From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f199.google.com (mail-pf0-f199.google.com [209.85.192.199]) by kanga.kvack.org (Postfix) with ESMTP id 268D96B0038 for ; Tue, 17 Oct 2017 04:02:47 -0400 (EDT) Received: by mail-pf0-f199.google.com with SMTP id h28so792134pfh.16 for ; Tue, 17 Oct 2017 01:02:47 -0700 (PDT) Received: from bombadil.infradead.org (bombadil.infradead.org. [65.50.211.133]) by mx.google.com with ESMTPS id g2si3240482pll.718.2017.10.17.01.02.46 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 17 Oct 2017 01:02:46 -0700 (PDT) Date: Tue, 17 Oct 2017 01:02:36 -0700 From: Christoph Hellwig Subject: Re: [Qemu-devel] [RFC 2/2] KVM: add virtio-pmem driver Message-ID: <20171017080236.GA27649@infradead.org> References: <20171012155027.3277-1-pagupta@redhat.com> <20171012155027.3277-3-pagupta@redhat.com> <20171017071633.GA9207@infradead.org> <1441791227.21027037.1508226056893.JavaMail.zimbra@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1441791227.21027037.1508226056893.JavaMail.zimbra@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Pankaj Gupta Cc: Christoph Hellwig , kwolf@redhat.com, haozhong zhang , jack@suse.cz, xiaoguangrong eric , kvm@vger.kernel.org, david@redhat.com, linux-nvdimm@ml01.01.org, ross zwisler , linux-kernel@vger.kernel.org, qemu-devel@nongnu.org, linux-mm@kvack.org, stefanha@redhat.com, pbonzini@redhat.com, dan j williams , nilal@redhat.com On Tue, Oct 17, 2017 at 03:40:56AM -0400, Pankaj Gupta wrote: > Are you saying do it as existing i.e ACPI pmem like interface? > The reason we have created this new driver is exiting pmem driver > does not define proper semantics for guest flushing requests. At this point I'm caring about the Linux-internal interface, and for that it should be integrated into the nvdimm subsystem and not a block driver. How the host <-> guest interface looks is a different idea. > > Regarding block support of driver, we want to achieve DAX support > to bypass guest page cache. Also, we want to utilize existing DAX > capable file-system interfaces(e.g fsync) from userspace file API's > to trigger the host side flush request. Well, if you want to support XFS+DAX better don't make it a block devices, because I'll post patches soon to stop using the block device entirely for the DAX case. -- 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