From: "hch@infradead.org" Subject: Re: [PATCH v4 5/7] fs: prioritize and separate direct_io from dax_io Date: Sun, 8 May 2016 02:01:48 -0700 Message-ID: <20160508090148.GF15458@infradead.org> References: <1461878218-3844-1-git-send-email-vishal.l.verma@intel.com> <1461878218-3844-6-git-send-email-vishal.l.verma@intel.com> <5727753F.6090104@plexistor.com> <20160505142433.GA4557@infradead.org> <1462484343.29294.1.camel@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "hch@infradead.org" , "boaz@plexistor.com" , "linux-kernel@vger.kernel.org" , "linux-block@vger.kernel.org" , "linux-nvdimm@ml01.01.org" , "xfs@oss.sgi.com" , "linux-mm@kvack.org" , "viro@zeniv.linux.org.uk" , "akpm@linux-foundation.org" , "axboe@fb.com" , "linux-fsdevel@vger.kernel.org" , "linux-ext4@vger.kernel.org" , "david@fromorbit.com" , "jack@suse.cz" , "matthew@wil.cx" To: "Verma, Vishal L" Return-path: Content-Disposition: inline In-Reply-To: <1462484343.29294.1.camel@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Thu, May 05, 2016 at 09:39:14PM +0000, Verma, Vishal L wrote: > How is it any 'less direct'? All it does now is follow the blockdev > O_DIRECT path. There still isn't any page cache involved.. It's still more overhead than the play DAX I/O path.