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Message-ID: <20160323143020.GA596@swordfish>
Date: Wed, 23 Mar 2016 23:30:20 +0900
From: Sergey Senozhatsky <sergey.senozhatsky@...il.com>
To: Jan Kara <jack@...e.cz>
Cc: Petr Mladek <pmladek@...e.com>,
Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Jan Kara <jack@...e.com>, Tejun Heo <tj@...nel.org>,
Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>,
linux-kernel@...r.kernel.org,
Byungchul Park <byungchul.park@....com>
Subject: Re: [RFC][PATCH v6 1/2] printk: Make printk() completely async
Hello,
On (03/23/16 14:20), Jan Kara wrote:
[..]
> > I though that it actually could be an advantage. console_verbore() is
> > called also by oops_begin() and it does not need to be fatal. But you
> > are right that it does not need to be the righ approach.
>
> If we oops, I want printk to be sync regardless whether the machine is able
> to live afterwards or not. You never know in advance... That's why I've
> chosen the console_verbose() trigger and I still think it is better than
> oops_in_progress or special console_panic() trigger.
console_verbose() is good enough. well, with special console_panic() trigger
we can have better control and distinguish between "print a lot" and "things
are bad for sure, print in sync mode". there are 2 archs that call console_verbose()
in setup_arch():
- arch/microblaze/kernel/setup.c
: void __init setup_arch(char **cmdline_p)
: {
: *cmdline_p = boot_command_line;
:
: console_verbose(); <<<<
:
: unflatten_device_tree();
:
: setup_cpuinfo();
:
: microblaze_cache_init();
:
: setup_memory();
- arch/nios2/kernel/setup.c
: void __init setup_arch(char **cmdline_p)
: {
: int bootmap_size;
:
: console_verbose(); <<<<
:
: #ifdef CONFIG_EARLY_PRINTK
: setup_early_printk();
: #endif
so printk will never work in async mode there. hm... should we care?
-ss
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