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Date: Fri, 9 May 2008 00:27:07 +0100
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>,
       "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>,
       Andi Kleen <andi@firstfloor.org>, Matthew Wilcox <matthew@wil.cx>,
       LKML <linux-kernel@vger.kernel.org>,
       Alexander Viro <viro@ftp.linux.org.uk>,
       Andrew Morton <akpm@linux-foundation.org>,
       Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [patch] speed up / fix the new generic semaphore code (fix AIM7
 40% regression with 2.6.26-rc1)
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>     380  down <= lock_kernel <= tty_release <= __fput <
>     422  down <= lock_kernel <= chrdev_open <= __dentry_open <
> 
> rather than the write routines. But it may be that Ingo was just profiling 
> two different sections, and it's really all of them.

tty release is probably a few months away from getting cured  - I'm
afraid it will almost certainly be the very last user of the BKL in tty
to get fixed as it depends on everything else being sanely locked.