From: John Ogness <john.ogness@linutronix.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
Petr Mladek <pmladek@suse.com>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Andrea Parri <andrea.parri@amarulasolutions.com>,
Thomas Gleixner <tglx@linutronix.de>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Brendan Higgins <brendanhiggins@google.com>
Subject: Re: [RFC PATCH v4 9/9] printk: use a new ringbuffer implementation
Date: Fri, 09 Aug 2019 09:08:25 +0200 [thread overview]
Message-ID: <87mugix1cm.fsf@linutronix.de> (raw)
In-Reply-To: <20190809061437.GE2332@hirez.programming.kicks-ass.net> (Peter Zijlstra's message of "Fri, 9 Aug 2019 08:14:37 +0200")
On 2019-08-09, Peter Zijlstra <peterz@infradead.org> wrote:
>> End result: a DRAM buffer can work, but is not "reliable".
>> Particularly if you turn power on and off, data retention of DRAM is
>> iffy. But it's possible, at least in theory.
>>
>> So I have a patch that implements a "stupid ring buffer" for thisa
>> case, with absolutely zero data structures (because in the presense of
>> DRAM corruption, all you can get is "hopefully only slightly garbled
>> ASCII".
>
> Note that you can hook this into printk as a fake early serial device;
> just have the serial device write to the DRAM buffer.
Or the other way around, implement a fake console to handle writing the
messages (as they are being emitted from printk) to some special
area. Then the messages would even be pre-processed so that all
meta-data is already in ASCII form.
John Ogness
next prev parent reply other threads:[~2019-08-09 7:08 UTC|newest]
Thread overview: 134+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-07 22:26 [RFC PATCH v4 0/9] printk: new ringbuffer implementation John Ogness
2019-08-07 22:26 ` [RFC PATCH v4 1/9] printk-rb: add a new printk " John Ogness
2019-08-20 8:15 ` numlist_pop(): " Petr Mladek
2019-08-21 5:41 ` John Ogness
2019-09-04 12:19 ` Peter Zijlstra
2019-08-20 8:22 ` assign_desc() barriers: " Petr Mladek
2019-08-20 14:14 ` Petr Mladek
2019-08-21 5:52 ` John Ogness
2019-08-22 11:53 ` Petr Mladek
2019-08-25 2:06 ` John Ogness
2019-08-26 8:21 ` John Ogness
2019-08-20 8:55 ` comments style: " Petr Mladek
2019-08-20 9:27 ` Sergey Senozhatsky
2019-08-21 5:46 ` John Ogness
2019-08-22 13:50 ` Petr Mladek
2019-08-22 17:38 ` Andrea Parri
2019-08-23 10:47 ` Petr Mladek
2019-08-23 14:27 ` Andrea Parri
2019-08-23 9:49 ` Sergey Senozhatsky
2019-08-23 5:54 ` Sergey Senozhatsky
2019-08-23 10:29 ` Petr Mladek
2019-08-21 5:42 ` John Ogness
2019-08-22 12:44 ` Petr Mladek
2019-08-20 13:50 ` dataring_push() barriers " Petr Mladek
2019-08-25 2:42 ` John Ogness
2019-08-27 14:36 ` Petr Mladek
2019-08-28 13:43 ` John Ogness
2019-08-20 15:12 ` datablock reuse races " Petr Mladek
2019-08-23 9:21 ` numlist_push() barriers " Petr Mladek
2019-08-26 8:34 ` Andrea Parri
2019-08-26 8:43 ` Andrea Parri
2019-08-26 14:10 ` Petr Mladek
2019-08-26 16:01 ` Andrea Parri
2019-08-26 22:36 ` John Ogness
2019-08-27 7:40 ` Petr Mladek
2019-08-27 14:28 ` John Ogness
2019-08-27 15:07 ` Petr Mladek
2019-08-28 10:24 ` John Ogness
2019-08-23 17:18 ` numlist API " Petr Mladek
2019-08-26 23:57 ` John Ogness
2019-08-27 13:03 ` Petr Mladek
2019-08-28 7:13 ` John Ogness
2019-08-28 8:58 ` Petr Mladek
2019-08-28 14:03 ` John Ogness
2019-08-29 11:28 ` Petr Mladek
2019-09-03 7:58 ` Sergey Senozhatsky
2019-08-30 14:48 ` dataring " Petr Mladek
2019-08-07 22:26 ` [RFC PATCH v4 2/9] printk-rb: add test module John Ogness
