From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933049AbcHCXUB (ORCPT ); Wed, 3 Aug 2016 19:20:01 -0400 Received: from out2-smtp.messagingengine.com ([66.111.4.26]:51088 "EHLO out2-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932914AbcHCXUA (ORCPT ); Wed, 3 Aug 2016 19:20:00 -0400 X-Sasl-enc: hWOHOcG3yZWBx4KPGyY14aj3GML6xXGKQUlTqQ5wIYyI 1470266398 Date: Wed, 3 Aug 2016 20:19:55 -0300 From: Henrique de Moraes Holschuh To: "Michael S. Tsirkin" Cc: "H. Peter Anvin" , Peter Zijlstra , Ingo Molnar , Dexuan Cui , "linux-x86_64@vger.kernel.org" , Thomas Gleixner , Ingo Molnar , David Howells , "Paul E. McKenney" , "linux-kernel@vger.kernel.org" Subject: Re: x86 memory barrier: why does Linux prefer MFENCE to Locked ADD? Message-ID: <20160803231955.GA9304@khazad-dum.debian.net> References: <20160303152739.GA16303@gmail.com> <20160303153453.GR6356@twins.programming.kicks-ass.net> <20160303203414-mutt-send-email-mst@redhat.com> <66C0F0F8-5D2C-47DB-8C7A-EF8A15F263DB@zytor.com> <20160803073134-mutt-send-email-mst@kernel.org> <20160803125025.GB680@khazad-dum.debian.net> <20160803160344-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160803160344-mutt-send-email-mst@kernel.org> X-GPG-Fingerprint1: 4096R/39CB4807 C467 A717 507B BAFE D3C1 6092 0BD9 E811 39CB 4807 User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 03 Aug 2016, Michael S. Tsirkin wrote: > Are any of these used in kernel though? These specific errata were not the point of my post, rather, it was the fact that errata related to *FENCE and LOCKed instructions exists. I didn't verify whether something attempts to use non-temporal loads or stores from WC memory in the kernel. -- "One disk to rule them all, One disk to find them. One disk to bring them all and in the darkness grind them. In the Land of Redmond where the shadows lie." -- The Silicon Valley Tarot Henrique Holschuh