Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756186AbXJIUrL (ORCPT ); Tue, 9 Oct 2007 16:47:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754381AbXJIUq6 (ORCPT ); Tue, 9 Oct 2007 16:46:58 -0400 Received: from turing-police.cc.vt.edu ([128.173.14.107]:58575 "EHLO turing-police.cc.vt.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753950AbXJIUq5 (ORCPT ); Tue, 9 Oct 2007 16:46:57 -0400 X-Mailer: exmh version 2.7.2 01/07/2005 with nmh-1.2 To: Oleg Verych Cc: Joerg Roedel , Andi Kleen , Christoph Egger , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] i386: mce cleanup part1: functional change In-Reply-To: Your message of "Tue, 09 Oct 2007 18:32:30 +0200." <20071009163230.GC22435@flower.upol.cz> From: Valdis.Kletnieks@vt.edu References: <11919341961890-git-send-email-joerg.roedel@amd.com> <11919341961530-git-send-email-joerg.roedel@amd.com> <20071009160605.GC13205@amd.com> <20071009163230.GC22435@flower.upol.cz> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="==_Exmh_1191962806_2838P"; micalg=pgp-sha1; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit Date: Tue, 09 Oct 2007 16:46:46 -0400 Message-ID: <1152.1191962806@turing-police.cc.vt.edu> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1518 Lines: 41 --==_Exmh_1191962806_2838P Content-Type: text/plain; charset=us-ascii On Tue, 09 Oct 2007 18:32:30 +0200, Oleg Verych said: > On Tue, Oct 09, 2007 at 06:06:05PM +0200, Joerg Roedel wrote: > > > cpu_has() returns int, > > > but would it be better to have something like > > > > > > if (!mce_disabled && > > > !(c->x86_capability & (X86_FEATURE_MCA | X86_FEATURE_MCE)) { > > > printk(KERN_INFO "CPU%i: No machine check support available\n", > > > smp_processor_id()); > > > > This looks complicated and is harder to read. Its exactly the purpose of the > > cpu_has() macro to avoid such constructs. > > It is done via test_bit(), which is designed for IO access with all that > `const volatile' stuff, 2 x unnecessary, can't be optimized here (IMHO). If this code is getting called often enough that optimization matters, you got *bigger* issues to worry about than optimization. Looks like it should only happen once at boot time. --==_Exmh_1191962806_2838P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (GNU/Linux) Comment: Exmh version 2.5 07/13/2001 iD8DBQFHC+i2cC3lWbTT17ARAu43AJ0T94XZXqfyA/ozz2GfjN+0XcWJHwCgw+uO ZX+xTeEr8S9nQJ7m1RXhoOI= =Nzz4 -----END PGP SIGNATURE----- --==_Exmh_1191962806_2838P-- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/