From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752161Ab1FHSjy (ORCPT ); Wed, 8 Jun 2011 14:39:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:23970 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750943Ab1FHSjw (ORCPT ); Wed, 8 Jun 2011 14:39:52 -0400 Date: Wed, 8 Jun 2011 20:37:20 +0200 From: Oleg Nesterov To: Eric Paris Cc: linux-kernel@vger.kernel.org, tony.luck@intel.com, fenghua.yu@intel.com, monstr@monstr.eu, ralf@linux-mips.org, benh@kernel.crashing.org, paulus@samba.org, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, linux390@de.ibm.com, lethal@linux-sh.org, davem@davemloft.net, jdike@addtoit.com, richard@nod.at, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, viro@zeniv.linux.org.uk, akpm@linux-foundation.org, linux-ia64@vger.kernel.org, microblaze-uclinux@itee.uq.edu.au, linux-mips@linux-mips.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net Subject: Re: [PATCH -v2] Audit: push audit success and retcode into arch ptrace.h Message-ID: <20110608183720.GA16883@redhat.com> References: <20110603220451.23134.47368.stgit@paris.rdu.redhat.com> <20110607171952.GA25729@redhat.com> <1307472796.2052.12.camel@localhost.localdomain> <20110608163653.GA9592@redhat.com> <1307556823.2577.5.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1307556823.2577.5.camel@localhost.localdomain> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/08, Eric Paris wrote: > > On Wed, 2011-06-08 at 18:36 +0200, Oleg Nesterov wrote: > > And I guess, all CONFIG_AUDITSYSCALL code in entry.S is only needed to > > microoptimize the case when TIF_SYSCALL_AUDIT is the only reason for the > > slow path. I wonder if it really makes the measureble difference... > > All I know is what Roland put in the changelog: > > Avoiding the iret return path when syscall audit is enabled helps > performance a lot. > > I believe this was a result of Fedora starting auditd by default and > then Linus bitching about how slow a null syscall in a tight loop was. > It was an optimization for a microbenchmark. How much it affects things > on a real syscall that does real work is probably going to be determined > by how much work is done in the syscall. and probably by how much work is done in audit_syscall_entry/exit. OK. Thanks a lot Eric for your explanations. Oleg.