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From: David Laight <David.Laight@ACULAB.COM>
To: 'John Ogness' <john.ogness@linutronix.de>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Petr Mladek <pmladek@suse.com>,
	Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Daniel Wang <wonderfly@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Alan Cox <gnomes@lxorguk.ukuu.org.uk>,
	Jiri Slaby <jslaby@suse.com>, Peter Feiner <pfeiner@google.com>,
	"linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Subject: RE: [RFC PATCH v1 00/25] printk: new implementation
Date: Wed, 13 Feb 2019 16:54:15 +0000	[thread overview]
Message-ID: <6f965383270d45d6ac26529fec5ad470@AcuMS.aculab.com> (raw)
In-Reply-To: <20190212143003.48446-1-john.ogness@linutronix.de>

From: John Ogness
> Sent: 12 February 2019 14:30
...
> - A dedicated kernel thread is created for printing to all consoles in
>   a fully preemptible context.
> 
> - A new (optional) console operation "write_atomic" is introduced that
>   console drivers may implement. This function must be NMI-safe. An
>   implementation for the 8250 UART driver is provided.
> 
> - The concept of "emergency messages" is introduced that allows
>   important messages (based on a new emergency loglevel threshold) to
>   be immediately written to any consoles supporting write_atomic,
>   regardless of the context.
...

Does this address my usual 'gripe' that the output is written to the console
by syslogd and not by the kernel itself?
When you are trying to find out where the system is completely deadlocking
you need the 'old fashioned' completely synchronous kernel printf().

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

  parent reply	other threads:[~2019-02-13 16:54 UTC|newest]

