From: Joe Perches <joe@perches.com>
To: Pranith Kumar <bobby.prani@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Petr Mladek <pmladek@suse.cz>, Jan Kara <jack@suse.cz>,
"Luis R. Rodriguez" <mcgrof@suse.com>,
Alex Elder <elder@linaro.org>,
Steven Rostedt <rostedt@goodmis.org>,
open list <linux-kernel@vger.kernel.org>,
paulmck@linux.vnet.ibm.com
Subject: Re: [RFC PATCH] printk: Use ACCESS_ONCE() instead of a volatile type
Date: Thu, 13 Nov 2014 19:41:00 -0800 [thread overview]
Message-ID: <1415936460.5912.1.camel@perches.com> (raw)
In-Reply-To: <1415935283-19198-1-git-send-email-bobby.prani@gmail.com>
On Thu, 2014-11-13 at 22:21 -0500, Pranith Kumar wrote:
> Remove volatile type qualifier and use ACCESS_ONCE() in its place for each
> access. Using volatile is not recommended as documented in
> Documentation/volatile-considered-harmful.txt.
>
> Here logbuf_cpu is a local variable and it is not clear how it is being accessed
> concurrently. We should remove volatile accesses entirely here, but for now make
> a safer change of using ACCESS_ONCE().
Not recommended does not mean "don't ever use".
Forcing the volatile at each use site instead
of the declaration isn't necessarily better.
I think the code is more readable as-is but I'm
not going to object if Andrew picks this up...
next prev parent reply other threads:[~2014-11-14 3:41 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-14 3:21 [RFC PATCH] printk: Use ACCESS_ONCE() instead of a volatile type Pranith Kumar
2014-11-14 3:41 ` Joe Perches [this message]
2014-11-14 3:51 ` Steven Rostedt
2014-11-14 3:47 ` Steven Rostedt
2014-11-14 4:02 ` Pranith Kumar
2014-11-14 4:48 ` Alex Elder
2014-11-14 4:57 ` Steven Rostedt
2014-11-14 5:24 ` Steven Rostedt
2014-11-14 16:39 ` Alex Elder
2014-11-14 16:57 ` Steven Rostedt
2014-11-14 18:23 ` Pranith Kumar
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