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From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
To: Michal Hocko <mhocko@kernel.org>, Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	linux-kernel@vger.kernel.org, Dmitry Safonov <dima@arista.com>,
	Yafang Shao <laoar.shao@gmail.com>
Subject: Re: [PATCH] printk: Add loglevel for "do not print to consoles".
Date: Wed, 13 May 2020 20:24:24 +0900	[thread overview]
Message-ID: <d66c38d9-dd97-072d-e1a7-949e9573b38d@i-love.sakura.ne.jp> (raw)
In-Reply-To: <20200513104938.GW29153@dhcp22.suse.cz>

On 2020/05/13 19:49, Michal Hocko wrote:
> On Wed 13-05-20 12:04:13, Petr Mladek wrote:
>> What is so special about  OOM dump task so that it would deserve such
>> complications?
> 
> Nothing really. Except for the potential amount of the output.

"echo t > /proc/sysrq-trigger" from userspace program is another example.

> But as
> you've said there are two ways around that. Disable this output if you
> do not need it or make it a lower loglevel. 

Disable this output for syslog is not acceptable for me, but disable this
output for consoles is preferable for me.

> I simply cannot tell whether somebody considers
> dump_tasks an important information to be printed on consoles.

I don't think dump_tasks() is important information to be printed on consoles.
But since somebody might think dump_tasks() is important information to be
printed on consoles, I suggest switching KERN_NO_CONSOLES using e.g. sysctl.

> 
> If there is any need to control which messages should be routed to which
> backend then the proper solution would be to filter messages per log
> level per backend.

Possible backends will be "zero or more than zero" consoles + "zero or one"
syslog, and KERN_NO_CONSOLES is a method for force selecting "zero" console
backend.

>                    But I have no idea how feasible this is for the
> existing infrastructure - or maybe it already exists...

There is per-console loglevel proposal (which allows selecting "some" console
backends). But it is based on KERN_$LOGLEVEL which is too rough-grained.

  reply	other threads:[~2020-05-13 11:25 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-24  2:42 [PATCH] printk: Add loglevel for "do not print to consoles" Tetsuo Handa
2020-04-24 13:28 ` Steven Rostedt
2020-04-24 14:00   ` Tetsuo Handa
2020-04-24 14:31     ` Steven Rostedt
2020-04-24 15:28       ` Tetsuo Handa
2020-04-24 15:42         ` Steven Rostedt
2020-04-24 15:52           ` Dmitry Safonov
2020-04-24 16:10           ` Tetsuo Handa
2020-04-24 16:21             ` Steven Rostedt
2020-04-24 16:34               ` Tetsuo Handa
2020-04-25  0:46 ` Sergey Senozhatsky
2020-04-25  1:07   ` Tetsuo Handa
2020-04-27  6:21     ` Sergey Senozhatsky
2020-04-28 11:33       ` Tetsuo Handa
2020-04-28 12:18         ` Michal Hocko
2020-04-28 13:11           ` Tetsuo Handa
2020-04-28 15:45             ` Michal Hocko
2020-04-28 16:23               ` Tetsuo Handa
2020-04-29 14:21                 ` Michal Hocko
2020-04-29 16:35                   ` Tetsuo Handa
2020-05-13  6:26                     ` Sergey Senozhatsky
2020-05-13  7:58                       ` Tetsuo Handa
2020-05-13 10:04                         ` Petr Mladek
2020-05-13 10:49                           ` Michal Hocko
2020-05-13 11:24                             ` Tetsuo Handa [this message]
2020-05-13 12:19                               ` Petr Mladek
2020-05-13 12:59                                 ` Tetsuo Handa
2020-05-14  8:00                                   ` Petr Mladek
2020-05-14 11:23                                     ` Tetsuo Handa
2020-05-14 16:26                                       ` Petr Mladek
2020-05-14 23:24                                         ` Tetsuo Handa
2020-05-13 11:03                           ` Tetsuo Handa
2020-05-13 12:34                             ` Petr Mladek
2020-05-13 13:46                             ` Steven Rostedt
2020-05-13 14:03                               ` Tetsuo Handa
2020-05-13 13:55                             ` Steven Rostedt
2020-05-13 15:20                               ` Tetsuo Handa
2020-05-06  9:45         ` Tetsuo Handa
2020-05-06 15:26           ` Joe Perches
2020-05-07  0:50             ` Tetsuo Handa
2020-05-07  1:02               ` Joe Perches
2020-05-07  5:13                 ` Tetsuo Handa
2020-05-07  5:30                   ` Joe Perches
2020-05-07  5:39                     ` Tetsuo Handa

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