From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753219AbYKZUEh (ORCPT ); Wed, 26 Nov 2008 15:04:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752383AbYKZUE2 (ORCPT ); Wed, 26 Nov 2008 15:04:28 -0500 Received: from one.firstfloor.org ([213.235.205.2]:38681 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752356AbYKZUE2 (ORCPT ); Wed, 26 Nov 2008 15:04:28 -0500 To: gorcunov@gmail.com Cc: mingo@elte.hu, tglx@linutronix.de, hpa@zytor.com, linux-kernel@vger.kernel.org, heukelum@fastmail.fm Subject: Re: [PATCH 2/5] x86: ret_from_fork - get rid of jump back From: Andi Kleen References: <1227727024-2281-1-git-send-email-gorcunov@gmail.com> <82259867e200855889261370c29bbd15a111d7fb.1227725632.git.gorcunov@gmail.com> Date: Wed, 26 Nov 2008 21:04:33 +0100 In-Reply-To: (gorcunov@gmail.com's message of "Wed, 26 Nov 2008 22:17:01 +0300") Message-ID: <874p1u45ke.fsf@basil.nowhere.org> User-Agent: Gnus/5.1008 (Gnus v5.10.8) Emacs/21.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org gorcunov@gmail.com writes: > --- a/arch/x86/kernel/entry_64.S > +++ b/arch/x86/kernel/entry_64.S > @@ -379,7 +379,10 @@ ENTRY(ret_from_fork) > GET_THREAD_INFO(%rcx) > testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT),TI_flags(%rcx) > CFI_REMEMBER_STATE > - jnz rff_trace > + jz rff_action > + movq %rsp,%rdi > + call syscall_trace_leave > + GET_THREAD_INFO(%rcx) The uncommon path is supposed to be out of line. I don't think the CPU will like that. -Andi > rff_action: -- ak@linux.intel.com