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Date:   Wed, 30 Sep 2020 09:35:52 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Cc:     Petr Mladek <pmladek@suse.com>,
        John Ogness <john.ogness@linutronix.de>,
        Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH printk 3/5] printk: use buffer pool for sprint buffers
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On Wed, 30 Sep 2020 10:06:24 +0200
Rasmus Villemoes <rasmus.villemoes@prevas.dk> wrote:

> True. But remember that printk is called from _everywhere_, with all
> sorts of locks held and/or preemption disabled or whatnot, and every
> cycle spent in printk makes those windows wider. Doubling the cost of
> every single printk by unconditionally doing vsnprintf() twice is a bad
> idea.

But the console output is usually magnitudes more expensive than the
vsnprintf(), would doing it twice really make a difference?

-- Steve