Re: [Xen-merge] Re: synch_bitops.h

[Jimi Xenidis <jimix@xxxxxxxxxxxxxx>]

One question that comes to mind, is that in a para-virtualized  
environment does CONFIG_SMP cost you anything?
On PPC and the IBM hypervisor we have found that is does not.

On Jan 6, 2006, at 11:06 AM, Jan Beulich wrote:

> > So AFAIK synch_bitops.h is equivilent to bitops.h with #defined
> > CONFIG_SMP
> >
> > Can't we use this somehow to reduce the amount of repeated code?
> Sure, this would be possible. But would anyone like the to be added
> conditionals
Not conditional but some CPP majik.
hmm, not a fan of clutter, but maybe some CPP magik?

this is what we have for powerpc:
#ifdef CONFIG_SMP
#include <asm/bitops.h>

#define synch_change_bit(a,b) change_bit(a,(unsigned long *)b)
#define synch_clear_bit(a,b) clear_bit(a,(unsigned long *)b)
#define synch_cmpxchg(a,b) cmpxchg(a,(unsigned long *)b)
#define synch_const_test_bit(a,b) const_test_bit(a,(unsigned long *)b)
#define synch_set_bit(a,b) set_bit(a,(unsigned long *)b)
#define synch_test_and_set_bit(a,b) test_and_set_bit(a,(unsigned long  
*)b)
#define synch_test_and_change_bit(a,b) test_and_change_bit(a, 
(unsigned long *)b)
#define synch_test_and_clear_bit(a,b) test_and_clear_bit(a,(unsigned  
long *)b)
#define synch_test_bit(a,b) test_bit(a,(unsigned long *)b)
#define synch_var_test_bit(a,b) var_test_bit(a,(unsigned long *)b)

#else
#error "this only works for CONFIG_SMP"
#endif

now for the !CONFIG_SMP one could easily imagine some CPP majik to  
solve that.
-JX
--
"I got an idea, an idea so smart my head would explode if I even
  began to know what I was talking about." -- Peter Griffin (Family  
Guy)



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