From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-x233.google.com (mail-wm0-x233.google.com [IPv6:2a00:1450:400c:c09::233]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 28AB11A1EDC for ; Mon, 2 May 2016 12:22:14 -0700 (PDT) Received: by mail-wm0-x233.google.com with SMTP id g17so2370691wme.1 for ; Mon, 02 May 2016 12:22:14 -0700 (PDT) Message-ID: <5727A8E2.8000507@plexistor.com> Date: Mon, 02 May 2016 22:22:10 +0300 From: Boaz Harrosh MIME-Version: 1.0 Subject: Re: [PATCH v4 5/7] fs: prioritize and separate direct_io from dax_io 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> <57277EDA.9000803@plexistor.com> <572791E1.7000103@plexistor.com> <57279D57.5020800@plexistor.com> In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Dan Williams Cc: Jens Axboe , Jan Kara , Matthew Wilcox , "linux-nvdimm@lists.01.org" , Dave Chinner , "linux-kernel@vger.kernel.org" , XFS Developers , linux-block@vger.kernel.org, Linux MM , Al Viro , Christoph Hellwig , linux-fsdevel , Andrew Morton , linux-ext4 List-ID: On 05/02/2016 09:48 PM, Dan Williams wrote: <> >> And then it keeps broken the aligned buffered writes, which are still >> broken after this set. > > ...identical to the current situation with a traditional disk. > Not true!! please see what I wrote "aligned buffered writes" If there are no reads involved then there are no errors returned to application. >> I have by now read the v2 patches. And I think you guys did not yet try >> the proper fix for dax_do_io. I think you need to go deeper into the loops >> and selectively call bdev_* when error on a specific page copy. No need to >> go through direct_IO path at all. > > We still reach a point where the minimum granularity of > bdev_direct_access() is larger than a sector, so you end up still > needing to have the application understand how to send a properly > aligned I/O. The semantics of how to send a properly aligned > direct-I/O are already well understood, so we simply reuse that path. > You are making a mountain out of a mouse. The simple copy of a file from start (offset ZERO) to end-of-file which is the most common usage on earth is perfectly aligned and needs not any O_DIRECT and is what is used everywhere. >> Do you need that I send you a patch to demonstrate what I mean? > > I remain skeptical of what you are proposing, but yes, a patch has a > better chance to move the discussion forward. > Sigh! OK Boaz _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm