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

From: Andrew Morton
Date: Wed Apr 29 2009 - 01:58:22 EST


On Wed, 29 Apr 2009 07:43:59 +0200 Ingo Molnar <mingo@xxxxxxx> wrote:

>
> * 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

Well no wonder I didn't know about it.

> > 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().
>

OK.
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