From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759234AbYDZQLn (ORCPT ); Sat, 26 Apr 2008 12:11:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754057AbYDZQLg (ORCPT ); Sat, 26 Apr 2008 12:11:36 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:53475 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754650AbYDZQLf (ORCPT ); Sat, 26 Apr 2008 12:11:35 -0400 Date: Sat, 26 Apr 2008 18:11:19 +0200 From: Ingo Molnar To: Linus Torvalds Cc: linux-kernel@vger.kernel.org, Andrew Morton , Thomas Gleixner , "H. Peter Anvin" , Arjan van de Ven Subject: [git pull] x86, generic: optimized inlining Message-ID: <20080426161119.GA13954@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Linus, please pull the "optimized inlining" feature from: git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-x86-optimized-inlining.git for-linus this is from x86.git but touches include/linux/compiler-gcc.h and can be enabled by other architectures as well. The motivation of this feature is a 2.3% kernel text size reduction on generic x86 distro kernel configs. (Perhaps gcc will also get smarter about inlining decisions if the kernel gives it leeway about it.) This change makes __always_inline more meaningful (and more critical). Testing so far showed no ill effects. Thanks, Ingo ------------------> Ingo Molnar (2): x86: add optimized inlining generic: make optimized inlining arch-opt-in arch/x86/Kconfig | 3 +++ arch/x86/Kconfig.debug | 13 +++++++++++++ arch/x86/configs/i386_defconfig | 1 + arch/x86/configs/x86_64_defconfig | 1 + include/linux/compiler-gcc.h | 13 ++++++++++--- 5 files changed, 28 insertions(+), 3 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 4d350b5..3b6ff3b 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -142,6 +142,9 @@ config AUDIT_ARCH config ARCH_SUPPORTS_AOUT def_bool y +config ARCH_SUPPORTS_OPTIMIZED_INLINING + def_bool y + # Use the generic interrupt handling code in kernel/irq/: config GENERIC_HARDIRQS bool diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index 239fd9f..5b1979a 100644 --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -257,3 +257,16 @@ config CPA_DEBUG Do change_page_attr() self-tests every 30 seconds. endmenu + +config OPTIMIZE_INLINING + bool "Allow gcc to uninline functions marked 'inline'" + default y + help + This option determines if the kernel forces gcc to inline the functions + developers have marked 'inline'. Doing so takes away freedom from gcc to + do what it thinks is best, which is desirable for the gcc 3.x series of + compilers. The gcc 4.x series have a rewritten inlining algorithm and + disabling this option will generate a smaller kernel there. Hopefully + this algorithm is so good that allowing gcc4 to make the decision can + become the default in the future, until then this option is there to + test gcc for this. diff --git a/arch/x86/configs/i386_defconfig b/arch/x86/configs/i386_defconfig index 3df340b..ad7ddaa 100644 --- a/arch/x86/configs/i386_defconfig +++ b/arch/x86/configs/i386_defconfig @@ -1421,6 +1421,7 @@ CONFIG_DEBUG_BUGVERBOSE=y # CONFIG_DEBUG_VM is not set # CONFIG_DEBUG_LIST is not set # CONFIG_FRAME_POINTER is not set +CONFIG_OPTIMIZE_INLINING=y # CONFIG_RCU_TORTURE_TEST is not set # CONFIG_LKDTM is not set # CONFIG_FAULT_INJECTION is not set diff --git a/arch/x86/configs/x86_64_defconfig b/arch/x86/configs/x86_64_defconfig index eef98cb..2d6f5b2 100644 --- a/arch/x86/configs/x86_64_defconfig +++ b/arch/x86/configs/x86_64_defconfig @@ -1346,6 +1346,7 @@ CONFIG_DEBUG_BUGVERBOSE=y # CONFIG_DEBUG_VM is not set # CONFIG_DEBUG_LIST is not set # CONFIG_FRAME_POINTER is not set +CONFIG_OPTIMIZE_INLINING=y # CONFIG_RCU_TORTURE_TEST is not set # CONFIG_LKDTM is not set # CONFIG_FAULT_INJECTION is not set diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index fe23792..b2fd754 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -28,9 +28,16 @@ #define __must_be_array(a) \ BUILD_BUG_ON_ZERO(__builtin_types_compatible_p(typeof(a), typeof(&a[0]))) -#define inline inline __attribute__((always_inline)) -#define __inline__ __inline__ __attribute__((always_inline)) -#define __inline __inline __attribute__((always_inline)) +/* + * Force always-inline if the user requests it so via the .config: + */ +#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \ + !defined(CONFIG_OPTIMIZE_INLINING) && (__GNUC__ >= 4) +# define inline inline __attribute__((always_inline)) +# define __inline__ __inline__ __attribute__((always_inline)) +# define __inline __inline __attribute__((always_inline)) +#endif + #define __deprecated __attribute__((deprecated)) #define __packed __attribute__((packed)) #define __weak __attribute__((weak))