From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261880AbVGPVMu (ORCPT ); Sat, 16 Jul 2005 17:12:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261889AbVGPVMu (ORCPT ); Sat, 16 Jul 2005 17:12:50 -0400 Received: from outpost.ds9a.nl ([213.244.168.210]:44443 "EHLO outpost.ds9a.nl") by vger.kernel.org with ESMTP id S261880AbVGPVMt (ORCPT ); Sat, 16 Jul 2005 17:12:49 -0400 Date: Sat, 16 Jul 2005 23:07:59 +0200 From: bert hubert To: Tom Zanussi Cc: linux-kernel@vger.kernel.org, karim@opersys.com, varap@us.ibm.com, richardj_moore@uk.ibm.com, relayfs-devel@lists.sourceforge.net Subject: relayfs documentation sucks? Message-ID: <20050716210759.GA1850@outpost.ds9a.nl> Mail-Followup-To: bert hubert , Tom Zanussi , linux-kernel@vger.kernel.org, karim@opersys.com, varap@us.ibm.com, richardj_moore@uk.ibm.com, relayfs-devel@lists.sourceforge.net References: <17107.6290.734560.231978@tut.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <17107.6290.734560.231978@tut.ibm.com> User-Agent: Mutt/1.3.28i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ok, I'm working furiously on my OLS presentation (Wednesday, 3pm, be there), but I'm running into a wall with relayfs, which I intend to use to convey large amounts of disk statistics towards userspace. Now, I've read Documentation/filesystems/relayfs.txt many times over, and I don't get it. It appears there is relayfs, and 'klog' on top of that. It also appears that to access relayed data from the kernel in userspace there is librelay.c. On reading librelay.c, I find code sending and receiving netlink messages, but relayfs.txt doesn't even contain the word netlink! I then launched the 'kleak-app' sample program, but told it to look at /relay/diskstat* instead of its own file, but it gives me unspecified netlink errors. Things I need to know, and which I hope to find documented somewhere: 1) Do I need to do the netlink thing? 2) What kind of messages do I need to send/receive? 3) What is the exact format userspace sees in the relayfs file? Iow, can I access that file w/o using librelay.c? 4) What are the semantics for reading from that file? 5) When using klog, is there only one channel? 6) does librelay.c talk to regular relayfs or to klog? Don't get me wrong, relayfs sure looks nice for what I'm trying to do but from userspace it is sort of a black box right now.. Thanks! -- http://www.PowerDNS.com Open source, database driven DNS Software http://netherlabs.nl Open and Closed source services