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

From: Ingo Molnar
Date: Wed Apr 29 2009 - 01:44:27 EST



* Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:

> On Wed, 29 Apr 2009 00:48:19 -0400 Steven Rostedt <rostedt@xxxxxxxxxxx> 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@xxxxxxxxxxxxxxxx

> 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
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