RE: [PATCH 11/13] irq debug: do not use print_symbol()

[David Laight]

From: Sergey Senozhatsky
> Sent: 11 December 2017 12:50
> print_symbol() uses extra stack space to sprintf() symbol
> information and then to feed that buffer to printk()
> 
>   char buffer[KSYM_SYMBOL_LEN];
> 
>   sprint_symbol(buffer, address);
>   printk(fmt, buffer);
> 
> Replace print_symbol() with a direct printk("%pS") call.
> 
> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> ---
>  kernel/irq/debug.h | 8 +++-----
>  1 file changed, 3 insertions(+), 5 deletions(-)
> 
> diff --git a/kernel/irq/debug.h b/kernel/irq/debug.h
> index 17f05ef8f575..5766e15c1160 100644
> --- a/kernel/irq/debug.h
> +++ b/kernel/irq/debug.h
...
> @@ -15,13 +13,13 @@ static inline void print_irq_desc(unsigned int irq, struct irq_desc *desc)
>  	printk("irq %d, desc: %p, depth: %d, count: %d, unhandled: %d\n",
>  		irq, desc, desc->depth, desc->irq_count, desc->irqs_unhandled);
>  	printk("->handle_irq():  %p, ", desc->handle_irq);
> -	print_symbol("%s\n", (unsigned long)desc->handle_irq);
> +	pr_cont("%pS\n", desc->handle_irq);

Looks like you can (and should) use a single printk() instead of pr_cont.

	David