From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Martin K. Petersen" Subject: Re: [LSF/MM TOPIC][ATTEND] protection information and userspace Date: Thu, 07 Feb 2013 14:12:57 -0500 Message-ID: References: <20130206195122.GA30652@sgi.com> <20130206202444.GA4771@blackbox.djwong.org> <20DAFDEA-0C44-478E-B406-C5B08BC67FBC@oracle.com> <20130207094012.GA28047@localhost> Mime-Version: 1.0 Content-Type: text/plain Cc: "Darrick J. Wong" , Ben Myers , lsf-pc@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-scsi@vger.kernel.org, martin.petersen@oracle.com To: Chuck Lever Return-path: Received: from userp1040.oracle.com ([156.151.31.81]:42298 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758934Ab3BGTMt (ORCPT ); Thu, 7 Feb 2013 14:12:49 -0500 In-Reply-To: <20130207094012.GA28047@localhost> (Joel Becker's message of "Thu, 7 Feb 2013 01:40:14 -0800") Sender: linux-fsdevel-owner@vger.kernel.org List-ID: >>>>> "Joel" == Joel Becker writes: Joel> I'm happy to chat about it. Unfortunately, like Darrick says, Joel> sys_dio() coding hasn't happened. I do think we're better off Joel> with some kind of explicit API than some magic state on the file. Joel> I mean, even something like: Joel> ssize_t write_with_pi(int fd, const void *buf, size_t count, Joel> const void *pi, size_t pi_count); Joel> It's not as nice as a non-historical API (eg sys_dio), but it also Joel> probably plays nicer with buffered I/O. Pretty much everyone I have talked to that are interested in explicitly attaching PI (as opposed to relying on the kernel doing it) are using Linux aio. I am not opposed to having more read()/write() like interface as well. But I think it's important to cater to the I/O paradigm used by the applications interested in this. It's a lot easier to tweak a few IOCB fields than it is to rewrite how an application does I/O. -- Martin K. Petersen Oracle Linux Engineering