2019-08-07 22:26 ` [RFC PATCH v4 3/9] printk-rb: fix missing includes/exports John Ogness
2019-08-07 22:26 ` [RFC PATCH v4 4/9] printk-rb: initialize new descriptors as invalid John Ogness
2019-08-20 9:23 ` Petr Mladek
2019-08-20 10:16 ` Sergey Senozhatsky
2019-08-21 5:56 ` John Ogness
2019-08-07 22:26 ` [RFC PATCH v4 5/9] printk-rb: remove extra data buffer size allocation John Ogness
2019-08-07 22:26 ` [RFC PATCH v4 6/9] printk-rb: adjust test module ringbuffer sizes John Ogness
2019-08-19 21:29 ` [PATCH] printk-rb: fix test module macro usage John Ogness
2019-08-07 22:26 ` [RFC PATCH v4 7/9] printk-rb: increase size of seq and size variables John Ogness
2019-08-07 22:26 ` [RFC PATCH v4 8/9] printk-rb: new functionality to support printk John Ogness
2019-08-20 9:59 ` Sergey Senozhatsky
2019-08-21 5:47 ` John Ogness
2019-08-07 22:26 ` [RFC PATCH v4 9/9] printk: use a new ringbuffer implementation John Ogness
2019-08-08 19:07 ` Linus Torvalds
2019-08-08 22:55 ` John Ogness
2019-08-08 23:33 ` Linus Torvalds
2019-08-08 23:45 ` Steven Rostedt
2019-08-09 0:21 ` Linus Torvalds
2019-08-09 0:48 ` Steven Rostedt
2019-08-09 1:15 ` Linus Torvalds
2019-08-09 11:15 ` Thomas Gleixner
2019-08-09 16:00 ` Linus Torvalds
2019-08-09 20:07 ` Thomas Gleixner
2019-08-09 20:20 ` Linus Torvalds
2019-08-09 6:14 ` Peter Zijlstra
2019-08-09 7:08 ` John Ogness [this message]
2019-08-09 15:57 ` Linus Torvalds
2019-08-10 5:53 ` Thomas Gleixner
2019-09-10 3:19 ` Sergey Senozhatsky
2019-08-12 9:54 ` Geert Uytterhoeven
2019-08-16 5:46 ` Dave Young
2019-08-16 5:46 ` Dave Young
2019-08-16 5:54 ` Dave Young
2019-08-16 5:54 ` Dave Young
2019-08-16 9:40 ` John Ogness
2019-08-16 9:40 ` John Ogness
2019-09-04 12:35 ` [RFC PATCH v4 0/9] printk: " Peter Zijlstra
2019-09-05 13:05 ` Petr Mladek
2019-09-05 14:31 ` Peter Zijlstra
2019-09-05 15:38 ` Thomas Gleixner
2019-09-05 16:11 ` Steven Rostedt
2019-09-05 21:10 ` John Ogness
2019-09-06 9:39 ` Petr Mladek
2019-09-09 14:11 ` printk meeting at LPC Thomas Gleixner
2019-09-13 13:26 ` John Ogness
2019-09-13 14:48 ` Daniel Vetter
2019-09-15 13:47 ` John Ogness
2019-09-16 8:44 ` Daniel Vetter
2019-09-16 4:30 ` Tetsuo Handa
2019-09-16 10:46 ` Petr Mladek
2019-09-16 13:43 ` Steven Rostedt
2019-09-16 14:28 ` John Ogness
2019-09-17 8:11 ` Petr Mladek
2019-09-17 7:52 ` Petr Mladek
2019-09-17 13:02 ` Steven Rostedt
2019-09-17 13:12 ` Greg Kroah-Hartman
2019-09-17 13:37 ` Steven Rostedt
2019-09-17 14:08 ` Tetsuo Handa
2019-09-17 7:51 ` Sergey Senozhatsky
2019-09-18 1:25 ` Sergey Senozhatsky
2019-09-18 2:08 ` Steven Rostedt
2019-09-18 2:36 ` Sergey Senozhatsky
2019-09-18 5:19 ` Sergey Senozhatsky
2019-09-18 7:42 ` John Ogness
2019-09-18 8:10 ` Sergey Senozhatsky
2019-09-18 9:05 ` John Ogness
2019-09-18 9:11 ` Sergey Senozhatsky
2019-09-18 16:41 ` Petr Mladek
2019-09-18 16:48 ` Steven Rostedt
2019-09-24 14:24 ` Petr Mladek
2019-09-19 8:06 ` Daniel Vetter
2019-09-18 7:33 ` John Ogness
2019-09-18 8:08 ` Sergey Senozhatsky
2019-10-04 14:48 ` Tony Asleson
2019-10-07 12:01 ` Petr Mladek
2019-09-06 9:06 ` [RFC PATCH v4 0/9] printk: new ringbuffer implementation Peter Zijlstra
2019-09-06 10:09 ` Sergey Senozhatsky
2019-09-06 10:49 ` Peter Zijlstra
2019-09-06 13:44 ` Sergey Senozhatsky
2019-09-06 12:42 ` Petr Mladek
2019-09-06 14:01 ` Peter Zijlstra
2019-09-06 14:22 ` Peter Zijlstra
2019-09-06 19:53 ` Sergey Senozhatsky
2019-09-06 22:47 ` John Ogness
2019-09-08 22:18 ` Peter Zijlstra
2019-09-10 3:22 ` Sergey Senozhatsky
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