From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751154Ab2LUG4Y (ORCPT ); Fri, 21 Dec 2012 01:56:24 -0500 Received: from us02smtp1.synopsys.com ([198.182.60.75]:44835 "EHLO vaxjo.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750748Ab2LUG4T (ORCPT ); Fri, 21 Dec 2012 01:56:19 -0500 From: Vineet Gupta To: Al Viro CC: Vineet Gupta , Rusty Russell , Jim Cromie , Andrew Morton , "H. Peter Anvin" , Subject: [PATCH RESEND] Ensure that kernel_init_freeable() is not inlined into non __init code Date: Fri, 21 Dec 2012 12:25:44 +0530 Message-ID: <1356072944-23800-1-git-send-email-vgupta@synopsys.com> X-Mailer: git-send-email 1.7.4.1 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.12.197.205] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit d6b2123802d "make sure that we always have a return path from kernel_execve()" reshuffled kernel_init()/init_post() to ensure that kernel_execve() has a caller to return to. It removed __init annotation for kernel_init() and introduced/calls a new routine kernel_init_freeable(). Latter however is inlined by any reasonable compiler (ARC gcc 4.4 in this case), causing slight code bloat. This patch forces kernel_init_freeable() as noinline reducing the .text bloat-o-meter vmlinux vmlinux_new add/remove: 1/0 grow/shrink: 0/1 up/down: 374/-334 (40) function old new delta kernel_init_freeable - 374 +374 (.init.text) kernel_init 628 294 -334 (.text) Just for documentation, here's what Al's orig commit did. Orig ---- THREAD __init kernel_init() smp_init() ... open("/dev/console") init_post() --> forced to be noinline return 0; init_post() free_initmem() --> reaps caller kernel_init() run_init_process("/init") kernel_execve New --- THREAD kernel_init() kernel_init_freeable() --> __init tagged smp_init() ... open("/dev/console") free_initmem() --> reaps kernel_init_freeable() run_init_process "init" kernel_execve Signed-off-by: Vineet Gupta CC: Rusty Russell CC: Jim Cromie CC: Andrew Morton CC: "H. Peter Anvin" CC: linux-kernel@vger.kernel.org --- init/main.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/init/main.c b/init/main.c index 85d69df..92d728a 100644 --- a/init/main.c +++ b/init/main.c @@ -802,7 +802,7 @@ static int run_init_process(const char *init_filename) (const char __user *const __user *)envp_init); } -static void __init kernel_init_freeable(void); +static noinline void __init kernel_init_freeable(void); static int __ref kernel_init(void *unused) { @@ -845,7 +845,7 @@ static int __ref kernel_init(void *unused) "See Linux Documentation/init.txt for guidance."); } -static void __init kernel_init_freeable(void) +static noinline void __init kernel_init_freeable(void) { /* * Wait until kthreadd is all set-up. -- 1.7.4.1