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Subject: Re: Kernel Benchmarking
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Michael Larabel <Michael@michaellarabel.com>,
        Matthew Wilcox <willy@infradead.org>,
        Amir Goldstein <amir73il@gmail.com>,
        Ted Ts'o <tytso@google.com>,
        Andreas Dilger <adilger.kernel@dilger.ca>,
        Ext4 Developers List <linux-ext4@vger.kernel.org>,
        Jan Kara <jack@suse.cz>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>
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From:   Matthieu Baerts <matthieu.baerts@tessares.net>
Message-ID: <b6f8df30-4fbe-a440-b205-dc90583097a7@tessares.net>
Date:   Tue, 15 Sep 2020 21:38:38 +0200
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On 15/09/2020 21:24, Linus Torvalds wrote:
> On Tue, Sep 15, 2020 at 12:01 PM Matthieu Baerts
> <matthieu.baerts@tessares.net> wrote:
 >
>> I forgot one important thing, I was on top of David Miller's net-next
>> branch by reflex. I can redo the traces on top of linux-next if needed.
> 
> Not likely an issue.
> 
> I'll go stare at the page lock code again to see if I've missed
> anything. I still suspect it's a latent ABBA deadlock that is just
> much *much* easier to trigger with the synchronous lock handoff, but I
> don't see where it is.
> 
> I guess this is all fairly theoretical since we apparently need to do
> that hybrid "limited fairness" patch anyway, and it fixes your issue,
> but I hate not understanding the problem.

I understand :)
Thank you again for looking at this issue!

Cheers,
Matt
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