From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andi Kleen <andi@firstfloor.org>
Subject: Re: [PATCH v2 1/2] spinlock: New spinlock_refcount.h for lockless
 update of refcount
Date: Thu, 27 Jun 2013 03:37:14 +0200
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Cc: Andi Kleen <andi@firstfloor.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Jeff Layton <jlayton@redhat.com>,
	Miklos Szeredi <mszeredi@suse.cz>,
	Ingo Molnar <mingo@redhat.com>, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	"Chandramouleeswaran, Aswin" <aswin@hp.com>,
	"Norton, Scott J" <scott.norton@hp.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Steven Rostedt <rostedt@goodmis.org>
To: Waiman Long <waiman.long@hp.com>
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> It will be hard to know what changes will be needed without knowing
> the exact semantics of the spinlock functions with lock elision. Can
> you explain a little more what bizarre semantics you are referring
> to?

Totally independent of elision.

For example, what semantics does spin_unlock_wait() have with a ticket
lock. Where in the queue does it wait?
It doesn't really make sense with a ticket lock.

What semantics would lockdep put on it?

-Andi