From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
To: Michal Hocko <mhocko@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Petr Mladek <pmladek@suse.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, 29 Apr 2020 01:23:15 +0900 [thread overview]
Message-ID: <b1d507b1-dae7-f526-c74a-d465ddecea6a@i-love.sakura.ne.jp> (raw)
In-Reply-To: <20200428154532.GU28637@dhcp22.suse.cz>
On 2020/04/29 0:45, Michal Hocko wrote:
> On Tue 28-04-20 22:11:19, Tetsuo Handa wrote:
>> Existing KERN_$LEVEL allows a user to determine whether he/she wants that message
>> to be printed on consoles (even if it spams his/her operation doing on consoles), and
>> at the same time constrains that user whether that message is saved to log files.
>> KERN_NO_CONSOLES allows a user to control whether he/she wants that message to be
>> saved to log files (without spamming his/her operation doing on consoles).
>
> I understand that. But how do I know whether the user considers the
> particular information important enough to be dumped on the console.
> This sounds like a policy in the kernel to me.
I'm still unable to understand your question.
> I simply cannot forsee
> any console configuration to tell whether my information is going to
> swamp the console to no use or not.
Neither can I.
> Compare that to KERN_$LEVEL instead.
> I know that an information is of low/high importance. It is the user
> policy to decide and base some filtering on top of that priority.
Whether to use KERN_NO_CONSOLES is not per-importance basis but per-content basis.
Since both pr_info("[%7d] %5d %5d %8lu %8lu %8ld %8lu %5hd %s\n", ...) from dump_tasks() and
pr_info("oom-kill:constraint=%s,nodemask=%*pbl", ...) from dump_oom_summary() use KERN_INFO importance,
existing KERN_$LEVEL-based approach cannot handle these messages differently. Since changing the former to
e.g. KERN_DEBUG will cause userspace to discard the messages, we effectively can't change KERN_$LEVEL.
If the kernel allows the former to use KERN_NO_CONSOLES in addition to KERN_INFO, the administrator can
select from two choices: printing "both the former and the latter" or "only the latter" to consoles.
next prev parent reply other threads:[~2020-04-28 16:24 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 [this message]
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
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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