Messages in this thread | | | From | Mikhail Gavrilov <> | Date | Fri, 27 Jan 2023 10:35:51 +0500 | Subject | Re: BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low! |
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On Fri, Jan 27, 2023 at 9:08 AM Boqun Feng <boqun.feng@gmail.com> wrote: > > 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?
I would like this option. This is better than rebuilding the kernel yourself and asking the distribution's maintainers to increase this value.
Thanks.
-- Best Regards, Mike Gavrilov.
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