From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]) by bombadil.infradead.org with esmtps (Exim 4.68 #1 (Red Hat Linux)) id 1JkX2C-0002tl-A5 for kexec@lists.infradead.org; Sat, 12 Apr 2008 04:08:12 +0000 Date: Fri, 11 Apr 2008 21:07:51 -0700 From: Andrew Morton Subject: Re: [PATCH 0/2] add new notifier function ,take3 Message-Id: <20080411210751.e4a468b2.akpm@linux-foundation.org> In-Reply-To: <47FF190B.6030406@ah.jp.nec.com> References: <47FF190B.6030406@ah.jp.nec.com> Mime-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: kexec-bounces@lists.infradead.org Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Takenori Nagano Cc: nickpiggin@yahoo.com.au, k-miyoshi@cb.jp.nec.com, greg@kroah.com, Bernhard Walle , kdb@oss.sgi.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, Randy Dunlap , vgoyal@in.ibm.com, "Eric W. Biederman" , Keith Owens On Fri, 11 Apr 2008 16:53:47 +0900 Takenori Nagano wrote: > Hi, > > A big thanks to everybody who read and replied to previous version. > > changelog take2 -> take3 > > - Rebased 2.6.25-rc8-mm1 > - comment updated > - renamed the notifiner name "tunable_notifier" to "tunable_atomic_notifier" > - fixed typo > - move control files debugfs to /sys/kernel > > These patches add new notifier function and implement it to panic_notifier_list. > We used the hardcoded notifier chain so far, but it was not flexible. New > notifier is very flexible, because user can change a list of order by control files. > > Example) > > # cd /sys/kernel/notifiers/ > # ls > panic_notifier_list > # cd panic_notifier_list/ > # ls > ipmi_msghandler ipmi_wdog > # insmod notifier_test.ko > # ls > ipmi_msghandler ipmi_wdog notifier_test1 notifier_test2 > # cat */priority > 200 > 150 > 500 > 1000 > Kernel panic - not syncing: Panic by panic_module. > __tunable_atomic_notifier_call_chain enter > notifier_test: notifier_test_panic2() is called. > notifier_test: notifier_test_panic() is called. > msg_handler:panic_event was called. > ipmi_wdog:wdog_panic_handler was called. > > .....(reboot) > > # cd /sys/kernel/notifiers/panic_notifier_list/ > # ls > ipmi_msghandler ipmi_wdog notifier_test1 notifier_test2 > # cat */priority > 200 > 150 > 500 > 1000 > # echo 10000 > ipmi_msghandler/priority > # echo 5000 > ipmi_wdog/priority > # echo 3000 > notifier_test1/priority > # echo 1500 > notifier_test2/priority > # cat */priority > 10000 > 5000 > 3000 > 1500 > Kernel panic - not syncing: Panic by panic_module. > __tunable_atomic_notifier_call_chain enter > msg_handler:panic_event was called. > ipmi_wdog:wdog_panic_handler was called. > notifier_test: notifier_test_panic() is called. > notifier_test: notifier_test_panic2() is called. OK. But I don't see anywhere in here the most important piece of information: why do we need this feature in Linux? What are the use-cases? What is the value? etc. Often I can guess (but I like the originator to remove the guesswork). In this case I'm stumped - I can't see any reason why anyone would want this. Awaiting enlightenment ;) Thanks. _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754018AbYDLEI7 (ORCPT ); Sat, 12 Apr 2008 00:08:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751162AbYDLEIv (ORCPT ); Sat, 12 Apr 2008 00:08:51 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:40129 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750952AbYDLEIu (ORCPT ); Sat, 12 Apr 2008 00:08:50 -0400 Date: Fri, 11 Apr 2008 21:07:51 -0700 From: Andrew Morton To: Takenori Nagano Cc: linux-kernel@vger.kernel.org, kdb@oss.sgi.com, vgoyal@in.ibm.com, "Eric W. Biederman" , k-miyoshi@cb.jp.nec.com, kexec@lists.infradead.org, Bernhard Walle , Keith Owens , nickpiggin@yahoo.com.au, Randy Dunlap , greg@kroah.com Subject: Re: [PATCH 0/2] add new notifier function ,take3 Message-Id: <20080411210751.e4a468b2.akpm@linux-foundation.org> In-Reply-To: <47FF190B.6030406@ah.jp.nec.com> References: <47FF190B.6030406@ah.jp.nec.com> X-Mailer: Sylpheed 2.4.8 (GTK+ 2.12.5; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 11 Apr 2008 16:53:47 +0900 Takenori Nagano wrote: > Hi, > > A big thanks to everybody who read and replied to previous version. > > changelog take2 -> take3 > > - Rebased 2.6.25-rc8-mm1 > - comment updated > - renamed the notifiner name "tunable_notifier" to "tunable_atomic_notifier" > - fixed typo > - move control files debugfs to /sys/kernel > > These patches add new notifier function and implement it to panic_notifier_list. > We used the hardcoded notifier chain so far, but it was not flexible. New > notifier is very flexible, because user can change a list of order by control files. > > Example) > > # cd /sys/kernel/notifiers/ > # ls > panic_notifier_list > # cd panic_notifier_list/ > # ls > ipmi_msghandler ipmi_wdog > # insmod notifier_test.ko > # ls > ipmi_msghandler ipmi_wdog notifier_test1 notifier_test2 > # cat */priority > 200 > 150 > 500 > 1000 > Kernel panic - not syncing: Panic by panic_module. > __tunable_atomic_notifier_call_chain enter > notifier_test: notifier_test_panic2() is called. > notifier_test: notifier_test_panic() is called. > msg_handler:panic_event was called. > ipmi_wdog:wdog_panic_handler was called. > > .....(reboot) > > # cd /sys/kernel/notifiers/panic_notifier_list/ > # ls > ipmi_msghandler ipmi_wdog notifier_test1 notifier_test2 > # cat */priority > 200 > 150 > 500 > 1000 > # echo 10000 > ipmi_msghandler/priority > # echo 5000 > ipmi_wdog/priority > # echo 3000 > notifier_test1/priority > # echo 1500 > notifier_test2/priority > # cat */priority > 10000 > 5000 > 3000 > 1500 > Kernel panic - not syncing: Panic by panic_module. > __tunable_atomic_notifier_call_chain enter > msg_handler:panic_event was called. > ipmi_wdog:wdog_panic_handler was called. > notifier_test: notifier_test_panic() is called. > notifier_test: notifier_test_panic2() is called. OK. But I don't see anywhere in here the most important piece of information: why do we need this feature in Linux? What are the use-cases? What is the value? etc. Often I can guess (but I like the originator to remove the guesswork). In this case I'm stumped - I can't see any reason why anyone would want this. Awaiting enlightenment ;) Thanks.