From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1752481AbdJDPCh (ORCPT <rfc822;w@1wt.eu>);
        Wed, 4 Oct 2017 11:02:37 -0400
Received: from mail.kernel.org ([198.145.29.99]:60010 "EHLO mail.kernel.org"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1752322AbdJDPCf (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Wed, 4 Oct 2017 11:02:35 -0400
DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 68F6E21883
Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org
Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=rostedt@goodmis.org
Date: Wed, 4 Oct 2017 11:02:32 -0400
From: Steven Rostedt <rostedt@goodmis.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>, pmladek@suse.com,
        sergey.senozhatsky@gmail.com, linux-kernel@vger.kernel.org,
        mingo@kernel.org, tglx@linutronix.de
Subject: Re: [PATCH 3/3] early_printk: Add simple serialization to
 early_vprintk()
Message-ID: <20171004110232.24579659@gandalf.local.home>
In-Reply-To: <20171004145247.4tp6r6ds6e5pkut5@hirez.programming.kicks-ass.net>
References: <20170928121823.430053219@infradead.org>
        <20170928122513.431444176@infradead.org>
        <20171003182422.025d0a67@gandalf.local.home>
        <20171004090830.p5kwzu6ex2wimh4v@hirez.programming.kicks-ass.net>
        <20171004090401.3a5123a6@gandalf.local.home>
        <20171004141745.GH3521@linux.vnet.ibm.com>
        <20171004104354.2ecb23e9@gandalf.local.home>
        <20171004145247.4tp6r6ds6e5pkut5@hirez.programming.kicks-ass.net>
X-Mailer: Claws Mail 3.14.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Wed, 4 Oct 2017 16:52:47 +0200
Peter Zijlstra <peterz@infradead.org> wrote:

> On Wed, Oct 04, 2017 at 10:43:54AM -0400, Steven Rostedt wrote:
> > 
> > My question is not about ordering, but about coherency. Can you have
> > one CPU read a variable that goes into cache, and keep using the cached
> > variable every time the program asks to read it, instead of going out
> > to memory.  
> 
> No, not on a coherent system.

In this case.

Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

-- Steve