From mboxrd@z Thu Jan 1 00:00:00 1970 From: changbin.du@intel.com Subject: [PATCH v5 2/4] kernel hacking: new config NO_AUTO_INLINE to disable compiler auto-inline optimizations Date: Tue, 5 Jun 2018 16:13:38 +0800 Message-ID: <1528186420-6615-3-git-send-email-changbin.du@intel.com> References: <1528186420-6615-1-git-send-email-changbin.du@intel.com> Return-path: In-Reply-To: <1528186420-6615-1-git-send-email-changbin.du@intel.com> Sender: linux-kernel-owner@vger.kernel.org To: mingo@redhat.com, akpm@linux-foundation.org, yamada.masahiro@socionext.com, michal.lkml@markovi.net Cc: rostedt@goodmis.org, tglx@linutronix.de, rdunlap@infradead.org, x86@kernel.org, linux@armlinux.org.uk, lgirdwood@gmail.com, broonie@kernel.org, arnd@arndb.de, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-sparse@vger.kernel.org, changbin.du@gmail.com, Changbin Du List-Id: linux-arch.vger.kernel.org From: Changbin Du This patch add a new kernel hacking option NO_AUTO_INLINE. Selecting this option will prevent the compiler from optimizing the kernel by auto-inlining functions not marked with the inline keyword. With this option, only functions explicitly marked with "inline" will be inlined. This will allow the function tracer to trace more functions because it only traces functions that the compiler has not inlined. Signed-off-by: Changbin Du Acked-by: Steven Rostedt (VMware) --- v2: Some grammar updates from Steven. --- Makefile | 6 ++++++ lib/Kconfig.debug | 17 +++++++++++++++++ 2 files changed, 23 insertions(+) diff --git a/Makefile b/Makefile index d0d2652..6720c40 100644 --- a/Makefile +++ b/Makefile @@ -775,6 +775,12 @@ KBUILD_CFLAGS += $(call cc-option, -femit-struct-debug-baseonly) \ $(call cc-option,-fno-var-tracking) endif +ifdef CONFIG_NO_AUTO_INLINE +KBUILD_CFLAGS += $(call cc-option, -fno-inline-functions) \ + $(call cc-option, -fno-inline-small-functions) \ + $(call cc-option, -fno-inline-functions-called-once) +endif + ifdef CONFIG_FUNCTION_TRACER ifndef CC_FLAGS_FTRACE CC_FLAGS_FTRACE := -pg diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index c40c7b7..da52243 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -198,6 +198,23 @@ config GDB_SCRIPTS instance. See Documentation/dev-tools/gdb-kernel-debugging.rst for further details. +config NO_AUTO_INLINE + bool "Disable compiler auto-inline optimizations" + help + This will prevent the compiler from optimizing the kernel by + auto-inlining functions not marked with the inline keyword. + With this option, only functions explicitly marked with + "inline" will be inlined. This will allow the function tracer + to trace more functions because it only traces functions that + the compiler has not inlined. + + Enabling this function can help debugging a kernel if using + the function tracer. But it can also change how the kernel + works, because inlining functions may change the timing, + which could make it difficult while debugging race conditions. + + If unsure, select N. + config ENABLE_WARN_DEPRECATED bool "Enable __deprecated logic" default y -- 2.7.4 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga07.intel.com ([134.134.136.100]:33944 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751856AbeFEIYk (ORCPT ); Tue, 5 Jun 2018 04:24:40 -0400 From: changbin.du@intel.com Subject: [PATCH v5 2/4] kernel hacking: new config NO_AUTO_INLINE to disable compiler auto-inline optimizations Date: Tue, 5 Jun 2018 16:13:38 +0800 Message-ID: <1528186420-6615-3-git-send-email-changbin.du@intel.com> In-Reply-To: <1528186420-6615-1-git-send-email-changbin.du@intel.com> References: <1528186420-6615-1-git-send-email-changbin.du@intel.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: mingo@redhat.com, akpm@linux-foundation.org, yamada.masahiro@socionext.com, michal.lkml@markovi.net Cc: rostedt@goodmis.org, tglx@linutronix.de, rdunlap@infradead.org, x86@kernel.org, linux@armlinux.org.uk, lgirdwood@gmail.com, broonie@kernel.org, arnd@arndb.de, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-sparse@vger.kernel.org, changbin.du@gmail.com, Changbin Du Message-ID: <20180605081338.Lk4gcg9g3iOL17UEpTO-koDpF_-lja6WrDILSEYgcpg@z> From: Changbin Du This patch add a new kernel hacking option NO_AUTO_INLINE. Selecting this option will prevent the compiler from optimizing the kernel by auto-inlining functions not marked with the inline keyword. With this option, only functions explicitly marked with "inline" will be inlined. This will allow the function tracer to trace more functions because it only traces functions that the compiler has not inlined. Signed-off-by: Changbin Du Acked-by: Steven Rostedt (VMware) --- v2: Some grammar updates from Steven. --- Makefile | 6 ++++++ lib/Kconfig.debug | 17 +++++++++++++++++ 2 files changed, 23 insertions(+) diff --git a/Makefile b/Makefile index d0d2652..6720c40 100644 --- a/Makefile +++ b/Makefile @@ -775,6 +775,12 @@ KBUILD_CFLAGS += $(call cc-option, -femit-struct-debug-baseonly) \ $(call cc-option,-fno-var-tracking) endif +ifdef CONFIG_NO_AUTO_INLINE +KBUILD_CFLAGS += $(call cc-option, -fno-inline-functions) \ + $(call cc-option, -fno-inline-small-functions) \ + $(call cc-option, -fno-inline-functions-called-once) +endif + ifdef CONFIG_FUNCTION_TRACER ifndef CC_FLAGS_FTRACE CC_FLAGS_FTRACE := -pg diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index c40c7b7..da52243 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -198,6 +198,23 @@ config GDB_SCRIPTS instance. See Documentation/dev-tools/gdb-kernel-debugging.rst for further details. +config NO_AUTO_INLINE + bool "Disable compiler auto-inline optimizations" + help + This will prevent the compiler from optimizing the kernel by + auto-inlining functions not marked with the inline keyword. + With this option, only functions explicitly marked with + "inline" will be inlined. This will allow the function tracer + to trace more functions because it only traces functions that + the compiler has not inlined. + + Enabling this function can help debugging a kernel if using + the function tracer. But it can also change how the kernel + works, because inlining functions may change the timing, + which could make it difficult while debugging race conditions. + + If unsure, select N. + config ENABLE_WARN_DEPRECATED bool "Enable __deprecated logic" default y -- 2.7.4