From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752722AbYKKUBT (ORCPT ); Tue, 11 Nov 2008 15:01:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751192AbYKKUBI (ORCPT ); Tue, 11 Nov 2008 15:01:08 -0500 Received: from ns.suse.de ([195.135.220.2]:59535 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751160AbYKKUBH (ORCPT ); Tue, 11 Nov 2008 15:01:07 -0500 Date: Tue, 11 Nov 2008 21:01:03 +0100 Message-ID: From: Takashi Iwai To: Rusty Russell Cc: Andreas Gruenbacher , Jan Blunck , Andrew Morton , linux-kernel@vger.kernel.org Subject: [PATCH] Allocate module.ref array dynamically User-Agent: Wanderlust/2.12.0 (Your Wildest Dreams) SEMI/1.14.6 (Maruoka) FLIM/1.14.7 (=?ISO-8859-4?Q?Sanj=F2?=) APEL/10.6 Emacs/22.3 (x86_64-suse-linux-gnu) MULE/5.0 (SAKAKI) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, we found that the kernel module sizes and memory footprints grow drastically when NR_CPUS is high. For example, with NR_CPUS=4096, SUSE kernel packages weigh over 500MB (even w/o debug info). A part of the reason is the fixed size array in struct module. The patch below fixes the problem by allocating it dynamically. With the patch, the size can go down to 20MB. Any comments/suggestions appreciated. thanks, Takashi == From: Takashi Iwai Subject: [PATCH] Allocate module.ref array dynamically This patch makes the module handling code to allocate the ref array of each module struct dynamically. It saves both module disk space and memory footprints when number of CPUs is high like 4096. Reference: Novell bnc#425240 https://bugzilla.novell.com/show_bug.cgi?id=425240 Signed-off-by: Takashi Iwai --- include/linux/module.h | 2 +- kernel/module.c | 21 ++++++++++++++++----- 2 files changed, 17 insertions(+), 6 deletions(-) diff --git a/kernel/module.c b/kernel/module.c --- a/kernel/module.c +++ b/kernel/module.c @@ -559,17 +559,24 @@ static char last_unloaded_module[MODULE_ #ifdef CONFIG_MODULE_UNLOAD /* Init the unload section of the module. */ -static void module_unload_init(struct module *mod) +static int module_unload_init(struct module *mod) { unsigned int i; INIT_LIST_HEAD(&mod->modules_which_use_me); - for (i = 0; i < NR_CPUS; i++) + + mod->ref = kcalloc(nr_cpu_ids, sizeof(*mod->ref), GFP_KERNEL); + if (!mod->ref) + return -ENOMEM; + + for (i = 0; i < nr_cpu_ids; i++) local_set(&mod->ref[i].count, 0); /* Hold reference count during initialization. */ local_set(&mod->ref[raw_smp_processor_id()].count, 1); /* Backwards compatibility macros put refcount during init. */ mod->waiter = current; + + return 0; } /* modules using other modules */ @@ -649,6 +656,7 @@ static void module_unload_free(struct mo } } } + kfree(mod->ref); } #ifdef CONFIG_MODULE_FORCE_UNLOAD @@ -707,7 +715,7 @@ unsigned int module_refcount(struct modu { unsigned int i, total = 0; - for (i = 0; i < NR_CPUS; i++) + for (i = 0; i < nr_cpu_ids; i++) total += local_read(&mod->ref[i].count); return total; } @@ -896,8 +904,9 @@ static inline int use_module(struct modu return strong_try_module_get(b) == 0; } -static inline void module_unload_init(struct module *mod) +static inline int module_unload_init(struct module *mod) { + return 0; } #endif /* CONFIG_MODULE_UNLOAD */ @@ -2123,7 +2132,9 @@ static noinline struct module *load_modu mod = (void *)sechdrs[modindex].sh_addr; /* Now we've moved module, initialize linked lists, etc. */ - module_unload_init(mod); + err = module_unload_init(mod); + if (err) + goto free_unload; /* add kobject, so we can reference it. */ err = mod_sysfs_init(mod); diff --git a/include/linux/module.h b/include/linux/module.h --- a/include/linux/module.h +++ b/include/linux/module.h @@ -349,7 +349,7 @@ struct module void (*exit)(void); /* Reference counts */ - struct module_ref ref[NR_CPUS]; + struct module_ref *ref; #endif }; #ifndef MODULE_ARCH_INIT