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From: David Howells <dhowells@redhat.com>
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References: <20061208022259.GB11551@wotan.suse.de>  <20061204144634.GA14383@wotan.suse.de> <20061204100607.GA20529@wotan.suse.de> <29183.1165236916@redhat.com> <25001.1165350982@redhat.com> 
Subject: Re: [patch][rfc] rwsem: generic rwsem 
Date: Fri, 08 Dec 2006 13:58:42 +0000
Message-ID: <4548.1165586322@redhat.com>
Sender: linux-arch-owner@vger.kernel.org
To: Nick Piggin <npiggin@suse.de>
Cc: David Howells <dhowells@redhat.com>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, linux-arch@vger.kernel.org, Linus Torvalds <torvalds@osdl.org>, Andrew Morton <akpm@osdl.org>
List-ID: <linux-arch.vger.kernel.org>

Nick Piggin <npiggin@suse.de> wrote:

> > Look at how the counter works in the XADD-based version.  That's the way
> > it is *because* I'm using XADD.  That's quite limiting.
> 
> Not really. ll/sc architectures "emulate" xadd the same as they would
> emulate a spinlock. There is nothing suboptimal about it.

Yes, really.  You've missed the point entirely.  Look at *how* the counter
*works*.

David