From mboxrd@z Thu Jan  1 00:00:00 1970
From: Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH -v7][RFC]: mutex: implement adaptive spinning
Date: Thu, 8 Jan 2009 08:11:22 -0800 (PST)
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Cc: Ingo Molnar <mingo@elte.hu>, Steven Rostedt <rostedt@goodmis.org>,
	paulmck@linux.vnet.ibm.com, Gregory Haskins <ghaskins@novell.com>,
	Matthew Wilcox <matthew@wil.cx>,
	Andi Kleen <andi@firstfloor.org>,
	Chris Mason <chris.mason@oracle.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	linux-btrfs <linux-btrfs@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Nick Piggin <npiggin@suse.de>,
	Peter Morreale <pmorreale@novell.com>,
	Sven Dietrich <SDietrich@novell.com>
To: Peter Zijlstra <peterz@infradead.org>
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On Thu, 8 Jan 2009, Peter Zijlstra wrote:
> 
> This was done because the interaction between trylock_slowpath and that
> -1000 state hurt my head.

Yeah, it was a stupid hacky thing to avoid the "list_empty()", but doing 
it explicitly is fine (we don't hold the lock, so the list isn't 
necessarily stable, but doing "list_empty()" is fine because we don't ever 
dereference the pointers, we just compare the pointers themselves).

I shouldn't have done that hacky thing, it wasn't worth it.

		Linus