linux-kernel - Re: [PATCH] locking/lockdep: Increase MAX_LOCKDEP

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Date:   Tue, 26 May 2020 21:56:30 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Qian Cai <cai@....pw>
Cc:     Waiman Long <longman@...hat.com>, Ingo Molnar <mingo@...hat.com>,
        Will Deacon <will.deacon@....com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] locking/lockdep: Increase MAX_LOCKDEP_ENTRIES by half

On Tue, May 26, 2020 at 02:58:50PM -0400, Qian Cai wrote:

> I still don't understand why reading all sysfs files on this system
> could increase that much, but here is the lockdep file after
> running sysfs read to see if you could spot anything obviously,
> 
> https://cailca.github.io/files/lockdep.txt

00000000f011a2a5 OPS:      20 FD:   45 BD:    1 .+.+: kn->active#834

is that somewhere near the number of CPUs you have?

Anyway, there's very long "kn->active#..." chains in there, which seems
to suggest some annotation is all sorts of buggered.