Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751138AbWCYJmK (ORCPT ); Sat, 25 Mar 2006 04:42:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751142AbWCYJmK (ORCPT ); Sat, 25 Mar 2006 04:42:10 -0500 Received: from e4.ny.us.ibm.com ([32.97.182.144]:16826 "EHLO e4.ny.us.ibm.com") by vger.kernel.org with ESMTP id S1751138AbWCYJmJ (ORCPT ); Sat, 25 Mar 2006 04:42:09 -0500 Date: Sat, 25 Mar 2006 15:11:26 +0530 From: Balbir Singh To: jamal Cc: Matt Helsley , Shailabh Nagar , linux-kernel , netdev Subject: Re: [RFC][UPDATED PATCH 2.6.16] [Patch 9/9] Generic netlink interface for delay accounting Message-ID: <20060325094126.GA9376@in.ibm.com> Reply-To: balbir@in.ibm.com References: <1142296834.5858.3.camel@elinux04.optonline.net> <1142297791.5858.31.camel@elinux04.optonline.net> <1142303607.24621.63.camel@stark> <1142304506.5219.34.camel@jzny2> <20060322074922.GA1164@in.ibm.com> <1143122686.5186.27.camel@jzny2> <20060323154106.GA13159@in.ibm.com> <1143209061.5076.14.camel@jzny2> <20060324145459.GA7495@in.ibm.com> <1143249565.5184.6.camel@jzny2> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1143249565.5184.6.camel@jzny2> User-Agent: Mutt/1.5.10i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1992 Lines: 63 On Fri, Mar 24, 2006 at 08:19:25PM -0500, jamal wrote: > On Fri, 2006-24-03 at 20:24 +0530, Balbir Singh wrote: > > > Hmm... Would it be ok to send one message with the following format > > > > 1. TLV=TASKSTATS_TYPE_PID > > 2. TLV=TASKSTATS_TYPE_STATS > > 3. TLV=TASKSTATS_TYPE_TGID > > 4. TLV=TASKSTATS_TYPE_STATS > > > > It would still be one message, except that 3 and 4 would be optional. > > What do you think? > > > > No, that wont work since #2 and #4 are basically the same TLV. [Recall > that "T" is used to index an array]. Your other alternative is to have > #4 perhaps called TASKSTATS_TGID_STATS and #2 TASKSTATS_PID_STATS > although that would smell a little. > Dont be afraid to do the nest, it will be a little painful initially but > i am sure once you figure it out you will appreciate it. > Thanks for the advice, I will dive into nesting. I could not find any in tree users who use nesting, so I have a few questions nla_nest_start() accepts two parameters an skb and an attribute type. Do I have to create a new attribute type like TASKSTATS_TYPE_AGGR to contain the nested attributes TASKSTATS_TYPE_AGGR TASKSTATS_TYPE_PID/TGID TASKSTATS_TYPE_STATS but this will lead to TASKSTATS_TYPE_AGGR TASKSTATS_TYPE_PID TASKSTATS_TYPE_STATS TASKSTATS_TYPE_AGGR TASKSTATS_TYPE_TGID TASKSTATS_TYPE_STATS being returned from taskstats_exit_pid(). The other option is to nest TASKSTATS_TYPE_PID/TGID TASKSTATS_TYPE_STATS but the problem with this approach is, nla_len contains the length of all attributes including the nested attribute. So it is hard to find the offset of TASKSTATS_TYPE_STATS in the buffer. Do I understand NLA nesting at all? May be I am missing something obvious. Thanks, Balbir - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/