Re: [PATCH 5/5] ring-buffer: fix printk output

Ingo Molnar
2009-04-29T05:44:26Z

* Andrew Morton <akpm@linux-foundation.org> wrote:

> On Wed, 29 Apr 2009 00:48:19 -0400 Steven Rostedt <rostedt@goodmis.org> wrote:
>
> > - printk_once(KERN_WARNING "Tracing recursion: depth[%d]:"
> > + printk_once(KERN_WARNING "Tracing recursion: depth[%ld]:"
>
> hrmph. I didn't know that printk_once() existed, and I should
> have known. I wonder how many other people don't know.

Was posted to linux-next@vger.kernel.org.

> Should it use unlikely()?

Not really. Any printk_once() usage site is an 'unlikely' branch
already in most cases. Double unlikely just spreads the instructions
needlessly. The condition that _leads_ to a printk_once() should be
an unlikely().

Ingo