you have large enough memory to test. > >> About just to increase the LOCKDEP_CHAINS_BITS by 1. Where should this > >> be done? In vanilla kernel on kernel.org? In a specific distribution? > >> or the user must rebuild the kernel himself? Maybe increase > >> LOCKDEP_CHAINS_BITS by 1 is most reliable solution, but it difficult > >> to distribute to end users because the meaning of using packaged > >> distributions is lost (user should change LOCKDEP_CHAINS_BITS in > >> config and rebuild the kernel by yourself). > > > > Note that lockdep is typically only enabled in a debug kernel shipped by > > a distro because of the high performance overhead. The non-debug kernel > > doesn't have lockdep enabled. When LOCKDEP_CHAINS_BITS isn't big enough > > when testing on the debug kernel, you can file a ticket to the distro > > asking for an increase in CONFIG_LOCKDEP_CHAIN_BITS. Or you can build > > your own debug kernel with a bigger CONFIG_LOCKDEP_CHAIN_BITS. > > Fedora bumped CONFIG_LOCKDEP_CHAINS_BITS=17 to 18 just 6 months ago for debug kernels. > https://gitlab.com/cki-project/kernel-ark/-/merge_requests/1921 > > If 19 the recommended value I don't mind sending an MR for it. But if > the idea is we're going to be back here talking about bumping it to 20 > in six months, I'd like to avoid that. >
How about a boot parameter then?
Regards, Boqun
> > > -- > Chris Murphy
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