Re: [PATCH] ARCH_HAS_IRQ_PER_CPU avoids dead code in __do_IRQ()

[Karsten Wiese]

Am Samstag, 6. August 2005 23:28 schrieb Ingo Oeser:
> Hi Karsten,
> 
> On Saturday 06 August 2005 18:14, Karsten Wiese wrote:
> > From: Karsten Wiese <annabellesgarden@xxxxxxxx>
> > 
> > IRQ_PER_CPU is not used by all architectures.
> > To avoid dead code generation in __do_IRQ()
> > this patch introduces the macro ARCH_HAS_IRQ_PER_CPU.
> > 
> > ARCH_HAS_IRQ_PER_CPU is defined by architectures using
> > IRQ_PER_CPU in their
> > 	include/asm_ARCH/irq.h
> > file.
> 
> Why not the other way around?
> 
> Just define IRQ_PER_CPU to 0 on architectures not needing it and
> add a FAT comment there, that this disables it. Or make it a config option.
> 
> Then just leave the code as is and let GCC optimize the dead code
> away without any changes in the C file. It works, I just checked it ;-)
> 
With my proposal the
	#if defined(ARCH_HAS_IRQ_PER_CPU)
	....
	#endif
lets readers of __do_IRQ() immediately grasp:
 "this block might not be compiled / depends an ARCH"
And you'll get compile error's using IRQ_PER_CPU on ie i386,
letting you immediately know,
that you've got to change something to be able to use IRQ_PER_CPU.

That are advantages I think.
Otherwise your proposal is ok for me too.

   Regards,
   Karsten

	

	
		
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