From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 247E1C433DF for ; Fri, 19 Jun 2020 07:46:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0A8492073E for ; Fri, 19 Jun 2020 07:46:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731104AbgFSHqA (ORCPT ); Fri, 19 Jun 2020 03:46:00 -0400 Received: from mx2.suse.de ([195.135.220.15]:56308 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730830AbgFSHqA (ORCPT ); Fri, 19 Jun 2020 03:46:00 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 0D9FDB18D; Fri, 19 Jun 2020 07:45:56 +0000 (UTC) Date: Fri, 19 Jun 2020 09:45:55 +0200 From: Petr Mladek To: jim.cromie@gmail.com Cc: Jason Baron , LKML , akpm@linuxfoundation.org, Greg KH , Rasmus Villemoes , Jonathan Corbet , Andrew Morton , Will Deacon , Orson Zhai , Linux Documentation List Subject: Re: [PATCH v3 20/21] dyndbg: add user-flag, negating-flags, and filtering on flags Message-ID: <20200619074555.GF3617@alley> References: <20200617162536.611386-1-jim.cromie@gmail.com> <20200617162536.611386-23-jim.cromie@gmail.com> <20200618161912.GD3617@alley> <20200618174058.GE3617@alley> <746984fb-00ee-9079-efac-50167f3c3e40@akamai.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Thu 2020-06-18 13:11:05, jim.cromie@gmail.com wrote: > On Thu, Jun 18, 2020 at 12:17 PM Jason Baron wrote: > > Yes, I'm wondering as well if people are really going to use the > > new flags and filter flags - I mentioned that here: > > https://lkml.org/lkml/2020/6/12/732 > > yes, I saw, and replied there. No, the repply only explains how the interface might be used. There is no prove that people would actually use it. > but since that was v1, and we're on v3, we should refresh. > > the central use-case is above, 1-liner version summarized here: > > 1- enable sites as you chase a problem with +up > 2- examine them with grep =pu > 3- change the set to suit, either by adding or subtracting callsites. > 4- continue debugging, and changing callsites to suit > 5- grep =pu control > ~/debugging-session-task1-callsites > 6- echo up-p >control # disable for now, leave u-set for later > 7- do other stuff > 8 echo uP+p >control # reactivate useful debug-state and resume In short, this feature allows repeatedly enable/disable some slowly growing maze of debug messages. Who need this, please? !!! If I am debugging then I add/remove debug messages. But I never enable/disable all of them repeatedly. Also this is far from the original problem. It was about debugging a single driver (venus, drm). In this case, people need something easy to use. The following is the easy way: drm.debug = area_of_interest venus.debug = level_of_interest echo module=drm group=area_of_interest +p >control [*] echo module=venus group=level_of_interes +p >control Anyway, why filtering and 'u' flag would be necessary to debug these drivers? Is anyone going to use it? I would really like to hear the motivation for these features. Has anyone asked for them? Or are these just some "interesting" ideas from some brainstorming? [*] Well, I wonder if the dyndbg interface would even be useful for drm because it it is actually split into many modules. So it might require creating/maintaining several filters. Best Regards, Petr PS: This is probably my last mail in this thread. It goes in cycle. You repeatedly explain how many possibilities the new features allow. I repeatedly doubt that they are worth it. I also proposed another solution for the original problem (venus) but it has never been commented. I just hope that these features will not get merged without a clear interest in them.