Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932729AbbDQSHi (ORCPT ); Fri, 17 Apr 2015 14:07:38 -0400 Received: from mail-qc0-f179.google.com ([209.85.216.179]:36714 "EHLO mail-qc0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753362AbbDQSHg (ORCPT ); Fri, 17 Apr 2015 14:07:36 -0400 Date: Fri, 17 Apr 2015 14:07:32 -0400 From: Tejun Heo To: Tetsuo Handa Cc: davem@davemloft.net, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCHSET] printk, netconsole: implement reliable netconsole Message-ID: <20150417180732.GF16743@htj.duckdns.org> References: <20150417162826.GB16743@htj.duckdns.org> <20150417.131712.1245246947203158168.davem@davemloft.net> <20150417173754.GC16743@htj.duckdns.org> <201504180243.IDB78159.tFVOOFQFSOHLMJ@I-love.SAKURA.ne.jp> <20150417174522.GD16743@htj.duckdns.org> <201504180303.GAB26011.OLJFSMVFFOHtOQ@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201504180303.GAB26011.OLJFSMVFFOHtOQ@I-love.SAKURA.ne.jp> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1385 Lines: 35 On Sat, Apr 18, 2015 at 03:03:46AM +0900, Tetsuo Handa wrote: > If you tolerate loss of kernel messages, adding sequence number to each UDP Well, there's a difference between accepting loss when log buffer overflows and when any packets get lost. > packet will be sufficient for finding out whether the packets were lost and/or > reordered in flight. > > printk("Hello"); > => netconsole sends "00000000 Hello" using UDP > printk("netconsole"); > => netconsole sends "00000001 netconsole" using UDP > printk("world\n"); > => netconsole sends "00000002 world\n" using UDP > > It might be nice to allow administrator to prefix a sequence number > to netconsole messages for those who are using special receiver > program (e.g. ncrx) which checks that sequence number. That said, this is pretty much what the first 12 patches do (except for the last printk patch, which can be taken out). We already have sequencing and established format to expose them to userland - try cat /dev/kmsg, which btw is what local loggers on modern systems use anyway. Why introduce netconsole's own version of metadata? Thanks. -- tejun -- 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/