From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zachary Amsden Subject: Re: [patch 13/21] Xen-paravirt: Add nosegneg capability to the vsyscall page notes Date: Tue, 13 Feb 2007 14:54:26 -0800 Message-ID: <45D241A2.6000401@vmware.com> References: <20070213221729.772002682@goop.org> <20070213221830.466651996@goop.org> <45D23F97.5040907@vmware.com> <45D24066.4070109@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <45D24066.4070109@goop.org> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Jeremy Fitzhardinge Cc: Andrew Morton , xen-devel@lists.xensource.com, Ian Pratt , virtualization@lists.osdl.org, linux-kernel@vger.kernel.org, Chris Wright , Andi Kleen , Christian Limpach List-Id: virtualization@lists.linuxfoundation.org Jeremy Fitzhardinge wrote: > Zachary Amsden wrote: > >> I don't like this because now a kernel compiled with both CONFIG_XEN >> and CONFIG_VMI has "nosegneg" turned on. We don't actually require >> this for performance or correctness, so it would be nice to be able to >> dynamically turn it off instead of having it forced. >> > > Any suggestions about how to do this? It seems hard to have a note > dynamically appear and disappear in the vsyscall.so. > > I wasn't terribly concerned about this, since there is effectively zero > performance difference between the two library implementations. > I'm not super concerned either, but I still don't like it. There already is dynamic replacement for vsyscall.so, so you could have just dropped in an an-note-ated version. Zach