Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932069AbbDMJfp (ORCPT ); Mon, 13 Apr 2015 05:35:45 -0400 Received: from verein.lst.de ([213.95.11.211]:60152 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753375AbbDMJfn (ORCPT ); Mon, 13 Apr 2015 05:35:43 -0400 Date: Mon, 13 Apr 2015 11:35:41 +0200 From: Christoph Hellwig To: Ingo Molnar Cc: Linus Torvalds , linux-kernel@vger.kernel.org, linux-nvdimm@ml01.01.org, Christoph Hellwig , Ross Zwisler , Dan Williams , Boaz Harrosh Subject: Re: [GIT PULL] PMEM driver for v4.1 Message-ID: <20150413093541.GA5147@lst.de> References: <20150413093309.GA30219@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150413093309.GA30219@gmail.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 774 Lines: 14 On Mon, Apr 13, 2015 at 11:33:09AM +0200, Ingo Molnar wrote: > Limitations: this is a regular block device, and since the pmem areas > are not struct page backed, they are invisible to the rest of the > system (other than the block IO device), so direct IO to/from pmem > areas, direct mmap() or XIP is not possible yet. The page cache will > also shadow and double buffer pmem contents, etc. Unless you use the DAX support in ext2/4 and soon XFS, in which case we avoid that double buffering when doing read/write and mmap -- 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/