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From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Petr Mladek <pmladek@suse.com>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Michal Hocko <mhocko@kernel.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: Thu, 14 May 2020 00:20:04 +0900	[thread overview]
Message-ID: <5f272afb-2d74-c051-ce0a-4332ff080ef3@i-love.sakura.ne.jp> (raw)
In-Reply-To: <20200513095503.7488b0d6@gandalf.local.home>

On 2020/05/13 22:55, Steven Rostedt wrote:
> On Wed, 13 May 2020 20:03:53 +0900
> Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> wrote:
> 
>> I think that basically only oops (e.g. WARN()/BUG()/panic()) messages worth
>> printing to consoles and the rest messages do not worth printing to consoles.
>> Existing KERN_$LOGLEVEL is too rough-grained.
> 
> Why don't you look into having a "noconsole" command line option that will
> not print anything to the consoles but oops messages.

Well, such global option can be as harmful as "ignore_loglevel" command line
option in that we have to worry about how per-console loglevel can co-exist.

The idea of per-console loglevel is to allow specifying different threshold
based on characteristics of each console while the effect of ignore_loglevel
is to disallow specifying different threshold. (I'm wondering whether
ignore_loglevel should be valid under CONSOLE_LOGLEVEL_SILENT, for
CONSOLE_LOGLEVEL_SILENT says "don't print to consoles" while ignore_loglevel
says "always print to consoles".)

If we want to implement per-console loglevel in the future, shouldn't we first
deprecate the conflicting "ignore_loglevel" command line option (and get rid
of it by asking users to use LOGLEVEL_DEBUG as console loglevel)?

The idea of "noconsole" command line option is to disallow printing almost all
messages regardless of KERN_$LOGLEVEL while the idea of per-console loglevel is
to allow printing some messages based on KERN_$LOGLEVEL.

> 
> Sounds more like what you would like, and something that perhaps would be
> acceptable by the larger community.

More we introduce global switches, more difficult to introduce fine-grained
switches (e.g. per-console loglevel).

  reply	other threads:[~2020-05-13 15:20 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
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 [this message]
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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