From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f71.google.com (mail-pa0-f71.google.com [209.85.220.71]) by kanga.kvack.org (Postfix) with ESMTP id EF6806B0038 for ; Mon, 12 Sep 2016 01:27:08 -0400 (EDT) Received: by mail-pa0-f71.google.com with SMTP id fu12so46778603pac.1 for ; Sun, 11 Sep 2016 22:27:08 -0700 (PDT) Received: from bombadil.infradead.org (bombadil.infradead.org. [2001:1868:205::9]) by mx.google.com with ESMTPS id q7si19735966pax.43.2016.09.11.22.27.08 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 11 Sep 2016 22:27:08 -0700 (PDT) Date: Sun, 11 Sep 2016 22:27:03 -0700 From: Christoph Hellwig Subject: Re: DAX mapping detection (was: Re: [PATCH] Fix region lost in /proc/self/smaps) Message-ID: <20160912052703.GA1897@infradead.org> References: <20160908225636.GB15167@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160908225636.GB15167@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Ross Zwisler , Dan Williams , Xiao Guangrong , Dave Hansen , Paolo Bonzini , Andrew Morton , Michal Hocko , Gleb Natapov , mtosatti@redhat.com, KVM list , "linux-kernel@vger.kernel.org" , Stefan Hajnoczi , Yumei Huang , Linux MM , "linux-nvdimm@lists.01.org" , linux-fsdevel On Thu, Sep 08, 2016 at 04:56:36PM -0600, Ross Zwisler wrote: > I think this goes back to our previous discussion about support for the PMEM > programming model. Really I think what NVML needs isn't a way to tell if it > is getting a DAX mapping, but whether it is getting a DAX mapping on a > filesystem that fully supports the PMEM programming model. This of course is > defined to be a filesystem where it can do all of its flushes from userspace > safely and never call fsync/msync, and that allocations that happen in page > faults will be synchronized to media before the page fault completes. That's a an easy way to flag: you will never get that from a Linux filesystem, period. NVML folks really need to stop taking crack and dreaming this could happen. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org