From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id q0O0YBQe166498 for ; Mon, 23 Jan 2012 18:34:11 -0600 Received: from greer.hardwarefreak.com (mo-65-41-216-221.sta.embarqhsd.net [65.41.216.221]) by cuda.sgi.com with ESMTP id MaXtkrvGUB4Oeqqr for ; Mon, 23 Jan 2012 16:34:10 -0800 (PST) Message-ID: <4F1DFC80.1040204@hardwarefreak.com> Date: Mon, 23 Jan 2012 18:34:08 -0600 From: Stan Hoeppner MIME-Version: 1.0 Subject: Re: concurrent direct IO write in xfs References: <20120116232549.GC6922@dastard> <20120123051155.GI15102@dastard> In-Reply-To: Reply-To: stan@hardwarefreak.com List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Zheng Da Cc: xfs@oss.sgi.com On 1/23/2012 2:51 PM, Zheng Da wrote: > tmpfs doesn't support direct IO. Of course not. tmpfs resides entirely within the page cache (or some of it in swap). The whole point of direct IO is to bypass the page cache, transferring data directly between user space memory and the storage device. As tmpfs is built entirely within the page cache, direct IO is obviously impossible. And it's also obviously unnecessary. Yes, you will need to rewrite your application to use tmpfs as direct IO calls won't work. This is something you obviously would rather not do. Which brings us back to Dave's question, which you have not answered: What exactly is the purpose of your program? What does it aim to accomplish? Is it for a database application? A word processor? Or simply a filesystem tester? What do _you_ aim to accomplish with this programming effort? -- Stan _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs