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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A4F54C433EF for ; Sun, 15 May 2022 22:15:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234482AbiEOWPD (ORCPT ); Sun, 15 May 2022 18:15:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37224 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234701AbiEOWO5 (ORCPT ); Sun, 15 May 2022 18:14:57 -0400 Received: from fanzine2.igalia.com (fanzine.igalia.com [178.60.130.6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EB0F12AE33; Sun, 15 May 2022 15:14:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=YHVcpMpwO8nyb8k3/FdyFSCMjS4nrs3MtFW4fah9gBU=; b=or/Fp90JrKe5WlMtL6cMgrtDTd KlQ8Vj1tprmMn4SD+c397HC1ukULCsTvCB4iLkFWE/e5eO3HFfAEwKhrKkKAtUd9klk2EZdbn6mIN Qd+4SALGR19YAeq7zzTYslQNi14hCF7XYTbP7jST+WF88j+/yFKclHfwZStwWLlezXivWrxaH8IdO FFInQai4LoqHg4Is254olZSUcp3WbX0NojyrclkAFtXk81MOkLDyQLJPvTXx/jJ5o9GkRAlJzHqhs Xl4VBJVpr4ONcW/qU5LapKJAeqGhxtirFucuu9tYQZm2MIj3QsWcao7mjJyCDthsv8RdX0nMP6hLP SN2gr77A==; Received: from [177.183.162.244] (helo=[192.168.0.5]) by fanzine2.igalia.com with esmtpsa (Cipher TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_128_GCM:128) (Exim) id 1nqMUS-005ij1-QV; Mon, 16 May 2022 00:13:29 +0200 Message-ID: <178a456d-3961-9bc2-83d2-2b9457d45fbd@igalia.com> Date: Sun, 15 May 2022 19:12:55 -0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.0 Subject: Re: [PATCH 11/30] um: Improve panic notifiers consistency and ordering Content-Language: en-US To: Johannes Berg , Petr Mladek , Anton Ivanov , Richard Weinberger Cc: akpm@linux-foundation.org, bhe@redhat.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8.de, corbet@lwn.net, d.hatayama@jp.fujitsu.com, dave.hansen@linux.intel.com, dyoung@redhat.com, feng.tang@intel.com, gregkh@linuxfoundation.org, mikelley@microsoft.com, hidehiro.kawai.ez@hitachi.com, jgross@suse.com, john.ogness@linutronix.de, keescook@chromium.org, luto@kernel.org, mhiramat@kernel.org, mingo@redhat.com, paulmck@kernel.org, peterz@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, stern@rowland.harvard.edu, tglx@linutronix.de, vgoyal@redhat.com, vkuznets@redhat.com, will@kernel.org References: <20220427224924.592546-1-gpiccoli@igalia.com> <20220427224924.592546-12-gpiccoli@igalia.com> <4b003501-f5c3-cd66-d222-88d98c93e141@igalia.com> <1760d499824f9ef053af7a8dac04b48ab7d7fd3d.camel@sipsolutions.net> From: "Guilherme G. Piccoli" In-Reply-To: <1760d499824f9ef053af7a8dac04b48ab7d7fd3d.camel@sipsolutions.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 13/05/2022 11:44, Johannes Berg wrote: > [...] >> Maybe Anton / Johannes / Richard could give their opinions - appreciate >> that, I'm not attached to the priority here, it's more about users' >> common usage of UML I can think of... > > It's hard to say ... In a sense I'm not sure it matters? > > OTOH something like the ftrace dump notifier (kernel/trace/trace.c) > might still be useful to run before the mconsole and coredump ones, even > if you could probably use gdb to figure out the information. > > Personally, I don't have a scenario where I'd care about the trace > buffers though, and most of the others I found would seem irrelevant > (drivers that aren't even compiled, hung tasks won't really happen since > we exit immediately, and similar.) > > johannes Thanks Johannes, I agree with you. We don't have great ordering now, one thing we need to enforce is the order between the 2 UML notifiers, and this patch is doing that..trying to order against other callbacks like the ftrace dumper is messy in the current code. OTOH if this patch set is accepted at some point, we'll likely have 3 lists, and with that we can improve ordering a lot - this notifier for instance would run in the pre-reboot list, *after* the ftrace dumper (if a kmsg dumper is set). So, my intention is to keep this patch as is for V2 (with some changes Johannes suggested before), unless Petr or the other maintainers want something different. Cheers, Guilherme