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Date: Tue, 13 Sep 2016 14:09:56 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Byungchul Park <byungchul.park@lge.com>
Cc: mingo@kernel.org, tglx@linutronix.de, walken@google.com,
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Subject: Re: [PATCH v3 07/15] lockdep: Implement crossrelease feature
Message-ID: <20160913120956.GA5020@twins.programming.kicks-ass.net>
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On Tue, Sep 13, 2016 at 12:05:20PM +0200, Peter Zijlstra wrote:
> On Tue, Sep 13, 2016 at 06:45:06PM +0900, Byungchul Park wrote:
> > Crossrelease feature calls a lock 'crosslock' if it is releasable
> > in any context. For crosslock, all locks having been held in the
> > release context of the crosslock, until eventually the crosslock
> > will be released, have dependency with the crosslock.
> > 
> > Using crossrelease feature, we can detect deadlock possibility even
> > for lock_page(), wait_for_complete() and so on.
> > 
> 
> Completely inadequate.
> 
> Please explain how cross-release does what it does. Talk about lock
> graphs and such.
> 
> I do not have time to reverse engineer this stuff.

Blergh, I'll do it anyway.. hold on for an email asking specific
questions.