Messages in this thread | | | Date | Sun, 18 May 2008 14:04:47 +0400 | From | Cyrill Gorcunov <> | Subject | Re: [RFC] x86: merge nmi_32-64 to nmi.c |
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[Thomas Gleixner - Sun, May 18, 2008 at 12:34:15AM +0200] | On Sat, 17 May 2008, Mikael Pettersson wrote: | > Maciej W. Rozycki writes: | > > On Sat, 17 May 2008, Tom Spink wrote: | > > | > > > static inline unsigned int get_nmi_count(int cpu) | > > > { | > > > #ifdef CONFIG_X86_64 | > > > return cpu_pda(cpu)->__nmi_count; | > > > #else | > > > return nmi_count(cpu); | > > > #endif | > > > } | > > > | > > > I know it introduces a lot of these conditionals, but at least there | > > > is one place to look for the get_nmi_count function, instead of | > > > searching for all variants of the function. | > > | > > Well, I suppose some header should provide a definition like: | > > | > > #ifdef CONFIG_X86_64 | > > #define cpu_x86_64 1 | > > #else | > > #define cpu_x86_64 0 | > > #endif | > > | > > and the you can remove the horrible #ifdef clutter and make the quoted | > > function look like: | > > | > > static inline unsigned int get_nmi_count(int cpu) | > > { | > > return cpu_x86_64 ? cpu_pda(cpu)->__nmi_count : nmi_count(cpu); | > > } | > > | > > Much better -- isn't it? | > | > IMO, no, the #ifdef is preferable. | > | > Why? Because the #ifdef is a very visible signal to the platform | > people that there are (in this case) subarch differences that force | > "clients" to behave differently on different subarchs. By removing | > the #ifdef you're IMO making it less likely for the platform people | > to take notice and work towards eliminating those differences. | | The #ifdef is a poor choice. Maciej is damned right, that the single | function with a clear distinction of the return value is better in | terms of readability and maintenance. | | As I said before, We can make this more visible with an uppercase | CONFIG_WHATEVER instaed of the innocent cpu_x86_64 one, but both | solutions are better than #ifdefs and provide simple grepable | patterns. | | The awareness of those differences does not depend at all on an | #ifdef. Developers who are aware of the platform differences prefer a | readable not ifdef poluted code base. People who need to be poked into | the difference via an #ifdef are probably not those who can actually | clean it up. | | Thanks, | | tglx |
Eventually these helpers could look like this, objections? ---
static inline unsigned int get_nmi_count(int cpu) { #ifdef CONFIG_X86_64 return cpu_pda(cpu)->__nmi_count; #else return nmi_count(cpu); #endif }
static inline void __die_nmi(char *str, struct pt_regs *regs, int do_panic) { #ifdef CONFIG_X86_64 die_nmi(str, regs, do_panic); #else die_nmi(regs, str); #endif }
static inline int mce_in_progress(void) { #if defined(CONFIX_X86_64) && defined(CONFIG_X86_MCE) return atomic_read(&mce_entry) > 0; #endif return 0; } ---
they are pretty ugly anyway ;)
- Cyrill -
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