Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933624AbaKMSOS (ORCPT ); Thu, 13 Nov 2014 13:14:18 -0500 Received: from mga03.intel.com ([134.134.136.65]:60239 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932610AbaKMSOR (ORCPT ); Thu, 13 Nov 2014 13:14:17 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.07,379,1413270000"; d="scan'208";a="607394500" Date: Thu, 13 Nov 2014 20:14:11 +0200 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Borislav Petkov Cc: Andy Lutomirski , intel-gfx@lists.freedesktop.org, X86 ML , "linux-kernel@vger.kernel.org" , DRI , Ingo Molnar , Ross Zwisler , H Peter Anvin , Thomas Gleixner Subject: Re: [PATCH 6/6] x86: Use clwb in drm_clflush_virt_range Message-ID: <20141113181411.GU10649@intel.com> References: <1415731396-19364-1-git-send-email-ross.zwisler@linux.intel.com> <1415731396-19364-7-git-send-email-ross.zwisler@linux.intel.com> <5464220D.6090204@amacapital.net> <20141113112017.GA14416@pd.tnic> <20141113171133.GD14070@pd.tnic> <20141113173354.GT10649@intel.com> <20141113174734.GF14070@pd.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20141113174734.GF14070@pd.tnic> User-Agent: Mutt/1.5.22 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 13, 2014 at 06:47:34PM +0100, Borislav Petkov wrote: > On Thu, Nov 13, 2014 at 07:33:54PM +0200, Ville Syrj?l? wrote: > > We use it both ways in i915. So please don't break it. > > Haha, we started from Intel with Ross' patch and made a full circle > back. Maybe you guys should talk about it. > > LOL. :-) Indeed. The problem I see with these patches is that they don't actually tell what the new instruction does, so a casual glance doesn't really raise any red flags. Another excuse I can use is that I just got used to the fact that the x86 hasn't historically bothered separating invalidate and writeback and just does both. In my previous life on the dark^Warm side I did actually know the difference :) But there's plenty of blame to go around to the other side of the fence too. We should have documented what we expect from these functions. Currently you just have to know/guess, and that's just not good enough. -- Ville Syrj?l? Intel OTC -- 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/