Thread overview: 147+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-12 14:29 [RFC PATCH v1 00/25] printk: new implementation John Ogness
2019-02-12 14:29 ` [RFC PATCH v1 01/25] printk-rb: add printk ring buffer documentation John Ogness
2019-02-12 14:45   ` Greg Kroah-Hartman
2019-02-12 14:29 ` [RFC PATCH v1 02/25] printk-rb: add prb locking functions John Ogness
2019-02-13 15:45   ` Petr Mladek
2019-02-13 21:39     ` John Ogness
2019-02-14 10:33       ` Petr Mladek
2019-02-14 12:10         ` John Ogness
2019-02-15 10:26           ` Petr Mladek
2019-02-15 10:56             ` John Ogness
2019-03-07  2:12   ` Sergey Senozhatsky
2019-02-12 14:29 ` [RFC PATCH v1 03/25] printk-rb: define ring buffer struct and initializer John Ogness
2019-02-12 14:46   ` Greg Kroah-Hartman
2019-02-14 12:46     ` Petr Mladek
2019-02-12 14:29 ` [RFC PATCH v1 04/25] printk-rb: add writer interface John Ogness
2019-02-14 15:16   ` Petr Mladek
2019-02-14 23:36     ` John Ogness
2019-02-15  1:19       ` John Ogness
2019-02-15 13:47       ` Petr Mladek
2019-02-17  1:32         ` John Ogness
2019-02-21 13:51           ` Petr Mladek
2019-02-12 14:29 ` [RFC PATCH v1 05/25] printk-rb: add basic non-blocking reading interface John Ogness
2019-02-18 12:54   ` Petr Mladek
2019-02-19 21:44     ` John Ogness
2019-02-21 16:22       ` Petr Mladek
2019-02-12 14:29 ` [RFC PATCH v1 06/25] printk-rb: add blocking reader support John Ogness
2019-02-18 14:05   ` Petr Mladek
2019-02-19 21:47     ` John Ogness
2019-02-12 14:29 ` [RFC PATCH v1 07/25] printk-rb: add functionality required by printk John Ogness
2019-02-12 17:15   ` Linus Torvalds
2019-02-13  9:20     ` John Ogness
2019-02-18 15:59   ` Petr Mladek
2019-02-19 22:08     ` John Ogness
2019-02-22  9:58       ` Petr Mladek
2019-02-12 14:29 ` [RFC PATCH v1 08/25] printk: add ring buffer and kthread John Ogness
2019-02-12 15:47   ` Sergey Senozhatsky
2019-02-19 13:54   ` Petr Mladek
2019-03-04  7:38   ` Sergey Senozhatsky
2019-03-04 10:00     ` Sergey Senozhatsky
2019-03-04 11:07       ` Sergey Senozhatsky
2019-03-05 21:00         ` John Ogness
2019-03-06 15:57           ` Petr Mladek
2019-03-06 21:17             ` John Ogness
2019-03-06 22:22               ` John Ogness
2019-03-07  6:41                 ` Sergey Senozhatsky
2019-03-07  6:51                   ` Sergey Senozhatsky
2019-03-07 12:50               ` Petr Mladek
2019-03-07  5:15           ` Sergey Senozhatsky
2019-03-11 10:51             ` John Ogness
2019-03-12  9:58               ` Sergey Senozhatsky
2019-03-12 10:30               ` Petr Mladek
2019-03-07 12:06     ` John Ogness
2019-03-08  1:31       ` Sergey Senozhatsky
2019-03-08 10:04         ` Petr Mladek
2019-02-12 14:29 ` [RFC PATCH v1 09/25] printk: remove exclusive console hack John Ogness
2019-02-19 14:03   ` Petr Mladek
2019-02-12 14:29 ` [RFC PATCH v1 10/25] printk: redirect emit/store to new ringbuffer John Ogness
2019-02-20  9:01   ` Petr Mladek
2019-02-20 21:25     ` John Ogness
2019-02-22 14:43       ` Petr Mladek
2019-02-22 15:06         ` John Ogness
2019-02-22 15:25           ` Petr Mladek
2019-02-25 12:11       ` Petr Mladek
2019-02-25 16:41         ` John Ogness
2019-02-26  9:45           ` Petr Mladek
2019-02-12 14:29 ` [RFC PATCH v1 11/25] printk_safe: remove printk safe code John Ogness
2019-02-22 10:37   ` Petr Mladek
2019-02-22 13:38     ` John Ogness
2019-02-22 15:15       ` Petr Mladek
2019-02-12 14:29 ` [RFC PATCH v1 12/25] printk: minimize console locking implementation John Ogness
2019-02-25 13:44   ` Petr Mladek
2019-02-12 14:29 ` [RFC PATCH v1 13/25] printk: track seq per console John Ogness
2019-02-25 14:59   ` Petr Mladek
2019-02-26  8:45     ` John Ogness
2019-02-26 13:11       ` Petr Mladek
2019-02-12 14:29 ` [RFC PATCH v1 14/25] printk: do boot_delay_msec inside printk_delay John Ogness
2019-02-12 14:29 ` [RFC PATCH v1 15/25] printk: print history for new consoles John Ogness
2019-02-26 14:58   ` Petr Mladek
2019-02-26 15:22     ` John Ogness
2019-02-27  9:02       ` Petr Mladek
2019-02-27 10:02         ` John Ogness
2019-02-27 13:12           ` Petr Mladek
2019-03-04  9:24       ` Sergey Senozhatsky
2019-02-12 14:29 ` [RFC PATCH v1 16/25] printk: implement CON_PRINTBUFFER John Ogness
2019-02-26 15:38   ` Petr Mladek
2019-02-12 14:29 ` [RFC PATCH v1 17/25] printk: add processor number to output John Ogness
2019-02-13 22:29   ` John Ogness
2019-02-12 14:29 ` [RFC PATCH v1 18/25] console: add write_atomic interface John Ogness
2019-02-12 14:29 ` [RFC PATCH v1 19/25] printk: introduce emergency messages John Ogness
2019-03-07  7:30   ` Sergey Senozhatsky
2019-03-08 10:31     ` Petr Mladek
2019-03-11 12:04       ` John Ogness
2019-03-12  2:51         ` Sergey Senozhatsky
2019-03-12  2:58       ` Sergey Senozhatsky
2019-02-12 14:29 ` [RFC PATCH v1 20/25] serial: 8250: implement write_atomic John Ogness
2019-02-27  9:46   ` Petr Mladek
2019-02-27 10:32     ` John Ogness
2019-02-27 13:55       ` Petr Mladek
2019-03-08  4:05         ` John Ogness
2019-03-08  4:17           ` John Ogness
2019-03-08 10:28           ` Petr Mladek
2019-02-12 14:29 ` [RFC PATCH v1 21/25] printk: implement KERN_CONT John Ogness
2019-02-12 14:30 ` [RFC PATCH v1 22/25] printk: implement /dev/kmsg John Ogness
2019-02-12 14:30 ` [RFC PATCH v1 23/25] printk: implement syslog John Ogness
2019-02-12 14:30 ` [RFC PATCH v1 24/25] printk: implement kmsg_dump John Ogness
2019-02-12 14:30 ` [RFC PATCH v1 25/25] printk: remove unused code John Ogness
2019-03-08 14:02   ` Sebastian Andrzej Siewior
2019-03-11  2:46     ` Sergey Senozhatsky
2019-03-11  8:18       ` Sebastian Andrzej Siewior
2019-03-12  9:38         ` Petr Mladek
2019-02-13  1:31 ` [RFC PATCH v1 00/25] printk: new implementation Sergey Senozhatsky
2019-02-13 13:43   ` John Ogness
2019-03-04  6:39     ` Sergey Senozhatsky
2019-02-13  1:41 ` Sergey Senozhatsky
2019-02-13 14:15   ` John Ogness
2019-03-04  5:31     ` Sergey Senozhatsky
2019-02-13  2:55 ` Sergey Senozhatsky
2019-02-13 14:43   ` John Ogness
2019-03-04  5:23     ` Sergey Senozhatsky
2019-03-07  9:53       ` John Ogness
2019-03-08 10:00         ` Petr Mladek
2019-03-11 10:54         ` Sergey Senozhatsky
2019-03-12 12:38           ` Petr Mladek
2019-03-12 15:15             ` John Ogness
2019-03-13  2:15               ` Sergey Senozhatsky
2019-03-13  8:19                 ` John Ogness
2019-03-13  8:40                   ` Sebastian Siewior
2019-03-13  9:27                     ` Sergey Senozhatsky
2019-03-13 10:06                       ` Sergey Senozhatsky
2019-03-14  9:27                       ` Petr Mladek
2019-03-13  8:46                   ` Sergey Senozhatsky
2019-03-14  9:14               ` Petr Mladek
2019-03-14  9:35                 ` John Ogness
2019-03-13  2:00             ` Sergey Senozhatsky
2019-02-13 16:54 ` David Laight [this message]
2019-02-13 22:20   ` John Ogness
2020-01-20 23:05 ` Eugeniu Rosca
2020-01-21 23:56   ` John Ogness
2020-01-22  2:34     ` Eugeniu Rosca
2020-01-22  7:31       ` Geert Uytterhoeven
2020-01-22 16:58         ` Eugeniu Rosca
2020-01-22 19:48           ` Geert Uytterhoeven
2020-01-24 16:09             ` Eugeniu Rosca
2020-01-27 12:32               ` Petr Mladek
2020-01-27 13:45                 ` Eugeniu Rosca
2020-01-22 10:33       ` John Ogness
2020-01-24 12:13         ` Eugeniu Rosca

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