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From: Peter Zijlstra <peterz@infradead.org>
To: John Ogness <john.ogness@linutronix.de>
Cc: Petr Mladek <pmladek@suse.com>,
	linux-kernel@vger.kernel.org,
	Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Andrea Parri <andrea.parri@amarulasolutions.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Subject: Re: [RFC PATCH v2 1/2] printk-rb: add a new printk ringbuffer implementation
Date: Wed, 26 Jun 2019 23:16:10 +0200	[thread overview]
Message-ID: <20190626211610.GY7905@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <87d0j31iyc.fsf@linutronix.de>

On Mon, Jun 24, 2019 at 10:33:15AM +0200, John Ogness wrote:
> Here are the writer-relevant memory barriers and their associated
> variables:
> 
> MB1: data_list.oldest
> MB2: data_list.newest
> MB3: data_block.id
> MB4: descr.data_next
> MB5: descr_list.newest
> MB6: descr.next

I think this is the fundamental divergence in parlance.

You seem to associate a barrier with a (single) variable, where normally
a barrier is between two (or more) variables.

As you wrote in that other email (I'm stlil going through all that);
your MB5 isn't desc_list.newest, but rather between desc_list.newest and
descr.next.

Remember, the topic is called 'memory ordering', and you cannot order
singles.

  parent reply	other threads:[~2019-06-26 21:16 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-07 16:23 [RFC PATCH v2 0/2] printk: new ringbuffer implementation John Ogness
2019-06-07 16:23 ` [RFC PATCH v2 1/2] printk-rb: add a new printk " John Ogness
2019-06-18  4:51   ` Sergey Senozhatsky
2019-06-18 22:12     ` John Ogness
2019-06-25  6:45       ` Sergey Senozhatsky
2019-06-25  7:15         ` Sergey Senozhatsky
2019-06-25  8:44           ` John Ogness
2019-06-25  9:06             ` Petr Mladek
2019-06-25 10:03               ` Sergey Senozhatsky
2019-06-25 12:03                 ` John Ogness
2019-06-26  2:08                   ` Sergey Senozhatsky
2019-06-26  7:16                     ` John Ogness
2019-06-26  7:45                       ` Sergey Senozhatsky
2019-06-26  7:47                       ` Petr Mladek
2019-06-26  7:59                         ` Sergey Senozhatsky
2019-06-25  9:09             ` Sergey Senozhatsky
2019-06-18 11:12   ` Peter Zijlstra
2019-06-18 22:18     ` John Ogness
2019-06-18 11:22   ` Peter Zijlstra
2019-06-18 22:30     ` John Ogness
2019-06-19 10:46       ` Andrea Parri
2019-06-20 22:50         ` John Ogness
2019-06-21 12:16           ` Andrea Parri
2019-06-19 11:08       ` Peter Zijlstra
2019-06-18 11:47   ` Peter Zijlstra
2019-06-20 22:23     ` John Ogness
2019-06-26 22:40       ` Peter Zijlstra
2019-06-26 22:53         ` Peter Zijlstra
2019-06-28  9:50         ` John Ogness
2019-06-28 15:44           ` Peter Zijlstra
2019-06-28 16:07             ` Peter Zijlstra
2019-07-01 10:39             ` John Ogness
2019-07-01 14:10               ` Peter Zijlstra
2019-07-01 14:11               ` Peter Zijlstra
2019-06-29 21:05           ` Andrea Parri
2019-06-30  2:03             ` John Ogness
2019-06-30 14:08               ` Andrea Parri
2019-07-02 14:13                 ` John Ogness
2019-06-26 22:47       ` Peter Zijlstra
2019-06-21 14:05   ` Petr Mladek
2019-06-24  8:33     ` John Ogness
2019-06-24 14:09       ` Petr Mladek
2019-06-25 13:29         ` John Ogness
2019-06-26  8:29           ` Petr Mladek
2019-06-26  9:09             ` John Ogness
2019-06-26 21:16       ` Peter Zijlstra [this message]
2019-06-26 21:43         ` John Ogness
2019-06-27  8:28           ` Petr Mladek
2019-07-04 10:33     ` [PATCH POC] printk_ringbuffer: Alternative implementation of lockless printk ringbuffer Petr Mladek
2019-07-04 14:59       ` John Ogness
2019-07-08 15:23         ` Petr Mladek
2019-07-09  1:34           ` John Ogness
2019-07-09  9:06             ` Petr Mladek
2019-07-09 10:21               ` John Ogness
2019-07-09 11:58                 ` Petr Mladek
2019-08-14  3:46                   ` John Ogness
2019-06-24 13:55   ` [RFC PATCH v2 1/2] printk-rb: add a new printk ringbuffer implementation John Ogness
2019-06-25  8:55   ` Sergey Senozhatsky
2019-06-25  9:19     ` John Ogness
2019-06-07 16:23 ` [RFC PATCH v2 2/2] printk-rb: add test module John Ogness
2019-06-17 21:09 ` [RFC PATCH v2 0/2] printk: new ringbuffer implementation Thomas Gleixner
2019-06-18  7:15   ` Petr Mladek

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