From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264639AbUHJMYh (ORCPT ); Tue, 10 Aug 2004 08:24:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264585AbUHJMYh (ORCPT ); Tue, 10 Aug 2004 08:24:37 -0400 Received: from smtp.rol.ru ([194.67.21.9]:3799 "EHLO smtp.rol.ru") by vger.kernel.org with ESMTP id S264639AbUHJMYE (ORCPT ); Tue, 10 Aug 2004 08:24:04 -0400 Message-ID: <4118BEFD.9090605@vlnb.net> Date: Tue, 10 Aug 2004 16:26:37 +0400 From: Vladislav Bolkhovitin User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.7) Gecko/20040616 X-Accept-Language: ru, en-us MIME-Version: 1.0 To: Andi Kleen CC: linux-kernel@vger.kernel.org, marcelo.tosatti@cyclades.com Subject: Re: [PATCH] x86 bitops.h commentary on instruction reordering References: <2pY7Y-W1-7@gated-at.bofh.it> <2qdJL-3sh-27@gated-at.bofh.it> <2qePx-4eM-21@gated-at.bofh.it> <2qf8S-4pI-31@gated-at.bofh.it> <2qg4V-54c-17@gated-at.bofh.it> <2qgoh-5og-29@gated-at.bofh.it> <2qhkn-649-41@gated-at.bofh.it> <2rkgh-zP-45@gated-at.bofh.it> <2rlFk-1wC-27@gated-at.bofh.it> <2rmhX-20I-17@gated-at.bofh.it> <2roWw-40d-19@gated-at.bofh.it> <2roWw-40d-17@gated-at.bofh.it> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andi Kleen wrote: > That makes them a *lot* slower on some systems. And most of the > set_bits in the kernel don't need strong ordering. > > >>difference with versions with `__` prefix (__set_bit(), for example)? >>Just adding the comments will lead to creating different functions >>with gurantees by everyone who need it in all over the kernel. Is it >>the right thing? In some places in SCST we heavy rely on non-ordering >>guarantees. > > > Better add lots of memory barriers then. It looks like we have to do that now. Thanks, Vlad