From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.11] helo=sc8-sf-mx1.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Exim 4.30) id 1D99tn-00067o-TJ for user-mode-linux-devel@lists.sourceforge.net; Wed, 09 Mar 2005 14:43:27 -0800 Received: from caramon.arm.linux.org.uk ([212.18.232.186]) by sc8-sf-mx1.sourceforge.net with esmtp (TLSv1:DES-CBC3-SHA:168) (Exim 4.41) id 1D99tl-00014p-PB for user-mode-linux-devel@lists.sourceforge.net; Wed, 09 Mar 2005 14:43:27 -0800 From: Russell King Message-ID: <20050309224259.J25398@flint.arm.linux.org.uk> References: <20050309094234.8FC0C6477@zion> <20050309171231.H25398@flint.arm.linux.org.uk> <200503092052.24803.blaisorblade@yahoo.it> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200503092052.24803.blaisorblade@yahoo.it>; from blaisorblade@yahoo.it on Wed, Mar 09, 2005 at 08:52:24PM +0100 Subject: [uml-devel] Re: [patch 1/1] unified spinlock initialization arch/um/drivers/port_kern.c Sender: user-mode-linux-devel-admin@lists.sourceforge.net Errors-To: user-mode-linux-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Id: The user-mode Linux development list List-Post: List-Help: List-Subscribe: , List-Archive: Date: Wed, 9 Mar 2005 22:42:59 +0000 To: Blaisorblade Cc: akpm@osdl.org, linux-kernel@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, domen@coderock.org, amitg@calsoftinc.com, gud@eth.net On Wed, Mar 09, 2005 at 08:52:24PM +0100, Blaisorblade wrote: > On Wednesday 09 March 2005 18:12, Russell King wrote: > > On Wed, Mar 09, 2005 at 10:42:33AM +0100, blaisorblade@yahoo.it wrote: > > > From: > > > Cc: , , > > > , > > > > > > Unify the spinlock initialization as far as possible. > > > Are you sure this is really the best option in this instance? > > Sometimes, static data initialisation is more efficient than > > code-based manual initialisation, especially when the memory > > is written to anyway. > Agreed, theoretically, but this was done for multiple reasons globally, for > instance as a preparation to Ingo Molnar's preemption patches. There was > mention of this on lwn.net about this: > > http://lwn.net/Articles/108719/ Was this announced on linux-kernel as well? I don't remember seeing it. I'm not convinced about the practicality of converting all static initialisations to code-based initialisations though - I can see that the number of initialisation functions scattered throughout the kernel is going to increase dramatically to achieve this. With a 2.4 to 2.6 kernel bloat already on the order of 140% for similar functionality, I can only see the kernel getting more and more bloated _for the same feature level_ because we're trying to add more features to the kernel. I'm not entirely convinced that is an all round sane approach. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 Serial core ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. 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Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262293AbVCJE3y (ORCPT ); Wed, 9 Mar 2005 23:29:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262197AbVCIXMl (ORCPT ); Wed, 9 Mar 2005 18:12:41 -0500 Received: from caramon.arm.linux.org.uk ([212.18.232.186]:55826 "EHLO caramon.arm.linux.org.uk") by vger.kernel.org with ESMTP id S262499AbVCIWnF (ORCPT ); Wed, 9 Mar 2005 17:43:05 -0500 Date: Wed, 9 Mar 2005 22:42:59 +0000 From: Russell King To: Blaisorblade Cc: akpm@osdl.org, linux-kernel@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, domen@coderock.org, amitg@calsoftinc.com, gud@eth.net Subject: Re: [patch 1/1] unified spinlock initialization arch/um/drivers/port_kern.c Message-ID: <20050309224259.J25398@flint.arm.linux.org.uk> Mail-Followup-To: Blaisorblade , akpm@osdl.org, linux-kernel@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, domen@coderock.org, amitg@calsoftinc.com, gud@eth.net References: <20050309094234.8FC0C6477@zion> <20050309171231.H25398@flint.arm.linux.org.uk> <200503092052.24803.blaisorblade@yahoo.it> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <200503092052.24803.blaisorblade@yahoo.it>; from blaisorblade@yahoo.it on Wed, Mar 09, 2005 at 08:52:24PM +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 09, 2005 at 08:52:24PM +0100, Blaisorblade wrote: > On Wednesday 09 March 2005 18:12, Russell King wrote: > > On Wed, Mar 09, 2005 at 10:42:33AM +0100, blaisorblade@yahoo.it wrote: > > > From: > > > Cc: , , > > > , > > > > > > Unify the spinlock initialization as far as possible. > > > Are you sure this is really the best option in this instance? > > Sometimes, static data initialisation is more efficient than > > code-based manual initialisation, especially when the memory > > is written to anyway. > Agreed, theoretically, but this was done for multiple reasons globally, for > instance as a preparation to Ingo Molnar's preemption patches. There was > mention of this on lwn.net about this: > > http://lwn.net/Articles/108719/ Was this announced on linux-kernel as well? I don't remember seeing it. I'm not convinced about the practicality of converting all static initialisations to code-based initialisations though - I can see that the number of initialisation functions scattered throughout the kernel is going to increase dramatically to achieve this. With a 2.4 to 2.6 kernel bloat already on the order of 140% for similar functionality, I can only see the kernel getting more and more bloated _for the same feature level_ because we're trying to add more features to the kernel. I'm not entirely convinced that is an all round sane approach. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 Serial core