From: Steven Rostedt <rostedt@goodmis.org>
To: Josh Triplett <josh@joshtriplett.org>
Cc: "ksummit-discuss@lists.linuxfoundation.org"
<ksummit-discuss@lists.linuxfoundation.org>
Subject: Re: [Ksummit-discuss] [TECH TOPIC] asynchronous printk
Date: Wed, 27 Jul 2016 23:05:32 -0400 [thread overview]
Message-ID: <20160727230532.2982b40d@grimm.local.home> (raw)
In-Reply-To: <20160721142127.GA23563@x>
On Thu, 21 Jul 2016 07:21:28 -0700
Josh Triplett <josh@joshtriplett.org> wrote:
>
> Given the discussion in this thread about wanting to eliminate
> earlyprintk in favor of a unified mechanism that works as early as
> possible, how would this case work on the system I described above where
> earlyprintk works and console doesn't?
No no no!!! Please do not eliminate earlyprintk(). It is critical to
the PREEMPT_RT project. It requires no sleeping locks, and can be used
in pretty much any context (with slight modifications). printk() is a
beast, and in -rt it calls sleeping locks. That is, if interrupts are
disabled, we prevent printk from print anything. (Note PREEMPT_RT
keeps interrupts enabled much more than the normal kernel does). If a
bug happens where interrupts are disabled, we fall back to earlyprintk
(and tracing), to debug it.
-- Steve
next prev parent reply other threads:[~2016-07-28 3:23 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-19 3:47 [Ksummit-discuss] [TECH TOPIC] asynchronous printk Sergey Senozhatsky
2016-07-19 3:56 ` Viresh Kumar
2016-07-19 6:17 ` Hannes Reinecke
2016-07-19 6:49 ` Josh Triplett
2016-07-19 7:02 ` Hannes Reinecke
2016-07-19 7:11 ` Geert Uytterhoeven
2016-07-20 6:02 ` Jan Kara
2016-07-20 22:54 ` Josh Triplett
2016-07-21 0:46 ` Sergey Senozhatsky
2016-07-21 1:12 ` Josh Triplett
2016-07-19 7:33 ` Sergey Senozhatsky
2016-07-19 7:38 ` Hannes Reinecke
2016-07-19 7:46 ` Sergey Senozhatsky
2016-07-19 8:02 ` Hannes Reinecke
2016-07-19 8:23 ` Sergey Senozhatsky
2016-07-21 10:36 ` David Woodhouse
2016-07-21 12:31 ` Jan Kara
2016-07-28 2:55 ` Steven Rostedt
2016-07-20 6:09 ` Jan Kara
2016-07-19 7:46 ` Christian Borntraeger
2016-07-19 7:53 ` Christian Borntraeger
2016-07-19 13:55 ` Jan Kara
2016-07-28 2:59 ` Steven Rostedt
2016-07-28 4:12 ` Sergey Senozhatsky
2016-07-28 13:02 ` Steven Rostedt
2016-07-20 3:35 ` Wangnan (F)
2016-07-21 1:16 ` Andy Lutomirski
2016-07-21 1:52 ` Wangnan (F)
2016-07-21 5:59 ` Hannes Reinecke
2016-07-21 10:31 ` David Woodhouse
2016-07-21 11:19 ` Josh Triplett
2016-07-21 11:59 ` David Woodhouse
2016-07-21 14:21 ` Josh Triplett
2016-07-21 14:40 ` David Woodhouse
2016-07-28 3:05 ` Steven Rostedt [this message]
2016-08-02 11:59 ` Petr Mladek
2016-07-21 15:05 ` Andy Lutomirski
2016-07-26 14:40 ` David Woodhouse
2016-07-26 15:44 ` Benjamin Herrenschmidt
2016-07-26 21:00 ` Andy Lutomirski
2016-07-27 0:03 ` David Woodhouse
2016-07-27 1:16 ` Sergey Senozhatsky
2016-07-21 10:28 ` David Woodhouse
2016-07-19 14:45 ` James Bottomley
2016-07-19 14:55 ` Sergey Senozhatsky
2016-07-19 17:58 ` James Bottomley
2016-07-19 18:24 ` Viresh Kumar
2016-07-20 2:08 ` Sergey Senozhatsky
2016-07-20 6:14 ` Jan Kara
2016-09-21 4:41 ` Sergey Senozhatsky
2016-10-31 6:54 ` Sergey Senozhatsky
2016-10-31 13:56 ` Theodore Ts'o
2016-10-31 13:59 ` Jiri Kosina
2016-10-31 14:56 ` [Ksummit-discuss] [TECH TOPIC] printk considered harmful (was: [TECH TOPIC] asynchronous printk) Sergey Senozhatsky
2016-10-31 16:18 ` Theodore Ts'o
2016-10-31 18:21 ` Sergey Senozhatsky
2016-10-31 18:26 ` [Ksummit-discuss] [TECH TOPIC] printk considered harmful Hannes Reinecke
2016-10-31 20:28 ` [Ksummit-discuss] [TECH TOPIC] printk considered harmful (was: [TECH TOPIC] asynchronous printk) Jan Kara
2016-11-01 12:27 ` [Ksummit-discuss] [TECH TOPIC] printk considered harmful Hannes Reinecke
2016-11-01 17:50 ` [Ksummit-discuss] [TECH TOPIC] printk considered harmful (was: [TECH TOPIC] asynchronous printk) Sergey Senozhatsky
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