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From: John Ogness <john.ogness@linutronix.de>
To: Petr Mladek <pmladek@suse.com>, Doug Anderson <dianders@chromium.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>,
	Jason Wessel <jason.wessel@windriver.com>,
	Daniel Thompson <daniel.thompson@linaro.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jirislaby@kernel.org>,
	Aaron Tomlin <atomlin@redhat.com>,
	Luis Chamberlain <mcgrof@kernel.org>,
	kgdb-bugreport@lists.sourceforge.net,
	linux-serial@vger.kernel.org
Subject: Re: [PATCH printk 10/18] kgbd: Pretend that console list walk is safe
Date: Fri, 30 Sep 2022 15:50:56 +0206	[thread overview]
Message-ID: <87o7uxugbr.fsf@jogness.linutronix.de> (raw)
In-Reply-To: <YzarXlj1NyFGTC08@alley>

On 2022-09-30, Petr Mladek <pmladek@suse.com> wrote:
> Anyway, what about using the later added SRCU walk here?
> After all, this is exactly what RCU is for, isn't it?

So I think a lot of the problems with this series is that SRCU is
introduced too late. We are debating things in patch 6 that are
irrelevant by patch 12.

I will rework the series so that the changes come in the following
order:

1. provide an atomic console_is_enabled()

2. convert the list to SRCU

3. move all iterators from console_lock()/console_trylock() to SRCU

Step 3 may result in console_lock()/console_trylock() calls disappearing
or relocating to where they are needed for non-list-synchronization
purposes.

John

  reply	other threads:[~2022-09-30 13:45 UTC|newest]

Thread overview: 75+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-24  0:04 [PATCH printk 00/18] preparation for threaded/atomic printing John Ogness
2022-09-24  0:04 ` [PATCH printk 01/18] printk: Make pr_flush() static John Ogness
2022-09-26 14:12   ` Petr Mladek
2022-09-24  0:04 ` [PATCH printk 02/18] printk: Declare log_wait properly John Ogness
2022-09-26 14:22   ` Petr Mladek
2022-09-24  0:04 ` [PATCH printk 03/18] printk: Remove write only variable nr_ext_console_drivers John Ogness
2022-09-26 14:25   ` Petr Mladek
2022-09-24  0:04 ` [PATCH printk 04/18] printk: Remove bogus comment vs. boot consoles John Ogness
2022-09-26 14:26   ` Petr Mladek
2022-09-24  0:04 ` [PATCH printk 05/18] printk: Mark __printk percpu data ready __ro_after_init John Ogness
2022-09-26 14:27   ` Petr Mladek
2022-09-24  0:04 ` [PATCH printk 06/18] printk: Protect [un]register_console() with a mutex John Ogness
2022-09-24  9:31   ` Sergey Senozhatsky
2022-09-27 15:16   ` Petr Mladek
2022-09-28  9:46     ` Sergey Senozhatsky
2022-09-28 23:42     ` John Ogness
2022-09-29 15:43       ` Petr Mladek
2022-09-30  9:24         ` Petr Mladek
2022-09-30 14:16           ` John Ogness
2022-09-30 18:04             ` Petr Mladek
2022-09-30 20:26               ` John Ogness
2022-10-03 14:37                 ` Petr Mladek
2022-10-03 19:35                   ` John Ogness
2022-10-04  2:06                     ` Sergey Senozhatsky
2022-10-04  7:28                     ` Petr Mladek
2022-09-30 13:30         ` John Ogness
2022-09-24  0:04 ` [PATCH printk 07/18] printk: Convert console list walks for readers to list lock John Ogness
2022-09-27 14:07   ` Petr Mladek
2022-09-24  0:04 ` [PATCH printk 08/18] parisc: Put console abuse into one place John Ogness
2022-09-24  0:20   ` Steven Rostedt
2022-09-30  7:54   ` Petr Mladek
2022-09-24  0:04 ` [PATCH printk 09/18] serial: kgdboc: Lock console list in probe function John Ogness
2022-09-28 23:32   ` Doug Anderson
2022-09-30  8:07   ` Petr Mladek
2022-09-24  0:04 ` [PATCH printk 10/18] kgbd: Pretend that console list walk is safe John Ogness
2022-09-26  9:33   ` Aaron Tomlin
2022-09-28 23:32   ` Doug Anderson
2022-09-30  8:39     ` Petr Mladek
2022-09-30 13:44       ` John Ogness [this message]
2022-09-30 17:27         ` Petr Mladek
2022-09-24  0:04 ` [PATCH printk 11/18] printk: Convert console_drivers list to hlist John Ogness
2022-09-24 10:53   ` Sergey Senozhatsky
2022-09-24 17:20   ` Helge Deller
2022-09-25  0:43     ` Sergey Senozhatsky
2022-09-24 17:27   ` Helge Deller
2022-09-30 14:20   ` Petr Mladek
2022-09-30 16:53     ` Helge Deller
2022-09-30 19:46       ` John Ogness
2022-09-30 22:41         ` Helge Deller
2022-09-24  0:04 ` [PATCH printk 12/18] printk: Prepare for SCRU console list protection John Ogness
2022-09-24 10:58   ` Sergey Senozhatsky
2022-09-24  0:04 ` [PATCH printk 13/18] printk: Move buffer size defines John Ogness
2022-09-24 11:01   ` Sergey Senozhatsky
2022-10-07  9:11   ` Petr Mladek
2022-09-24  0:04 ` [PATCH printk 14/18] printk: Document struct console John Ogness
2022-09-24 11:08   ` Sergey Senozhatsky
2022-10-07 11:57   ` Petr Mladek
2022-09-24  0:04 ` [PATCH printk 15/18] printk: Add struct cons_text_buf John Ogness
2022-09-24 11:09   ` Sergey Senozhatsky
2022-10-07 15:15   ` Petr Mladek
2022-09-24  0:04 ` [PATCH printk 16/18] printk: Use " John Ogness
2022-09-24 11:34   ` Sergey Senozhatsky
2022-10-10 10:11   ` Petr Mladek
2022-09-24  0:04 ` [PATCH printk 17/18] printk: Use an output descriptor struct for emit John Ogness
2022-10-10 15:40   ` Petr Mladek
2022-09-24  0:04 ` [PATCH printk 18/18] printk: Handle dropped message smarter John Ogness
2022-09-26  4:19   ` Sergey Senozhatsky
2022-09-26  7:54     ` John Ogness
2022-09-26  9:18       ` Sergey Senozhatsky
2022-10-10 16:07       ` Petr Mladek
2022-09-26  9:22   ` Sergey Senozhatsky
2022-09-24  6:44 ` [PATCH printk 00/18] preparation for threaded/atomic printing Greg Kroah-Hartman
2022-09-25 15:23   ` John Ogness
2022-09-24  9:47 ` Sergey Senozhatsky
2022-09-29 16:33 ` Petr Mladek

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