Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <7b45bc2b-f74d-8604-bd8a-4930f7b8f926@igalia.com>
Date:   Thu, 10 Feb 2022 13:39:50 -0300
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.5.0
Subject: Re: [PATCH V4] notifier/panic: Introduce panic_notifier_filter
Content-Language: en-US
To:     "bhe@redhat.com" <bhe@redhat.com>
Cc:     Petr Mladek <pmladek@suse.com>,
        "dyoung@redhat.com" <dyoung@redhat.com>,
        "vgoyal@redhat.com" <vgoyal@redhat.com>,
        "d.hatayama@fujitsu.com" <d.hatayama@fujitsu.com>,
        "kexec@lists.infradead.org" <kexec@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
        "stern@rowland.harvard.edu" <stern@rowland.harvard.edu>,
        "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
        "andriy.shevchenko@linux.intel.com" 
        <andriy.shevchenko@linux.intel.com>,
        "corbet@lwn.net" <corbet@lwn.net>,
        "halves@canonical.com" <halves@canonical.com>,
        "kernel@gpiccoli.net" <kernel@gpiccoli.net>, mhiramat@kernel.org,
        d.hatayama@jp.fujitsu.com
References: <20220108153451.195121-1-gpiccoli@igalia.com>
 <TYAPR01MB6507D06BA6D32218F6E88198955F9@TYAPR01MB6507.jpnprd01.prod.outlook.com>
 <fda509a5-ea0d-4d1d-a1c1-ca5e80010fc0@igalia.com>
 <TYAPR01MB6507D9747647685B554B8F8F955F9@TYAPR01MB6507.jpnprd01.prod.outlook.com>
 <fb5e66b6-049a-22ab-5913-a04cc302b629@igalia.com> <YfPxvzSzDLjO5ldp@alley>
 <e2d39675-5df6-73fb-fa24-df906a97ee50@igalia.com>
 <YgMLd+avxyBplfk2@MiWiFi-R3L-srv>
From:   "Guilherme G. Piccoli" <gpiccoli@igalia.com>
In-Reply-To: <YgMLd+avxyBplfk2@MiWiFi-R3L-srv>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 08/02/2022 21:31, bhe@redhat.com wrote:
> [...]
>> So, what are the opinions from kdump maintainers about this idea?
>> Baoquan / Vivek / Dave, does it make sense to you? Do you have any
>> suggestions/concerns to add on top of Petr draft?
> 
> Yeah, it's reasonable. As I replied to Michael in another thread, I
> think splitting the current notifier list is a good idea. At least the
> code to archieve hyper-V's goal with panic_notifier is a little odd and
> should be taken out and execute w/o conditional before kdump, and maybe
> some others Petr has combed out.
> 
> For those which will be switched on with the need of adding panic_notifier
> or panic_print into cmdline, the heavy users like HATAYAMA and Masa can
> help check.
> 
> For Petr's draft code, does it mean hyper-V need another knob to trigger
> the needed notifiers? Will you go with the draft direclty? Hyper-V now
> runs panic notifiers by default, just a reminder.
> 

Hi Baoquan, thanks for your comments.

I'll need to study the Hyper-V code and how it's done today - I guess
most part of this implementation will be studying the notifiers we have
currently, split them among the 3 new notifiers and comb them into
patches, so they can be reviewed for all relevant maintainers (who know
the code we are changing).

I'm not sure if I go directly with the draft, likely it'll have some
changes, but the draft should be the skeleton of the new implementation.
Specially if you/other kdump maintainers agree it's a good idea =)

Cheers,


Guilherme