Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761434Ab3DCLB1 (ORCPT ); Wed, 3 Apr 2013 07:01:27 -0400 Received: from mail-la0-f41.google.com ([209.85.215.41]:63694 "EHLO mail-la0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760388Ab3DCLBZ (ORCPT ); Wed, 3 Apr 2013 07:01:25 -0400 MIME-Version: 1.0 In-Reply-To: <20130403075017.GA2534@suse.de> References: <20130403075017.GA2534@suse.de> Date: Wed, 3 Apr 2013 13:01:23 +0200 Message-ID: Subject: Re: systemtap broken by removal of register_timer_hook From: Frederic Weisbecker To: Mel Gorman Cc: Ingo Molnar , LKML , SystemTap Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1940 Lines: 37 2013/4/3 Mel Gorman : > Commit ba6fdda4 (profiling: Remove unused timer hook) removed > [un]register_timer_hook due to a lack of upstream users and a belief > that there were no out-of-tree users. However, systemtap uses it and > with that patch applied, some stap scripts fail with > > WARNING: "unregister_timer_hook" [/tmp/stapJoLMxD/stap_de6e19eaf7bd94629aba9d6f56cdfca5_8156.ko] undefined! > WARNING: "register_timer_hook" [/tmp/stapJoLMxD/stap_de6e19eaf7bd94629aba9d6f56cdfca5_8156.ko] undefined! > Error inserting module '/tmp/stapJoLMxD/stap_de6e19eaf7bd94629aba9d6f56cdfca5_8156.ko': Unknown symbol in module > WARNING: /usr/bin/staprun exited with status: 1 > Pass 5: run failed. Try again with another '--vp 00001' option. > Unexpected exit of STAP script at ./watch-dstate.pl line 305. Ah I missed that. > > Can the patch be reverted or at least put a warning in place about it > being obsoleted until the systemtap folks come up with a replacement? Sometimes I don't mind keeping around code in the kernel for out of tree users, depending on the case. But in this specific matter we have more standard ways to do this kind of hook: kprobes, static tracepoints. A tracepoint on the timer tick would be useful BTW, and you could reuse it. How does that sound to system tap guys? It would be nice if we can avoid the feature-removal.txt step. I mean, I heard some doleful whispers once when my pointer selected that file. Instead of opening the file I just closed the directory instantly. I never told anybody about that before, this is the first time. I also heard that somebody added an entry to that file to schedule the removal of that file? This is devilry. -- 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/