From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753379AbZALDSw (ORCPT ); Sun, 11 Jan 2009 22:18:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752069AbZALDSn (ORCPT ); Sun, 11 Jan 2009 22:18:43 -0500 Received: from bombadil.infradead.org ([18.85.46.34]:40783 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752058AbZALDSn (ORCPT ); Sun, 11 Jan 2009 22:18:43 -0500 Date: Sun, 11 Jan 2009 22:18:41 -0500 From: Kyle McMartin To: linux-kernel@vger.kernel.org Cc: rusty@rustcorp.com.au Subject: [PATCH] [RFC] remove (more or less) unnecessary cacheline_aligned from module_ref Message-ID: <20090112031841.GC21090@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On x86_64 systems with CONFIG_MAXSMP set, NR_CPUS is exploded to 4096 cpus. This cacheline_aligned attribute on the local_t in module_ref results in struct module bloating to over 512KB in size on x86_64, which tends to, er, add up. This results in insane disk usage on distro kernel configs (1GB+ on Fedora.) Killing cacheline_aligned reduces the size of struct module to somewhat more sane levels. Signed-off-by: Kyle McMartin --- I'll followup with a patch to make mod->ref dynamically allocated, but that needs a bit more thinking because module_unload_init currently doesn't have a failure path. Of course, reducing NR_CPUS to something sane was an easy way to patch over the problem. diff --git a/include/linux/module.h b/include/linux/module.h index 4f7ea12..32b0bda 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -222,7 +222,7 @@ void *__symbol_get_gpl(const char *symbol); struct module_ref { local_t count; -} ____cacheline_aligned; +}; enum module_state {