From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: John Ogness <john.ogness@linutronix.de>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Petr Mladek <pmladek@suse.com>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH next v2 2/3] printk: change @clear_seq to atomic64_t
Date: Wed, 9 Dec 2020 18:22:04 +0900 [thread overview]
Message-ID: <20201209092204.GD1667627@google.com> (raw)
In-Reply-To: <20201209081623.GI2414@hirez.programming.kicks-ass.net>
On (20/12/09 09:16), Peter Zijlstra wrote:
> On Tue, Dec 08, 2020 at 11:36:44PM +0106, John Ogness wrote:
> > For the state variable we chose atomic_long_t instead of atomic64_t for
> > this reason. atomic_long_t operations are available atomically on all
> > architectures.
>
> Please put on your eye cancer gear and inspect the atomic implementation
> of PA-RISC, Sparc32, feh, I forgot who else.
>
> Those SMP capable architectures are gifted with just one XCHG like
> atomic instruction :/ Anyway, as said in the other email, they also
> don't have NMIs so it mostly works.
Hmm, wow. OK, I definitely want to look further.
When some CONFIG_DEBUG_FOO_BAR code wants to pr_err from prb->atomic_op
on those archs then we deadlock in printk once again?
-ss
next prev parent reply other threads:[~2020-12-09 9:22 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-01 20:53 [PATCH next v2 0/3] printk: remove logbuf_lock John Ogness
2020-12-01 20:53 ` [PATCH next v2 1/3] printk: inline log_output(),log_store() in vprintk_store() John Ogness
2020-12-03 15:57 ` Petr Mladek
2020-12-03 16:25 ` John Ogness
2020-12-04 6:13 ` Sergey Senozhatsky
2020-12-04 8:26 ` Petr Mladek
2020-12-01 20:53 ` [PATCH next v2 2/3] printk: change @clear_seq to atomic64_t John Ogness
2020-12-04 9:12 ` Petr Mladek
2020-12-06 20:23 ` John Ogness
2020-12-07 9:34 ` Peter Zijlstra
2020-12-07 10:03 ` John Ogness
2020-12-07 12:56 ` Peter Zijlstra
2020-12-07 12:56 ` Petr Mladek
2020-12-07 16:46 ` David Laight
2020-12-08 20:34 ` Sergey Senozhatsky
2020-12-08 22:30 ` John Ogness
2020-12-09 1:04 ` Sergey Senozhatsky
2020-12-09 8:16 ` Peter Zijlstra
2020-12-09 9:22 ` Sergey Senozhatsky [this message]
2020-12-09 10:46 ` Sergey Senozhatsky
2020-12-09 11:00 ` Peter Zijlstra
2020-12-09 11:28 ` Sergey Senozhatsky
2020-12-09 12:29 ` Peter Zijlstra
2020-12-09 8:07 ` Peter Zijlstra
2020-12-01 20:53 ` [PATCH next v2 3/3] printk: remove logbuf_lock, add syslog_lock John Ogness
2020-12-04 6:41 ` Sergey Senozhatsky
2020-12-06 20:44 ` John Ogness
2020-12-04 15:52 ` devkmsg: was " Petr Mladek
2020-12-06 20:51 ` John Ogness
2020-12-07 9:56 ` Petr Mladek
2020-12-04 15:57 ` syslog: was: " Petr Mladek
2020-12-06 21:06 ` John Ogness
2020-12-07 10:01 ` Petr Mladek
2020-12-04 16:10 ` recursion handling: " Petr Mladek
2020-12-05 4:25 ` Sergey Senozhatsky
2020-12-06 22:08 ` John Ogness
2020-12-05 9:41 ` Sergey Senozhatsky
2020-12-06 22:17 ` John Ogness
2020-12-06 21:44 ` John Ogness
2020-12-07 11:17 ` Petr Mladek
2020-12-04 16:15 ` vprintk_store: was: " Petr Mladek
2020-12-06 22:30 ` John Ogness
2020-12-07 12:46 ` Petr Mladek
2020-12-04 16:19 ` consoles: " Petr Mladek
2020-12-05 4:39 ` Sergey Senozhatsky
2020-12-07 9:50 ` Petr Mladek
2020-12-08 20:51 ` Sergey Senozhatsky
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