RE: [PATCH printk 3/5] printk: use buffer pool for sprint buffers

[David Laight]

From: Steven Rostedt
> Sent: 30 September 2020 14:36
> 
> On Wed, 30 Sep 2020 10:06:24 +0200
> Rasmus Villemoes <rasmus.villemoes@xxxxxxxxx> 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?

Are there any strange %pX modifiers that do anything really horrid?

	David

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