From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754354Ab2D1Jd3 (ORCPT ); Sat, 28 Apr 2012 05:33:29 -0400 Received: from mx1.b1-systems.de ([217.11.58.35]:37667 "EHLO mx1.b1-systems.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751935Ab2D1Jd2 (ORCPT ); Sat, 28 Apr 2012 05:33:28 -0400 Message-ID: <4F9BB87C.4050103@b1-systems.de> Date: Sat, 28 Apr 2012 11:29:32 +0200 From: Karsten Keil User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0) Gecko/20120129 Thunderbird/10.0 MIME-Version: 1.0 To: Tilman Schmidt CC: Karsten Keil , David Miller , Hansjoerg Lipp , i4ldeveloper@listserv.isdn4linux.de, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/8] isdn/gigaset: ratelimit CAPI message dumps References: <20120425-patch-gigaset-00.tilman@imap.cc> <20120425-patch-gigaset-01.tilman@imap.cc> <4F98EDB1.5090702@b1-systems.de> <4F9A7510.5010808@imap.cc> In-Reply-To: <4F9A7510.5010808@imap.cc> X-Enigmail-Version: 1.4 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Am 27.04.2012 12:29, schrieb Tilman Schmidt: > Am 26.04.2012 08:39, schrieb Karsten Keil: >> Am 26.04.2012 01:02, schrieb Tilman Schmidt: >>> Introduce a global ratelimit for CAPI message dumps to protect >>> against possible log flood. Drop the ratelimit for ignored >>> messages which is now covered by the global one. >> >> Hmm, I think the only CAPI messages which would need a ratelimit >> are related to the DATA_B3 messages. If you need CAPI debug >> messages in most cases you do not need all of the DATA_B3, but >> you do not want to miss any other message related to the call >> control. With a general rate limit you do not have the control, >> which messages are logged and which are not. > > The ratelimit introduced by this patch only applies to messages > other than DATA_B3. Logging DATA_B3 messages is not done via > dump_cmsg(). > Thanks for the clarification, forget about my objection. I ack this patch now. > I'd like to ratelimit specifically non-DATA_B3 messages because I > saw a (possibly buggy) CAPI application flooding the log with > FACILITY messages. Equally important, I'd like to make the > ratelimit in do_nothing() / do_unsupported() bursty because I had > a case where I needed to see several ignored/unhandled CAPI > messages in quick succession. So this patch is killing two birds > with one stone for me. > > The burst limit of 20 messages in 20 seconds is chosen to allow a > complete call setup sequence to be logged, while limiting to one > message per second in the long run. > >> And here maybe some cases, when even the DATA_B3 are important >> (e.g. searching bugs in flow control), so I would make it still >> conditional to allow to print all messages. > > DATA_B3 dumps produce an enormous amount of log data and are > therefore controlled separately by the DEBUG_MCMD flag. Someone > who enables that should know what she or he does. But if you need > them, you need them all. A ratelimit doesn't make sense there in > my experience. > >> And I'm not sure, if this is really something for stable. > > It's pretty simple and localized, a net simplification, and only > affects generation of debugging messages, so I think it's safe. > But if you see a problem there I can drop the "CC: stable" line. > I let the decision about it to you and the stable maintainers. - -- Karsten Keil Linux Kernel Development Tel: +49 175 7249132 Mail: keil@b1-systems.de B1 Systems GmbH Osterfeldstraße 7 / 85088 Vohburg / http://www.b1-systems.de GF: Ralph Dehner / Unternehmenssitz: Vohburg / AG: Ingolstadt,HRB 3537 -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.16 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk+buHwACgkQo5VVC52CNcRoygCfWwPlWZ+A48OwEkr/MtK6PeNG 0UEAnipdxPSZDKa4s99LlGYwvggWIIAJ =CLr6 -----END PGP SIGNATURE-----