Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754313AbbLOSVK (ORCPT ); Tue, 15 Dec 2015 13:21:10 -0500 Received: from mail.skyhub.de ([78.46.96.112]:57146 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754289AbbLOSVH (ORCPT ); Tue, 15 Dec 2015 13:21:07 -0500 Date: Tue, 15 Dec 2015 19:21:00 +0100 From: Borislav Petkov To: "Luck, Tony" Cc: "Williams, Dan J" , Ingo Molnar , Andrew Morton , Andy Lutomirski , "linux-kernel@vger.kernel.org" , Linux MM , linux-nvdimm , X86 ML Subject: Re: [PATCHV2 3/3] x86, ras: Add mcsafe_memcpy() function to recover from machine checks Message-ID: <20151215182059.GH25973@pd.tnic> References: <23b2515da9d06b198044ad83ca0a15ba38c24e6e.1449861203.git.tony.luck@intel.com> <20151215131135.GE25973@pd.tnic> <3908561D78D1C84285E8C5FCA982C28F39F8566E@ORSMSX114.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <3908561D78D1C84285E8C5FCA982C28F39F8566E@ORSMSX114.amr.corp.intel.com> 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 Content-Length: 1491 Lines: 43 On Tue, Dec 15, 2015 at 05:53:31PM +0000, Luck, Tony wrote: > My current generation cpu has a bit of an issue with recovering from a > machine check in a "rep mov" ... so I'm working with a version of memcpy > that unrolls into individual mov instructions for now. Ah. > I can drop the "nti" from the destination moves. Does "nti" work > on the load from source address side to avoid cache allocation? I don't think so: +1: movq (%rsi),%r8 +2: movq 1*8(%rsi),%r9 +3: movq 2*8(%rsi),%r10 +4: movq 3*8(%rsi),%r11 ... You need to load the data into registers first because MOVNTI needs them there as it does reg -> mem movement. That first load from memory into registers with a normal MOV will pull the data into the cache. Perhaps the first thing to try would be to see what slowdown normal MOVs bring and if not really noticeable, use those instead. > On another topic raised by Boris ... is there some CONFIG_PMEM* > that I should use as a dependency to enable all this? I found CONFIG_LIBNVDIMM only today: drivers/nvdimm/Kconfig:1:menuconfig LIBNVDIMM drivers/nvdimm/Kconfig:2: tristate "NVDIMM (Non-Volatile Memory Device) Support" -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. -- 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/