From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751833AbbE2ETg (ORCPT ); Fri, 29 May 2015 00:19:36 -0400 Received: from terminus.zytor.com ([198.137.202.10]:55915 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750741AbbE2ET2 (ORCPT ); Fri, 29 May 2015 00:19:28 -0400 Message-ID: <5567E8B5.3080801@zytor.com> Date: Thu, 28 May 2015 21:19:01 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Dan Williams CC: Ross Zwisler , "linux-kernel@vger.kernel.org" , Linux ACPI , linux-nvdimm , Thomas Gleixner , Ingo Molnar , X86 ML Subject: Re: [PATCH 3/6] x86, pmem: add PMEM API for persistent memory References: <1432852553-24865-1-git-send-email-ross.zwisler@linux.intel.com> <1432852553-24865-4-git-send-email-ross.zwisler@linux.intel.com> <5567A2C4.3040407@zytor.com> In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/28/2015 05:02 PM, Dan Williams wrote: > > Hmm, yes, but I believe Ross (on vacation now) was following the > precedent set by commit cd8ddf1a2800 "x86: clflush_page_range needs > mfence" whereby the api handles all necessary fencing internally. > Shall we introduce something like __unordered_clflush_cache_range() > for arch_persistent_flush() to use with the understanding it will be > following up with the wmb() in arch_persistent_sync()? > Are we ever going to have arch_persistent_sync() without arch_persistent_flush()? However, thinking about it, it would be more efficient to do all flushes first and then have a single barrier. -hpa