Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753622AbYACV2t (ORCPT ); Thu, 3 Jan 2008 16:28:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752226AbYACV2l (ORCPT ); Thu, 3 Jan 2008 16:28:41 -0500 Received: from mga06.intel.com ([134.134.136.21]:15475 "EHLO orsmga101.jf.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752195AbYACV2l (ORCPT ); Thu, 3 Jan 2008 16:28:41 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.24,240,1196668800"; d="scan'208";a="248526159" Message-ID: <477D52ED.7000403@linux.intel.com> Date: Thu, 03 Jan 2008 22:26:05 +0100 From: Arjan van de Ven User-Agent: Thunderbird 1.5 (Windows/20051201) MIME-Version: 1.0 To: linux-kernel@vger.kernel.org CC: mingo@elte.hu, akpm@linux-foundation.org, olof@lixom.net, mpm@selenic.com Subject: [patch 1/2] move WARN_ON() out of line Content-Type: multipart/mixed; boundary="------------040405010005000301070402" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5764 Lines: 182 This is a multi-part message in MIME format. --------------040405010005000301070402 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: move WARN_ON() out of line From: Arjan van de Ven CC: Ingo Molnar CC: Andrew Morton CC: Olof Johansson CC: Matt Meckall A quick grep shows that there are currently 1145 instances of WARN_ON in the kernel. Currently, WARN_ON is pretty much entirely inlined, which makes it hard to enhance it without growing the size of the kernel (and getting Andrew rightfully unhappy). This patch build on top of Olof's patch that introduces __WARN, and places the slowpath out of line. It also uses Ingo's suggestion to not use __FUNCTION__ but to use kallsyms to do the lookup; this saves a ton of extra space since gcc doesn't need to store the function string twice now: 3936367 833603 624736 5394706 525112 vmlinux.before 3917508 833603 624736 5375847 520767 vmlinux-slowpath 15Kb savings... Signed-off-by: Arjan van de Ven --- include/asm-generic/bug.h | 7 ++----- kernel/panic.c | 14 ++++++++++++++ 2 files changed, 16 insertions(+), 5 deletions(-) Index: linux-2.6.24-rc6/include/asm-generic/bug.h =================================================================== --- linux-2.6.24-rc6.orig/include/asm-generic/bug.h +++ linux-2.6.24-rc6/include/asm-generic/bug.h @@ -32,11 +32,8 @@ struct bug_entry { #endif #ifndef __WARN -#define __WARN() do { \ - printk("WARNING: at %s:%d %s()\n", __FILE__, \ - __LINE__, __FUNCTION__); \ - dump_stack(); \ -} while (0) +extern void warn_on_slowpath(const char *file, const int line); +#define __WARN() warn_on_slowpath(__FILE__, __LINE__) #endif #ifndef WARN_ON Index: linux-2.6.24-rc6/kernel/panic.c =================================================================== --- linux-2.6.24-rc6.orig/kernel/panic.c +++ linux-2.6.24-rc6/kernel/panic.c @@ -20,6 +20,7 @@ #include #include #include +#include int panic_on_oops; int tainted; @@ -292,6 +293,19 @@ void oops_exit(void) (unsigned long long)oops_id); } + +void warn_on_slowpath(const char *file, int line) +{ + char function[KSYM_SYMBOL_LEN]; + unsigned long caller = (unsigned long) __builtin_return_address(0); + + sprint_symbol(function, caller); + printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file, + line, function); + dump_stack(); +} +EXPORT_SYMBOL(warn_on_slowpath); + #ifdef CONFIG_CC_STACKPROTECTOR /* * Called when gcc's -fstack-protector feature is used, and --------------040405010005000301070402 Content-Type: text/x-patch; name="out_of_line_WARN_ON.patch" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="out_of_line_WARN_ON.patch" Subject: move WARN_ON() out of line From: Arjan van de Ven CC: Ingo Molnar CC: Andrew Morton CC: Olof Johansson CC: Matt Meckall A quick grep shows that there are currently 1145 instances of WARN_ON in the kernel. Currently, WARN_ON is pretty much entirely inlined, which makes it hard to enhance it without growing the size of the kernel (and getting Andrew unhappy). This patch build on top of Olof's patch that introduces __WARN, and places the slowpath out of line. It also uses Ingo's suggestion to not use __FUNCTION__ but to use kallsyms to do the lookup; this saves a ton of extra space since gcc doesn't need to store the function string twice now: 3936367 833603 624736 5394706 525112 vmlinux.before 3917508 833603 624736 5375847 520767 vmlinux-slowpath 15Kb savings... Signed-off-by: Arjan van de Ven --- include/asm-generic/bug.h | 7 ++----- kernel/panic.c | 14 ++++++++++++++ 2 files changed, 16 insertions(+), 5 deletions(-) Index: linux-2.6.24-rc6/include/asm-generic/bug.h =================================================================== --- linux-2.6.24-rc6.orig/include/asm-generic/bug.h +++ linux-2.6.24-rc6/include/asm-generic/bug.h @@ -32,11 +32,8 @@ struct bug_entry { #endif #ifndef __WARN -#define __WARN() do { \ - printk("WARNING: at %s:%d %s()\n", __FILE__, \ - __LINE__, __FUNCTION__); \ - dump_stack(); \ -} while (0) +extern void warn_on_slowpath(const char *file, const int line); +#define __WARN() warn_on_slowpath(__FILE__, __LINE__) #endif #ifndef WARN_ON Index: linux-2.6.24-rc6/kernel/panic.c =================================================================== --- linux-2.6.24-rc6.orig/kernel/panic.c +++ linux-2.6.24-rc6/kernel/panic.c @@ -20,6 +20,7 @@ #include #include #include +#include int panic_on_oops; int tainted; @@ -292,6 +293,19 @@ void oops_exit(void) (unsigned long long)oops_id); } + +void warn_on_slowpath(const char *file, int line) +{ + char function[KSYM_SYMBOL_LEN]; + unsigned long caller = (unsigned long) __builtin_return_address(0); + + sprint_symbol(function, caller); + printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file, + line, function); + dump_stack(); +} +EXPORT_SYMBOL(warn_on_slowpath); + #ifdef CONFIG_CC_STACKPROTECTOR /* * Called when gcc's -fstack-protector feature is used, and --------------040405010005000301070402-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/