From: John Ogness <john.ogness@linutronix.de>
To: Petr Mladek <pmladek@suse.com>
Cc: Nigel Croxon <ncroxon@redhat.com>,
"Theodore Y. Ts'o" <tytso@mit.edu>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Steven Rostedt <rostedt@goodmis.org>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
dm-devel@redhat.com, Mikulas Patocka <mpatocka@redhat.com>,
linux-serial@vger.kernel.org
Subject: Re: Serial console is causing system lock-up
Date: Tue, 12 Mar 2019 16:19:28 +0100 [thread overview]
Message-ID: <87zhq0yvb3.fsf@linutronix.de> (raw)
In-Reply-To: <20190312120824.4eaa4eyjcxvuzm23@pathway.suse.cz> (Petr Mladek's message of "Tue, 12 Mar 2019 13:08:24 +0100")
On 2019-03-12, Petr Mladek <pmladek@suse.com> wrote:
> On Tue 2019-03-12 09:17:49, John Ogness wrote:
>> The current printk implementation is handling all console printing as
>> best effort. Trying hard enough to dramatically affect the system,
>> but not trying hard enough to guarantee success.
>
> I agree that direct output is more reliable. It might be very useful
> for debugging some types of problems. The question is if it is worth
> the cost (code complexity, serializing CPUs == slowing down the
> entire system).
>
> But it is is possible that a reasonable offloading (in the direction
> of last Sergey's approach) might be a better deal.
>
>
> I suggest the following way forward (separate patchsets):
>
> 1. Replace log buffer (least controversial thing)
> 2. Reliable offload to kthread (would be useful anyway)
> 3. Atomic consoles (a lot of tricky code, might not be
> worth the effort)
>
> Could we agree on this?
Since this is about the new RFC printk design, I've responded in that
thread [0].
John Ogness
[0] https://lkml.kernel.org/r/874l8815uc.fsf@linutronix.de
next prev parent reply other threads:[~2019-03-12 15:19 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-06 14:27 Serial console is causing system lock-up Mikulas Patocka
2019-03-06 15:22 ` Petr Mladek
2019-03-06 16:07 ` Mikulas Patocka
2019-03-06 16:30 ` Theodore Y. Ts'o
2019-03-06 17:11 ` Mikulas Patocka
2019-03-06 22:19 ` Steven Rostedt
2019-03-06 22:43 ` John Ogness
2019-03-07 2:22 ` Sergey Senozhatsky
2019-03-07 8:17 ` John Ogness
2019-03-07 8:25 ` Sergey Senozhatsky
2019-03-07 8:34 ` John Ogness
2019-03-07 9:17 ` Sergey Senozhatsky
2019-03-07 10:37 ` John Ogness
2019-03-07 12:26 ` Sergey Senozhatsky
2019-03-07 12:54 ` Mikulas Patocka
2019-03-07 14:21 ` John Ogness
2019-03-07 15:35 ` Petr Mladek
2019-03-12 2:32 ` Sergey Senozhatsky
2019-03-12 8:17 ` John Ogness
2019-03-12 8:59 ` Sergey Senozhatsky
2019-03-12 10:05 ` Mikulas Patocka
2019-03-12 13:19 ` John Ogness
2019-03-12 13:44 ` Petr Mladek
2019-03-12 12:08 ` Petr Mladek
2019-03-12 15:19 ` John Ogness [this message]
2019-03-13 2:38 ` Sergey Senozhatsky
2019-03-13 8:43 ` John Ogness
2019-03-14 10:30 ` Sergey Senozhatsky
2019-03-07 14:08 ` John Stoffel
2019-03-07 14:26 ` Mikulas Patocka
2019-03-08 1:22 ` Sergey Senozhatsky
2019-03-08 1:39 ` Sergey Senozhatsky
2019-03-08 2:36 ` John Ogness
2019-03-07 15:16 ` Petr Mladek
2019-03-07 1:56 ` Sergey Senozhatsky
2019-03-07 13:12 ` Mikulas Patocka
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