linux-kernel - Re: [PATCH] x86: Avoid pr_cont() in show

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Date:   Wed, 18 Jul 2018 01:41:07 -0700
From:   Joe Perches <joe@...ches.com>
To:     Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Ingo Molnar <mingo@...nel.org>
Cc:     mingo@...hat.com, linux-kernel@...r.kernel.org,
        Andy Lutomirski <luto@...capital.net>,
        Borislav Petkov <bp@...e.de>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH] x86: Avoid pr_cont() in show_opcodes()

On Tue, 2018-07-17 at 14:19 -0700, Joe Perches wrote:
> diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
> []
> > @@ -93,26 +93,15 @@ static void printk_stack_address(unsigned long address, int reliable,
> >   */
> >  void show_opcodes(u8 *rip, const char *loglvl)
> >  {
> > -	unsigned int code_prologue = OPCODE_BUFSIZE * 2 / 3;
> > +	const unsigned int prologue = OPCODE_BUFSIZE * 2 / 3;
> 
> And this might be better as a #define to avoid
> a few more bytes of stack consumption.

Apologies for this silly suggestion.

automatics are not structs and gcc will eliminate
this declaration at all compiler optimization levels.