From: Michal Hocko <mhocko@kernel.org>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
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: Tue, 28 Apr 2020 17:45:32 +0200 [thread overview]
Message-ID: <20200428154532.GU28637@dhcp22.suse.cz> (raw)
In-Reply-To: <b4d74234-8009-9ffd-011f-bd5d1a4b85f6@i-love.sakura.ne.jp>
On Tue 28-04-20 22:11:19, Tetsuo Handa wrote:
> On 2020/04/28 21:18, Michal Hocko wrote:
> > On Tue 28-04-20 20:33:21, Tetsuo Handa wrote:
> >> On 2020/04/27 15:21, Sergey Senozhatsky wrote:
> >>>> KERN_NO_CONSOLES is for type of messages where "saved for later analysis" is
> >>>> important but "printed for immediate notification" is not important.
> >>>> In other words, KERN_NO_CONSOLES is NOT for dying messages where "printed for
> >>>> immediate notification" is important.
> >>>
> >>> per-console loglevel is a user configurable parameter.
> >>> KERN_NO_CONSOLES is a hard-coded policy.
> >>
> >> But given that whether to use KERN_NO_CONSOLES is configurable via e.g. sysctl,
> >> KERN_NO_CONSOLES will become a user configurable parameter. What's still wrong?
> >
> > How do I as a kernel developer know that KERN_NO_CONSOLES should be
> > used? In other words, how can I assume what a user will consider
> > important on the console?
> >
>
> Existing KERN_$LEVEL allows a user to determine whether he/she wants that message
> to be printed on consoles (even if it spams his/her operation doing on consoles), and
> at the same time constrains that user whether that message is saved to log files.
> KERN_NO_CONSOLES allows a user to control whether he/she wants that message to be
> saved to log files (without spamming his/her operation doing on consoles).
I understand that. But how do I know whether the user considers the
particular information important enough to be dumped on the console.
This sounds like a policy in the kernel to me. I simply cannot forsee
any console configuration to tell whether my information is going to
swamp the console to no use or not. Compare that to KERN_$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.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2020-04-28 15:45 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 [this message]
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
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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