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Date:   Fri, 13 Nov 2020 18:19:28 +0100
From:   David Sterba <dsterba@suse.cz>
To:     Boqun Feng <boqun.feng@gmail.com>
Cc:     linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        Filipe Manana <fdmanana@gmail.com>,
        Peter Zijlstra <peterz@infradead.org>, Jan Kara <jack@suse.cz>,
        David Sterba <dsterba@suse.com>,
        Nikolay Borisov <nborisov@suse.com>,
        "Darrick J. Wong" <darrick.wong@oracle.com>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Ingo Molnar <mingo@kernel.org>
Subject: Re: [RFC] fs: Avoid to use lockdep information if it's turned off
Message-ID: <20201113171927.GG6756@suse.cz>
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        Filipe Manana <fdmanana@gmail.com>,
        Peter Zijlstra <peterz@infradead.org>, Jan Kara <jack@suse.cz>,
        David Sterba <dsterba@suse.com>,
        Nikolay Borisov <nborisov@suse.com>,
        "Darrick J. Wong" <darrick.wong@oracle.com>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Ingo Molnar <mingo@kernel.org>
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On Thu, Nov 12, 2020 at 11:22:12AM +0800, Boqun Feng wrote:
> For the "BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!" warning, do you see
> that every time when you run xfstests and don't see other lockdep
> splats? If so, that means we reach the limitation of number of lockdep
> hlock chains, and we should fix that.

It's not every time and depends on the release, eg. I found no reports
in a sample log for 5.7..5.9, while there are many for 5.2..5.6 and
5.10, every 2nd or 3rd run.

[    0.185150] ... MAX_LOCKDEP_SUBCLASSES:  8
[    0.186202] ... MAX_LOCK_DEPTH:          48
[    0.187286] ... MAX_LOCKDEP_KEYS:        8192
[    0.188404] ... CLASSHASH_SIZE:          4096
[    0.189519] ... MAX_LOCKDEP_ENTRIES:     32768
[    0.190672] ... MAX_LOCKDEP_CHAINS:      65536
[    0.191814] ... CHAINHASH_SIZE:          32768