From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932491AbWAFWqW (ORCPT ); Fri, 6 Jan 2006 17:46:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932498AbWAFWqW (ORCPT ); Fri, 6 Jan 2006 17:46:22 -0500 Received: from mf01.sitadelle.com ([212.94.174.68]:15726 "EHLO smtp.cegetel.net") by vger.kernel.org with ESMTP id S932491AbWAFWqV (ORCPT ); Fri, 6 Jan 2006 17:46:21 -0500 Message-ID: <43BEF338.3010403@cosmosbay.com> Date: Fri, 06 Jan 2006 23:46:16 +0100 From: Eric Dumazet User-Agent: Thunderbird 1.5 (Windows/20051201) MIME-Version: 1.0 To: Arjan van de Ven Cc: linux-kernel@vger.kernel.org, akpm@osdl.org Subject: Re: [patch 0/4] Series to allow a "const" file_operations struct References: <1136583937.2940.90.camel@laptopd505.fenrus.org> <1136584539.2940.105.camel@laptopd505.fenrus.org> In-Reply-To: <1136584539.2940.105.camel@laptopd505.fenrus.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Arjan van de Ven a écrit : > On Fri, 2006-01-06 at 22:45 +0100, Arjan van de Ven wrote: >> Hi, >> >> this series allows drivers to have "const" file_operations, by making >> the f_ops field in the inode const. This has another benefit, there have > > ok there was a sentence missing here. The first benefit is that this > moves these hot datastructures to the rodata section, which means they > won't accidentally be doing false cacheline sharing. > Definitly a good thing I agree. But your patches miss to really declare all 'struct file_operations' as const, dont they ? On my x86_64 machine, I managed to reduce by 10% .data section by moving all file_operations, but also 'address_space_operations', 'inode_operations, super_operations, dentry_operations, seq_operations, ... to rodata section. size vmlinux* text data bss dec hex filename 2476156 522236 244868 3243260 317cfc vmlinux 2588685 571348 246692 3406725 33fb85 vmlinux.old Eric