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From: Joe Perches <joe@perches.com>
To: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Chenggang Wang <wangchenggang@vivo.com>,
	linux-kernel@vger.kernel.org, Petr Mladek <pmladek@suse.com>,
	Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [RFC PATCH 2/2] init: Allow multi-line output of kernel command line
Date: Wed, 20 May 2020 13:36:45 -0700	[thread overview]
Message-ID: <19a8c717f8d9dc76f2b09e6dd19f3fbb71bf29c5.camel@perches.com> (raw)
In-Reply-To: <20200520121000.GF520@jagdpanzerIV.localdomain>

On Wed, 2020-05-20 at 21:10 +0900, Sergey Senozhatsky wrote:
> On (20/05/19 21:58), Joe Perches wrote:
> [..]
> > >  Maybe we can
> > > use here something rather random and much shorter instead. E.g.
> > > 256 chars. Hmm. How 
> > 
> > 	min(some_max like 132/256, PRINTK_LOG_LINE_MAX)
> > 
> > would work.
> 
> An alternative approach would be to do what we do in the
> print_modules() (the list of modules which can definitely
> be longer than 1K chars).
> 
> We can split command line in a loop - memchr(pos, ' ') - and
> pr_cont() parts of the command line. pr_cont() has overflow
> control and it flushes cont buffer before it overflows, so
> we should not lose anything.

It doesn't matter much here, but I believe
there's an 8k max buffer for pr_cont output.

include/linux/printk.h:#define CONSOLE_EXT_LOG_MAX      8192

Anyway, no worries, it simplifies the loop if
done that way.



  reply	other threads:[~2020-05-20 20:36 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-19  3:29 [PATCH] init/main.c: Print all command line when boot 王程刚
2020-05-19  3:44 ` Andrew Morton
2020-05-19  5:09   ` Joe Perches
2020-05-19 14:34     ` Arvind Sankar
2020-05-19 19:42     ` [RFC PATCH 0/2] printk/init: multi-line kernel command line logging Joe Perches
2020-05-19 19:42       ` [RFC PATCH 1/2] printk: Move and rename maximum printk output line length defines Joe Perches
2020-05-21 13:49         ` Petr Mladek
2020-05-19 19:42       ` [RFC PATCH 2/2] init: Allow multi-line output of kernel command line Joe Perches
2020-05-20  4:41         ` Sergey Senozhatsky
2020-05-20  4:58           ` Joe Perches
2020-05-20 12:10             ` Sergey Senozhatsky
2020-05-20 20:36               ` Joe Perches [this message]
2020-05-21  1:00                 ` Andrew Morton
2020-05-21  2:09                   ` Joe Perches
2020-05-21  4:36                   ` Sergey Senozhatsky
2020-05-21  4:40                     ` Andrew Morton
2020-05-21 12:31                       ` Petr Mladek
2020-05-21 15:08                         ` Arvind Sankar
2020-05-21 12:48                       ` Sergey Senozhatsky
2020-05-21  4:32                 ` Sergey Senozhatsky
2020-05-21 13:46         ` Petr Mladek
2020-05-21 15:59         ` Arvind Sankar
2020-05-21 16:09           ` Joe Perches
2020-06-03  8:48         ` [init] d0bcc26c0d: BUG:kernel_hang_in_early-boot_stage,last_printk:early_console_in_setup_code kernel test robot
2020-05-21 18:40       ` [PATCH] printk: Move and rename maximum printk output line length defines Joe Perches
2020-05-25  8:38         ` Sergey Senozhatsky
2020-05-20 14:01 ` [PATCH] init/main.c: Print all command line when boot Masami Hiramatsu

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