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Date: Wed, 14 May 2008 14:16:41 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Andi Kleen <andi@firstfloor.org>
CC: Alan Cox <alan@lxorguk.ukuu.org.uk>, Ingo Molnar <mingo@elte.hu>,
       linux-kernel@vger.kernel.org,
       Linus Torvalds <torvalds@linux-foundation.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       Peter Zijlstra <a.p.zijlstra@chello.nl>,
       Thomas Gleixner <tglx@linutronix.de>,
       Alexander Viro <viro@ftp.linux.org.uk>
Subject: Re: [announce] "kill the Big Kernel Lock (BKL)" tree
References: <20080514174955.GA515@elte.hu>	<87fxsk7n7e.fsf@basil.nowhere.org> <20080514220034.51eae9e0@core> <482B5614.3060203@firstfloor.org>
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Andi Kleen wrote:
> Alan Cox wrote:
>>> Most of the legacy users are unlikely to be latency problems,
>>> simply because only very few people (or nobody) still has that hardware
>>> and the code will never run.
>>>
>>> Also I wouldn't lose sleep over e.g. let ISDN continue using BKL forever.
>> Most 
> 
> Most?
> 
>> of the legacy users inflict that locking on other code - eg the ISN
>> use of the BKL directly impacts on the tty layer work.
> 
> So you just stick unlock_kernel()/lock_kernel() around the call
> to TTY (or similar to the entry points)
> 

... assuming that the ISDN code doesn't assume lock continuity across 
the TTY call.

	-hpa